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Found an Old IBM

paul said:
I think all MDA's, Hercules (monchrome), and clones I've seen had a printer port.
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I think the situation was probably:
IBM knew that almost everyone buying a PC needed a parallel port to communicate with a parallel printer, and so rather than having a separate card, decided to add a parallel port to the MDA (where there was obviously space for the chips and connector).
The makers of the clone MDA boards were hoping that you'd buy their (cheaper) MDA board instead of the IBM one, and so it was important that they offered the same functionality as IBM's MDA board.
 
If I got an 8-bit VGA card with a DB15 connector, could I use a DB15-to-HD15 adapter so that I could use a modern VGA monitor?
 
Gallium said:
If I got an 8-bit VGA card with a DB15 connector, could I use a DB15-to-HD15 adapter so that I could use a modern VGA monitor?
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If you're talking about hooking it to a plasma, yes, the adapters are readily available.

I have 8-bit VGA cards (just recently put one in a Tandy 1000TX), CGA with composite out, EGA with composite out and even 12" amber TTL monitors.
 
Druid6900 said:
If you're talking about hooking it to a plasma, yes, the adapters are readily available.
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How about a CRT? I know they have the same number of pins but I don't know if the signals are compatible.

DB15
........
.......
to
HD15
.....
.....
.....

Edit: I could see driver support for the monitor being a possible problem.
 
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Wow, all the parts inside looks really big.. Did you manage to make it work? How is it? just curious :)
 
fatskin08 said:
Wow, all the parts inside looks really big.. Did you manage to make it work? How is it? just curious :)
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If you'd try, this should happend:
1. The fan in the PSU should spin.
2. Nothing else should happen for a half to a whole minute.
3. If a XT 83-key keyboard is attached, there should be a sound from the floppy disk drive, followed by a loud, short beep. I don't remember what'll happen if no keyboard is attached.
 
per said:
If you'd try, this should happend:
3. If a XT 83-key keyboard is attached, there should be a sound from the floppy disk drive, followed by a loud, short beep. I don't remember what'll happen if no keyboard is attached.
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I was going to swab/clean the expansion card connectors and vacuum dust from the PSU. I have a 101-key AT/XT key board. I'm guessing it should be switched to the "XT" position. I'll try to fire it up later today.
 
if you get the machine working, definitely put Trixter's "8088 corruption" on there, it is so very very cool! you will need an SB pro or better sound card in there i believe though. i requires a DMA card to work.

Trixter, we still need a release of the video encoder! :p

i'd like to watch a beavis and butthead episode on my 8088.
 
Gallium said:
How about a CRT? I know they have the same number of pins but I don't know if the signals are compatible.

DB15
........
.......
to
HD15
.....
.....
.....

Edit: I could see driver support for the monitor being a possible problem.
Click to expand...

if its a VGA card with 15 pins, you're golden. you can use any modern monitor on it. EGA or older, and you're hosed.
 
Gallium said:
:( Boot up attempt #1 failed. PSU fan didn't even spin. Should I buy a replacement PSU?
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Don't go out & try to buy another psu yet (you'll probably have a job getting one anyway) disconnect it from the mother board & floppy drive. If you have a spare hard drive, disconnect the old one & put that on the psu to give it a bit of load, then check if it works. If not then take it to a good TV repair man to repair. the technology is pretty similar to the power supply parts of TVs.

If it does work then it's probably a faulty capacitor on either the motherboard or one of the cards. in which case wait for my next post.....
 
Mike Chambers said:
if its a VGA card with 15 pins, you're golden. you can use any modern monitor on it. EGA or older, and you're hosed.
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Good to hear; I just picked up an 8Bit Western Digital VGA card with modern 15-pin-out($5).

nige the hippy said:
Don't go out & try to buy another psu yet (you'll probably have a job getting one anyway) disconnect it from the mother board & floppy drive. If you have a spare hard drive, disconnect the old one & put that on the psu to give it a bit of load, then check if it works. If not then take it to a good TV repair man to repair. the technology is pretty similar to the power supply parts of TVs.

If it does work then it's probably a faulty capacitor on either the motherboard or one of the cards. in which case wait for my next post.....
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Good info, I don't have an old spare drive, but I do have a modern hard drive, The 4-pin power connector could be the same. I think I know of a local TV repair shop(just in case).
 
Okay looks like it's a bad PSU. I'd rather it be the PSU than the main board.
Rather than using a dummy load, I used a volt meter. I put it across a +5V and a ground, flipped the PSU on. The voltage is 5V for about a third of a second then it decays over 10-15 seconds to the point where it's mV. The fan only runs for the first 1/2 second also.
 
Gallium said:
Rather than using a dummy load, I used a volt meter.
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That will generate a few comments! You can't test a switch-mode power supply without some loading. A perfectly good PS might do the same thing as it will shut down to protect itself. Use a spare hard disk of the 3.5" x 1" high variety.
 
The hard drive, if operational, will spin up when power is applied. One second should be enough to get it to start spinning.

Since it doesn't, and it only takes +5V and +12V, I'd say it's a good bet that the problem lies with one of those sections. Since the fan is probably a 12V one, I'd look in that section.
 
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