I am happy to help whenever I can, James.
I was able to get the first set of Sender Resistance Tests reviewed today with my now nicely calibrated RCA VoltOhmyst VTVM, after letting it warm up and stabilize for half an hour.
On the first go back on 10 April 2022, 18 of the 72 tests in this set came back noticeably off specifications and/or ‘odd’. Of those 18 reviewed today, five now came back on specification and the others were noticeably lower in value, or unchanged. So roughly 30% of those 18 readings are now resolved and the rest will need to be investigated.
The Socket for Valve V1J (an ARP-3) has half of its terminals hidden behind the Microphone Transformer T2A, which forms part of the V1J Grid Circuit. For the 10 April 2022 testing, I had chosen to test the V1J Socket terminals from the top, and the probe pins felt a bit too sloppy in the holes, so this time, I decided to remove the T2A Transformer from the lower rear chassis wall of the Sender. This is easily done, as it turns out, by simply removing the two sets of hex nuts and lock washers, as shown in the attached photos. I just let it hang carefully on its leads until the tests were completed from the bottom side of the V1J Socket and then reattached the T2A Transformer to the chassis.
Now onto rechecking the suspicious results for the second test.
David
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