CurtPalme.com Home Theater Forum

[gjaky]

The failure of the deflection board due to overheating is probably the bigest problem with the NEC PG sets. The combination of wide raster settings and high scan frequencies are often resulting a premature failure of the deflection board. Adding fans to the heatsink of the deflection board has long been known, I did this too. However I noticed that while the heatsink is kept cool by the fan I barely can touch the plastic case of the horizontal output transistor because it's so hot, even at moderate scan frequencies (~60kHz), then added heat conducting grease to the original silicone insulator, but that didn't help much. So I changed the original (yellow) insulator to a ceramic insulator as they conduct heat much better than the silicone insulators, for this, however, you MUST use a thermal grease, so less convenient.
But the end result was that even at 92kHz scan frequency the plastic case of the horizontal output transistor was barely warmer than the heatsink, so I think this is a cheap solution to reduce the chance of overheating.

[CasetheCorvetteman]

I found my convergence board ran very hot when using a large raster, but it still stayed dead stable for over 3 years. It got so hot you couldnt hold your hand on the base of the projector in that area.

I was using most of the tube face and near zero keystone, put about 7,000 hours on it with no visible tube face wear on green, it does look to be very slightly darker than red and blue, but no outline can be seen.

[gjaky]

[CasetheCorvetteman]

Yours being an XTRA may not suffer so bad as my plain did, i was going to heatsink the base too but the machine is currently decomissioned, it worked right up til it was taken down, but the convergence board failed after about 20 minutes the next time i set it up, it shut down right in the middle of a bank robbery on my Lethal Enforcers arcade machine...

[gjaky]

[Nashou66]

I think it is good practice to clean and replace the thermal compound every couple years. On my Marquees when i first got them I had to take one of the rear heat sink boards off and removed them all and cleaned and put new thermal compound. That PJ drifts much less now and the heat sink is hotter than the other PJ by 10c. I need to do the other one too.

Nashou

[CasetheCorvetteman]

Gábor, it was a board failure, i put another one in and it was back up

[gjaky]

I played with the pj a few hours yesterday and to me it looks the focus board runs hotter than convergence, in fact the convergence board is not so hot to touch.

[CasetheCorvetteman]

They were both hot in mine, convergence board more so, took a great amount of correction in the corners with all that tube face.