Announcing a Novel Diagnostic PROM Set for Apple-1 builders

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Announcing a Novel Diagnostic PROM Set for Apple-1 builders

Any Apple-1 builder not using complete, 100% pre-tested and burned-in IC kits more often than not runs into a roadblock and gets stuck in the following dire situation: the newly built Apple-1 just refuses to work. The standard firmware known as WOZMON  or  "hexmon" crashes all to often or does not work at all, so there is no chance to enter any diagnostic programs, such as Mike Willegal's memtest. A chicken-and-egg problem. Without being able to enter and run diagnostic programs or to peek and poke around in the memory, the chances are slim to debug the machine and make it work. Here is a typical example of the agony, pain and suffering of one builder who ran into this malaise, and there are many other victims of this Apple-1 curse:

 

https://www.applefritter.com/content/mimeo-power

 

The root cause of the problem is that the WOZMON, as brilliant as its programming may be, depends on a fully functional DRAM in the machine, as it uses several zero page locations for its own housekeeping, it uses the stack page for JSR/RTS, and it uses an input buffer beginning at 0x200 to take the user commands which then are parsed later.

 

Imagine what happens if the RAM does not work well enough yet: the housekeeping bytes in the zero page lie, the stack does not remember the proper return address, and the input buffer turns all the user inputs into gibberish the WOZMON could not possibly understand, even if it would not just crash due to the wrong return adresses coming off the yet dysfunctional stack !

 

So far there has been no remedy for this disease, other than trial and error, changing ICs, and poking around with an oscilloscope probe, which is time consuming and frustrating, and often leads to nowhere, and so all too many Apple-1 builds ended (and still end) up as non-functional wall hangers, or worse: I was so frustrated with my first build I really was tempted to take it to Dragonman's and blast it to smithereens with 12ga 00-Buckshot out of my Mossberg 500. Still, logic and reason prevailed. I decided to seek the root causes of that curse and exorcise all the demons from the Apple-1. The results and remedies I found you can read elsewhere, right here on this forum !

 

Here is another one of my proven remedies: a novel diagnostic PROM set that plugs into the A1/A2 sockets and it includes four spartanic, but powerful tools, neither of which depends on any RAM:

 

Tool #1: Terminal Section Test: all characters shown in all possible screen positions, allows to weed out bad PMOS shift registers (2519, 2504, 1404) and various bad TTLs.

 

Tool #2: RAM Test with exact syndrome messages, used to weed out bad DRAM ICs and to adjust the /CAS timing resistor without need of an oscilloscope. A multimeter able to measure resistance is good enough, but even that humble instrument is not needed.

 

Tool #3: A TV Typewriter. You can type anything you want and observe it on the screen. Sounds really silly, but is very useful to test the keyboard and associated circuitry. And as a bonus,  it gives you the look & feel of why a "TV TYPEWRITER" was so exciting back in the early 1970s, in the era before microprocessors became affordable for the masses. (Yes, people built TV TYPEWRITERs having no microprocessor, just for typing and seeing, and it was like magic !)

 

Tool #4: A hex monitor. You can peek and poke around in the RAM, enter and start user diagnostic programs, and it won't crash even if the memory does not work yet. It even works with all DRAM sockets empty. Of course, with no RAM, you obviously can't enter programs, just examine what random garbage is there in that memory "hole". This hex monitor is crashproof, as it uses no RAM for its own housekeeping. So it is a valuable tool for those cases where the RAM almost works, but not good enough yet to use the WOZMON. I had many cases of marginally working RAM where this monitor allowed me to load and run small diagnostics to further probe what's going wrong, such as my (in)famous "MAdHammer" program, among others.

 

This is how these Diagnostic PROMs look installed in an Apple-1:

 

 

The red wire goes to the PCB backside and is connected to CPU pin #17, which is A8, because this toolkit is 512 bytes in size.

 

And this, alas, is the problem. These PROMs are heinously expensive, $15.38 each plus shipping plus credit card fees from the IC broker. Then I need to program them, put them into a jewel box complete with ESD foam (you would not believe how expensive that foam has become, if is genuine, beware of the Chinese fraudsters who sell cheap black "ESD" foam on Ebay that is not conductive at all, and causes it own ESD damage, so weasel-wording lawyers could construe this fraud not even being a fraud, because "ESD" was advertised and "ESD" is what you got ! --- I only got burned once by this fraud. Buyer beware !) After closing the box with the PROMs I need to put the box into a bubble mailer and pay the postage. And then comes Ebay with their usurious fees. Do the math: there is absolutely no way I could sell these kits for less than $39.95, if it ships to the USA. To Europe, it's $14.50 more. Terrible. We are now in an era where shipping costs may exceed the value of the items shipped. Not the case with these PROMs, but try to ship a transformer ! Or a parcel with six jars of homemade jam !

 

Is it worth my time and effort to even write a manual ? Will Apple-1 builders be willing to pay so much money for a toolkit that is used only once and is useless for them after it helped to get their Apple-1 build into a working condition ?

