Is it broken? Odd Platinum //e behavior

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Is it broken? Odd Platinum //e behavior

I have what appears to be a Platinum //e motherboard which I was assured worked by the ebay seller (we all know what that's worth)  

 

 

So before I pull out the scope and chase my tail:

  • What happens on a Platinum //e if the 80col card is missing? 
  • Shouldn't it just boot up as normal? 
  • Does anyone recognize that ROM?

EDIT: ACK! There's no keyboard attached... it's doing diagnostics isn't it?  

EDIT ][: Now with J17-5 and J17-7 pulled low, I get this image https://i.imgur.com/08rYs4Y.jpg

That doesn't appear to be diagnostics.  If I force AppleWin into self diagnostics it shows LoRes color blocks all over the screen which change from time to time before it beeps rapidly and says "SYSTEM OK" across the screen.  Either version I've shown is all I get unless I goose the reset.

 

DC Voltages are a bit off, and I've never seen what the tollerance is for that.  +5=4.998 +12=12.4 -12=-12.3 -5=-4.998 Pin 40 of the 65C02 is at +5 (+4.998) but pin 31 of the slots seems to be wandering...  I might have been on the wrong pin.

 

I was on the wrong pin...

 

 

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The characters are correctly

The characters are correctly formed and because the screen should be mostly filled with spaces the fact that it is not mostly filled with different character says you have a good CG ROM.

Graphics appears to work and self test passes, that rules out a RAM error.

 

My guess is you either have an issue with the LS374 that latches data to feed the CG ROM or an issue with the IOU selecting the wrong text page for display. 

 

Does the speaker beep when you power on?

 

 

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No it doesn't - Or I don't

No it doesn't - Or I don't belive it does, I hung a little 8ohm speaker on the speaker terminals and no sound - but I should check that the speaker is good.

 

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Today has been interesting. 

Today has been interesting.  I pulled out my scope and tried having a look at the various data and address busses.  I noticed some very sickly looking signals around the MMU, and upon closer inspection noticed green corrosion on some pins.

 

So I powered down the board and popped the MMU chip only to discover numerous blackened or greenened (?) pins.  I did a bit of scraping, and cleaning with denatured alcohol, and after several insertions and removals and a bit of WD40 It seems I'm getting good contact again.  Sickly signals look healthy, and the random A, {, and @ characters are gone - I now get a repeating pattern of the Boxes and whatever the C is (it's not a "C" or "(" ).

https://i.imgur.com/08rYs4Y.jpg

 

Or maybe it is?  Since I have a nonapple character ROM. 

 

After my first attempt to clean up the pins, I did start getting static and random noise out of the speaker - which would change or be incited by my pushing on the MMU - that all stopped after the final cleanup.

 

Now I just get a consistent pattern and no beep. 

I do notice that numerous signals are swinging 0-4v not sure if that's important...

 

I'll mention again, there is no 80 col card in it.  

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TedThompson wrote:Today has

TedThompson wrote:

Today has been interesting.

Or maybe it is?  Since I have a nonapple character ROM.


Did you ever test with correct Apple Roms ( not salvaged fromn non-Apple mainboard ) ???

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The character rom is the only

The character rom is the only odd ball (aftermarket I'm guessing) but I don't have any others. 

 

I think tomorrow I'll try popping it out and firing it up. See if anything changes.

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Update:

Update:

 

I took some time today and cobbeled up a replacement keyboard, of sorts. It has 6 buttons which are the ones which aren't in the matrix (Shift, Control, Caps Lock, Reset, Open Apple, and Closed Apple) with the Apple Keys arranged with their pull down resistors, it should trick the board into thinking it has a keyboard attached.  I figured it would be useful, and safer then trying to hang jumpers on the 26 pin connector.

 

Following that I fired it up and checked that my board was OK. Then powered down the board and pulled the Character ROM. Power up and I get a black screen, no beep. So at the very leaset I know that pattern I'm getting is becuase the system is commanding it of the ROM - if they were all character 255 I'd be less convinced...  

 

I then reinstalled the ROM and fired it up again - got the same pattern as before - and I shorted J19 and as expected the screen would go blank when I shorted it, return again when I didn't.

 

Then I got an idea to pull the 3600-PRO.  The interesting result is that with the 3600-PRO pulled out, I get the same pattern as when the 3600-PRO is installed...  So I'm going to do some digging and see if that means anything.

 

Meanwhile, if any of y'all have done such a thing (powered up a //e or Platinum //e with the keyboard chip pulled out) I'd love to hear what an otherwise working board would do.

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If the MMU ands IOU are

If the MMU ands IOU are socketed I'd replace the sockets and clean up both chips.

If the pins on a chip get corroded, the socket probably hasn't fared much better.

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Yeah, I'm fearing the socket

Yeah, I'm fearing the socket may have issues (BTW is this board plate thru holes?)

 

However, this may be of issue - I just noticed that the keyboard encoder is supposed to be a KR9600-PRO and the chip in the socket is a AY-5-3600-PRO - They are pin compatible, with one exception, 27 on the AY05-3600-PRO is supposed to have -12v on it, and the KR9600-PRO is NO CONNECTION, so that pin is floating with no voltage on it.

That may be a larger issue at this point.

 

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And from the "Don't

And from the "Don't Troubleshoot Tired Department" - While I see photos of P//e mobos with 9600 chips in them, mine has 3600 clearly silkscreened on it.  DOH!  

 

I ordered an 80col card a few days back (I know it's not the problem but the "All Platinum IIe's shipped with an 80col card from the factory" is going to be nagging at me and poluting my thinking until I put one in, fire it up, and see it makes no damn difference.  

