Re: Hameg HM307-3 Cleaning and Repair
I've installed the new 741 op amp, socket and tried both new transistors. The -1000V rail is still too low!
With BD232:
-1000V rail: ranges from -960V --760V.
C of T301: 400V
Input V of pin 2: 0V
Input V of pin 3: 0V
Output V of pin 6: -5.3V.
With BF259:
-1000V rail: ranges from -960V --760V.
C of T301: 310V
Input V of pin 2: 0V
Input V of pin 3: 0.65V
Output V of pin 6: -5.3V.
What should the voltage be at the inputs of the IC?
Does anybody wonder if something connected to the -1000V rail is pulling it down?
I'm going to lift one end of R305 and see what I measure.
Last edited by OldTechFan96; 5th Jun 2019 at 8:07 pm.
Reason: More info
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