CurtPalme.com Home Theater Forum

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Dear all,

this is about my 10PG, where all boards had been swapped with a 6PGplus. Only the point convergence board is the original one as the donating unit did not have one. The 10PGplus is projecting on a curved screen for a good 2000 h now. Most of the time excessive point convergence correction was applied to green and red. Due to the curved picture geometry and the projector position not beeing optimal I used a compromise resulting in mediocre optical focus throughout the whole screen at maxed out bow and pin balance settings. Point convergence was abused to further extend the downward bow setting.

Those of you who don't go curved probably can't follow and this not about "With good mechanical alignment only very minor electronic correction needs to be applied". I know that.

Since a couple of weeks the picture is flipping when point settings are touched (see attached pic). I found a similar picture on avs also related to excessive point correction. With the point board disabled or settings normalized the picture is stable. This sensitivity of point correction seems to be getting worse. Unfortunately it is not reversible so that now, even at very minor point correction, the flipping occurs. With a cold machine directly after start up it could be okay but after warm up point board is unusable. The system board cage does not have an extra fan (yet) and gets a little warm so I figure the chips inside are really hot.

Okay, so I installed the point board from my spare 10PG unit. Two years ago or so the whole projector had been working okay. But the 10PGplus with the swapped point board still is failing. The picture disturbance looks quite different but with the point board disabled everything is okay again.

So I guess that a broken (overheated abused) original point convergence board ist not the only issue. Right? Of course both point boards could be broken and having different defects. However, I think this is rather unlikely and some other electronics went bad too. None of the point boards has visual defects (leaks) or burn smell.

Any advice where else to look for?

Cheers
hansilili

edit: I should have added the 4 pics in revers order

**Curt Palme** · Posted: Fri Mar 01, 2013 2:01 pm Post subject:

Nice screen! Smile

LEaking caps on the point board, and I'll bet the other boards in teh CPU cage aren't far behind. Chances are there's some traces on the point board that have been eaten away. THere's about a 50% chance you can fix it if you're good at soldering. I personally won't look at it as there's no guarantee that the board won't fail again shortly.

I think I do have a good board here that I'd sell at $100 plus shipping if you can't get that one going.

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

My spare board is supposed to be good too. Would have to reassemble the spare machine to test it though. That is why I ask if the point board is really the only thing to look after.

I am not good at soldering but if nothing else helps I can at least give it a try. It can't get any worse (okay, it probably can) Only first I would like to confirm that this is really what I am looking for.

UNfortunatly no spares for the other system cage boards around, only have plain Pg boards left.

THE PRoJECTOR IS IN A HUSHBOX without the outer case. All fans have been changed for new ones, some added. None yet for the system cage. Do you think the lid on the cage serves any real purpose or can I remove it and add a couple of small fans instead?

**Curt Palme** · Posted: Fri Mar 01, 2013 2:29 pm Post subject:

Take the lid off. Also take the cover over the system boards off. I notice that the later PG Xtras have much bigger holes in the cover than the PG and PG+.

I've only ever seen the point board cause this. Once caps start leaking, they will continue to do so, even if not used. I've put away PG boards in good shape, only to pull them out 2 years later and then they are defective. I've seen this exact picture a number of times, and it's always been the point board.

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Thanks, that's good advice. I will work on cooling and maybe replacing the caps. If somebody would send me the shopping list, that would be great.

The screen is built from a bed frame, Phifer Seerweave and rubber rope. One pic http://www.curtpalme.com/forum/viewtopic.php?p=337172#337172 here and more in this German board http://www.beisammen.de/board/index.php?page=Thread&threadID=108048&highlight= (registration and 10 sensible posts needed for enlarged pics)

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

We ran to a similar problen on my boss' 9PG, we've swapped it to a spare board and it works fine since, so I'd bet on point board only.

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Guy,

this is my PWC-3718. In zhe close up pics I have circled the two caps that were a little wet. On the front they are labled C862 and C856, on the back that's C861 and C859.

