I am resurrecting this thread not because I have arrived at a resolution but rather because I have come to a certain stopping point and wanted to write up the results so far and not leave things hanging. (A long time ago, when I came aboard, this advice was passed along with the advisory to do so in order that others may benefit.)
Since my last comment, further analysis/testing was done on the relay switching "logic" focusing on the voltages:
(1) Ran unit for about 2 hours.
(2) Failed somewhere in that time frame.
(3) ALL relays were hot to the touch - even K103, K152, K252.
(4) Removed relays K106, K100, K101, K103.
(5) Checked voltages on the appropriate pin of each relay.
(6) "High" voltage was correct, i.e., +15 VDC.
(7) Voltage appeared correctly on relays per AC/DC and INPUT SENS switch.
(8) After checks done, the relays had cooled.
(9) They were re-inserted and unit powered up again.
(10) Frequency displayed correctly on both CHANNEL "A" and TRIG SOURCE settings.
I have posted this on my blog at the URL below along with pictures and the resulting measurements:
Attempting to represent the measurements here would be chaotic. I apologize for not porting the results to the pictures section of this group; doing so on the blog would make for a more coherent presentation of the testing.
At this point, I cannot explain why the relays ALL are hot to the touch. A friend tells me that his 7D14s' relays do not get hot at all. Since these relays are not commonly available, the only option is to score some from a parts unit and substitute them to see what happens.
Unless someone with direct experience with this plug-in has a better suggestion.
I will probably be evaluating the switching with respect to the signal path. That is, speculating where the signals should be present depending upon the INPUT SENS switch selection, etc.
But that should not cause all of the relays in the 7D14 to be hot to the touch, should it? Therefore, I am led to believe that the relays might be faulty somehow.
Thanks for all the help. If something happens that warrants posting, I shall do so.
--
William, k6whp
"A friend told me to cheer up, things could be worse.
So I cheered up and, sure enough, things got worse!"
k6whp