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Old 18th February 2007, 09:48 AM   #1
Kooka is offline Kooka  Italy
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Default Help Aleph30

Need someone's help, guys: just finished my Aleph30 (Peter PCBs).
I assembled everything and tested both channels with two 12v batteries connected in series (25v). Both channel worked pretty well and I decided to assemble everything.
After doing this only one channel works...
The other channel (nothing visually strange) receives the 50V from the supply but does not even start heating.

Now my question is simple: any idea of what could be the problem?
I also have some problems because I used 1/2w resistors instead of the suggested 1/4w, so my resistors are "standing" on the pcb, and mechanical access is quite difficult...

I would really appreciate any help. Thanks in advance for anyone helping!
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Old 18th February 2007, 10:49 AM   #2
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check wiring
check soldering
check for shorts
etc
you really did not give us enough info

when you check all this........write again

edit:

how,on earth , you have 50 V when it's supposed that A30 work on +-25V ?!!
you can have only 25 on output ,+ or - ,whatever ;anyway-what you mean with "50V" ?

check wiring again!!
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Old 18th February 2007, 11:01 AM   #3
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+-25V means 50V on the rails.
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Old 18th February 2007, 01:06 PM   #4
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BTW, I don't think I have a problem with shorts or solderings, the board was working with the battery supply...
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Old 18th February 2007, 01:16 PM   #5
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Quote:
Originally posted by Kooka
BTW, I don't think I have a problem with shorts or solderings, the board was working with the battery supply...

you must tell us that you actually checked at least something,so we can try to help you from somewhere;

this way we can just guess what can be.......

I told you what to do for start
later we can go further,with exact schematic,just to have mutual nomenclature of parts

there is nice pdf with voltages
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File Type: pdf aleph30.pdf (29.9 KB, 113 views)
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Old 18th February 2007, 01:23 PM   #6
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My problem, as told, is that with bigger resistors I have a really hard time (actually impossibility) of checking the voltages with power supply. I must remove the board from the heatsink and supply it with the two 12v batteries, not to "burn" everything (with this low power supply mosfet did not even get hot when I tested first time).
With lower power supply I can remove the board from the heatsink and test from the back of the board.
So the problem is: are, with half voltage power supply, the voltages all around half than they would be with normal power supply?
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Old 18th February 2007, 01:47 PM   #7
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Quote:
Originally posted by Kooka
My problem, as told, is that with bigger resistors I have a really hard time (actually impossibility) of checking the voltages with power supply. I must remove the board from the heatsink and supply it with the two 12v batteries, not to "burn" everything (with this low power supply mosfet did not even get hot when I tested first time).
With lower power supply I can remove the board from the heatsink and test from the back of the board.

you can't reach parts with probes?
you can't lay heatsink sidewise?

Quote:
So the problem is: are, with half voltage power supply, the voltages all around half than they would be with normal power supply?
some are,but most important ones are not
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Old 18th February 2007, 01:58 PM   #8
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No, without removing the board from the heatsink I can reach only few parts.
But since the board looks "dead" I would like to see "any" voltage somewhere... My question is where to start and what could fail after connecting to the power supply. Connecting with the two batteries it worked (now it does not wok even with the batteries, BTW).
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Old 18th February 2007, 02:02 PM   #9
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print (or just look) at this pdf.......and -sfter few hours of just staring at ,write what you don't understand;

that way is most beneficial to you
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Old 18th February 2007, 02:03 PM   #10
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This is a pic, just to see how it looks. You can understand it is quite difficult to reach the parts on the board...
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