CurtPalme.com Home Theater Forum

garysorenson · Posted: Fri Oct 17, 2008 7:27 pm Post subject: Always tweeking my NEC PG9

Why is it that every time I turn on my NEC PG9, I have to tweak the point convergence. And on my Sony 1030 Ive set it up once and its remained in perfect convergence for 2 years straight.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Change the caps on the convergence board, i bet it stabilizes. happened with my marquee.

Athanasios

Mr. Green · Posted: Fri Oct 17, 2008 7:52 pm Post subject:

I have to tweak mine all the time too. I can usually go one or two sessions without tweaking it.

caps? If it's basic soldering, then sure, but anything more complex than that and I'd be worried about damaging something.

garysorenson · Posted: Fri Oct 17, 2008 8:10 pm Post subject:

how easy is it changing the caps, and witch ones do i change

garysorenson · Posted: Fri Oct 17, 2008 8:13 pm Post subject:

Could this be the real super high pitched whine that is from the bad caps?

Mark_A_W · Posted: Fri Oct 17, 2008 9:44 pm Post subject:

Mark_A_W · Posted: Fri Oct 17, 2008 9:46 pm Post subject: Re: Always tweeking my NEC PG9

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I have never heard of caps whining , I bet that whine could be a HV leak some where or a bad fan maybe?

For caps swap just get a high quality cap I like the panasonic FC and FM series, get the same value but you can go up in voltage.
so if you have 10uf 25v V cap go to a 10 uf 50 or 100 V cap. Som of the higher voltage caps dont come in the FC or FM series,
i also use the cornell dubilier sek or sxe i think cant remeber for sure on the sxe.

Athanasios

Mark_A_W · Posted: Fri Oct 17, 2008 10:11 pm Post subject:

There is a known issue with an undersized filter cap on the deflection board (where the powersupply connects). It causes a transformer or something in the powersupply to whine.

They fitted a 47uf cap instead of a 470uf one. It's right next to the PA connector (front middle, big bugger), and it needs a Low ESR cap replacement.

I cannot help with which caps to change on the C drive, but I would be checking setup and adding cooling fans first.

kschmit2 · Posted: Sat Oct 18, 2008 2:38 pm Post subject:

one important question:

When do you tune up the point convergence?

If you do that right after powering up the PJ, it won't be good.

You should do it after a movie or so, before you power it down.

Also, I would recommend that you reset Point Convergence, and first touch up normal convergence. Once that has been touched up as good as possible (should be good down to at least a max of 0.5 line width using the internal test patterns), go to point convergence and touch it up.
You may have to do that 2 or 3 times (on different days), but then the PJ should be fine for about 6-10 months depending on how stable the ambient temps in your theater are

lostmandan · Posted: Sat Oct 18, 2008 4:30 pm Post subject:

I believe this is the mod:

http://bomrat.org/hometheater_website/10pg/keystonemod/keystonemod.htm

I ran across this URL but I have not done this mod myself so your mileage may vary.

Also I have read numerous posts stating that the power supply filter capacitors for this B+ rail could also be aging and not filtering as well as designed therefore they should also be looked at. An ESR meter would be a good tool to check them.

- Dan

Mark_A_W · Posted: Sat Oct 18, 2008 8:50 pm Post subject:

Yes, that is the mod.

I've done any number of Xtras now, it fixes the whine 100%.

Just don't put the cap in backwards.

Tinman · Posted: Sun Oct 19, 2008 5:49 pm Post subject:

Generally, unstable convergence is caused by A Smile

sloppy mechanical setup and B Smile

the small caps on the WAVE board. As I discovered on my last PG9. It always needed touch up. I re-capped the wave board and it became completely stable. The caps were leaking, so that was my first clue.

I'd start by looking at the wave board capacitors. If you can see ANY greenish or dark crap on any of the capacitor leads, re-cap the board. There aren't many on it.

Marc

stefuel · Posted: Sun Oct 19, 2008 6:06 pm Post subject:

If the projector is mounted perfectly, you should be able to get perfect alignment without the use of point. Point is for cheaters. The less point you use the more stable it will be.

wallace123456 · Joined: 14 Aug 2006 Posts: 2236 Location: Northwest VA area

**AnalogRocks** · Posted: Sun Oct 26, 2008 5:48 am Post subject:

Electrogeek · Posted: Tue Oct 28, 2008 10:39 am Post subject:

hi, you say something about an HV leak, what would one do about such a leak, when my SONY VPH 1020 has no video input it screams like nothing on earth, and if the room is dead silent with a video input you can hear the faintest high pitch whitle ideas?