Rikintosh wrote on 2021-09-10, 20:36:

Remove the cmos battery, wait a few hours, then wash the motherboard thoroughly using mild detergent and a toothbrush or brush, let it dry well for about 3 days, I've saved many boards this way, and don't worry, wash it's totally safe as long as it doesn't have energy and it dries well.

when you say wash, do you mean like run it under the sink? I forgot to clarify this one yesterday so I got in front of the faucet and started having doubts.. So far I've only scrubbed it with iso alcohol and a toothbrush (the suspect PCI pin and the 1-2 traces around it don't look that much better, but still waiting on my meter)

I’ve been washing motherboards, video cards, sound cards, etc for 20+ years. And not just washing them in the sink - nooooo, I give them a nice 10 minute high pressure shower in the bathtub, using a multifunctional Grohe shower head.
After that I take my time with the hair dryer, making sure that the board is completely dry.

Having said that, I never had any issues. 😀

bloodem wrote on 2021-09-11, 15:09:

I’ve been washing motherboards, video cards, sound cards, etc for 20+ years. And not just washing them in the sink - nooooo, I give them a nice 10 minute high pressure shower in the bathtub, using a multifunctional Grohe shower head.
After that I take my time with the hair dryer, making sure that the board is completely dry.

Having said that, I never had any issues. 😀

I wouldn't have to worry about anything floating about in the water staying behind after said water dries out? I don't think I'd be that confident with my bathtub, 🤣, as it definitely likes leaving behind some hard stuff

TehGuy wrote on 2021-09-11, 14:27:

Rikintosh wrote on 2021-09-10, 20:36:

Remove the cmos battery, wait a few hours, then wash the motherboard thoroughly using mild detergent and a toothbrush or brush, let it dry well for about 3 days, I've saved many boards this way, and don't worry, wash it's totally safe as long as it doesn't have energy and it dries well.

when you say wash, do you mean like run it under the sink? I forgot to clarify this one yesterday so I got in front of the faucet and started having doubts.. So far I've only scrubbed it with iso alcohol and a toothbrush (the suspect PCI pin and the 1-2 traces around it don't look that much better, but still waiting on my meter)

Well, I live in Brazil and here it is very hot most of the year, I wash them in the sink, or sometimes on the garage floor using a garden hose (when they are very dirty), if I wash them in the morning, and I put it on my roof to dry, by the end of the afternoon they are 100% dry and I can turn them on. I believe that in colder countries, it would be good to wait a little longer before turning them on. One trick is after washing and letting it dry for a while, wash it with isopropyl alcohol, because when it mixes with water, it causes it to evaporate instantly.

Sometimes capacitors leak, or mold and moisture build up between the board's contacts, which causes problems like this, and a simple wash will solve everything.

As for the stain on the PCB, you can use a paper towel with a little solvent, thinner, and see if there is progress. Vinegar is also useful to remove oxidation and stains.

I wash things if they're really clagged up with fine or furry dust. Shower usually, or maybe the laundry sink. I like sticking them in the heating ducts to dry out in winter. In summer I stick them out in the sun or prop them up on top of the water heater if it's wet weather.... if you get a keyboard with really gross keycaps, tie them in a pillowcase and put them through with a load of laundry. .. I'd subscribe to the dishwasher method as seeming practical, but I don't have one... do not fail to get everything bone freaking dry though before powering it. If you feel like you're in a rush, check by blowing compressed air under every soldered down chip or under and into every card slot.. if drops of water come out, leave it in the warm place to dry more, work it over with the hairdryer or paint stripper gun on low at a distance, or continue blasting it with the air under and around from every angle until you're certain not a drop remains. If you're still a bit uncertain about a BGA, shoot some alcohol under it, and blast out again.

Multimeter finally arrived!

Probing for continuity shows that, despite that one pin and the surrounding looking really sketch, it actually passes signals just fine (unless my meter beeping at me is bad, but the manual says it'll do that if the result is under 30 ohms) to that pin, and any of the pins following the strange areas on the surrounding traces

Testing the caps is next

EDIT: maybe im poking something wrong, but some of my 1200uF caps are reading at 7.85mF / 7850uF and it doesn't matter which way I poke it with the leads 😐

EDIT2: fluke site on testing for capacitance says i should remove the caps first... guess its solder time?

Actually, thinking on it now, it should've come off as strange that after power is removed hitting the power button doesn't turn it on for that brief second before power is drained from the board (also multimeter in relative mode pops up as OL and I doubt 1200uF is out of range for it)... I guess the caps are just straight up dead

EDIT: just to be sure I wasn't crazy, because I measured some caps on my working p4 board and they also read funny, I grabbed my Orpheus card and measured its caps with my meter and they read exactly what they should (within normal tolerances, anyways)

I have a lot of bad caps on my hands it seems 😀

TehGuy wrote on 2021-09-11, 23:07:

Multimeter finally arrived! […]
Show full quote

Multimeter finally arrived!

