Miphee wrote on 2021-02-26, 18:30:

OP should get a TL866 with a chip adapter to diagnose it.

Sadly TL866 would be more expensive that buying new 486 mobo to reuse that case for other build.

Frankly speaking, I've bought that PC in a price I could get just a case. So if it's dead I'll build other PC in that case.

Bernkastel7734 wrote on 2021-02-26, 19:39:

So if it's dead I'll build other PC in that case.

Try removing all RAM and see if you can get the POST card to display something.

This case is proprietary so you need a hp Vectra motherboard. You may be able to find one from times to times (in my area there's been one for sale for a while)

Deksor wrote on 2021-02-26, 20:20:

This case is proprietary so you need a hp Vectra motherboard. You may be able to find one from times to times (in my area there's been one for sale for a while)

Yeah, I know. But getting just a normal desktop case is hard here, so I'll modify it a bit. Maybe even not a bit. As I said, I got it really cheap. In a price of a empty case.

Miphee wrote on 2021-02-26, 20:04:

Bernkastel7734 wrote on 2021-02-26, 19:39:

So if it's dead I'll build other PC in that case.

Try removing all RAM and see if you can get the POST card to display something.

With or without ram it behaves the same. I mean some post codes every couple of booting attemp.

Tried to boot up without case, no improvement, sadly. Back side of the mobo seems fine, I mean no touching elements. Is it possible that system does not boot up because althought voltages are fine, power good signal is somehow wrong? Also, You were talking about battery leakage, is it possible for that cylinder type of battery to leak?

I guess anything containing chemicals can leak ... now I think you'd see the damage if the leakage was this bad.

By the way where are you from ? Maybe I can buy this board that's available in my country and ship it to you ? It's been around for a while and I know the seller still has it. It's not the exact same but it should be compatible with your PSU and case (it's a HP motherboard as well).

Deksor wrote on 2021-02-28, 18:15:

I guess anything containing chemicals can leak ... now I think you'd see the damage if the leakage was this bad.

By the way where are you from ? Maybe I can buy this board that's available in my country and ship it to you ? It's been around for a while and I know the seller still has it. It's not the exact same but it should be compatible with your PSU and case (it's a HP motherboard as well).

I'm from Poland, but well, first I'll try to fix it.

I've noticed that in that pc cpu can be inserted in all directions, is it possible that I've inserted cpu in wrong direction or would it damage that cpu?

Yes you can insert it in any direction and yes it can damage the CPU as well as the motherboard.

But according to your photos, it was inserted properly 😀

Deksor wrote on 2021-03-01, 21:44:

Yes you can insert it in any direction and yes it can damage the CPU as well as the motherboard.

But according to your photos, it was inserted properly 😀

Thanks

Well, I have checked for any bent pins in slots and obvious looking bad soldering. Found none. But can't succeed in getting any POST code now, no matter how many times I've tried. All I have noticed is inconsistant work of IRDY diode on that card. What I mean by that, is sometimes that diode shines, sometimes blinks and sometimes stays off.

It sounds savage and may scare you but are you willing to try a deep clean-up?
Dish soap, sponge, brush and some elbow grease. Sometimes dirt can build up in places you can't imagine and a good cleaning session can do wonders.

Obviously you'll have to dry everything to avoid rust. Not a difficult task 😀

Don't be too beat up, now you don't know how to solve this but in the future maybe you'll regret throwing it away. Be patient.
If you really want to throw it away there are many crazy chaps here that would like to have it even if dead, ask before doing anything.

Never said I'm gonna throw it away. Also started to search for some abnormalities with my multimeter. Noticed that this one smd capacitor near battery socket (22-16 d4 2)seems to be broken, because only that one reports as open circut, while other with same markings shows some capacity.(Soldered it out and still - open circut). Do I make any mistake here, or it's dead?

Unless you have schematics, i.e. know all connections and values, testing smds one by one is pure nightmare.
I have very poor knowledge on the subject but if maybe there's a short in some place or even some filter has gone bad and is giving a high resistance instead of none.

I wouldn't trust POST card readings, its functionality relies solely on BIOS, if BIOS chip is bad or image inside of it is corrupted, POST card will be of little use.

When a motherboard shows no signs of life, I use a "Supersoft" diagnostic ROM to quickly pinpoint the problem. This diagnostic software is meant for IBM PC/XT/AT computers, but it does one thing that is enough to determine whether CPU and chipset are in operational condition - it initializes timer/counter and makes speaker beep. A beeping speaker tells us that: CPU and chipset are OK and that CPU can fetch instructions from BIOS chip, very simple, right?

Now you might ask - whats the point? I don't even have a dedicated programmer to write the chip. This problem can be circumvented easily, all you need is any PCI or AGP card with PLCC32 socket, a compatible donor flash chip of at least 8KB in size and UNIFLASH.

Folks here know very well what I'm talking about 😀

P.S. Passive components are not the culprit here.

Now something weird happened. I got some post messages and after some reboots speaker beeped once, which have never happened before. And after another reboot it stays silent again.

SSTV2 wrote on 2021-03-02, 01:57:

I wouldn't trust POST card readings, its functionality relies solely on BIOS, if BIOS chip is bad or image inside of it is corru […]
Show full quote

I wouldn't trust POST card readings, its functionality relies solely on BIOS, if BIOS chip is bad or image inside of it is corrupted, POST card will be of little use.

When a motherboard shows no signs of life, I use a "Supersoft" diagnostic ROM to quickly pinpoint the problem. This diagnostic software is meant for IBM PC/XT/AT computers, but it does one thing that is enough to determine whether CPU and chipset are in operational condition - it initializes timer/counter and makes speaker beep. A beeping speaker tells us that: CPU and chipset are OK and that CPU can fetch instructions from BIOS chip, very simple, right?

Now you might ask - whats the point? I don't even have a dedicated programmer to write the chip. This problem can be circumvented easily, all you need is any PCI or AGP card with PLCC32 socket, a compatible donor flash chip of at least 8KB in size and UNIFLASH.

Folks here know very well what I'm talking about 😀

P.S. Passive components are not the culprit here.

So, what version of 'supersoft' I need to use for that purpose ? Also I cannot find any pci card with such socket. But I have seen, that one guy around me sells such chips with possibility to programm it. So I guess getting it won't be a problem.

If it actually beeped, then your CPU and chipset should be OK, skip test using a diag ROM for now, perhaps a bad connection/short or cold solder joint somewhere causes MB to return momentarily.

Wash board using natural bristle brush and soap, reseat every removable component, dry well and test again. Also make sure that Power Good is at 5V at PSU and MB.

SSTV2 wrote on 2021-03-02, 14:59:

If it actually beeped, then your CPU and chipset should be OK, skip test using a diag ROM for now, perhaps a bad connection/short or cold solder joint somewhere causes MB to return momentarily.

Wash board using natural bristle brush and soap, reseat every removable component, dry well and test again. Also make sure that Power Good is at 5V at PSU and MB.

When it comes to PG at MB, should I check it directly at power connector or at some chip?