I've a 80 column card for the Apple II+ and I don't have video on a videomonitor. Does someone recognize this card and does know how this card works.There are twoconnectors at the top left corner, does someone know which of them is the video output and what is the purpose of the other connector? There's a UM6845 video controller and CXK5816PN (2048 word x 8 Bit High Speed CMOS Static RAM) on the card. It seems it is not a standard Videx card.
There are two cables available with the card, one with a female rca connector and one with a male rca connector.
The male RCA plug connects to the female RCA socket on the back of the Apple II, and one of the connectors on the card. The other connector on the card connects to the female RCA lead, which then goes to the monitor. The idea is that the regular Apple II video is passed through unmodified, until you type "PR#3" at which point the card replaces the Apple II video with its own 80-column generated signal, until you type "PR#0" to turn it off again.
That doesn't help figure out which connector on the card is which, but hopefully it makes the theory of operation a little clearer.
J2 looks like the standard videx 6-pin connector, of which only the first two are needed for the video out, therefore that's the video out, and the other one is the video in. It's probably fully videx compatible.
Thank you, this makes sense: I connect the connectors as you told : at J2 the video monitor, at the other connector the video output of the Apple II+. I have video in normal mode but when I type PR #6 the screen becomes black. When I type PR #0 the computer turns back to normal mode and the cursor is back. So the card needs more attention. I tested all 74xx and 40xx chips with my Retro Chip Tester and according to the tester they're ok. The tester can read the two eproms and gives a crc value. I can try to compare with files of a standard videx card but I don't know if they're the same. I cannot test the CXK5816 ram chip and the UM6845 ctr controller and don't have spares. I will make additional measurements to see if the oscillator runs and the signal round the crt controller.
I think it might be the other way around. I think J1 is the video monitor. Just to be safe, connect only J1 to the video monitor and then type PR#6. If it works and you see the 80-column text, then you can connect J2 to the back of the Apple II.
I agree with CVT on this one. This looks like a pretty common later type of Videx compatible card which has the "soft switch" functionality built in.
Oh, yeah. My theory doesn't make as much sense when softswitch is built-in, since pins 1 and 2 of the 6-pin connector normally go TO the softswitch.
The card should be installed in Slot 3 and the command should be PR#3 not PR#6.
When I connect J1 to the videomonitor and J2 to Video out of the Apple II, I see the same behavior.: I have video and the cursor, when I type PR#3, the screen becomes black and no cursor anymore. Then PR#0 and the cursor is back. I 've tested the RAM and is also ok.
I understand that this probably is a late Videx card or clone, does someone know where to find the documentation of this card with a 6845 crt controller and maybe a softswitch?
ps. I've Apple II plus machine with PAL, is it possible that this card doesn't work with Pal and only with NTSC?
You are right, I made a typo in my message, at the Apple, I typed PR#3.
Almost all the Videx type cards I've ever seen only output NTSC, as do non "Europlus". If you are trying to connect to a monitor that is PAL it probably won't work. Also, there are a lot of monitors, especially modern ones and NTSC->HDMI converters I've run into that will not accept the signal from an 80 column card and generate an image even though they will display the 40 column output from an Apple II.
If you are typing PR#3, the card needs to be in slot 3. If you are typing PR#6, then it needs to be in slot 6. It doesn't really matter which slot you put it in.
What kind of monitor do you have?
Ok, I will describe the setup:
- Apple II plus with 220 V input and PAL video output
- Clone Videx card as describe above in slot 3
- LCD monitor that's support both PAL and NTSC
When I power on the Apple II plus and I connect the video monitor to the video output of the Apple, the monitor detects a PAL signal and I see the startup screen. CTRL-Reset -> I get a cursor
Then I connect the Video monitor to JP2 of the clone Videx card and connects JP1 of the clone Videx card to the video output of the Apple II plus -> I have again a PAL signal -> then type PR #3: the screen becomes black (the video monitor detects no video signal anymore -> PR #0 -> I have again a PAL signal.
When I exchange the connetions of the Videx card:
I connect the Video monitor to JP1 of the clone Videx card and connects JP2 of the clone Videx card to the vidoe output of the Apple II plus I get the same behavior so no difference .
I have another Videx card with only one connector and that's working in the computer, but I need to disconnect the monitor from the video ouput of the computer and connects it to the connector of the Videx card and with the command PR#3 I have a video signal and see the 80 column card is working.
But I like to have this card also working for another machine Apple Europlus.
My questions:
- Is it possible to use this Videx card with a PAL machine?
- Does someone know where to find the documentation of this card (schematic or technical description) with the UM6845 crt controller on it?
-
All software that detectsand uses it expects it only in Slot#3. I bet you haven't disassembled / reversed its firmware to be sure it is not slot dependable ;)
Yes, the card can work in "PAL" computers. Get rid of that LCD monitor.
http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/80%20Column%20Cards/Videx%20Videoterm/
A lot of software expects it in slot 3, but that is beside the point. In Basic it works from any slot from 1 to 7 and it can be tested by typing PR#n, where n is the slot number. This is true for this and every other Videx clone.
I can't say this is true of every 80 column card but most Videx clones ROMs are slot independent and they will actually work in slots 1-6 even though software expects it in 3. It is even possible to put one in another slot besides 3 on a //e and tun a separate display from it. Some people did this with the Videx UltraTerm card to get 132 column output in a //e, which they loved for spreadsheets like VisiCalc and for displaying text reports and stuff. Not all monitors can display 132 column, but the Apple Monitor /// produced a very readable display from an UltraTerm. If I recall you needed special "pre-boot" software to enable the other display before booting VisiCalc.