 

The two voices in my head go back and forth "Apple IIs don't NEED the 80col card" - "Yeahbut the platinums all had them, so the ROM code could be expecting it and getting upset it can't get an answer...". Rinse. Repeat.

 

God I wish those two would shut up...  XD

 

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FYI -- I can tell you from

FYI -- I can tell you from experience that a Platinum //e in proper working order will boot up fine with no 80 column card installed.  So you can tell at least one of those voices to be quiet.

 

 

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Your board is damaged. With

Your board is damaged. With no keyboard, it should go through diagnostics and pass with "System OK".

 

If it was sold as working from eBay, you should have immediately filed not as described. Now you have tampered with it, which even if I was a dishonest seller (I am definitely not) I would have a problem with that.

 

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So you bought just a Platinum

So you bought just a Platinum //e mobo off eBay, no case, keyboard, ps, etc?  I bought 4 complete Platinum //e off eBay a couple years ago.  One was pretty beat and the power supply was blown, but it had all the keycaps I needed to replace the missing ones on the other three plus plenty of donor key switches to replace the broken ones in the other three.  The mobo in the donor other than being a little dirty seems to be working, it was just the PS that had gone like they typically do.  I was also able to fix the PS (replaced several caps and the fuse) and used that PS to get a ][+ that I had running.  Platinum //e with a few broken keys are usually < $100 if you watch eBay.  Most of the time it does not take much to get them running.  I really should sell a couple of the working ones, I don't really need all three.  I have a regular //e that I had since back in the day as well.

 

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rittwage wrote:Your board is

rittwage wrote:

Your board is damaged. With no keyboard, it should go through diagnostics and pass with "System OK".

 

If it was sold as working from eBay, you should have immediately filed not as described. Now you have tampered with it, which even if I was a dishonest seller (I am definitely not) I would have a problem with that.

 

 

Tampering is a bit strong. I've reseated chips, cleaned the pins of one LSI, and taken measurements.  Oh, and I've been a tech, albeit in the audio industry, since 1978 so I'm qualified.

 

At any rate, while I am disappointed it wasn't as advertised I've been enjoying my adventure. I won't be returning it (paid $45 shipped to my door) but I also haven't left any feedback... Yet.

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softwarejanitor wrote:

softwarejanitor wrote:
 Platinum //e with a few broken keys are usually < $100 if you watch eBay. 

 

Clearly I'm not looking where you are looking.  :)

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I bought 4 of them off eBay

I bought 4 of them off eBay in that price range within the last 3 years

 

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No bids on this one.  Make

No bids on this one.  Make them an offer.  It isn't a Platinum, and from the screen it obviously has a small issue, but it would probably be pretty easy to fix and when you figure what a Duodisk, the monitor, joystick and books usually go for the //e itself is pretty cheap.

 

https://www.ebay.com/itm/Vintage-Apple-IIE-2E-Computer-Dbl-Floppy-Disc-Drive-Monitor-Manuals-Joystick/283188255388?hash=item41ef55da9c:g:yfIAAOSw8JZbq92i

 

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Here's another one, that when

Here's another one, that when you figure the extras included the //e itself is pretty reasonable...  Needs one key fixed, but that's a simple repair.  SSC is worth about $30-$40, a sound card, probably another $40-50, Apple 5.25 drive and controller probably another $40-$50.  Whatever that monitor is worth, maybe another $50-$75.  At the BIN, that means the //e itself is $100-ish.

 

https://www.ebay.com/itm/Vintage-Apple-IIe-Computer-A2S2128-Color-Monitor-A2M6021-disk-drive-cables-cords/323470840517?epid=1000349677&hash=item4b505d52c5:g:d-AAAOSwZw1brFFj

 

If you are patient you can probably find better deals than these, this was just one quick search on eBay.

 

 

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In both cases the $80-$90

In both cases the $80-$90 shipping is a deal breaker for me. That seems somewhat universal. I dont know if its a seller playing the "make my money on the shipping" game or because I'm in SoCal and, ironically, these beasties aren't.

 

I was also specifically searching for a naked logic board both for cost and because I didn't want to experiment on, or vivisect, a complete working specimen. 

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You can test the computer and

You can test the computer and have no concern about the socket if you install the chip under the logic board with wires soldered to the appropriate pins.

 

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If you think they are trying

If you think they are trying to make the money on the shipping, then look at what UPS, Fedex, etc, charge for the shipping.  You can get estimates based on zip codes and the weight and size the packages should be.  Unfortunately for packages the size and weight of these, especially the monitors, the $80-$90 probably isn't leaving a whole lot for packing materials when you look at what the shippers charge.  If you only want the system unit itself, and you are patient you can find unbundled units where the shipping should be a lot lower.  Patience pays when bidding on auctions.  The bargains are there, you've just got to find them.

 

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Having now dumped the

Having now dumped the character ROM I can see that what I am getting on screen is 0000000 and 11111111 which may provide a clue. I'll have to think on it some more.

 

Currently I'm thinking this may point to a bad MMU since I wouldn't expect RAM to fail in such a regimented fashion.

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Unfortunately if it is the

Unfortunately if it is the MMU, the only source for those is a donor mobo these days.

 

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Yesterday I was poking around

Yesterday I was poking around the MMU and noticed that an address line wasn't really going to low. It was only dropping maybe a half volt or so.  So I shut off the board and did some continuity checks and found a few pins that seemed broken.

 

I grabbed a new 40 pin socket today and installed it. After which I rang out all 40 pins and found one (pin 7) that didn't make it. So I added a short jumper under the board and got all 40 circuits complete. 

 

Popped in the MMU and fired it up.  Here is the result:

SYSTEM OK

 

 

It lives again!

 

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That's good news!  Now all

That's good news!  Now all you need is the rest of the system!  :-)

 

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