CurtPalme.com Home Theater Forum

[kmascotto]

I picked up a pair of NEC 9PG's from work. One works fine and the other projector powers up, but there is no light output from any of the three tubes. I can see a faint light at the rear of the tubes, which would indicate power to the tubes. I have switched out every board that I can get access to (eg, the three boards between the green and blue tubes, the H and C boards between the green and red tubes and the board that is located at the back of the projector opposite the power supply. Nothing has worked.

Any one have any ideas??

Thanks
Kent

[kschmit2]

tried the PIC MUTE button on the remote?

[dropzone7]

Do you have a source connected to the projector while testing? Also, what Kai said, hit the PIC MUTE button and also try hitting the END button in case it's in some kind of warm-up mode.

[Curt Palme]

Oh, one more thing I forgot:

Try pressing 'ctrl' and 'display' on the remote. That can unlock a function in the set that locks out most of the remote functions.

[Curt Palme]

Oh, one more thing I forgot:

Try pressing 'ctrl' and 'display' on the remote. That can unlock a function in the set that locks out most of the remote functions.

[kmascotto]

Yes thanks, I did try the pic mute and I also had a video camera hooked up...still nothing.

I will try pressing 'ctrl' and 'display' on the remote and let you know if that has any effect.

Thanks again
Kent

[Brooklyn]

Did you try the RGBHV input? Some PG's don't have the expansion card to support the composite and s-video inputs on the front even though they are physically there. On my 6pg though I still get something out of the tubes even with no source.

[kmascotto]

Well I held my breath and tried the Ctrl + Display...

It did not work.

This is really bizarre

K

[Elaine Benes]

Did you swap out the LVPS under the lenses ? What about pushing the "1" button on the remote when an RGBHV source is connected ?

[deronmoped]

No test patterns? No green information text coming up?

So the heaters light up at the base of the tubes, any HV?

I wonder if anyone messed with the G2 pots? You could mark one of them and try turning one up.

Deron.

[kmascotto]

No test patterns, no green, I have not touched the G2 pots but they appear to be in the same location as the other projector that's working. I have not switched any power supplies...was trying to avoid that.

But I have switched with the working projector all items below.

deflection board
F board
c Board
Video board
and the three boards in the cage (between the green and blue tubes)

did I miss a board...or something??

Thanks
K

[dropzone7]

Have you checked that large red G2 wire that runs to the neck board? I think I recall Curt mentioning that if tubes are changed or the machine gets jarred around a lot then this wire can come loose and cause problems.

Take a look at this link which shows what I'm talking about in an XG projector. I'm assuming there is something similar at the PG's neck boards.
http://www.curtpalme.com/NECXG_Layout5.shtm

[Curt Palme]

If you have a meter, measure the voltage on one of those red G2 leads running from the screen/focus block to each CRT socket.

if you get say 20-50 volts, you are missing HV. Normal voltage there should be 500-800 volts. USe a meter that can handle the voltage!

If you see the voltage ramp up towards 500-800 volts, but then drops way down, the set is initializing, but then something is shutting down the HV. you've more or less covered all of the common issues, try swapping the LVPS and any other board you haven't swapped yet.

It's also really easy to 'lose' a screw in those sets. It's rare but possible that a screw has snuck under the motherboard that houses the CPU/system boards. I've had three like that, strange problem, seemingly no reason for the set not to work, then I scrap the set, and find a screw under the motherboard. I scrapped two sets, got smart and managed to repair the third.*











* I blame myself for only one of the three screws..

[Curt Palme]

If you have a meter, measure the voltage on one of those red G2 leads running from the screen/focus block to each CRT socket.

if you get say 20-50 volts, you are missing HV. Normal voltage there should be 500-800 volts. USe a meter that can handle the voltage!

If you see the voltage ramp up towards 500-800 volts, but then drops way down, the set is initializing, but then something is shutting down the HV. you've more or less covered all of the common issues, try swapping the LVPS and any other board you haven't swapped yet.

It's also really easy to 'lose' a screw in those sets. It's rare but possible that a screw has snuck under the motherboard that houses the CPU/system boards. I've had three like that, strange problem, seemingly no reason for the set not to work, then I scrap the set, and find a screw under the motherboard. I scrapped two sets, got smart and managed to repair the third.*











* I blame myself for only one of the three screws..

[Elaine Benes]

I too have had a "spare" screw keep an NEC from powering up. Weird how they always seem to end up under the motherboard...

[kmascotto]

After I check the HV (God...let that be it!!) I will have to ripe that projector apart to get that mother board out...well I have to add an air bubble to all the CRT's any way.

Thank you all! for getting me this far...I will let you know when I get to the root for the problem.

[kmascotto]

Now I have another issue...with the good projector.
I was going through the NEC set up (as shown on Curts site) on the working projector and every thing was going fine, but when I got to the (Test pattern Centering) section I was saving those settings...the RGB input quit working. I removed the DVDO and VCR I was using to show an image through the RGB inputs, and plugged in the composite video to check that input, and it was still working fine.

I switched the Video/RGB/S-video input board located on the front of the projector, with no effect.

Any Ideas??

Kent

[kmascotto]

Well I found the issue with the Working projector... I had to delete the input line that I had created when I was doing the initial set-up and then start from scratch.
K

[kmascotto]

Here is the issue, have measure the voltage from those red G2 leads running from the screen/focus block to CRT socket.
As it turns out I have no voltage...at all. Which I assume means a bad HV...What else do I need to check and what do I need to replace, to get this projector up and running.

Thanks!
Kent

[kmascotto]

If you switch out enough boards...you are bound to find the solution... In my case it was the video board that stopped working.

Thanks for everyones help!