CurtPalme.com Home Theater Forum

[benny]

Hi folks,

I have a mate who has a NEC 9PG Xtra that for the last 6 months or so has intermittently been reluctant to lock onto memory blocks that have been solid for years. It now simply brings up the "unregistered signal" condition when the HTPC he uses settles on the normal desktop resolution ( 1280x720x50Hz).

Thinking it might be a dodgy cap , I've replaced C5033 which hangs off pin 20 of IC5004 ( on the deflection board ), but the condition still exists.

Any other pointers as to where to look next for the cause ?

Thanks in advance

Russ

[jarseneau]

My nephew's 6PG does that. I reseat the system board a few times and it works again for a while. I haven't had a chance to investigate further.

[benny]

Thanks Jerry ... worth a try I guess.

Any other ideas out there ??

Cheers,

Russ

[CasetheCorvetteman]

My 9PG Plain was doing that on almost all signals that werent 1080i, because the pots up the top right of the def board have been moved, but i doubt that is your problem, what i would look at though is the caps around those pots at top right, that is where mine were leaking. the Rubycon caps seemed to all be fine, but the other brand caps were leaking, also leaking on the system board were the 16v 100uF caps, the short ones, and same ones on the point convergence board.

Those leaking caps killed my point board, and im reasonably confident they killed AussieAl's system board ( which lost the phase menus, and hence cant be converged on the right side of the screen ) so id check all those, and if your set still has those short 100uF caps, id replace them before they start to leak.

Ill go and left the lid on my 9PG and see what numbers on the caps on that def board to give you something to look for, not certain if the XTRA def board will have the same numbering though.

[CasetheCorvetteman]

C064, C017, C018, C019, C026, C030, C068, C059, C016, C063 were all replaced on my def board all the Nichicon brand caps were leaking, and it wouldnt lock onto anything after only a couple days. Its been fine since i replaced those though.

[benny]

[CasetheCorvetteman]

No worries mate, hope it helps you out

I dont know what youll find there, but its sure worth a look!!

[benny]

Happy to report my mate's Xtra is now back in the land of the living

I passed on the list of caps that might have been the cause and his son replaced those together with a few more adjacent. Upon firing up the PJ it didn't lock onto any of the existing mem blocks so paid him a visit.

I purged all mem blocks except one that I created yonks ago that basically had all the alignment/convergence setting at zero/neutral, and proceeded to build new mem blocks from scratch. Many hours later everything seems stable and my mate is a happy chappie once again!

Only outstanding issue is that now when the PC that feeds the projector switches from one desktop res to another, the projector shows a lightened reddish blank screen that shows the retrace lines vividly. I recall seeing this, and curing it, years ago, but for the life of me I can't recall what the fix is. If someone knows off the top of their head it will save me an extensive search back through the archives. I think it's probably related to the default Kelvin setting somehow, and there was a particular sequence of saving that needed to be performed.

Cheers,

Russ

[macgyver655]

[benny]

[benny]

[benny]

Quick question:

would a 6PG Xtra system board ( PWC-4045 ) work correctly in a malfunctioning 9PG Xtra ( with a PWC-3964 ) once the 3 ROM are inserted from the 9PG Xtra?

Ta

Russ

[CasetheCorvetteman]

I wonder if that big 1 farad cap is going bad or gone bad on that system board?

[benny]

[CasetheCorvetteman]

I doubt they would put in such an expensive capacitor for that sole purpose of keeping time and date only. A lithium battery would have done that job for alot less cost. They may have though, i dont know.

I could be wrong and probably am, but i dont see them using such an expensive option for a clock that is not critical to the operation of the set.

Being that it is on the system board and that is where the signal entry data is stored, id have to think it would be related in some way. most arcade video games use a 1 farad capacitor to store settings and high scores, and in my experience will store it for a very long time, my machines stored saved high scores for over 4 years of storage with no use. That cap will hold a charge for WAY longer than a few days or so with no power.