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IBM AT 5170 motherboard problem

ssdj

Member
Joined
Mar 6, 2012
Messages
36
Location
Los Angeles, CA
Hi everyone,

I got a 256K 8bit memory expansion board for my 5170. Hoping to expand it's memory from 512K to 640K. I think I set the switch in the memory board correctly according to it's manual. But when I plug the memory card in, I got not response from the computer when starting up. So I removed the card and thinking the system will be back to normal, but it didn't. Just the black screen when power up.

I tried couple tests including remove all the cards on board, disconnect the power from the motherboard and switch the ram chips around. But still get no responds.

What would possibly be damaged in my system? My 5170 is type-1 motherboard.
 
That's odd.

I got not response from the computer when starting up. .... Just the black screen when power up. ... But still get no responds.
Please tell us exactly what you see and hear when you flip the red power switch.

So, do you hear the power supply fan turning ?
If so, do you see the power LED on the front panel turn on ?
If so, do you see floppy drive A: being accessed (about 30 seconds after power on) ?
 
When I turned on the power switch, the power supply fan is running and the power LED on the front panel is on.

And the keyboard light was on for like 0.5 second.

But there is nothing on the monitor, no reading on the disk drive.
 
Hi everyone,

I got a 256K 8bit memory expansion board for my 5170...

I could be mistaken, but don't you need to use a 16-bit memory card in a 5170 since its a 286 machine? I have never tried, so I honestly don't know, just posing a thought :)
 
Is the internal speaker attached and do you hear any beeps from the speaker ?

You should measure the power supply output voltages to verify its working.
 
Do you get any signs of a successful POST? Any beeps from the speaker? Also, when you removed the cards, did you leave the video card in to see if anything came up on the screen?
 
I could be mistaken, but don't you need to use a 16-bit memory card in a 5170 since its a 286 machine? I have never tried, so I honestly don't know, just posing a thought :)
An 8-bit RAM card will work, but will be slower than a 16-bit one, because the RAM will be read 8 bits at a time rather than 16.
 
Hi everyone,

I got a 256K 8bit memory expansion board for my 5170. Hoping to expand it's memory from 512K to 640K. I think I set the switch in the memory board correctly according to it's manual. But when I plug the memory card in, I got not response from the computer when starting up. So I removed the card and thinking the system will be back to normal, but it didn't. Just the black screen when power up.

I tried couple tests including remove all the cards on board, disconnect the power from the motherboard and switch the ram chips around. But still get no responds.

What would possibly be damaged in my system? My 5170 is type-1 motherboard.

Are you 100% sure you have any system jumpers back to the pre-memory card settings now? I don't know AT's per-se, I have only ever worked on AT clones, so not sure what is even set by jumper on an actual AT. If this were some of the later 286 AT clones I have dealt with, I would say reset the BIOS to defaults, in case some memory setting was changed in BIOS, I have seen things like that prevent POST.

An 8-bit RAM card will work, but will be slower than a 16-bit one, because the RAM will be read 8 bits at a time rather than 16.

Good to know, I have a few different memory cards lying around, good to know they could be useful in more than just 8-bit machines.
 
And the keyboard light was on for like 0.5 second.
That will be the keyboard doing a self test when it receives +5 volts. Part of the keyboard's self test is to briefly turn on all three keyboard LEDS.

When I turned on the power switch, the power supply fan is running and the power LED on the front panel is on.
So at least +5 volts is present from the power supply.

, no reading on the disk drive.

Part of the 5170 motherboard's Power On Self Test (POST) is to check the A: drive for the presence of a boot floppy. You are not seeing that. It certainly sounds like your motherboard is either not starting, or is starting but stopping during one of the early checks.

Do you have a voltmeter or multimeter? The next step is to ensure that the power supply is putting out a signal named POWER GOOD. POWER GOOD (together with +5 volts) is what enables the motherboard to start.
And when measuring POWER GOOD, you may has well measure the DC voltages ( +5V, -5V, +12V, -12V).
 
