Under/Over Voltage Sensor

hharney · #1 10-20-16, 09:01 PM

My model 1968 C Skymaster has a Under/Over Voltage Sensor that is located behind the throttle quadrant. This unit is suppose to sense High Volts and Batt Discharge situations and then lights up a light above the Master Switch. Mine hasn't worked for a long time and I was trying to get it back on line. I have two other units that are "as removed" from Skymasters but can not get either of those to work either.

Has anyone had any experience with this unit? There is a board with resistors and transistors also a capacitor. I tried my board with another capacitor and nope.

See the attachments for info

fsnewton · #2 10-21-16, 01:02 AM

I'm guessing you did an ohm check for all the resistors? Could very well be a friend resistor that opened the circuit.

pilotpat · #3 10-21-16, 06:00 AM

Any chance there is no power to the circuit, like a broken power or ground wire somewhere? Would be consistent with no unit working.

hharney · #4 10-21-16, 07:06 PM

There is power to the unit as the light does glow dim. There are pots that can be adjusted for calibration but no luck trying to use those.

I will check with Craig to see if he ohmed the resistors

Thanks guys

DrDave · #5 10-22-16, 03:02 AM

Herb:

The most common component in that schematic to fail is the capacitor (C1). These are inexpensive foil caps that tend to leak.

Dave

hharney · #6 10-23-16, 03:48 PM

Tried a different capacitor off one of the "as removed" units on my unit and it did the same thing as my unit was doing. Any ideas where a person can get the capacitor?