AidanLunn wrote:Measuring CN1 pin 1 with my other meter, an Eagle Y122KB, it's also 17.5V.
Minus the post regulator voltages, the results are:
1) 17.6V (uni-t meter) should be around 16V, so not too bad with O/C CP802
4) 17.5V. The input of L21 should measure 16.3V. as above with O/C CP803
5) just 8V. Something amiss here (see below) needs to be about 17V, this is an input to the STK chip for the sw 12V line
6) 8.7V. looks OK with CP804 O/C should be about 7.4V when loaded properly
2) -0.5V something amiss here This should be -30V
6) 50V will be OK (should be 45V) because the supply is still not loaded properly
Will the o/c CPs cause the wildly different results, as the difference is confusing. See above in red
One anomaly here is pin 5) of CN1 is connected via R20 (8.2K) to pin 6) of CN2, we have a large volt drop across that resistor, either the resistor is high or the regulator STK chip is pulling it down, you might want to re-check the measurement of that one to see if that is the case.
EDIT: I'll post the post-regulator voltages when I have the CPs replaced.
Refugee wrote:We need to make sure the battery in the meter is good before we go any further. A new one would be best.
A waveform on the scope will tell us if it is tripping.
A photo of the front of the scope showing the names and numbers on the controls will help us get you a trace of the transformer secondary waveform.
I think it is a bad sense or capacitor or perhaps the opto isolator/regulator if the meter battery is fresh.
Bad capacitors send ripple back to the control chip on the live mains part and make it switch on and off all the time. It is looking for clean DC.
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