27-11-2015, 04:54 PM
O.K., glad to see this thread hasn't been closed while I've been away. There have been developments in the HMV project that took me by surprise. It is actually now working and picking up lots of stations. In fact, not only is it now working as it ought to be but it's working extremely well, in terms of tone and audio. And, of course, I'm very happy about that as you can imagine. The only thing I ought to add is there is still a band (or two) on the waveband selector switch that are rebellious. However, Longwave was very lively and I was picking up Spain last night on my boat as clearly as you'd get a local station.
How did I get to this point? Basically it boiled down to 2 capacitors that I changed - one being in the grid circuit of the Double Diode Detector. This one was an audio coupling capacitor. I used 10 Nanofarads for the replacement.
Another development was what I found to be a miniscule short circuit in the system. This was barely visible and was only revealed after cleaning more wires with WD40 and cotton buds (as I do). You could then see tiny strands of wire projected through insulation but these had probably made contact with nearby joints. The serious swearing and cussing then began when I found there was no access to re-solder new wire so I had the job of manually insulating the wire with electrical tape + a dab of superglue. I couldn't get my hands in the gaps to wrap the wire which led to major frustration. Likewise soldering in the new capacitor where access at the rear was extremely awkward.
On powering on, I noticed lots of stations were coming in when tuning the V.C. but also a marked increase in speaker volume. Audio quality was very good indeed. I boiled the kettle and was unfortunately subjected to a speech by David Cameron.
At night I turned off all my ceiling lights and got onto Longwave. Spanish language reception was awesome and many other stations were picked up.
So, there you have it. I'll comment in my following post.
How did I get to this point? Basically it boiled down to 2 capacitors that I changed - one being in the grid circuit of the Double Diode Detector. This one was an audio coupling capacitor. I used 10 Nanofarads for the replacement.
Another development was what I found to be a miniscule short circuit in the system. This was barely visible and was only revealed after cleaning more wires with WD40 and cotton buds (as I do). You could then see tiny strands of wire projected through insulation but these had probably made contact with nearby joints. The serious swearing and cussing then began when I found there was no access to re-solder new wire so I had the job of manually insulating the wire with electrical tape + a dab of superglue. I couldn't get my hands in the gaps to wrap the wire which led to major frustration. Likewise soldering in the new capacitor where access at the rear was extremely awkward.
On powering on, I noticed lots of stations were coming in when tuning the V.C. but also a marked increase in speaker volume. Audio quality was very good indeed. I boiled the kettle and was unfortunately subjected to a speech by David Cameron.
At night I turned off all my ceiling lights and got onto Longwave. Spanish language reception was awesome and many other stations were picked up.
So, there you have it. I'll comment in my following post.