Are you 100% sure you have any system jumpers back to the pre-memory card settings now? I don't know AT's per-se, I have only ever worked on AT clones, so not sure what is even set by jumper on an actual AT.
On a 5170 motherboard, there is one jumper and one switch. Incorrect setting of either/both will not result in what the OP is seeing (or should that be, not seeing) - there is always a display shown.

If this were some of the later 286 AT clones I have dealt with, I would say reset the BIOS to defaults, in case some memory setting was changed in BIOS, I have seen things like that prevent POST.
Worth a try. Done by removing the battery. For a 5170 motherboard, the battery needs to be disconnected for about 3 minutes.
 
Actually I forgot to mention that I was using the computer normally just right before I plug in the memory card. So I assume if the card does not work, I should be able to put everything back to normal just by removing the card.
So all the jumper settings are still the same as when the computer is in the working state.
I did try to disconnect the CMOS battery for 5 min and reconnect it, but still doesn't work.
The speaker is working because I when I power it up without the graphic card, it makes a long beep and 2 short beeps.
But when I put back the graphic card, there is nothing. No beep and nothing on the screen. Just the sound of the power unit fan spinning.
 
Actually I forgot to mention that I was using the computer normally just right before I plug in the memory card. So I assume if the card does not work, I should be able to put everything back to normal just by removing the card.
So all the jumper settings are still the same as when the computer is in the working state.
I did try to disconnect the CMOS battery for 5 min and reconnect it, but still doesn't work.
The speaker is working because I when I power it up without the graphic card, it makes a long beep and 2 short beeps.
But when I put back the graphic card, there is nothing. No beep and nothing on the screen. Just the sound of the power unit fan spinning.

What kind of graphics adapter do you have now? Do you have a different graphics adapter you can try to boot the system with? Can you try the existing one in another slot? I am kind of grasping at straws, really odd symptoms!
 
You should run the setup program. It sounds like after you discharged the CMOS you're getting the same result as before. So that might be the initial problem, too. Somehow your CMOS settings were lost.
 
What kind of graphics adapter do you have now? Do you have a different graphics adapter you can try to boot the system with? Can you try the existing one in another slot? I am kind of grasping at straws, really odd symptoms!
The fact that it doesn't beep when he replaces the graphics card indicates that the card is functioning properly.
 
The speaker is working because I when I power it up without the graphic card, it makes a long beep and 2 short beeps.
It is the POST in the 5170 motherboard doing the "long beep and 2 short beeps", because it can not find the video card.
So, at least with the video card removed, your motherboard is starting.
With the video card removed, is the POST accessing floppy drive A: (about 30 seconds after power on) ?
 
The fact that it doesn't beep when he replaces the graphics card indicates that the card is functioning properly.
At least partially functioning (enough for the POST to 'see' the card). There is no way that the POST can determine if the video card is fully functional.
 
Actually I forgot to mention that I was using the computer normally just right before I plug in the memory card. So I assume if the card does not work, I should be able to put everything back to normal just by removing the card.
It could be that something failed just at the same time that you were trying out the RAM card. Purely coincidental.
 
The fact that it doesn't beep when he replaces the graphics card indicates that the card is functioning properly.

Except he doesn't see POST, which is why I suggested relocating or trying a new card, its like its getting stuck initializing the graphics card.

It could be that something failed just at the same time that you were trying out the RAM card. Purely coincidental.

I was thinking this, and leaning to graphics card, since the PC actually beeps error codes without the card, suggesting the rest is working (in theory).


This is a situation where one of those cheap ISA post-code card could be of some real use, see what its getting stopped up on.
 
My video card is trident 256K VGA. It's a 16 bit card.

I just made some progress!! I tried pulling the VGA card out and just have the floppy control card installed. Both floppy drive lights were on after 30 seconds. The computer actually tried to read drive A:
Does that mean the VGA card is causing the problem?

Unfortunately I don't have another ISA VGA card to test with. The only cards I have are PCI.
 
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