 

Of course, they could put the toolkit up on Ebay again, re-sell it, to recover some of their costs, and to keep them in circulation, to the benefit of other builders. Actually, for me, this would be the preferred solution, so I have less work with them.

Keep in mind that I try to avoid profits from my hobbies. Not that I would hate to make more money than I ever need, but the caveat with the Apple-1 hobby is that the "market" is exceedingly small, and unless usurious prices would be asked, any "profit" would be totally annihilated by the extra fees of the licensed tax accountant who does my tax returns. So avoiding any profits from that hobby is a must. But don't worry, I'm still in the hole by a few grand, so I can continue to offer my 100% burned-in and tested IC kits on Ebay, at least for a while, until the red numbers turn into a black 0, and then I will stop selling them. Hope I still get the statistics for my experiment.

 

So, this background story told, you may understand that my motivation to make and sell any of these Diagnostic PROM sets is not that great. I primarily developed these PROMs for my own use, many incremental changes and improvements over more than 9 months (!) to many little disconnected tools, some of them useless, and in the last two months I was able to aggregate the most important and successful of these tools into a mere 512 Bytes of code, which was a nice pastime. I estimate my time expenditure to do this aggregation was about 100 hours. For 512 bytes of code ? If I would show this kind of performance in a software company, I would get fired instantly. But keep in mind that providing all this functionality using no RAM, no JSR/RTS, and only the CPU registers of the 6502 involves some really tricky coding. There are not many 6502 programmers in the world who could pull that off. On the 8080 / Z80, having many more CPU registers, it would have been much easier and taken less time.

 

If you happen to be interested in one (or more) of these Diagnostic PROM Sets, reply to this post and tell me what you think, or send me a message on the Applefritter message system. If there is enough interest, I will invest more of my time and maybe post some screenshots and more information. And if finally, I would arrive at the conclusion it may be worth my time to make this Diagnostic PROM Set available to the worldwide Apple-1 builder community, I might even write a manual, buy a tube or two of those PROMs, and make some PROM sets. Otherwise, I just keep them for myself. They are really cool, proven, do their job, and I use them in every Apple-1 build I make, to bring it to life, and to tune the DRAM timing, and to test the DRAM, before I put the WOZMON in, which, after all these preparations of the hardware, of course works instantly and trouble-free.

 

(Just for the history of these tools, prior to this new PROM version, these tools were in a 2732 EPROM with 15 tool pages + the WOZMON page, selectable by a hexadecimal rotary switch, and that "gadget" saw so much use that it now is in its last legs, and I did not want to build another one due to the tedious hand-wiring and the flimsy header pins that always break off, but there is no choice, as larger diameter header pins would ruin the IC sockets. So "real" PROMs with normal IC pins of just the right size, are the preferred solution. So far I have made three of these PROM sets for my own use, and they do their job to my fullest satisfaction.)

 

Still curious ?

Comments invited !

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count me in for one set

That looks great! I'd definitely buy one set. Even if you're trying NOT to make money on a hobby, $40 for that actually sounds low to me.

On the other hand, I'd also be perfectly happy with a 27xx or 28Cxx on a board that plugs into the expansion slot, or onto the edge connector. If you left the A1 & A2 sockets empty, and included an address decoder on the board, then no additional signal on the main PCB would be required.

I don't even care to hazard a guess as to how much trouble I'll run into with my upcoming replica builds.

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I would also be interestet in

I would also be interestet in your Diagnostic PROMs even when I live in Europe.

I started with my Apple-1 Project a few years ago with collecting parts. Now I assemble the unit slowly and I think your tool will help me with debug a lot.

 

BR, Kaoala

 

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A diagnostic PROM is a great

A diagnostic PROM is a great idea, but I would try to make a daughter board using modern EPROMs and dip switches to choose the test so that you can get use of the 256 buytes for each test.    Using two 16 pin DIP ribbon cables would also be a good idea on how it would connect to the PCB's ROM sockets.

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4 tests + original WOZmon
Corey986 wrote:

A diagnostic PROM is a great idea, but I would try to make a daughter board using modern EPROMs and dip switches to choose the test so that you can get use of the 256 buytes for each test.    Using two 16 pin DIP ribbon cables would also be a good idea on how it would connect to the PCB's ROM sockets.

I like Corey's idea of using a more modern and cost effective EPROM (say 2716, 2732, etc) and the dip switches to select tests.

I would add a 5th option, via a five position micro-rotary switch: #5)  original WOZmon code, using a bigger EPROM would allow this.

Once you are finished debugging, you can run the Woz monitor.

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Hey guys, before making suggestions about a 2732 ...

... version, please read my post #1 completely. The 2732 based solution with 16 selectable pages including the WOZMON is exactly what I have used initially, but is has drawbacks, chiefly the problem that not much can be done in a 256 byte page if no RAM is used for JSR/RTS and other housekeeping, and these little pins of the headers tend to break off. You could make a 2732 based thingy with a PCB and 512 bytes pages, but that would not solve the problem with these headers losing their pins all too often. And with the 2732, the PCB, the two headers, the hex rotary switch, you probably also get close to $40, as there are no economies of scale. You can't make / sell a hundred of these. Maybe a dozen. Does your PCB layout guy work for food and shelter only ?

