1. Home
  2. Electronics Repair
  3. Philips Widescreen TV EM1.2UAA / 30PW850H37A

Philips Widescreen TV EM1.2UAA / 30PW850H37A

Hi , any TV repair folks help out here.

This widescreen TV had a flashover, took out the red output on the TDA6108JF Video Output Amp on the crt board.

I bought replacement chip and fitted it, now instead of a bright red screen with flyback lines I get a very bright white screen reduced in size with flyback lines.

Previously I had Vin of 2.8Vdc, Vout(Cathode) 139Vdc on the dud chip (remaining working parts) Now I have 0.8Vdc input and 18Vdc output (Cathodes)

Black current measurement output pin 5 old chip 0.8Vdc, new chip 7.5Vdc

I don't have a schematic, any ideas where to buy ? I'm not in the TV servicing business anymore, prefer watching them than fixing them but this is my own TV and I guess I have to fix the sucker.

I don't see any adjustments in this set, is there anything I need to do to set up/ recalibrate the black level? Isn't this automatic on these fangled new sets? Is the new chip duff? It did arrive in a polybag, guess its not that static sensitive. Nothing else reads as out of spec and using the duff chip, disabling the red output and shorting the red and green cathodes at the tube gives a reasonable picture.

TIA for any help,

JC

Reply to
Archon
Loading thread data ...

OK, No matter, fixed it, new chip was duff, wtf, lucky I ordered 2.

Reply to
Archon

Are duff chips a common problem? I recently bought a frame output chip for a Hitachi TV that was shorted across two pins.

Reply to
Graz

In looking ahead, to answer your question I myself have had bad IC's that were new.

Because the drive IC had to be changed, it would be a good idea to see if there is anything unusual that could have caused it to fail in the first place. I have had everything from a CRT that arcs intermittantly to components becoming defective in the circuit area that works with the IC.

Jerry G.

--

Reply to
Jerry G.

For parts to be defective from new is unbelievable, this was a Philips part made in Thailand from a reputable parts dealer. Where is the quality control? God help us when they start making chips in china.

From researching this fault on the web it seems this tube/tv has a history of flashovers and early tube failure. Flashovers usually occur when switching from cable input to component video. In fact this is the third flashover that I have seen (heard) on this, the chip surviving the previous two. I have seen modification bulletins for other brands using the TDA6108JF involving extra earth bonding between the CRT board and aquadag/tube bonding but on this crt board the amount of ground copper is almost nil. In fact the board is of such poor quality the tracks lift as soon as they see an iron, very bad for Philips but typical of the decline in quality of domestic electronics, one reason I got out of the TV/video repair scene in the late 80's and went to medical/test equipment servicing where quality was still in evidence.

Reply to
Archon

In the field I work in now, test equipment/medical no, but domestic repairs I couldn't say. I did replace the Lopt in a projection TV along with all the associated stuff that fails with it and that lasted only 12 months where the previous had run for 10 years without problem. That got binned, just couldn't be bothered with it.

Reply to
Archon

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.