CurtPalme.com Home Theater Forum

[thelasernut]

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After several years of watching films on my BG808s and wondering why it sometimes switched itself ON or at other times, when switching inputs on my receiver or pausing my VCR, it would lose the picture but still remain switched ON - I have just watched two films which caused the screen to go blank all of a sudden.

For background information I generally have Contrast at 60 with Brightness at 50 for PAL or around 25 for NTSC with raised Black Level. This gives me a reasonably bright picture on a White painted wall for DVD etc but it's quite obvious that Bluray discs are a fair bit brighter than most DVD's however the pictures are fine so I dont bother to turn the Contrast down. At the same time I can wind the Contrast up to 99 and I get a brighter picture that doesnt flair or have significant problems so it seems reasonable to assume that the EHT PSU can supply adequate beam current to the CRT's.

Now what happened in the two films was sudden scene changes that involved a high brightness cut to white or a flash - in both cases picture loss occured at the point of the bright scene and the PJ needed to be turned OFF and then ON to restore the picture.

I was a bit suspicious that the CRT protection circuits had been triggered by the peak white screen so I tried repeating the scene with a lower contrast setting and found that 50 would take the scene without picture loss - albeit with a lower level of brightness than I like to see.

So my question has to be - Why does a sudden and short lived white screen cause shut down - when it's possible to turn up the CRT Contrast and hence the CRT Beam Current to a much higher level for a longer term without invoking a shut down ?

I would have thought that a transient white screen - even at a higher level from the apparently brighter Bluray Disc - would have been permitted in the PJ without triggering protection ?

[gregstv]

Have you checked the 17v rail?

[Curt Palme]

You have a bad quad most likely.

Check to see if the red light is on on the EHT board. If so, then you have a bad quad or maybe an HV splitter. No way to check them without swapping them. I've got stock of both.

[Curt Palme]

You have a bad quad most likely.

Check to see if the red light is on on the EHT board. If so, then you have a bad quad or maybe an HV splitter. No way to check them without swapping them. I've got stock of both.

[HaydnG90]

VCR? Whats that?

[thelasernut]

"VCR? Whats that?"

VCR = Video Cassette Recorder, or in my case = VHS tape replay for Films that I haven't yet found on Laser Disc or DVD or BluRay