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WozMon on a 2732 EPROM

Speaking of PCB guy working for free... I just finished a layout for a board that I plan to use on a "Replica-1", this will replace the A1 and A2 ROMs and will provide a continuous memory block at $F000. Large enough for the WozMon and several utility programs.

The extra 4 address lines can be picked up at B5 and B6 with short thin jumper wires.

A8 -  B6.10

A9 -  B5.3

A10 - B5.6

A11 - B5.10

 

Note that only 4 pins are reqiured to connect on the A1 footprint.

 

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Some screenshots from the Diagnostic PROM Set in action

To find out more about possible interested users (2 so far, need 12) here are some screenshots and explanation of what the tools in the PROMs do:

 

After installing the Diagnostic PROM Set, and powering up the Apple-1, give a CLR SCREEN signal, and then a RESET. Tool number #1 will start up and fill the screen with all characters supported by the Apple-1 in a sliding, endless pattern:

 

 

Photo 1: Output of tool #1, terminal section test

 

Note that no keyboard is needed yet, the CLR SCREEN and RESET can be given with a jumper wire used on the keyboard connector. This sliding pattern greatly helps to find flaws in the video hardware. Not only will it allow to diagnose bad PMOS shift registers, but it also exercises all the cursor and scrolling logic. Some builds have nasty bugs where the occasional character is dropped, or the linefeed doesn't work. All these ailments are easily exposed and diagnosed with this first tool.

 

Then, use a jumper wire (or a keyboard) to give it one keyboard strobe. This starts up tool #2, the RAM test. If you get bombarded with lots and lots of error messages like this:

 

 

Photo 2: Output of tool #2, RAM test, in case of a very sick RAM

 

... then your RAM does not work yet. These messages are in the form SS@HHLL, where SS is the syndrome and HHLL is the address where the error was seen. Any "1" bit in the syndrome means that this bit has failed, and each bit corresponds to one of the DRAMs in PCB locations X7...X0 (the lower 4K). From the bit pattern it is easy to see which DRAM ICs are the culprit. It also could be the /CAS timing is wrong. So, if you have put in a 50KOhm trim pot in lieu of the 27K timing resistor, you can tune the trim pot until the memory errors get less and less and eventually disappear:

 

 

Photo 3: Output of Tool #2, RAM test, while probing the /CAS timing limits using a trim pot in lieu of the 27K resistor.

 

The procedure is as follows: tune the trim pot until a stream of dots appears, meaning the test of the lowest 1KByte of RAM has passed, once for each dot. Then tune it back where errors juuust appear again. Power down the Apple-1. Take the 74123 at location B3 out of its socket. Measure the resistance between pins #16 and #15 and note it down. Re-insert the 74123. Power up. Go to the memory test. Tune the trim pot in the other direction where you should get a stream of dots. Tune further until a few errors appear again. Power down. Take the 74123 out. Measure the resistance again and note it down. Take average of the two measurements. Adjust trim pot to that average resistance. Put 74123 in and power up. CAS timing now should be centered in the middle of the go/nogo zone, and the RAM should work. If there still are occasional RAM errors being reported, swap the offending DRAM IC identified by the syndrome with another one, i.e. to locations X7 or X0. (All IC swaps to be done in power down of course). Syndrome bit(s) should move with the swap and hereby prove a bad DRAM IC. Replace it. If the syndrome bits did not move according to the swap, it's something else. It could be a shorted or open data line, or bad 8T97s. You can also put in the termination resistor mod on the multiplexed address lines, to see if the errors go away. Each of these possible causations have a very characteristic syndrome / address pattern, which would be found in the manual I still would need to write.

 

After the RAM is debugged and the RAM test of tool #2 passes, it's time to connect a keyboard or keyboard emulator. During the RAM test, hit any key. This enters tool #3, the TV Typewriter. You can type anything you want, but avoid semicolons. You can type some art like this, which, prior to 1975, was a sure way to absolutely amaze and baffle your friends while showing them your (otherwise utterly useless) newly built TV Typewriter:

 

 

Photo 4: Output of Tool #3, TV Typewriter. Any desired text or ASCII art can be entered from the keyboard.

 

As trivial this funny little tool may look, it allows full test of the keyboard, before some nit-picking "monitor program" scrutinizes every keystroke and does weird things. You want to make sure every key on the keyboard works, including the shifted functions. Then, it's time to enter the monitor program, tool #4, by entering a semicolon:

 

 

Photo 5: Output of Tool #4, the hexadecimal monitor program.

