[ARC5] SCR274 field test

[J Mcvey via ARC5]

sure, here is what i found to be the mysterious problem with the deselected PA activation;
It was a "mia culpa" stemming from the modification of the select relay to a 14V "ARC type" .The replacement was slightly larger because it was a DPDT . The unused contact was very close to where the bottom case "nut" is aligned, so when the bottom was on, enough contact was apparently made to short it to the case. When the wiper ,which was connected to the cathode, was in "deselected" position, it would once again be connected to ground. The problem was only present with the bottom installed!!! There was no "feel" that anything was touching when I put the bottom on, nor did the relay look disturbed. It was the perfect storm and this is why it drove me crazy!

My solution was to slightly elongate the mount holes to push the the mount position away from the bottom case nut area. I also bent the unused contact out of the way for additional safety. All is well...It's always the stupid stuff that's the hardest to fix.
 


     On Sunday, July 19, 2015 6:21 PM, AKLDGUY . <neilb0627 at gmail.com> wrote:
   

 > Someone asked if I resoled the deselected Tx  current draw problem. Yes, I
> described my findings in that thread as I always do if I have any. We are
> all here to help and learn things along the way, so if a solution is found
> it should be shared with the group. Unfortunately, this is NOT the case all
> too often in many forums. I try to be part of the solution rather than part
> of the problem...

I'm sorry that I raised that issue again, but I did not see any post
describing the resolution. I watched carefully for one because I was
very interested. Perhaps the post was sent only to those who had most
recently replied to you and you didn't cc the ARC-5 list.

I would be very grateful if you would post a quick explanation.
Thanking you in advance, I know it's an inconvenience to do it again.

73 de Neil ZL1ANM