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monocrome moniter on ega card

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generic486

Experienced Member
Joined
Mar 30, 2012
Messages
290
Location
Australia
So i recieved my second XT and to my suprise it has a hard drive. A tandon tm-262.
The machine is from 1989 and is quite late for it to have a 8088
The video card in the computer is a Everex Systems INC ev-657. I believe this is a EGA card.
Here are the jumpers for it.
http://stason.org/TULARC/pc/graphic...TEMS-INC-Monochrome-CGA-EGA-EV-657-PWA-0.html
I only have a monochrome monitor that I used on my other XT. It uses a hercules card.
I see that a switch on the ev-657 has to be selected for it to enable Hercules mode.
It has a dip switches. I have put down switches 3,5,
Is that all I have to do or is there something else? I want to be sure. I don't want to wreck anything.
There will most likely be more issues as I bought the the machine untested.
 
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generic486 said:
It has a dip switches. I have put down switches 3,5,6.
Is that all I have to do or is there something else? I want to be sure. I don't want to wreck anything.
Click to expand...

Re switch #3. The TH99 reference that you pointed to indicates "on". So I'm guessing that you have established that the "down" position of the switches corresponds to "on".

Re switch #5. The TH99 reference that you pointed to indicates "closed". I take that to be equivalent to "on.

Re switch #6. Why are you adjusting that? The TH99 reference indicates "Factory configured - do not alter" and "open".
 
just took the leap of faith. I pluged it in. Monitor worked. XT bios came up. Got 301 and 601 error then I heard a differnet hum, i think it was coming from the monitor so I switched it off. 301 maybe be because of the battery on the mobo. It had not exploded yet but there was some blue corrosion (very minute). I desoldered that when I cleaned it.
 
Do you think the hum (high pitched noise) will wreck the monitor? I know I set the jumpers correctly. It works fine until I press F1 then it starts humming. I know it is coming from the monitor. And sometimes the 601 error doesn't come up. Only the 301 and memory test and then it hangs.
 
generic486 said:
Do you think the hum (high pitched noise) will wreck the monitor? I know I set the jumpers correctly. It works fine until I press F1 then it starts humming. I know it is coming from the monitor.
Click to expand...
Does that change if you turn video card switch #5 off ("Hercules emulation disabled").
 
No 301!:p
Strange considering they are both XT keyboards and both work on my other XT.
But... 601 is back with a vengence.
I Flipped cable (cable isn't keyed)
Tryed different cable. Still 601
Also it's funny how the hard drive still works. The computer notices the hard drive.
 
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modem7 said:
Not the IBM XT, but certain XT clones may have.
Click to expand...
That was my assumption. Just my way of suggesting that it might be useful to mention that it's a clone, not an IBM XT; in his other thread he was surprised that 'XTs' did NOT have a battery on the motherboard,

Remote diagnostics are challenging enough...
 
generic486 said:
But... 601 is back with a vengence.
Flipped cable (cable isn't keyed)
Tryed different cable. Stil 601
Click to expand...
Hopefully the cable 'flipping' didn't cause damage.
The floppy drive may be faulty or require servicing.
Do you have a different floppy drive (perhaps from your first XT) to try?
 
oh. I just tryed the computer again and no 601. Straight to the humming and blank display.
Then I tryed it again and it has the 601 again. Boy, this thing is erratic.
And when it didn't have the error, there were no beeps, no seeks just the hum from the monitor.
Just tryed another floppy drive that was working before. Nothing again.
 
generic486 said:
Straight to the humming and blank display.
Click to expand...
But did you try turning video card switch #5 off ("Hercules emulation disabled")? You don't say.

generic486 said:
oh. I just tryed the computer again and no 601. .... Then I tryed it again and it has the 601 again. Boy, this thing is erratic.
Click to expand...
I've seen 5.25" floppy drives that require servicing do that (specifically a clean/lubricate of the rails).
That's only one possibility.
 
YEs. no more humming and blank screen. Thanks modem7. Now it comes up with error loading operating system. So i'll have to get those floppy drives working.
 
It took a whole days work but I got MS DOS 3.3 on there. FDD's still don't work. I used my other XT and connected the MFM card in that machine and loaded msdos 3.3 thru my other XT. Hard drive works so well. Shame the FDD's don't work because it is a pain to set that rig up. Also is there any chance there could be corrosion? I see no corrosion around the FDD connector but maybe there is. If so, is it possible to put in a floppy controller card in to replace the onboard FDD controller? I would like to copy a few things from my older XT to this XT. I tryed both FDD's in my other XT; work perfectly. It must be the onboard controller.
 
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