 

The syntax of this monitor program is a bit different from the WOZMON, but it is easy to learn and similar enough to avoid mistakes. The main difference is that you can only work on one byte on one address at a time, and only in the first KByte of memory. This is even more spartanic than the WOZMON, but it is unavoidable due to using only the CPU registers, and no RAM locations, for the housekeeping of the monitor.  The limitation to the 1st Kilobyte does not hurt the purpose of these tools. The hex monitor is meant to allow you to peek and poke around in the RAM in case you want to exercise things, and you can also enter little machine code programs and run them. These are supposed to be smaller than 1K. Once the Apple-1 is debugged to a point where larger user programs are appropriate, and the RAM works, just plug in the WOZMON.

 

In the above screenshot you may see that after entering the monitor with the semicolon command, it begins at address 00FE containing F5. Then I entered a dot command with a new address 0000, and hit RETURN a few times to show the first few bytes of the zero page, all containing F5. After showing the contents at address 0005 I entered another dot command to go back to address 0000, still containing F5, and then I entered the sequence 99 AA BB CC followed by a semicolon, which should change address 0000 to 99, 0001 to AA, 0002 to BB, 0003 to CC, and then display the contents of address 0004, which still is F5. In the next line, in the middle of the screen, I now use the dot command again, followed by some RETURNs, to show the contents of the previously altered addresses 0000 to 0006, which is F9, FA, FB, FC, F5, F5, F5. Oooops !?

 

Not exactly what you did expect based on the above discussion, right ? The F5 are probably OK, because they were there from the beginning, a residue of the RAM test. But the contents from address 0000 to 0003 should have been 99, AA, BB, CC as entered. The reason for this apparent fault is this:

 

 

 

Photo 6: some DRAM sockets not populated

 

There are only four DRAM ICs in the machine: the sockets for the upper nibble are empty. This is why the upper nibble always stayed at value 'F' in the above hex monitor demonstration, which is because the 8T97 bus drivers see floating DRAM data lines, which TTL interprets as logical '1'.

 

I played this little trick on you to demonstrate that this monitor (and all the other tools) do not depend on any functional RAM in the machine. The memory test did complain, of course. But I did not show you that. The syndrome reported was $F0,  binary 11110000, which means the upper four bits of the RAM have a fault.

 

Applause, please !

 

(It's possibly the first demonstration of a RAM-less hexmon program for the 6502 in human history, which all by itself is not a mean feat, considering the length of human history, and y'all had the immense honor to witness this feat, here on the famous Applefritter !) 

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While I won't be #3 of 12, I

While I won't be #3 of 12, I just want to say this is damn fine work.  I'm impressed!

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Interesting!  one question: I

Interesting!  

one question: I see that you use N82S131N as prom's. My question is if Signetics N82S129N can work too.

 

 Thank you 

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Zijjel....

... the answer is no. 82S129 is a 256x4  PROM. My diagnostic routines need 512x4 PROMs, and to use them, you need to run a wire from the PROMs to the CPU A8 signal. But this does not involve any changes to the Apple-1 as such (no traces cut), because the A8 pin on the 512x4 PROMs can be bent upwards and the wire soldered there, so the DIAGNOSTIC PROM SET can be removed again later from the Apple without leaving a trace.

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Sorry, I didn't explain well.

Sorry, I didn't explain well. Not as diagnostic rom, just as normal A1 & A2 rom. Can N82S129N replace the original ones?

 

Thank you

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Nice work shown up above, UncleBernie

Nice work shown up above UncleBernie, wish I had more time to play like that.  Soon I hope.

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Hi macnoyd,

thanks for the praise. The most difficult part of course was to program a complete hexmon without using any RAM and then fit that into 512 bytes with all the rest of the tools. But it was a fun project and great to kill time during the pandemic. Of course I could waste my time with watching movies on DVD etc. but this is too passive and does not help to keep the mind sharp.

 

All I need is 12 takers who would pay me $40 for a set and I would program the PROMs and write a nice manual to go with them. But with only three prospective takers worldwide having indicated interest so far, nah, not worth my time and effort.

 

This also made me very very cautious about buying larger amounts of blank 256x4 PROMs for A1/A2/3/4 standard firmware PROM sets. I just don't know how many Apple-1 builders are out there. I keep some eyes on the PCB vendors and see that rarecircuits has sold 18 PCB so far on Ebay  (despite their price is really OK). If they had sold 100 PCB by now, I would go ahead and buy some 250-500 blank PROMs (the minimum order value of chip brokers setting the lowest possible number).

 

 

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Compatible 256x4 PROMs for Apple-1

Zijjel wrote:

Sorry, I didn't explain well. Not as diagnostic rom, just as normal A1 & A2 rom. Can N82S129N replace the original ones?

 

 

Uncle Bernie answers:

 

To answer your question, which may be of interest for all Apple-1 builders out there seeking suitable PROMs:

 

According to a compatibility chart I have, these 10 PROMs all are compatible 256x4 types:

 

AMD 27S11, 27S21

Signetics 82S27, 82S129

TI TBP24S10, TBP34S10

MMI 6301-1, 63S141

NSC DM74S287

OKI MBL8521A

 

And so they all should work in the Apple-1, but I tried only 27S21, 82S129, and 74S287, so I can't vouch for the others listed (buy samples first). Some of them are quite rare (and heinously expensive, like the MMI), but others, like the AMD, are abundant and cheap.