And yeah, that LCD monitor probably won't display 80 columns from that card even if it is fully working. I've had very hit or miss results with 80 column video on LCD NTSC devices or with NTSC->HDMI converters. Some will work with some cards and not with others. And some will work with a //e or IIgs in 80 columns but with no ][+ 80 column card I've tried. Others will produce a picture from just about anything.
The later version of the Videx firmware was hard-coded to slot 3. A lot of clones (which simply stole the videx firmware) only ever came with the earlier version which did support other slots.
This weekend, I continued with the 80 column card, I was able to read the eproms and I am sharing the bin files. I am curious if the content of the eproms is correct.
The card still doesn't work, the link to the Videx card above is not completely the same as this card, for example there are no 2114 ram chips on it.
The CRT controller is ok, I put this controller in another 80 column card and works. The RAM and all logical chips are testing ok with the Retro chip tester (https://8bit-museum.de/hardware-projekte-chip-tester-english/).
It contains Videx's VideoTerm Interface Firmware 2.4, as given in the third edition of the VideoTerm manual. As bradleyb commented, version 2.4 of the firmware is hard-coded for slot 3.
Exactly one byte is different, the CRT register R3 (horizontal sync width) is being initialized as
R3=2F, instead ofR3=29as it was in Videx's original firmware. It wasn't uncommon for clone cards to use different parameters to use different CRT controllers other than the 6845, so this one-byte difference could be intentional.I belive the Sony labeled chip is the RAM, in this case I am assuming it is something similar to a 2116 SRAM. Many later Videx clones used a single 24 pin DIP package like that instead of the 4 DRAM chips that the original cards used. Earlier SRAMs were far more expensive than DRAMs but over the years that difference dropped, so many later devices switch ro SRAM because it makes other parts of the design easier (like not needing any refresh circuitry).
I found another thread where the topic starter was asked to execute the command C300L
When I do so, I get the following result, Can someone tell me if this is ok (this time I take a real crt monitor :) )? Does someone look at the bin files of the two eproms (2732 and 2516), is the content ok?
I have also done some measurements, I don't see any signals at the address lines of the CXK5816 RAM, at the eprom I see the data and address signals. Also at the CRT controller I see no signals at pin 18 DE (display enable). At pin 21 there's a clock signal.
IMG_20250510_173251.jpg
That looks like garbage. Possibly the EPROM has lost its memory.
That's indeed garbage, but do you also examine the bin files of the eproms, is the content also garbage? Is the address c300 the same as the start address of the eprom?
C300 should be correct if the card is in slot 3. A hex dump of the EPROM .bin file I find online starts out like this:
And a disassembly list looks like this:
Sorry the formatting looks like crap, AppleFritter really needs an easy way to paste in code in a fixed width font with no formatting.
I've checked the eprom again and indeed the content is crap, it seems the eprom is broken. I will program another one with the content I saved earlier and will give an update soon.
I compared the content of the eprom on my 80 column card with the bin file I found on the internet and it appears that on memory location 0xA4 of the eprom there is a different value ($2F instead of $29). I was hopeful that this would be the reason why the card does not work and programmed a new eprom, but alas, still no 80 column output after typing PR#3. I can go back to 40 column after typing PR#0, IN#0. In the meantime I tested all 74xx, 40xx series and RAM chip and I exchanged the crt controller from a working card. Tough problem!
You can find the original Videx Videoterm ROM v2.4 disassembled and properly commented here: click!
Thank you for the disassembled bin file of the Videoterm rom. I have another question: what's happen if the character eprom is also broken do I get random information a the screen or a black screen? I can read the eprom
2732_eprom_80ColumnCardCRT6845(character).bin_.zip (see earlier in this topic for the bin file) but when I compare it with bin files I found on internet, it contains not the same content. Also the character eprom is a 2732 eprom (4k byte eprom) while I find a lot of 2k byte epromfiles. Which character bin file I can use to program an eprom to use for this card?
I loaded your character EPROM dump into GIMP as a "raw Image data" file, 1 bit per pixel, 8 pixels wide and 4096 pixels high, and it looks like a pretty straight-forward ASCII character set:
2732_eprom_80ColumnCardCRT6845(character).png
The reason it's 4KB rather than 2KB seems to be because it uses 8x16 characters rather than the regular 8x8... although the actual character shapes seem to be the CGA 8x8 font, padded to 16px tall. Possibly it draws them at 9px high to fit a typical NTSC 240-line display rather than the CGA 200-line display? At any rate, the character ROM seems fine.
That is not the reason. The reason for the 4K font ROM is the special line drawing characters for tables and what Videx called MID-RES graphics and some other character variations: https://youtu.be/rGZa-A5S6uw?si=NdpGWcgIi_urp5mR&t=90
My Videx clone simply has 2 separate 2K ROM font chips, for a total of 4K for fonts:
C80 CPL-3.JPG
It looks like the line-drawing and "mid-res" block-drawing characters are the first 32 glyphs of the image I posted, in place of the ASCII control characters. Eight bytes per character, times (32 drawing glyphs + 96 ASCII glyphs) times two (adding an inverse variant of every character) is still only 2KB.
Yes, but the Videx (and clones) support 2 character sets, which brings the total to 4K for fonts. The Videx utility disks also contain a font editor with several predefined fonts, which I also showed on my video from the previous post stating around 2:38. This allows you to put other character variations, like another alphabet, math symbols or even Japanese characters.