15-07-2012, 01:02 PM
When I first tried this it worked though wasn't very loud, in fact VHF had to be on full volume to be heard, and was a bit muffled.
The first thing I did was change the grid coupler. This was a waxie but wasn't very leaky so I put the scatter gun away and tested the rest. They were all very leaky.
After doing the output stage MW and LW were fine but VHF was still very quiet. I changed one of it's associated capacitors and a Hunt's which dropped to bits as soon as I touched it and when I check for progress found that VHF had vanished completely and is refusing to come back.
I've tried swapping the Z77s (EF91s) with the ones out of my Jasonkit tuner and the GEC ones work in that but the Jason ones make no odds to the GEC. I'm as sure as I can be that the wave switch is innocent as HT is getting to the valves and noting can be heard where the AF goes into it.
I'm sure I've fitted the correct value caps in the right place, in fact I can still see stumps of wires of the old ones. The obvious conclusion is that I've disturbed something or possibly an ailing component has given up the ghost while I've been working on it - this did happen to me while working on my Pye R33. There is one waxy left which only reads 500kΩ on the AVO but it's a 1µF one and the only things that size I've got are electrolyitcs.
Taking voltage readings on the EF91 bases is impossible as they are buried under passive components in a tin box which is soldered in place, shades of Mullard modules!
What REALLY puzzles me is this. I tried injecting a signal from the E2 into the aerial socket. The modulated tone could be heard very faintly in the speaker but the really odd thing is that twiddling the output frequency brings in stations including Classic FM.
There are still some Hunt's in situ, including one which doesn't leak, but I don't think that they are in critical locations.
I've got other things to keep me amused and coming back to things with fresh eyes often helps. I'm also hoping to be able to consult with the Wise Man or Burton soon and beeing able to see what's what with my new 'scope may also be handy.
- Joe
The first thing I did was change the grid coupler. This was a waxie but wasn't very leaky so I put the scatter gun away and tested the rest. They were all very leaky.
After doing the output stage MW and LW were fine but VHF was still very quiet. I changed one of it's associated capacitors and a Hunt's which dropped to bits as soon as I touched it and when I check for progress found that VHF had vanished completely and is refusing to come back.
I've tried swapping the Z77s (EF91s) with the ones out of my Jasonkit tuner and the GEC ones work in that but the Jason ones make no odds to the GEC. I'm as sure as I can be that the wave switch is innocent as HT is getting to the valves and noting can be heard where the AF goes into it.
I'm sure I've fitted the correct value caps in the right place, in fact I can still see stumps of wires of the old ones. The obvious conclusion is that I've disturbed something or possibly an ailing component has given up the ghost while I've been working on it - this did happen to me while working on my Pye R33. There is one waxy left which only reads 500kΩ on the AVO but it's a 1µF one and the only things that size I've got are electrolyitcs.
Taking voltage readings on the EF91 bases is impossible as they are buried under passive components in a tin box which is soldered in place, shades of Mullard modules!
What REALLY puzzles me is this. I tried injecting a signal from the E2 into the aerial socket. The modulated tone could be heard very faintly in the speaker but the really odd thing is that twiddling the output frequency brings in stations including Classic FM.
There are still some Hunt's in situ, including one which doesn't leak, but I don't think that they are in critical locations.
I've got other things to keep me amused and coming back to things with fresh eyes often helps. I'm also hoping to be able to consult with the Wise Man or Burton soon and beeing able to see what's what with my new 'scope may also be handy.
- Joe