 

The problem, as always, and I did explain this several times now, is the minimum order amount in US$ of those chip brokers. Sure, some sell them in qty 1, too, but at a ridicolous price tag, which is unacceptable for anyone who does not just need one of them to repair a valuable piece of vintage electronic equipment. And buyer beware, many surplus places peddling them don't know if they are really blank or not. The Chinese electronic junk IC dealers on Alibaba sell them even if they know they are programmed. I got burned often enough to avoid any Chinese IC vendor unless I'm really desperate for a particular part.

 

Allow me to offer a little bit of historical background and my opinion on bipolar PROMs and PLDs:

 

Other than for repair purposes, nobody in the industry uses bipolar PROMs anymore, as they have been obsoleted since nearly half a century, and there may be a handful people in the world who still have the ancient programming equipment of the early 1970s needed to program them in a functional condition. Most professional programming centers threw these old Data I/O System 19 or 29 into the next dumpster in the 1980s, when no further orders for bipolar PROM programming services had been seen since many years.

 

The irony is that nowadays, the funny Apple-1 builder crowd comes along, just some 40-50 years too late, and wants just those programming services on these ancient programming systems long gone. IMHO these people are the only "crazies" who demand these long obsolete bipolar PROMs, other than the Arcade video games scene, who also are crazy. No pun intended, I belong to both groups myself.  I ran into a few early Arcade game PCBs which had bipolar PROMs on them, and more often than not those PROMs were the culprit for the game not working properly anymore (there are also some notorious high speed bipolar RAMs used in the video line buffers who always run too hot and die).

 

The reason for the PROM troubles is grow-back of blown fuses or other fuses which once were left intact corroding away. Bipolar PROMs always have been troublesome and were not very reliable. Their fuse links must have a passivation opening over them, which spells "trouble" for any semiconductor industry insider "in the know". This also is the Achilles Heel of bipolar PLDs, which had replaced most of the smaller PROMs: it was not so common that these small PROMs were used for program storage in microcomputers, as in the Apple-I, but more often than not they were used to build state machines, the famous "Woz Machine" of the Apple Disk-II controller card being one very prominent example. But in 1978, MMI introduced the bipolar PAL, which was much better suited to implement random logic and state machines, and the small bipolar PROMs started to lose ground. The bigger bipolar PROMs, however, were replaced by MOS EPROMs, unless for high speed niche applications. But as most of the microprocessors were also MOS-based, the MOS-based EPROMs always were fast enough for the MOS microprocessors. It's basically the same NMOS or CMOS process technology.

 

Then, in 1985, a "meteor" struck the PLD marketplace and all the bipolar PLDs were obsoleted overnight, and doomed, like the Dinosaurs. A small company by the name "Lattice Semiconductors" had introduced the revolutionary GAL16V8 and GAL 20V8  devices which were EEPROM based (electrically erasable, and hence, quickly reprogrammable) and they could replace almost all 20 and 24 pin bipolar PAL devices. So, just 7 years after the bipolar PAL started to wipe out the bipolar PROMs, the GAL started to wipe out the bipolar PALs. MMI gave up in 1987 and merged with AMD in a stock swap.  But Lattice also did suffer despite their revolutionary GALs: they went through a chapter 11 bankruptcy in July 1987. This worried me because I had a product in mass production which used a GAL16V8. But what unexpectedly did happen and came to the rescue is that GAL drop-in compatible ICs popped up everywhere, from numerous other manufacturers, big names among them. I can only dare a guess that somehow the chapter 11 bankruptcy had caused Lattice to license their revolutionary IP to competitors, who really could produce these ICs in huge quantities.  And it was this huge flood of 16V8 and 20V8 which killed most bipolar PALs dead for good. Manufacturers and Distributors sold their excess inventory of obsoleted bipolar PROMs and PALs to chip brokers at "per pound" prices and programming service companies threw out their obsoleted Data I/O System 19 and 29 dinosaurs, which were great programming machines to program bipolar PROMs and PLDs, except that nobody ordered that service for any bipolar parts anymore, after the GALs and the EPROMs had replaced them.

 

This is why we will never run out of blank bipolar PROMs. These chip brokers have immense quantities in stock, which the Apple-1 and Arcade machine crowd can't use up in a thousand years. But if you need a very rare PROM or PLD be prepared to pay hundreds of US$ each. If you can get them at all. This is the point where making a little daughter card to replace them with more modern parts starts to make sense. But for the Apple-1, we will never get into that situation. The 256x4 types are just too abundant. 

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Uncle Bernie hello, the
Uncle Bernie hello, the Soviet-made K556RT11 is still suitable as a PROM.  They are as reliable as the AK-47 assault rifle.

 

 

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Nice info about the K556RT11,

Thank you Uncle Bernie!