At least those two seem to be doable, even for a double lefty like me. Would be good to have a parts list for the whole board though.

will keep you posted
hanslilili

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

As you can see only a dozen electrolytics caps on the board, no list needed, just replace the caps with a same new one. On this board it is highly suggested that cut the bad caps off and solder the new caps on the old caps' legs, because the 4 layer PCB is very sensitive and hard to solder without a good equipment.

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

The PWC-3718 board has 11 caps, 5 x 100uF 16 V , 4 x 100uF 25V and 2 x 10uF 25V (if I read correctly)

gjaki, can you tell a bit more about "4 layer" board? UNsoldering these caps looks rather easy to me, for sure easier than cutting the very short legs. Which tool to use for that? A thin saw blade? Fingernail scissors?

hansilili

**Curt Palme** · Posted: Tue Mar 05, 2013 2:04 pm Post subject:

No, brute force! Grab each electrolytic with a pair of pliers and pull straight up. The leads will pull out of the caps, and then you can cut them down and solder new ones on. Once the soldering iron hits the electrolyte that has leaked onto the leads, you'll get a very familiar (in a while from now) smell that I completely associate with NEC PG sets. Smile

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Zolzar · Joined: 26 Jun 2009 Posts: 252

No need to change the SMDs. I just did 350 caps in my 10PG. I had pretty decent success pulling them up with the needle nose but actually used a set of precision low profile cutters to cut the leads close to the body of the old cap as possible. I will reiterate what others have said and that is do not attempt to desolder any caps on any boards. The only ones I desoldered were on the focus and convergence boards.

I found that at least 100 caps out of the 350 were leaking. Many showed no evidence until they were removed.

Best of luck!

John

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

So

yesterday we soldered together with a buddy. He is kinda experienced or should I say was experienced in the good old times so he said, "Soldering onto the old legs, nah, you just son't do that."

The first two and most suspicious capacitors actually went out quite well. A bit of good will helped but no brute force needed. This action seemed to have been successful, because of the onset of two new caps the board showed exactly the same behavior as before when tested in the projector . Phew, at least we didn't make it worse.

So we ventured to the next 4 candidates. This time there are sitting very small traces closely at the contacts. And unfortunately, this time we were not quite so lucky. After installing the"repaired" board and starting the projector the status of standby LED (Brown) to power (green) changes and you can hear a faint clicking atca. 2 Hz, but nothing else happens. We better should have listend to you guys and leave th eold legs in place. Without the point board however, the NEC running as before.

Without really have a clue I guess on a ground fault, since the click sounded like a fault interrupter. However, the display shows no error message. Ground faults to the newly soldered contacts should be detectable with a simple multitester, right? I will searching next week or so.

sh*t, I would have taken the time to print out the advice from a fellow German HT board member and meditate a bit about it:

hansilili · Joined: 09 Mar 2007 Posts: 302 Location: Köln, Germany

Hi,

while exchanging the 6 caps we indeed fabricated a ground fault. This was identified by a budget multimeter resistance measurement very easy, as it was the only one with 0 ohm resistance! Slight rework of the soldering connection has eliminated the ground fault. So the projector is starting up as before the operation but the point convergence function is still not restored looks exactly like before the cap change

I give up. If you want, I will send the defective board. However, without the expectation of a concrete repair chance.

Please keep your eyes open for a 45 EUR / $60 point board incl. shipping to Germany. Oh, I will be visiting New York in May and could smuggle the board in my luggage.

Thanks
hansili.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

You were warned!! Laughing

Couldve been worse...

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Sure, thats fine, and normally you wouldnt. But in this case, its a nice safe quick easy option that works Wink

**Curt Palme** · Posted: Sat Jun 01, 2013 2:56 pm Post subject:

$100 incl shipping to NY is as good as I can do.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

And thats pretty good anyway Wink