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Old 9th May 2011, 1:46 pm   #27
Join Date: Jun 2009
Location: Royston
Posts: 116
Default Re: Help with a HMV TV

I pushed the send button too early!!!

I have tried three NOS DY86's (1S2) and three EL36's (6CM5). All high value resistors are within 12% of values. All waxies and electrolytics have ben replaced. Externally, I put 1.4V to the DY86 and it does glow with a similar amount as the one in the set. The "boost" vlotage which says it sould be 650V is 450VDC with 150VAC superiposed on it. The 400V line that goes to pin 3 is 280VDC and quite well smoothed with a 0.22uF cap (new), but low of course.

The EL36 (6CM5) has the following voltages:
Screen is 165V, circuit syas 150V
Grid is -33V, circuit says -32V
Cathode says 0.13V, circuit says 0.14V.
This valve gets really really hot!

HT1, HT1A annd HT2 rails are quite close as stated earlier.

All the wiring around the LOPT has been checked and put back the same as the circuit diagram.

I haven't tried another EY88 (6AL3) yet, but this was NOS.

The cathode of V8 ECF82 (6U8), in the AGC\contrast section is 60V and the circuit says 48V. I didn't think this was related to the low EHT and boost though.

The LOPT does not get warm at all. Someone mentioned it might be time to suspect the LOPT. Is there anyway to test it. Its not getting warm, and does work to soem extent.

Any other suggestions on how to proceed from here would be great.

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