I received a mint Apple IIe, 3 5.25" drives, a cassette drive, light pen and a bajillion other disks / cables / peripherals over the holidays, and I'm going through all this stuff.
Anyway, when I opened it up, there is a disk controller card in slot 6, and a Proclock card in slot 4. In slot 1, there was a very plain-looking card, and I cannot tell what it does, or what it's for. On the back, it has "(C) 1984 Dunrich Computer Products Inc." and "SLOT 1" on the back. On the front, it has a 20pin male hookup (similar to that on a floppy disk controller card) and there are 3 chips and a capacitor on it, the largest chip says, "MC6821P" and "M9N8419" on it. It was made in Canada, and is a very aquamarine colour.
Google wasn't much help here. Any ideas?
BAH - it occurred to me about 30sec after I posted this that I'm an idiot, this is probably a printer adapter card. Wow, do I suck.
Yeah, that sounds about right (that it's a printer card, not that you're an idiot or suck).
Congrats on the Proclock card as well!
The "MC6821P" is like MOS Technology's 6522 or 6526..
Just the kind of Part you need to communicate with a Parallel Device, like a printer..
I agree, probably a printer interface card.
Thanks, guys. Given that it was in Slot 1, it should have been reasonably obvious, but you never know, when you get these computers, what's actually plugged into things.
Now I need a printer - when I was a kid in 1985, I had a Panasonic KX-P2023. I thought it was the best thing going.
Can you post a picture of the card, please ?
More than likely a standard 26pin ribbon to db25 would work. Something like this:
SinLoon DB25 to IDC 26 Pin Cable,Motherboard Slot Plate Parallel Panel DB-25 Female to 26 Pin IDC Socket Flat Cable https://www.amazon.com/dp/B01M9FDX9E/
Since these used ribbon cables, the pin outs would all be the same since the ends are crimped on to the ribbon. But I'd wait for someone smarter than me to confirm that. And now Im curious as well. I recently acquired a Slotware RV611 parallel interface with no external connector. It also has a 26 pin header.
I was wondering the same - https://www.amazon.ca/gp/product/B07SC1KJ5K/ref=crt_ewc_img_oth_1 and then a male 25 to centronics male as the old school Dot Matrix units I have use centronics (ROLAND PR-1012, STAR ND-10, DMP-105, DMP-500). I do have a 24-pin Epson LX-300 + II (and a LaserWriter is being given to me) but I like to use items appropriate to the time period if possible. So theoretically yes - but IIRC some of those pinouts didn't follow the standard and put voltages where they could cause harm.
EDIT: just occurred to me, I may not be able to find the pinout for the card but I -CAN- see if the header outs correspond to a standard 26 ! Thanks for the good idea, I didn't realize the "next step" of what you were pointing out to me nick3092 Now I just have to find that particular pinout and voltage ref (and likely trigger it from the Apple IIe)
I would think printing a constant stream would make the header live. Something like:
10 print chr$(4);"pr#1"
20 print "hello world"
30 goto 20
Good idea, I think I will give that a go. Have to find a standard header pinout.
This might help. Scroll to bottom.
Thanks! Copy/pasted that bit of content here for later reference by people encountering this thread in future in case the link goes bad.
Parallel Printer DB-25 cable pinouts
... also the connections needed to connect that to a 'MPC parallel card’
MPC DB25 Function
---- ---- --------------
1 17 Ground
2 10 ACK
6 15 Error
8 1 Strobe
9 12 Out of Paper
10 2 Data 0 (LSB)
11 3 Data 1
12 4 Data 2
13 5 Data 3
14 6 Data 4
15 7 Data 5
16 8 Data 6
17 9 Data 7 (MSB)
18 13 Select
20 19-25 Ground
I know I'm looking at a different card, but I suspect the pin out info is the same. I found an old 26pin IDC to db25 parallel port connector in a box of old PC hardware and connected it to my RV611. The RV611 card I have basically connects every IDC even pin except 26 to ground. And all the even pins all wind up on the bottom of the db25. So pins 14-25 are all ground on the db25. Which I think might be ok for an older parallel port? Although the error pin is 15, so I'm. It sure if that is an issue.
I personally don't know enough to check anything else from here. As I have an IW2, I have no real use for it, and it's mostly a curiosity to me. I do have a Commodore MPS1250 though that has a parallel port and can emulate an Epson. So it might be interesting to see if this card can drive it. If I can confirm the other pins somehow.
Possibly error from the printer was never sent by the card (design choice?) - question is if Error is high or low, suspecting on older units the signals always were high. In this case, if an error comes from the printer, the computer won't know. The opposite (improbable?) case is that error is low in which case the system would think an error has occurred right away. I suspect that the test on it would be fine.
You could (should?) check the voltages off of the cable, but seems like you may be good to go. Another option if you have a data check tool / pen or some multimeters have that. You can see if the data lines and ACK activate or are scrambled. If voltages aren't out of range or that gnd is missing I suspect it wouldn't be dangerous to test but old units...thinking you want to know the voltages are in range.
I have a Rigol 1054z that would probably work great for this. But I'm not very good at using it, or know what I should be looking for.