Tektronix 7D14 Fix-Up Part IV - Relay Switching

 

To continue where I left off, I still have not arrived at a resolution but have come to a certain stopping point and wanted to write up the results so far and not leave this hanging. Since my last comment, further analysis/testing was done on the relay switching "logic" focusing on the voltages taking the following steps:

 

 

 

 

 

 

 

Here are the voltage measurements based on the AC/DC and INPUT SENS switch settings:

 And, for reference, here is the pin-out for the  SPDT and DPDT relays:

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.

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.

Stay tuned.