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Post by radiohead314 on Mar 17, 2016 8:11:04 GMT -5
There is 24,3V on 17V!
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Post by radiohead314 on Mar 17, 2016 8:06:44 GMT -5
C25 measures 14,35V what a coincidence???
Z50 still 0V
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Post by radiohead314 on Mar 17, 2016 8:03:27 GMT -5
Sry wait a minute I check c25 and z50 again I am mixing thing up or do not know.
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Post by radiohead314 on Mar 17, 2016 7:59:33 GMT -5
I would wait in changing the c25,first try to solve why there is no start up . (every time you replace components you degrade the pcb board do it as few as possible) The voltage on Z50 is only shortly on and is cut by +17vm generated by I1 when the power supply comes a live and takes over from TH1 (but it's zero so no take over) The squealing bothers me is there a short on one off the outputs from the fixed power supply preventing it from starting up ,one of the caps shorting the supply ,with no load the voltages are a lot higher then normal and that can make a cap fail but then again there should be a supply at c25 before the supply can start up. Maybe reconnect d114 see if squealing changes , did it start after disconnecting d114? Ah ok I did not get that first. So in the end the I1 is making its own supply with the 17V. Cool. c25 is certainly connected right. I will check for a bad cap.
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Post by radiohead314 on Mar 17, 2016 7:50:55 GMT -5
Ok I made a mistake. Must be getting tired. For some reason I removed j30 and forgot to put it back.
I now measure 14,35V on the zener Z50.
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Post by radiohead314 on Mar 17, 2016 7:16:18 GMT -5
Double checked no short from z90 to groun and no opel loop from top r52
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Post by radiohead314 on Mar 17, 2016 7:06:44 GMT -5
That seems ok ,there should be 15v over Z50 if not check z50 and q60 for short and r52 and r53 if they are not open. 0V on Z50 z50 not shorted q60 not shorted r52 and r53 not open
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Post by radiohead314 on Mar 17, 2016 6:51:19 GMT -5
Squeling might come from c25 very hard to determine
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Post by radiohead314 on Mar 17, 2016 6:46:17 GMT -5
Ok the squeling comes from the area where there are a lot of caps close. Not from the pfc and the resistor on the pfc is cold.
Hthd measures 0V
i put the old c25 back just to be sure but same measurements.
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Post by radiohead314 on Mar 17, 2016 6:27:01 GMT -5
That confirms the 0v on c25 , so the start up voltage is not present with j30 in place ,did you replace c25 recently ,check if pin 9 is not shorted (c25) to mains ground. Check on pfc if sr1 ,ptc1,ptc2 are hot after about half minute on (j30 in place) ,disconnect mains wait until +9v led is out before you touch them. So where is the squealing come from? With diode meter on pin 9 I measure 643mA one direction and OL in the other direction plus on pin 9.
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Post by radiohead314 on Mar 17, 2016 6:21:10 GMT -5
17VM on primary side is also 0V
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Post by radiohead314 on Mar 17, 2016 6:00:24 GMT -5
Measure if +17v is present . No something like 1.14V I am measuring 17V on the secondary side. There is also a 17V on the primary side I could measure?
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Post by radiohead314 on Mar 17, 2016 5:53:23 GMT -5
I would like to know if voltage comes on c25 with d114 disconnected. Ok this is strange. With d114 disconnected I hear caps squealing but the voltage on C25 is 0V. I double checked everything. -Jumper j30 on subboard -standby led burns only
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Post by radiohead314 on Mar 17, 2016 5:29:56 GMT -5
Try an other meter or check battery , I have a meter that start showing of values when battery becomes to low. (you use the correct ground ,not chasis) You are good! Look at that, the battery was low on the other meter. Untitled by Radio Head, on Flickr
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Post by radiohead314 on Mar 17, 2016 5:18:22 GMT -5
Just put some boards back ,is there a reason to presume the fix voltage part generated by I1 are at fault ,did you do any work ,replace components in that section? Or if you can start it whithout extra boards just for a few seconds to measure +17v it should be around 22v (whithout load) you can assume it works correctly and then add extra boards and measure again if its between 17v and 18,5v you are fine. I would like to know if voltage comes on c25 with d114 disconnected. Ok I try just a few seconds for now. I only replaced C25 with a low esr one but checked it many times so little work on I1. I will remove D114 next. This is a picture how I measure the voltages. Mostly directly over the component. With Q101 I take the ground from the heatsinc screw. Untitled by Radio Head, on Flickr
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