Some electrical equipment on WITHOUT the master switch ON?

[cessnadriver]

JAG. Thanks for the reply. My 1965 C337 is SN: 0200. I can get a picture of the solenoid BUT I've already removed the wires from the bottom posts? If you check the BATTERY CIRCUIT and/or Charging system schematics for SNs 001- 0525 they're the same. Cessna changed the part number and type of the solenoid, ie, from S1578 ( SNs 0235-0525 I think) to a newer PN is S-1580-1 which has been superseded several times since (But they are basically the same type). My worries are that moving the "generator" wire to a fuse from the Positive side of the solenoid to the load side may affect the RUN/STAND-BY switch? LET ME KNOW IF YOU STILL WANT THE PICTURE??
BILLS

[JAG]

Hi Bill,

Since you already disconnected the wires - no need for the picture. I will go to the hangar tomorrow and take a picture of mine - so that we can compare. I will look at wiring diagram tonight. Likely back to you by tomorrow afternoon.
Jeff

[cessnadriver]

JAG-Many thanks for the assistance! I look forward to hearing from you again. ALSO I see you're in Texas-where? I went to High school in Ft, Worth, TX, many decades ago!
BILLS

[JAG]

Bill,

Here is a snap shot of your wiring diagram. Is this how it was wired before - or does this reflect how you have moved the generator wire now to the other side? The four posts on the older solenoid, was simply a way to get the standby power to the system when the master was off - solenoid relaxed.

This is a very strange problem - then again, electrical issues are always a challenge. Are you able to check to make sure the diode on the positive side of the solenoid is working?

Jeff

[JAG]

Bill,

Yes, if you move the generator fuse wire to the downstream side of the master solenoid, it will impact the standby/run system, as it will no longer be connected directly to the battery. For this system to work right, it needs to be direct to the battery (should you ever require it).

I am located in Houston, Texas. My aircraft are based at Fair Weather Field, TX42, just west of Houston.

Jeff

[cessnadriver]

JAG. Yes my solenoid WAS wired the way the schematic shows. So IF the diode is bad do you think that's how the power is getting through? How is the diode checked? I'm thinking there is a special selection on a Multi-meter??
Many thanks, Happy Holidays.
BILLS

[JAG]

Bill,
Somehow, you are creating a ground with your lead tester, and if that diode is bad, it could be closing the solenoid. I am having a difficult time though now that you tell me yours was wired properly in the first place...

Yes, a good multi-meter will have a diode checking capability. The setting usually has a symbol of a diode - and you use that to check to see if it is working properly.

Jeff