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Old 12th February 2012, 06:29 PM   #5361
ungie is online now ungie  Canada
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Here are my readings hoping to have some enlightening feedback
Can you measure the voltage at the emitter of Q27?
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Old 12th February 2012, 06:29 PM   #5362
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Please measure at emitter Q27.
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Old 12th February 2012, 06:30 PM   #5363
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The idle current in the input stagae is ok.
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Old 12th February 2012, 07:56 PM   #5364
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by ungie View Post
Can you measure the voltage at the emitter of Q27?
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Originally Posted by Joachim Gerhard View Post
Please measure at emitter Q27.
Q27 emitter -13.13
Q28 emitter +14V

The collectors of these should be near zero but they measure 14v

Allready replaced Q28 and Q15 without any changes
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Old 12th February 2012, 08:07 PM   #5365
ungie is online now ungie  Canada
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Q27 emitter -13.13
Q28 emitter +14V

The collectors of these should be near zero but they measure 14v

Allready replaced Q28 and Q15 without any changes
You have two voltages written beside TP3 and TP4. Which is the actual one in each case?

Andrew
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Old 12th February 2012, 08:14 PM   #5366
RCruz is offline RCruz  Switzerland
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TP3 13.3v
TP4 -12.5v

The other values are the ideal ones
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Old 12th February 2012, 08:16 PM   #5367
ungie is online now ungie  Canada
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If TP4 is indeed -12.5V and the emitter of Q27 is -13.13V you are close to Q27 not being forward biased and there will be no Ic through Q27.
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Old 12th February 2012, 08:25 PM   #5368
ungie is online now ungie  Canada
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Can you measure the voltage at the node between R27 and R6 and also the node between R34 and R29?
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Old 12th February 2012, 08:38 PM   #5369
RCruz is offline RCruz  Switzerland
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Hi ungie... where are those resistors ?
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Old 12th February 2012, 08:47 PM   #5370
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R27 to R6 node 18.8V
R34 to R29 node -18.6V
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