ASRock G31M-VS no post - 3 beeps continuously

[alindumitru46]

ASRock G31M-VS, rev.G/A1.02
The fans are spinning but instantly the mobo make 3 long beep continuously.
I replaced three types of DDR2 RAM, PSU is stable, 3 kinds of videocard: internal PCIe and PCI old.
Reset CMOS or BIOS battery removal for several hours has no effect.
The sound seems to be an error of RAM.
I carefully inspected and found PCB oxidation zone between ATX connector and socket LGA 775.
Maybe through this area is supplied with current the DIMM RAM and that is damaged, it appears as an error of RAM?
Many thanks anticipated .

[RJARRRPCGP]

Re: ASRock G31M-VS no post - 3 beeps continuously

ASRock G31M-VS, rev.G/A1.02
The fans are spinning but instantly the mobo make 3 long beep continuously.
I replaced three types of DDR2 RAM, PSU is stable, 3 kinds of videocard: internal PCIe and PCI old.
Reset CMOS or BIOS battery removal for several hours has no effect.
The sound seems to be an error of RAM.
I carefully inspected and found PCB oxidation zone between ATX connector and socket LGA 775.
Maybe through this area is supplied with current the DIMM RAM and that is damaged, it appears as an error of RAM?
Many thanks anticipated .

RAM issue should sound like 1 long and 2 short bleeps repeated. Especially if a slot issue.

[momaka]

Re: ASRock G31M-VS no post - 3 beeps continuously

I carefully inspected and found PCB oxidation zone between ATX connector and socket LGA 775.
Maybe through this area is supplied with current the DIMM RAM and that is damaged, it appears as an error of RAM?

Could be. Or it could be residual soldering flux from the factory.

You can try cleaning that area with some IPA (Isopropyl Alcohol). The chip between the ATX connector and the LGA 775 socket with label "393" is a dual comparator. Cheap, common part, so no need to panic even if it is bad.

But personally, I think a better starting point would be to replace the KZG and some of the OST caps. I will tell you which ones tomorrow, as it is 2 in the morning here and I am about to fall asleep on the keyboard.

[alindumitru46]

Re: ASRock G31M-VS no post - 3 beeps continuously

First I cleaned carefully in the oxidized perimeter by dabbing with a cotton wool soaked in vinegar and then with isopropyl alcohol.
I'm worried about the appearance of microscopic components because they seem affected, and I cannot identify what type or what value it may have.
If it's just about capacitors, already it's child's play.
Thanks again.

[alindumitru46]

Re: ASRock G31M-VS no post - 3 beeps continuously

I extracted 3 capacitors (one OST 1000uF, 6.3V and two KZG 1000uF, 16V) and the value measured are:
capacitance=980-1005 uF,
ESR=0-0.13,
Vloss=0.05-1.7%.
Must really be replaced?

[alindumitru46]

Re: ASRock G31M-VS no post - 3 beeps continuously

19.03.2016 edit:
The motherboard was slightly "washed" with vinegar, distilled water and isopropyl alcohol and left to dry for 7 days.
Still waiting for an opinion or advice (specially from @momaka, if he can make time for it).

[momaka]

Re: ASRock G31M-VS no post - 3 beeps continuously

I extracted 3 capacitors (one OST 1000uF, 6.3V and two KZG 1000uF, 16V) and the value measured are:
capacitance=980-1005 uF,
ESR=0-0.13,
Vloss=0.05-1.7%.
Must really be replaced?

Get the board to 20C (room) temperature and measure again.
Whichever one(s) read more than 0.09 ESR should be replaced.

And regardless of that, try replacing the following OST RLS 6.3V 1000 uF caps:
- PCE7 and PCE3(?) (located between ATX connector and one end of RAM slots)
- CE56, CE58, and CExx (3 caps between PCI-E connector and Northbridge)
- PCE4 (next to Northbridge)
- and also the cap next to the memory slots where it says "AsRock G31M-VS"

Use good quality low-ESR caps, especially for PCE7 and PCE3 as well as CE56, CE58, and CExx I mentioned above. PCE7 and PCE3 likely filter the RAM Vdd output, so bad caps there can definitely cause memory issues.

And if you do have some left-over good low-ESR caps (i.e. Nichicon HM/HN, Rubycon MBZ/MCZ, or Panasonic FL/FR/FM), definitely replace those KZG caps around the CPU. Even Chemicon KZE would likely be okay.

First I cleaned carefully in the oxidized perimeter by dabbing with a cotton wool soaked in vinegar and then with isopropyl alcohol.

Okay, DO NOT use vinegar or any other solution with acid to clean electronics. Same goes for cleaning products that contain Amonia (NH3) or Clorine (Cl). These chemicals can corrode the board traces over time and cause a lot of damage.

Dish or laundry detergent is usually safe, provided you wash the board with plenty of water afterwards. Alcohol is not needed, but it does help the board dry faster. Though 7 days of drying in dry climate (or during a dry season, such as winter) is more than enough.

....

Anyways, let me know what happens (if anything) after replacing those caps I mentioned above.

[alindumitru46]

Re: ASRock G31M-VS no post - 3 beeps continuously

I replaced all OST 1000uF, 6.3V capacitors with green Chemicon KZE (ultra low impedance ...) an all KZG 1500uF, 16V/1000uF, 16V capacitors with green Sanyo WG/Samwha RD since then @momaka said.
I had problems with diameter of KZG capacitors (10mm - default is 8 mm) but the bonding operation, because it was not done accurately. In fact the board does not start, just trying to spin the fan on the CPU, and no longer hear beeps.
Two weeks ago I resolder all capacitors because I found cold solder trying to see with a magnifying glass, the result is the same.
I noticed that if I remove the 12v power of the CPU is the CPU fan starts...
Tommorow I'll try to check the voltages on mosfets and IC's.

[momaka]

Re: ASRock G31M-VS no post - 3 beeps continuously

I noticed that if I remove the 12v power of the CPU is the CPU fan starts...

Hmmm... The board started the last time you tried to test it. Check your soldering again, especially the caps around the CPU. Perhaps you have a solder bridge causing a short-circuit somewhere in that area?

Or it could also be a cap installed backwards (i.e. + and - reversed). In fact, definitely check that. This is an AsRock motherboard, after all: the shaded semi-circle on the board indicates the positive (+) side of the capacitor. Same goes for ASUS boards of that era.

[alindumitru46]

Re: ASRock G31M-VS no post - 3 beeps continuously

I found 4 Rubycon 16V, 1000uF, 0,8mm diameter, the perfect substitutes for NCC KZG 1000uF, 16V.
After soldernig, the good job is the motherboard power on, but the mobo shows the same problems for beginning: the fans are spinning but instantly the mobo makes 3 long beep continuously...