 

 

And nice info Macintosh_nik about the K556PT11, but how you program those;

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As well as MMI 6301.  This is

As well as MMI 6301.  This is a complete analogue.

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Hi macintosh_nik ...

... thanks for the info on the K556RT11, and no pun intended, but I have serious doubts about Eastern Bloc integrated circuits, and their electronics in general. This comes from a survey I did in 1991 or 1992, don't remember exactly the year, for prospective western investors in former Eastern Bloc (that just had fallen apart) wafer fabs. I never saw a clean room of Russian wafer fabs, though, but I visited some fabs in Poland, the GDR, and the CSSR, and what I saw there was horrible. They even tried to "cook" up their own process chemicals on site because the state planned economy did not provide chemicals of the required purity in the plan, so they were never made by their state-run chemical industry. Cleanroom gowns were not disposed after one use, as in the West, but were washed in the laundry department belonging to the fab. Hello, ever heard of Sodium ion contamination from human sweat ?

The best process that Tesla in Piestany / Slovakia had was something like 3.5um CMOS, dual metal, but they admitted that the 2nd metal layer should better not be used, as they had metal spikes growing from M1 to M2 making shorts and did not know how to fix it. But they promised to soon build a 1um capable clean room, the air ducts of which were sitting in an open field adjacent to the factory, and were already rusting. I ran into a Russian delegation who bragged they had a great 1um CMOS process running somewhere behind the Ural Mountains. Yeah, sure.

The only positive thing I can say about Russian ICs is that they made (or still make ?) military bipolar ICs using dielectric isolation, and not the junction isolation common in Western ICs. So the Russian ICs will survive an EMP, and the Western ones won't. Russians obviously being smarter here. Military ICs made in Russia also carry a special mark for top quality, which - I think - is absent on the one in your photo. I know that the GDR (East Germany) had the opposite thing, they had a special stamp for lousy ICs which were not meeting spec, for sale to hobbyists. The last chess computers made in GDR after the "iron curtain" went down had their U880 knockoff of the Z80, but only very poor quality 2Kx8 mask ROMs inside, and these died often. Those chess computers "Made in GDR" I have in my collection all don't work anymore because of bad ROMs.

Other than that, Russia has the best Vodka and nice, beautiful women who still are feminine and love their husband, and Putin has put the Oligarchs in their place, while the American Oligarch class plunders and pillages whatever is left from the once well-off American middle class.

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N82S129
Yes, the N82S129 will work fine in an Apple-1 board.  Those are what I use.
 
Zijjel wrote:

Sorry, I didn't explain well. Not as diagnostic rom, just as normal A1 & A2 rom. Can N82S129N replace the original ones?

 

Thank you

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Hi Uncle Bernie!  I am not

Hi Uncle Bernie!  I am not interested in politics and especially in vodka, it is a waste of time.  As for beautiful women, I'm sure there are no less of them in America than in Australia, Senegal or Russia.  There are no ugly women, there is little vodka!  As for your PROM diagnostic kit, I think it would be better to put it openly, as Mike Willegal and my compatriot Mdesk did with their developments earlier, whose gerber files I published in a Facebook group this summer.  You still won't be able to make some serious money on this.  You haven't become an overnight millionaire selling your awesome building kits on eBay, are you?  So, 2-3 bottles a week of your favorite The Famous Grouse.  Apple lovers community 1 is a few hundred dedicated fans all over the world, you will not be able to sell them in the required quantity.  Sorry, it's probably not customary for you to speak so bluntly.

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About the "economics" of Apple-1 "products" ...

Macintosh_nik wrote:

Hi Uncle Bernie!  I am not interested in politics and especially in vodka, it is a waste of time.  As for beautiful women, I'm sure there are no less of them in America than in Australia, Senegal or Russia.  There are no ugly women, there is little vodka!  As for your PROM diagnostic kit, I think it would be better to put it openly ...

 

Wow, I first Russian I meet (this time online) who does not like vodka. Well, please apologize for closing my previous post #19 on the state-of-the-art of ex-Eastern bloc semiconductors as of 3 decades ago with a remark on the political situation, it's due to the "cabin fever" as we call it here in the USA,  caused by staying at home and not being able to meet friends and family due to all the pandemic related "lockdowns" (a term from prisons aka "the slammer"). It's politicians who do that to us, The People.  We all live in a sort of prison now. And we all should be mad as hell against the perpetrators who did that to us.

 

But the upside of this is that I can spend so much of my time on Apple-1 related work. Without the nasty virus situation I would have perhaps built only one Apple-1 clone, and not seven (and more to come). Without being "locked down", I would rent or buy a small airplane and fly all around the USA to visit all the interesting sightseeing spots. Not only computer museums, but also aviation museums and the work of famous architects. This is how I envisioned to spend my retirement. And not this mess.

