No post with selectivly recapped P4MA Pro

[Datz]

Hi all,
I just finished recapping a board that I got from a buddy that had died on him. There were 6 visibly bad caps, so I decided that I would replace them, and see where that got me.

When I try to power on the board though the fpanel connecter with a jumper, I get nothing.(I downloaded the motherboard manual to find out which is the power)

I used Panasonic FM 3300uf 6.3v replacements. (had to work around the size issue which I mistakenly made)
All capacitors are correctly oriented afaik, and leads are all soldered. My friend used the board with bad caps for awhile, so I don't know if this could have caused any other problems, but I assume so.
When I try to power on the board, it does nothing, no fan movement etc..

I don't have a ESR meter to test the rest of the caps, but I was wondering if it is worth trying to replace the others which are mainly 1000uf 6.3v and 1500uf 16v (the latter I don't have any) Or iif there are any other suggestions..

Thanks for any help.

P.S. I also tried removing the battery, and clearing cmos.

[Toasty]

Re: No post with selectivly recapped P4MA Pro

Does it beep any POST code when you power on?

Does the indicator LED on the mobo come on showing the power supply is connected and ready?

Does the PSU fan run?

Have you tried another PSU?

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

Check for solder hairs or spatter.

Reset CMOS.

If that doesn't work replace the 16v OST's.

[Toasty]

Re: No post with selectivly recapped P4MA Pro

The pictures were taking too long to come up so I didn't see the possible problem right away.

Put your magnifying glasses on and:

Redo all the solder joints with the Yellow arrows.

The joint with the Red arrow looks like it has a gap. It's missing solder.

All of those should look like the connections with the Green arrows, with the little "moat" around them clear of any muck.

Those pads have a gap around them which insulates them from the ground plane. As PCBONEZ said, there may be a "whisker" of solder there. That will keep the PSU from coming on because it detects a short circuit.

Toast

[Datz]

Re: No post with selectivly recapped P4MA Pro

Thanks for the Replies guys.

No beep or any POST code when attempting to power on.

No indicator LED on board that I can see.

PSU is ok, got it from a working machine, and tested it with paperclip and fan spun.

Checked for soldier hairs + spatter, none that I could see.

Reset CMOS with jumper.

Damn, comes down to the 16v "OST's". Had them ordered, but the ones I had selected were out of stock and I didn't want to put them on back order, so I said forget it. humm, if replacing these might make it work, maybe I'll order them... and while I'm at it, maybe I'll get some correct size caps for the ones that I already replaced, although I guess it would be purely cosmetic...lol

On a good note, my recapped graphics card works fine so far.

[Datz]

Re: No post with selectivly recapped P4MA Pro

The pictures were taking too long to come up so I didn't see the possible problem right away.

Put your magnifying glasses on and:

Redo all the solder joints with the Yellow arrows.

The joint with the Red arrow looks like it has a gap. It's missing solder.

All of those should look like the connections with the Green arrows, with the little "moat" around them clear of any muck.

Those pads have a gap around them which insulates them from the ground plane. As PCBONEZ said, there may be a "whisker" of solder there. That will keep the PSU from coming on because it detects a short circuit.

Toast

Hi Toasty,
Thanks for the pic and suggestion, I will take it, and redo these joints. I know they all made contact with the solder, but I suppose it wouldn't hurt to try and do a better job. (yep I know it was shoddy.) Working with a 45Watt iron seems to take forever to heat stuff up. I'll try to clean it up and see what happens.
Thanks
Datz

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

I dunno where you are at.

Fry's Electronics (here at least) carries a not-to-bad generic 60 watt for ~$10.

Can get el'cheapo 60 watt on eBay for less but expect cheap cords and handles that get hot. Still good enough for occasional use.

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

Also use small diameter solder.

[Datz]

Re: No post with selectivly recapped P4MA Pro

PCBONEZ, thanks.
Found one on Fry's for not a bad price. Now if only they sold caps too, or I will find myself paying for shipping thrice to get this mobo working. xD Think I will have to stick with the 45W for the moment, but good to know that Fry's carries soldering equip, thanks.

[momaka]

Re: No post with selectivly recapped P4MA Pro

Hi Datz,
I noticed you put some of the caps high off the board (due to limited space). Problem is, when caps are high off the board, their ESR goes up and they are not effective. If you are re-ordering replacements for the OSTs, you might as well order some caps that are the right size (and maybe save those Panny FMs you have right now for other boards that might come in ). Make sure the new ones are flushed with the board (like the ones you installed on your video card).

Also, if you have an old tootbrush, use it to scrape away any solder splatts that might be present after you have put in the new caps.

As for your soldiering iron, I think it's fine. I have a cheap 30-watt Radio Shack one and it seems to handle anything I throw at it. The trick is to make sure the tip is clean (remove any old solder that has accumulated on it). Also, apply a little bit of new soldier to it before removing the caps as this should help with the heat transfering.

