Quote:
Originally Posted by Heatercathodeshort
The alignment should be OK unless it has been previously fiddled. It will not drift on it's own.
Sound problems are usually due to reduction in value [eventually ending in a burn up] of the resistors associated with the EH90 AF amp 405/discriminator FM valve.
R73 18K R71 5.5K R69 180ohm. This fault will cause a very heavy drain across the HT line.
Other than this a conventional check of the output stage PCL84 and if distorted at low volume, the loudspeaker. J.
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Hi John,
Thank you for the information. When I did the original work on this set back in the summer, I checked every resistor on the PCB. I find it helpful to follow the circuit diagram and trace out what is actually on the board (or chassis) checking component values as I go. It takes a while but I find it enjoyable and also get me familiar with the circuit and layout! All the resistors, almost without exception were exactly 20% high. Strangely, several 'stock fault' resistors which I expected to be high, were spot on- rather strange!
As they were all 20% high, I didn't change any of them
I wonder why the resistors you mention would go low in value?
I've not focused my attention on the sound yet, but as Edward points out, it does have a really 'tiddly' speaker which may not be any good.
I'm surprised they fitted such a small one as the rest of the set seems very well designed and built.
Certainly, we got 20 years out of the one we had when I was a kid, although dad did have to repair it quite often towards the end!
I would be really interested if anyone has any sales literature for this model.
Many thanks
Nick