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Old 6th November 2012, 07:23 PM   #1041
Salas is offline Salas  Greece
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See you got 10V in-out for sure, then change Q1 too. Burned Zeners you found show that something went wrong at a point sometime.
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Old 6th November 2012, 07:27 PM   #1042
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Quote:
Originally Posted by Salas View Post
R5 should be 10R if you will lift one pin and measure it. It should be ~9.45R on TP for 47//47R instead of trimmer. See about changing the Zeners, about surely having a Vout that allows at least 10V difference to Vin, and that also Q1 shows ~1-1.5V Vgs which you can also measure as Vds Q2 when you have the power on.
diff Vin-Vout 10V
Q1 4.8V
Q2 0.9V
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Old 6th November 2012, 07:30 PM   #1043
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Quote:
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See you got 10V in-out for sure, then change Q1 too. Burned Zeners you found show that something went wrong at a point sometime.
I suspected the same, I will change Q1.
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Old 6th November 2012, 08:04 PM   #1044
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Vin reg 320.8VDC
Vout reg 300VDC
TP 0.1mA
Q2 2.7V
Q1 0.53V
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Old 6th November 2012, 08:24 PM   #1045
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TP 0.1mA??? What is it in DCmV mode?
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Old 6th November 2012, 08:28 PM   #1046
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0.001V
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File Type: jpg DSC00026.jpg (520.8 KB, 87 views)
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Old 6th November 2012, 08:31 PM   #1047
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That Q1 you put in could be problematic from previous use in other tests and regs? Now it does not draw any current. Zeners are OK still?
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Old 6th November 2012, 08:32 PM   #1048
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Let's power off and measure.
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Old 6th November 2012, 08:34 PM   #1049
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But you got an operating led. 1mV through 10 Ohm TP means 0.1mA. How it can operate the Vref's CCS to set 300V and light the LED? Fishy measurement. Is the sink getting warm?
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Old 6th November 2012, 09:08 PM   #1050
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Zener near trimmer measures continuity both poles, the other zener don't measure continuity both poles, have I to desolder the zeners to measure them well?

Last edited by merlin el mago; 6th November 2012 at 09:11 PM.
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