[Datz]

Re: No post with selectivly recapped P4MA Pro

Hi Datz,
I noticed you put some of the caps high off the board (due to limited space). Problem is, when caps are high off the board, their ESR goes up and they are not effective. If you are re-ordering replacements for the OSTs, you might as well order some caps that are the right size (and maybe save those Panny FMs you have right now for other boards that might come in ). Make sure the new ones are flushed with the board (like the ones you installed on your video card).

Thanks, momaka, I did not know about the increase in ESR. If I order more replacements, I will make sure to get the right sizes this time.(I didn't think 2mm could make such a difference, but now I know I was dead wrong...lol)

Also, if you have an old tootbrush, use it to scrape away any solder splatts that might be present after you have put in the new caps.

I had the same idea earlier today.

As for your soldiering iron, I think it's fine. I have a cheap 30-watt Radio Shack one and it seems to handle anything I throw at it. The trick is to make sure the tip is clean (remove any old solder that has accumulated on it). Also, apply a little bit of new soldier to it before removing the caps as this should help with the heat transfering.

I got mine cheap from radio shack too. Thanks for the tips, I will give them a try.

[Datz]

Re: No post with selectivly recapped P4MA Pro

Ok, so I ordered replacement 6.3v 3300uf caps. (Panasonic NHG) -> http://search.digikey.com/scripts/Dk...&name=P5511-ND

And

16v 1500uf (Panasonic FC) -> http://search.digikey.com/scripts/Dk...name=P10254-ND

Replaced the OST's and previously too large caps.

But, same deal. No post, no nothing when I short the power pins on the Fpanel conector.
Are there any other options, things to test? I am using a 2.2GHz celeron processor with a 400MHz FSB with this board, it was not the one originally used, but according to the board manual, it should work. Reset CMOS, replaced battery with one from another mobo; still nothing.
I have put too much effort into this to want to walk away with it not working, so open for suggestion.

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

NHG, not so good. - Not low enough ESR.
But they should still last long enough to boot and test the board out.

Same-same with FC if you are using them in VRM.
If you have like 6 - 16v caps in VRM they might be okay there but most boards I see lately only have 3 or 4.
.
But like I said.
Even with those it sound get through POST and last for a little while.

Something else is wrong.
- Are you connecting the 2x2-pin 'P4' connector?
- Some PSU's need +5v load to kick-on. Connect a Hard Drive as a dummy load.
[Don't need data cables to drive, just power.]

.

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

Also check CMOS jumper to make sure it wasn't left in clear CMOS position.

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

And stop laying the board on wool blankets.
That's called STATIC!
Use a clean chunk of cardboard or plywood.

[Datz]

Re: No post with selectivly recapped P4MA Pro

Thanks for the reply PCBONES.

Should have checked about ESR on those caps before ordering...

Anyway, CMOS jumper is not in clear CMOS position.

P4 connector is connected.

Tried connecting power supply to drive already too, a no go as well.

I've tried the same setup on another mobo and it worked, so it is not a CPU, RAM, etc.

Think I may have to give up. Oh well, at least I have a bit more know-how in case I have to try this again sometime.

Thanks for your help guys.

[Toasty]

Re: No post with selectivly recapped P4MA Pro

Hmmm.

Thoughts -

Going from the first post where I saw the soldering mess, I'm thinking maybe you fried the VRM MOSFET's when you powered it on. Or, maybe they were fried when you got it. Don't know how quick the PSU caught the problem.

Check Q45, Q46, Q47, Q49, Q50, Q51 - Don't know where Q48 is, if there is one...

Did you perhaps reverse any of the caps when you replaced them? Negative (usually) goes to the white or hash-marked side of the silk screened circle under the caps.

Using an ohmmeter, check from the negative terminal on those caps to the positive and see if you get a reading of zero ohms (the same as when you touch the probes together). Then reverse the leads and see if the reading is the same. If you get a zero reading it might mean that the cap(s) are shorted somewhere. You may still have a soldering problem.

[Datz]

Re: No post with selectivly recapped P4MA Pro

Regarding the VRM MOSFET's, they all look fine. I don't know how to check them otherwise.

I don't think any of the caps were ever revered when installing them. I'll have to wait till I get my multimeter back to check the caps, but thanks for the suggestion, this may give me some clue as to whats wrong. Do I need the PSU hooked to the board when testing this? Also, I have made sure the solder joints are done much better this time around. And I don't see any splatter that would cause a short. Is it possible some of the caps were ruined by getter too hot in the soldering process?

[Toasty]

Re: No post with selectivly recapped P4MA Pro

>>Do I need the PSU hooked to the board when testing this?<<
No! Absolutely not!

>>Is it possible some of the caps were ruined by getter too hot...<<
Anything is possible... Likely? Not.

>>...VRM MOSFET's, they all look fine. I don't know how to check them...<<
We'll go through that when you get the meter back.

[PCBONEZ]

Re: No post with selectivly recapped P4MA Pro

There is a sticky thread in here somewhere that covers how to check MOSFETs.