Quote:
Originally Posted by Vectis68
I have no background in electronics and this is my first attempt at restoring a valve radio.
I have a Bush VHF61 that I have recapped (both wax and Hunts capacitors) and I am able to tune stations on both MW and VHF (long wave is quite poor, but that might be due to the lack of a decent aerial at the moment).
The magic eye closes fine on medium wave but not so on VHF, it flatly refuses to change on the ten stations that I can pick up here.
Can I have some pointers please as to what I should be looking for?
Phil.
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Hi Phil, I'm assuming you have the circuit? Going by the Trader Sheet 1301 the grid of the magic eye (shown as TI...Tuning Indicator) is driven from the AGC rail on AM via S18 and from the discriminator on FM via S19. It would be worth cleaning the switches first which are part of the wavechange switch (if you haven't done so already). As suggested already, check that electrolytic C56 which is in the DC reservoir circuit. If this component is faulty (quite likely) there will be insufficient DC developed and the eye will not operate correctly or at all. Usually if this component has completely failed it will cause distortion on FM. Don't forget this capacitor goes
positive to chassis. It's shown as a 5uF. The modern replacement will be 4.7uF. Choose a working voltage the same or higher than the one fitted.
If you can receive 10 stations then the ECC85 seems pretty healthy but still worth trying a new one.