Thread: Bush TV22 Mk 1
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Old 16th Jan 2017, 10:31 am   #49
Voxophone
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Join Date: Oct 2015
Location: Sunderland, Tyne and Wear, UK.
Posts: 340
Default Re: Bush TV22 Mk 1

I did more testing on the TV22 over the weekend and managed to get a signal through using the method suggested.

The problem which prevented it working initially seems to have been the contrast control on the r.f. deck. When taking voltage measurements I noticed that the cathodes of the first and third EF91s were measuring more than double the Trader voltage. Since the contrast control is in the cathode circuit I tried turning it, and found that at one extremity the correct voltages were restored and interference could be heard from the speaker. I’ll have to examine the contrast pot again to see what the problem may be.

With the above problem discovered, I was able to get tones from the speaker and lines from the CRT using the sig-gen, and to confirm the operation of the tuner despite the missing knob. The various picture controls seem to work mostly ok, however I noticed that as the height control is moved towards its upper extremity a low frequency mechanical sound can be heard. At one point I also heard a spark but did not see where it came from. Can anyone shed any light on what might be causing this?

All wax capacitors have now been replaced on both decks. Aside from figuring out the contrast problem and replacing the brightness and volume pots, it seems there is little more I can do now until I can get hold of an Aurora.
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