Probing for continuity shows that, despite that one pin and the surrounding looking really sketch, it actually passes signals just fine (unless my meter beeping at me is bad, but the manual says it'll do that if the result is under 30 ohms) to that pin, and any of the pins following the strange areas on the surrounding traces

Testing the caps is next

EDIT: maybe im poking something wrong, but some of my 1200uF caps are reading at 7.85mF / 7850uF and it doesn't matter which way I poke it with the leads 😐

EDIT2: fluke site on testing for capacitance says i should remove the caps first... guess its solder time?

Capacitors should ALWAYS be measured off the board, measuring them on the board makes no sense as they are connected to each other, think of them as batteries, interconnected with other batteries, if one battery is discharged it will accumulate charge from the others to equalize .

You have to unsolder all capacitors and test them, test if they charge and discharge (invert the tips of the multimeter), but not only that, you also need a capacitance meter, some multimeters have it built in, capacitors are like batteries, and like batteries, as soon as they get old, they start to store less charge than they should. There is a third problem (severely affecting the processor sector) something called ESR, which we've seen, would be the "response time of a capacitor". The processor region needs fast responding capacitors, so even if it is working and building charge correctly, if it takes longer than expected to discharge then the system will not work.

You can have fun testing them one by one, or if you're in a hurry, simply buy a bunch of assorted capacitors, and simply replace them all.

Rikintosh wrote on 2021-09-12, 00:26:

Capacitors should ALWAYS be measured off the board, measuring them on the board makes no sense as they are connected to each other, think of them as batteries, interconnected with other batteries, if one battery is discharged it will accumulate charge from the others to equalize .

sounds like my excuse for a station, then

Permanent reset status can also be caused by bad cap, as many reset circuits are of RC type.

TehGuy wrote on 2021-09-12, 00:32:

Rikintosh wrote on 2021-09-12, 00:26:

Capacitors should ALWAYS be measured off the board, measuring them on the board makes no sense as they are connected to each other, think of them as batteries, interconnected with other batteries, if one battery is discharged it will accumulate charge from the others to equalize .

sounds like my excuse for a station, then

You don't need to invest in something expensive and professional, even a Chinese Yaxum 878 (I have one) is good enough. It has a soldering iron and hot air blower, which work up to 480 degrees and have ESD protection.

I don't know how much it costs in other countries, but I believe it costs less than 60 US dollars

retardware wrote on 2021-09-12, 01:35:

Permanent reset status can also be caused by bad cap, as many reset circuits are of RC type.

Until they can hold enough charge, they'll reset.
As soon as they can system will work.

A recap is cheap (unless you go for the best of the best).

Rikintosh wrote on 2021-09-12, 05:33:

You don't need to invest in something expensive and professional, even a Chinese Yaxum 878 (I have one) is good enough. It has a soldering iron and hot air blower, which work up to 480 degrees and have ESD protection.

I don't know how much it costs in other countries, but I believe it costs less than 60 US dollars

Air + iron is a good starting kit. I'm happy I got both and it's just a world of ease to do stuff.
It's the kind of thing that just helps, always a +.

Rikintosh wrote on 2021-09-12, 05:33:

You don't need to invest in something expensive and professional, even a Chinese Yaxum 878 (I have one) is good enough. It has a soldering iron and hot air blower, which work up to 480 degrees and have ESD protection.

I don't know how much it costs in other countries, but I believe it costs less than 60 US dollars

Closest I can find is YIHUA but some of the stations are priced close enough to a Hakko or Weller that I may as well go with the tried-and-trues at the cost of some extras.

Get a $3 discount store iron, then it's pure joy every time you manage to finish a job with it vs ... "warm up already you expensive POS, damn need a new tip already? shall I buy you one or another three cheap irons for spare.." 🤣

Whelp, I'll be back in a week when my new 'workbench setup' comes in and I blow something up or light it on fire

Alrighty; After much waiting and then fumbling I got one whole cap out after wiggling it out of some molten solder. This one is one of the 330uF ones: measures ~340uF and starts at ~ 0.65MΩ and rises ~+0.03MΩ every second or two. From what I can gather, short of finding a way to juice it a bit to read voltage (guess who doesnt have batteries~) it's not completely dead at least.

Anyway, off to remove the rest over the next few days since the goal was to replace them regardless but I figured learning how to measure some of it and how my multimeter acts would be nifty

TehGuy wrote on 2021-09-21, 00:14:

Alrighty; After much waiting and then fumbling I got one whole cap out after wiggling it out of some molten solder. This one is one of the 330uF ones: measures ~340uF and starts at ~ 0.65MΩ and rises ~+0.03MΩ every second or two. From what I can gather, short of finding a way to juice it a bit to read voltage (guess who doesnt have batteries~) it's not completely dead at least.

Anyway, off to remove the rest over the next few days since the goal was to replace them regardless but I figured learning how to measure some of it and how my multimeter acts would be nifty

Take a pic and write the values of all caps before removing them all.
It's easy to make a mistake or forget the right place.