 

I fully agree with you that  Apple-1 related "products" won't make anyone a millionaire. I don't need to, because two successful business ventures made me financially independent before I turned 30 years of age. I engage in all this Apple-1 activity as a nice pastime to sit out the pandemic until the virus (hopefully) goes away and is a thing of the past. And I don't intend to make a profit out of my Apple-1 related work. So far I'm still in the hole by many thousands of US$ since I have bought just too many parts for my abandoned plan to mass produce the Apple-1 again using professional wave soldering equipment. I think this could have made me (and my unemployed friend, too) some decent profit. But now I'm humbled down to a point that I shall be perfectly happy if I can ever get my money back by selling these superflous parts, essentially at cost. Most of my non-material "products" such as instructions etc. I publish for free, right here in Applefritter, along with the software that comes with it, it's in the public domain, anyone can use it, or even build it and sell it, I won't care, I don't need the peanuts I could make in terms of money, if, for example, I would build my keyboard emulator cable and sell it. It's here:

 

https://www.applefritter.com/content/apple-1-keyboard-emulator-cable-plans

 

You may note that there was zero response, nada, zilch, nothing.  As of today, 2/21/21: No feedback. No praise. I must assume there were no takers who ever built such an adapter. Which BTW, would be a great thing for Apple-1 builders, as it has an auto-type feature that can enter programs like Mike Willegals's DRAM test or my MAdHammer DRAM challenge program automatically into the Apple I. Note that I wrote a nice manual for it. Writing that manual did cost me a lot of my RQLT (Residual Quality Lifetime, explained later). I wasted all this irreplaceable RQLT that went into writing the manual and snapping the photos to document the build process for naught. That is, for no praise. And not even one "thank you".

 

My grievances with the DIAGNOSTIC PROM SET go into the same direction. There were only four (!) people from the estimated "several hundred" strong worldwide Apple-1 fan crowd who did express interest to get one of these from me. Nobody should think that for such a small interest, and so few people, I would write up a manual for it. It's not worth spending my RQLT on pursuing it any further. There is also some monetary aspect, as I spent some hundred US$ on blank 512 x 4 PROMs for it, assuming that I could sell enough DIAGNOSTIC PROM SETs to at least get that money back. Despite I'm quite well off financially, I hate waste, and I hate losses. Useless electronic parts sitting in my basement laughing at me and mocking me whenever I get down there to fetch a bottle of wine. I could have bought 2 bottles of Dom Perignon for these useless 512x4 PROMs. (See my point).

 

Hope you now understand it's not about making profits. Profits are evil because they are punished by TPTB (the powers that be). This is why most corporations (even those who have a free cash flow in the billions of US$) never make any taxable profit. The powers of GAAP. All you need is top-notch lawyers and accountants and all (or at least most of) the taxable profits magically disappear. The profit is still there, of course, but not taxable anymore, as it's in a different jurisdiction, or tax exempt, or whatever loophole was found. The "Going Galt" of the corporations. But now we are again deviating into politics. Sorry. But you can see, there is a link to economics.

 

In closing, let me explain what RQLT, or "Residual Quality Life Time" is. Readers younger than 55 years of age may not even understand the very concept, but they better should listen up and pay attention. I think that the "Life Time", expressed in hours, of a young person, say, a teenager or younger, is absolutely worthless. Proof: if it had any value, or worth, they would not squander it on watching TV, playing video games, or being glued to "social media" like Farcebook or Instacrap. All a waste of time. Of irreplaceable life time. You only got so much of it. When you turn older, much older, at some point, you will recognize that the "glass is not half full" anymore. You will note some parts of your body are worn out, or at least not as good anymore, as they used to be when you were young (and stupid). Now, at that higher age, you are wise, and start to worry about how much "quality life time" you have left. And with "quality" I mean "quality life" that is enjoyable, and not in a decayed final state, like a vegetable-like pitiful existence in some nursing home.  Then, you will understand that your "RQLT", or "Residual Quality Life Time", is infinitely precious. You don't know exactly when it's over, as even a small stroke can mean it's over with the "Quality" part of it, but you now that hour by hour, it runs away, and is ticking off. A frightening thought to even waste one hour of it on unworthy endavors. So we need to engage in worthy activity only (which I hope this small philosophical conclusion of my post has been for the reader --- as far as I'm concerned I wish I had gotten that insight about the value of my LQLT a few decades earlier).

 

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Hi Uncle Bernie!

These are all outdated myths about Russians, vodka, bears and balalaika. In fact, this is far from the case. This is from the same story that white Americans sit on their verandas with shotguns in hand, dreaming to destroy him into a poor African American who stepped on his lawn. I was convinced of this by communicating with like-minded people in a group on Facebook while collecting my replica.Something tells me that you will still write this instruction and post it, regardless of whether there are dozens of people interested in your kits or not. You will not take it with you to the grave (God grant you long years and excellent health in this difficult time!) You love this business, write such useful and long posts and get great pleasure doing it. You are by far the most interesting and widely read author on this forum. And you will do the right thing, maybe not now, but later, I'm sure of that.I made a short video about my replica, if you're interested, take a look. Good luck!

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I would be interested.

