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SONY AE1C intermittant green-color HELP

Hello,

I have a 16-year old ;) SONY KV-X2531D (AE1C-Chassis) set which has been repaired several times already but still doing tough so far. Now it has started to drop green-color intermittantly meaning that it comes back after certain circumstances. I have made the following observations/measurements so far:

Green drops in normal reception-mode giving the picture a red tint but picture visible, turning set into StandBy and turning it on again will sometimes bring the green back but mostly screen will just remain black (slight raster visible though). What really puzzles me is that activating videotext works (i.e. I get the text-picture) with green-color missing. But normal reception or OSD (green) does not show up (I'd expect the video also to appear with green missing, but video is just black and videotext with green missing). I cannot influence the color-dropping mechanically which would probably unveal dry solder joints.

Anyway, I checked the voltages on the CRT-neck board:

- 12V from video-board is okay

- R,G,B from video-board measure around 12V AC

- R,G,B directly on CRT-neck measure 280 (R), 350 (B), 480(G) AC-V

So has anyone any suggestions ? I suppose this must originate somewhere on the video-board, since all video generated by the set itself works (except for green missing thus no OSD/videotext with no green) but external sources (tuner/AV) do not.

Best Regards,

Adrian

Reply to
Adrian Glaubitz
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they they are very good with TV's.

Good Luck

Reply to
Boba

Hello,

Hmm, but I checked the voltages of all colors and they seemed to be okay, didn't they (all read about 12V AC).

Yes, thats where I already poked around but didn't find anything (at least cooling down with cooler-spray did not change anything). Databases say, that either jungle IC may be bad or one of the XTALs. I have now acquired the appropriate schematics for AE1C, I will check all the voltages and scope-diagrams on this board and compare with the references in the schematic. But what do I do when I find one voltage/diagrams to differ from the schematic ?

Thanks,

Adrian

Reply to
Adrian Glaubitz

Hello,

well, the set is pulling me a leg. Once I was about to start to check the voltages on the video-board, the picture turned back to normal while on without me even touching it *aaargh*. But I have resoldered many suspicous joints on the mainboard (D-board) including GND-connectors. The video-board had not any bad joints visible (it has small parts on it only). If the problem will come back, I will have to check the jungle-chip voltages and the clock-signal from both XTALs.

Regards,

Adrian

Reply to
Adrian Glaubitz

Hi,

Hooray !

With the help of the Service Manual with schematics for AE1C, my DMM/Scope and freeze spray I finally found the one to blame ;). I traced the luma-signal up to the jungle-IC (TDA-4580/IC301) and up it to the latter it was okay. But the RGB-output of it was not ok. So I gave the jungle-IC a breathe of freeze spray with the set being on and a video signal connected and voila - the picture turned back to perfectly normal. After short period it would turn black again, so the jungle-IC is bad. I could reproduce this behavior any time and I also found some other posts with "NO PIC->REPLACE TDA4580", so I'll give it a try.

I already bought replacement online and will have the IC (28DIL) be replaced by an professional technican at my work in university (I simply pulled out the B1 video-board), as he has a profesional rework station (as opposed to my soldering iron bought at Home Improvement ;)). I'm looking forward, whether this will fix it. I will post the results anyway.

Regards,

Adrian

Reply to
Adrian Glaubitz

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