Well, its not easy to say!
After making the initial modifications, that is, removing the crystals and the switching board, and disconnecting the Tx power paths via the Tx/Rx reed switches, I found I wasnt getting any response from the unit! I had a bit of initial success but that soon tapered off! I also noted that I didnt seem to be drawing any current.
It does seem to be though that these problems were due to the somewhat too large for the available space crocodile clips I was using to connect power. After swapping the croc leads for soldered on flying leads, ive had repeatable success, although sometimes seemingly different results for the same tests! Good, measurable currents, and plenty of audio.
Before I can go much further though I have to sleeve the newly created soldered connections for the transducer and power wires, so these cannot short to anything. I also want to remove the battery housing (which means breaching the seal where the power wires go through - not a worry as im not going to be immersing the radio in salt-water!) in order to get to and identify the battery terminals.
The next thing then is to connect a temporary antenna feed from the Marconi 2955 and test the receiver stages with real AM signals! If all is well, then its time to look at retuning.
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