Recap dilemma

[quattro]

I'm hoping some one can offer me some advice with my capacitor dilemma.

I've got a few pc components lying around with leaking/bulging caps. I have previously looked into replacing them to save some of the parts, but after availability and cost issues I gave up. Now I have some free time and I pulled them back out again, I have:

2 socket A motherboards (Soltek/Albatron)
Geforce 2 and 4 videocards (Leadtek)

All the capacitors in question are GSC.

The problem I'm facing is that I get the feeling that the motherboards failed, in part due to the GSC's of course, but also due to the crap PSU (Hyena, aka Deer) they were hooked up to. I figure this basically means that if I go ahead and replace the caps, I will also need to replace the PSU to avoid repeating the whole ordeal. The thing is, half decent PSUs cost many times more than the cheapest ones, and many times more than I want to spend, just the replacement capacitors are expensive enough.

I looked in one of the PSUs and there are a few unnamed (as far as I can tell) 3300uF/16v bulging caps (they say ‘Low.ESR' on them as well as: im0118). Would replacing these be enough to make the PSU useable with recapped boards?

I guess the videocards might be saveable but there's not much point if they have nothing to be used with.

Any ideas? Should I just write it all off? Or can someone see an alternative?

[kc8adu]

Re: Recap dilemma

most deer psu i have seen are only fit for rifle targets.
junk them.
recap your boards and get a good psu.
crap psu are not only bad for your system but can be downright dangerous!

[linuxguru]

Re: Recap dilemma

Are the Deer PSUs still functional - i.e. do they power up and provide all voltages (not necessarily within spec)? If so, they can be used with caution after performing the following upgrades:

1) Level 1: recap all the secondary side caps with higher-quality caps from the recommended list.
2) Level 2: upgrade the two 3A rectifiers on the +12v rail with a 10A or 15A Schottky-Barrier Rectifier (SBL1040/1540 or similar)
3) Level 3: upgrade the two 10A rectifiers on the +5v and +3.3v rails with 15A or 20A Schottky-Barrier Rectifiers (SBL2040 or similar).
4) Level 4: Populate all the primary-side EMI/RFI components if they're missing.
5) Level 5: Populate the missing inductors on the secondary-side pi-filters.

The upgrades are listed in order of decreasing priority - i.e. do the first one first.

The Leadtek Geforce 2/4 cards can almost certainly be revived by replacing the electrolytics - I've used Rubycon YXG, but would recommend Chemicon LXZ, Panasonic FC or Nichicon PW non-aqueous caps.

The Socket A motherboards are iffy - you can replace the caps near the CPU/VRM for starters, check if it POSTs, and then do the other caps. A failing mobo with bad caps can take the CPU, Northbridge, and various other components with it.

[yanz]

Re: Recap dilemma

Ya, that Deer PSU is fun to toy with

Linuxguru, is it ok to use MBR 3045CT for all the scottchky in the secondary heatsink?

I done level 1, 4, and 5, altough just using components from other broken PSU. Would you give a guide what is the spec for the coil in pi-filter and the bridge rectifier and LF/coil in the input filter/EMI? What are the universal value/spec for them?

[linuxguru]

Re: Recap dilemma

Yanz: 3045 is overkill (30A, 45V). You can use them if they're available at hand - check the package to see if it fits the mounting-hole on the heat-sink as well as the PCB part-outline. I can't get 30A rectifiers in TO220 packages locally, but they're probably available.

The L in the pi-filter is not critical - I substitute the coils from busted 'donor' PSUs. I just visually verify if the gauge of the wire is thick enough to carry the rated current on that rail, using this table:

http://www.powerstream.com/Wire_Size.htm

The approximate rule of the thumb is that 18 AWG can carry 16 amps, and every decrease of 2 AWG (->thicker) increases the current-carrying capacity by 50%.

Likewise, I obtain the EMI/RFI components from busted PSUs, too.

[yanz]

Re: Recap dilemma

I have plenty of them in my hand, and can't return it to the shop for re-fund. so, it is ok to use them. usually the pcb support a bigger chip/wider legs and they will fit in them (5 holes).

Thanks for info and the link. I guess i'll run out of busted PSus, so i i'll searching for compatible components in the local electronic shops.

[quattro]

Re: Recap dilemma

Seems like a big effort with fixing the PSU, and most of those steps don't mean anything to me...

I still have one of the two PSUs, it has worked fine for the last 4 years, but recently, before I retired the system completely, there were strange problems, either due to it, the mb, or the video card. Sometimes the system wouldn't boot, it would just give some strange bios beeps, (I was never able to determine what they corresponded to), and nothing would be displayed on screen, which lead me to believe it was the video card responsible.

