I checked for burnt / out of tolorance resistors in the area around U1000 U1001 didn’t find any
here is what I get on U1000,1001
U1000
Leg 1:voltage is climbing then falling and repeats this
Leg 2: same as leg 1
Leg 3:26.97
U1001
Leg 1:doing the same as U1000
Leg 2:-27.08
Leg 3: voltage is doing the same as leg 1
here is what I get on U1000,1001
U1000
Leg 1:voltage is climbing then falling and repeats this
Leg 2: same as leg 1
Leg 3:26.97
U1001
Leg 1:doing the same as U1000
Leg 2:-27.08
Leg 3: voltage is doing the same as leg 1
If you look at pins 4 and 8 of U3 with your scope, do you see a changing voltage or a steady ±15v?
On pin 4 the voltage is steady
pin 8 I can see the voltage changing and something on the board starts ticking
pin 8 I can see the voltage changing and something on the board starts ticking
There are two 499k resistors near U3. Do you read 0 ohms from one end of each resistor to ground?
If you measure the pin 4-8 voltage on U3 and then probe pin 8 with your scope, does the 4-8 voltage vary?
Do you still see a varying voltage on the scope?
How much is the voltage changing on the scope?
Do you still see a varying voltage on the scope?
How much is the voltage changing on the scope?
Pins4-8 I get 29.55 volts
And when I probe pin 8 the voltage still varies
Pin 8 will start at 15 volts and drop to 0 volts and keep repeating the cycle .
I can see on the scope when probing pin 8 the trace goes to 15v then the trace drops back down to the reference line over and over
And when I probe pin 8 the voltage still varies
Pin 8 will start at 15 volts and drop to 0 volts and keep repeating the cycle .
I can see on the scope when probing pin 8 the trace goes to 15v then the trace drops back down to the reference line over and over
I replaced the filter cap for the positive regulator . No change .
The voltage still does the same thing and the voltages on U3 don’t appear to be correct
I also now get 25 volts on all 3 legs of U1000
The voltage still does the same thing and the voltages on U3 don’t appear to be correct
I also now get 25 volts on all 3 legs of U1000
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29.85 volts from pin 4
pin 4 reads -4.85
Pin 8 reads 29.85
there is a resistor that sits next to U3 that is discolored it says O1C or something like that is the value 1K?
pin 4 reads -4.85
Pin 8 reads 29.85
there is a resistor that sits next to U3 that is discolored it says O1C or something like that is the value 1K?