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Old 10th November 2011, 08:14 PM   #1021
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Doing that now , but if I go too fast it just goes straight to negative ... none of the polarised components are in backwards ...?
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Old 10th November 2011, 08:57 PM   #1022
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Is it possible for P1 to be Fubar . I have tried adjusting for about an hour . I get to about 11.3 vdc and it swing to the negative ... is it telling me something ? it swings to - 24.32 vdc
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Old 10th November 2011, 09:32 PM   #1023
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Quote:
Originally Posted by richluvsound View Post
Is it possible for P1 to be Fubar . I have tried adjusting for about an hour . I get to about 11.3 vdc and it swing to the negative ... is it telling me something ? it swings to - 24.32 vdc
Yes. Get rid of C7, if you use release boards from passdiy and ZVP3310. Then fire again

Best,

nAr
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Old 10th November 2011, 09:57 PM   #1024
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changed P1 ... no difference . down to fuses lol . one led is way brighter than the other .

Can't find a schematic with voltages ....

thats enough for me today. If I charged myself my normal rate , I'd fire my **** !


Rich
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Old 10th November 2011, 10:01 PM   #1025
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Don't get too desperate. At least now PSU is turned the good way, and voltages are correct.

Unmount C7 as I said. Change leds and bipolars and see how it works. Can you get the voltages on the lowest resistors on schematic. At least it can help finding is biasing of each stage is correct or not. You'll also have to determine whether all the resistors are OK, or if one has now uncorrect value or seems damaged. last thing would be replacing jfets if one or more seem not to pass the intended current.

Best,

nAr
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Old 10th November 2011, 10:09 PM   #1026
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Thank you Nar .... C7 10pf out of both boards , but in the morning .
Yes, these are the official Pass boards . Just as well they were built to take my abuse !
Rich.
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Old 11th November 2011, 06:00 PM   #1027
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Hi Nar ,

do I remove 3310 from the board also ?

I put a 500mA fuse in and fried R 29 ... why would that only happen on one board ?

Rich
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Old 11th November 2011, 06:07 PM   #1028
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Hi Nar ,

do I remove 3310 from the board also ?

I put a 500mA fuse in and fried R 29 ... why would that only happen on one board ?

Rich
In that case I would also replace Q2, Q11 and R29

Can you do some measures and tell us which voltage you get in the usual places ? V+/ V-;
V on drain of Q6-Q9;
Voltage across R28 and R29.


Best,

nAr
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Old 11th November 2011, 06:50 PM   #1029
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Board 1

Q 6 , 31.2 mv
7 , 45.5 mv
8 , 32.3 mv
9 , 31.5 mv

R 28 , - 21.69
29 , - 21.69

Pad = -24.42

Board 2

Q 6 , 32.8 mv
7 , 31.6 mv
8 , 31.9 mv
9 , 32.9 mv

R 28 , -21.59
29, -21.49

Pad = - 24.33

Down to my last 250mA fuse . If I turn it off to remove ZTX 450 and ZVP 3310 . I'll blow it turning it back on ..... Why is this ? If I put a NTC before the fuse would it help ?

Rich

Last edited by richluvsound; 11th November 2011 at 06:57 PM.
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Old 11th November 2011, 06:55 PM   #1030
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Originally Posted by richluvsound View Post
Board 1 Board 2

Q 6 , 31.2 mv Q 6 , 32.8 mv
7 , 45.5 mv 7 , 31.6 mv
8 , 32.3 mv 8 , 31.9 mv
9 , 31.5 mv 9 , 32.9 mv

R 28 , - 21.69 R 28 , -21.59
29 , - 21.69 29, -21.49

Pad = -24.42 pad = -24.33

Down to my last 250mA fuse . If I turn it off to remove ZTX 450 and ZVP 3310 . I'll blow it turning it back on ..... Why is this ? If I put a NTC before the fuse would it help ?

Rich
Across R28 and also R29 you should have 1 volt or so. I dunno 1st stage Q6_Q9 seems fine, slightly low but maybe in relation with IDSS of the particular devices.

It seems current flows without been controlled. Could be the CCS (bipolars-leds) / jfets / mosfet of the 2nd stage all blown. I'm afraid you'll have to change all leds, bipolars jfets and mosfets of the 2nd stage before firing up again.

Best,

nAr
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