First post, by marcushg85
After the successful repair of a 5150 and an original CGA card, came a 5160 board (bought it as removed from a working computer but being stored in the cold for years...) and surprise but it doesn't work, no beeps, nothing. Here's a list of all what I've done:
5160 motherboard diagnose.
Checking with a generic AT psu
Replaced most prone to failure tantalum caps with some low ESR electrolytic caps (until new tantalums arrive)
Reflown the solder in many main ICs
Diagnostics card doesn't show any numbers, all lights power on except reset (powers on most instantly) on
CPU pin 22 on boot 4.5v. also tested good replacements
8284 chip tested replacement and in another board ok
8284 chip clk signal 0.55v ????
8284 chip reset goes high 5.3v and stays high
8288 chip had some marks of paint so replaced it for a new one just in case. Replacement has a different name sab8288ap instead of the sab8288p (is there any difference?)
Tested all Ram chips and they're ok
Tested the CPU ok
Tested the ROM chips and ok
Replaced 14.318 crystal
Replaced C1 for a 22pf cap
Replaced C-55 with 47nf ceramic cap
Tried to add load to PSU with hdd
All tests without the CGA card or anything else other than the test card and pc speaker
Upon visual inspection I see that AMD IC with some strange discoloration..
Other than that the board is visually perfect.
Let's see if someone can point me into the right direction. Thanks