I would be interested. Although, I am still having trouble finding programmed proms in general. I can't finish my build without them :( There are a few listed on ebay for $$$.

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About the PROMs...

MajorMar wrote:

 

 "I would be interested. Although, I am still having trouble finding programmed proms in general. I can't finish my build without them :( There are a few listed on ebay for $$$".

 

Uncle Bernie answers:

 

I know the "pain" out there in the Apple-1 builder scene since I have stopped selling my reasonably priced PROM sets for the Apple-1 earlier this year.

 

The problem is, that much to my surprise, I had discovered a shortage of 256x4 PROMs in my inventory. More than 200 should be left but are missing. My remaining stock of blank PROMs  is juuuust barely enough for the complete IC kits  I intend to sell. Without the PROMs, I could not sell any of these complete IC kits, so I can't use any of my remaining blank PROMs in stock for PROM-only sets.

 

The price for PROMs I've seen on Ebay recently was a seller from Belgium (IIRC), and he had MMI labeled PROMs for about twice the price of my PROMs. I think this is not excessive for original MMI PROMs, which are very hard to get and very expensive. Alas, just a minute ago I looked on Ebay and could not find him anymore. Beware of these "open collector" PROMs being offered, they won't work in an Apple-1 because they don't have tristate outputs. This is a pity. Because they are really nice and have the desirable ceramic package.

 

You could try to ask Newton Mike from Hong Kong for Apple-1 PROMs. He still sells his "Newton" brand Apple-1 PCBs on Ebay (against the harsh competition from the cheaper PCBs based on the open source gerbers, but the Newton PCBs have a much better quality, real gold plated edge connectors, etc.) and I think he still may have programmed PROMs and other rare Apple-1 ICs. Alas, his shop on Ebay is somehow hard to find, so here is a link:

 

https://www.ebay.com/itm/Apple-1-Replica-Motherboard-NTI-ACI-SCC-Bare-Board-NTI-Newton-Mac-I-II-lisa/265064049404

 

Click at "contact seller" and ask for PROMs. Maybe this works. I don't know. But if he has some left I can vouch for them because I made them.

 

 

 

 

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Thanks for that explanation,

Thanks for that explanation, UncleBernie. I did send Newton Mike a PM and he said he would send a quote, but I haven't heard back from him in a while. I started this project when I found one of these boards on ebay. Initially, I was just going to frame it and hang it on the wall, but then I got excited and started buying parts. I didn't know anything about the different mainboard replicas before that. Corey from myapplecomputer said he would only sell them if I bought his boards, too, which if he has a limited supply I can understand. Also, thanks for the tip on "open collector" PROMs. I wasn't aware.

 

I am hoping to document the whole process on video as a resource for others once I am sure I can get the PROMs. I am sure I will have many more questions in the future to make sure I get my details correct :)

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What about these Intel D3621

What about these Intel D3621 and D3622 chips? I have no way to program them, but could they be used? I have no way to program them, but $25 for a pair seems like a fair price right now.

 

https://www.ebay.com/itm/2-pcs-Intel-D3622-2048-bit-512-x-4-PROMs-Tri-State-can-be-used-in-APPLE-1/291067683070

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Intel 3621 and 3622 PROMS ....

MajorMar asked:

 

"What about these Intel D3621 and D3622 chips? I have no way to program them, but could they be used? I have no way to program them, but $25 for a pair seems like a fair price right now".

 

Uncle Bernie answers:

 

According to a cross reference table I have, the Intel 3622 has the same pinout as the other "usual suspects" of 512x4 PROMs that work in the Apple-1.

This is no guarantee that it would work in the Apple-1, but we could try ;-)

The problem seems to be the programming system. In the device list for my Data I/O System 19, I did not find it. So I can't program them.

 

What might be interesting in this context is that they mention "poly fuses". Hmmm. Before my retirement, I worked as an analog IC designer and since these things nowadays need lots of trim bits, I also designed fuse link PROMs based on various technologies. Poly fuses have an edge over metal fuses as poly fuses don't corrode even with the passivation  opening that is needed over the fuse link area.  But polysilicon fuses  always have been much more tricky to program without leaving debris from the blown fuse, which could cause "grow back" phenomena leading to data corruption.  This difficulty could explain why Data I/O did not support these PROMs on the System 19. Maybe they were not that popular.  Or came much later. I'm too lazy to research that.

 

The price as such is OK. Currently, 512x4 PROMs cost about $10-$12 if bought in huge quantities from IC brokers. (See why I can't sell those $36 PROM sets anymore).  But an OK price does not help if nobody can program them.

 

 

 

 

 

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Fantastic

I'm in for a set if this ever goes. I once made this sort of thing for another old computer circa 1984, so I know how useful and how difficult this can be.  Unfortunately in desperation for a blank ROM I erased it one day not realizing what I was doing.

 

PM me if you have some for sale please.

 

 

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I would be interrested in a

I would be interrested in a BIN file of the PROMs to use it with an EEPROM and SRAM Adapter that gets plugged into the CPU Socket.

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