Re: Trio 9R-59D restoration
I's day that it really is worth getting to the bottom of the intermittent problem. Putting some switch cleaner on the rotary switches may well help.
Replacing the dial bulbs with leds - perfectly possible - but do you really want to? There's something attractive about incandescent lighting in these older receivers! But there are many ways of replacing the bulbs. It's probably worth using a bridge rectifier to generate the dc from the original bulb supply together with a series resistor to limit the led current (trial and error). No real need for any smoothing (but it can be added) because you will end up with flicker at 100Hz which you can't really see. You can also put 2 leds in parallel (anode to cathose and cathode to anode) with a series resistor - the leds (which are of course diodes) will do their own rectification.
A marker oscillator is really useful. When I first acquired this receiver (ages ago when I was a teenager!) I did the modification mentioned in the manual (I think), adding a 1MHz crystal. It adds a lot to the functionality of the receiver. I can dig out the details if you don't have them available.
It's a nice piece of kit. I used it for ages as my station receiver. It's nice to have it going again!
Best wishes
Des
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