PDA

View Full Version : IBM 5160 "Dead" Board



aguerrero810
March 19th, 2017, 05:04 PM
I may have a dead one folks! I can't seem to get a display out of my IBM 5160 with my SUPERSOFT Diagnostic ROM. No Beeps either. The Power Supply fan turns on and the voltages look right. I have my switches set to 01110011. That should be No POST-Loop, No Co-Processor, Bank 0 RAM Enabled, MDA, 1 Floppy Drive. I don't really know if my Display is working, but I should be hearing some beeps, right? Which chips should I be looking at? I can probably get my hands on an oscilloscope if I should need one.

Thanks!
Anthony

modem7
March 26th, 2017, 02:11 AM
Lots of 5160 information at minuszerodegrees.net

Noted that your VDU and graphics card status is presently unknown.


The Power Supply fan turns on and the voltages look right.
Does that include the POWER GOOD line. The motherboard needs that to start.


I can't seem to get a display out of my IBM 5160 with my SUPERSOFT Diagnostic ROM. No Beeps either.
The Supersoft diagnostic ROM is a good low-level tool for the symptom of 'motherboard appears dead'. It even caters for bad RAM in bank 0. With no video card inserted into the 5160 motherboard, expect the Supersoft diagnostic ROM to beep the speaker very shortly after power-on (the beeping due to the Supersoft ROM not finding an appropriate video card to initialise).

Is your Supersoft diagnostic ROM known to be good ? (I.e. we may need to allow for the fact that its good/bad status is unknown.)


Which chips should I be looking at?
If the Supersoft diagnostic ROM is not beeping the speaker per above, then quite a few chips could be at fault.
Have you done a very thorough visual inspection of the motherboard ?


I can probably get my hands on an oscilloscope if I should need one.
Good for repetitive signals (such as clocks). Beyond that, use is pretty much restricted to 'is this line changing state'. I prefer a logic probe (one with pulse detection capability) for that kind of analysis.

aguerrero810
March 26th, 2017, 12:47 PM
Lots of 5160 information at minuszerodegrees.net
Yeah, I went there first and tried the Minimum Diagnostic Configuration to determine that I should use the SUPERSOFT ROM.


Does that include the POWER GOOD line.
All power lines (including the POWER GOOD line) are good and within the voltages listed on http://www.minuszerodegrees.net/5150_5160/MDC/no_beeps_2.htm


Is your Supersoft diagnostic ROM known to be good ?
I had it burned by a user by the name of glitch. I assume it's good, but I don't have any way of testing it.


Have you done a very thorough visual inspection of the motherboard ?
I think so. I have some pictures here (http://imgur.com/a/M5wd4). Everything looks OK. No corrosion that I can see. That questionable bus just above the middle of the picture is fine; I checked it with a multimeter. I also noticed a yellow wire fix that was not done by me. I think it's fixing a bad trace, but I'm not sure.

I figured it might be nice to see a clock signal going into the CPU to make sure it is actually stepping. I should see if I can get one.

Thank you very much!