Anyway, I'm unlikely to do all that stuff to the PSU (apart from maybe replace the caps, but how much will that do?). What I really want to know is, if I do nothing to it, and fix the mb/videocard caps, what's the worst that could happen (apart from an absolute disaster), would the new, quality caps just fail again? If it takes another 4 years, I'm happy to do that.

Strangely, I just checked another old system I have, a duron 800, about 5 years old, it's running absolutely fine (well as fine as a duron system can). It has some 'novia' brand psu, which I assume is as bad as the hyena, the mb and video card are also covered with 'licon' branded caps, but they're all perfect...

[linuxguru]

Re: Recap dilemma

Anyway, I'm unlikely to do all that stuff to the PSU (apart from maybe replace the caps, but how much will that do?). What I really want to know is, if I do nothing to it, and fix the mb/videocard caps, what's the worst that could happen (apart from an absolute disaster), would the new, quality caps just fail again? If it takes another 4 years, I'm happy to do that.

A PSU with bad caps can cause the motherboard and AGP card caps to fail again quickly, sometimes even if they're fairly high-quality.

It's far easier to re-cap a PSU - it only has a single-sided PCB, no PTH, and thick traces. There are usually no more than 10 caps to replace: 2 each on +5Vsb, +5V, +3.3V and +12V; and 1 each on -12V and -5V. In a pinch, you only need 10 identical 1000uF, 16V caps to replace all ten of these caps. If you can't get low ESR caps, you can manage with general-purpose caps, preferably 105c. The values aren't very critical - +200% to -50% will work.

A PSU re-capped with the recommended caps and put into a non-critical low-load system (say Pentium, Pentium-II) can easily last another 5-10 years. The fan will usually fail before anything else.

[tazwegion]

Re: Recap dilemma

I'm curious quattro... which model Soltek s462 do you have? is it the SL-75KAV?

[quattro]

Re: Recap dilemma

Not quite, its the SL-75DRV2:



I have no problem replacing the PSU caps if that will help, especially since there are only about 4 that need it:



Its all the other things I wasn't sure of. (BTW, i had a better look, i think the PSU caps are 'Rulycon'...)

Thanks for the advice, I think that's what ill do, replace the caps in the PSU, GeForces, and the Albatron (the Soltek needs 10x 2200uF/10mm, which are expensive here).

These are the ones I've found, I used the 'List of Low ESR caps' post as a guide:

MB/VID:
3x 3300uF/10v/12.5mm (Should be 10mm, should fit)
9x 1000uF/6.3v/8mm
5x 1500uF/6.3v/10mm
PSU:
1x 3300uF/16v/12.5mm
4x 3300uF/10v/12.5mm (these 2 should also all be 10mm...)

Are they all ok?

[tazwegion]

Re: Recap dilemma

Farnell's are quite expensive, I found some low ESR (samXon) caps available in NZ from JayCar.NZ & Rubycon YXF series @ RS New Zealand... so you could still afford to revive that Soltek motherboard

[quattro]

Re: Recap dilemma

I did look at both Jaycar and Radiospares but neither seem to have the 10mm low ESR 2200uF's and there's no room on the Soltek for 12.5's as you can see in the photo.

But yeah, Farnell... I just emailed them and found out shipping will be almost a third of the total price. I think they send them from your side of the Tasman. I wouldnt mind the price if i knew it was a sure thing, but im still not 100% sure i wont stuff up installing them.

[linuxguru]

Re: Recap dilemma

Yeah - the PSU caps are JEE/Rulycon. Measure and check if 12.5mm caps will fit before ordering - most Deer PSUs will only have space for 10mm caps on the secondary side.

[tazwegion]

Re: Recap dilemma

I did look at both Jaycar and Radiospares but neither seem to have the 10mm low ESR 2200uF's and there's no room on the Soltek for 12.5's as you can see in the photo.

I'm currently recapping an Epox 8KHA+ and like you had to search out some affordable/available low ESR capacitors, I located 10x21mm Hitano's via a local supplier but they're not ultra low ESR, and only rated @ 0.052Ohm just a fraction higher than those samXon's from Jaycar... they'd fit if you could get them, but they're an unknown/untried product in relation to capacitors used/recommended by many on these forums

Good luck... just seems a shame to have to junk an otherwise good board

[quattro]

Re: Recap dilemma

Yeah, i cant stand to throw it away, ill probably keep store it somewhere and try again in a year or so, but i think ill go ahead and replace the rest.

Thanks for everyones help.

[quattro]

Re: Recap dilemma

Well, i didnt look very hard. Seems RS do have 2200/10mm (Rubycon LZ series), but theyre only 6.3 volt and are still expensive at about NZ$2 each, and i need 10...

Ive been thinking about it, and have done the sums, i just dont think i can justify spending ~NZ$80 on all these capacitors.

Damn, back to square one...