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Old 15th January 2007, 06:08 PM   #1
ccereda is offline ccereda  Europe
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Default T amp not working, Help please

I am a beginner so I understand very little about electronics an I do my best to learn.

I have a modded S.I. Tamp, I made the input modifications following Michael Mardis recommendations: Stealth modification, then changed the input cap and inductances with toroids (39 turns of 0.5 mm wire).
I also changed the speaker cables with some CAT 5 computer cable.
Recently I received a new input cap Low Esr, and decided to rewind the toroids since they where loose.
The sound comes directly to the plastic connector after the original pot since I placed the amplifier in an integrated with the amplifier part broken.
It sounded very nice.
After this last changes but the amp does not work anymore and the led does not lit.

To verify I did the following:
I have a tester so I verified I get current from the input to the led, both sides but the led does not turn on.
I cleaned with alcohol and a brush all the amplifier
I went piece by piece and tested if the current passes through the components, particularly in the new welded pieces in order to discard bad welding.

I have to say that the toroids are welded on the back side to give room to the new cap and they are welded only on the upper side (Where i see the connections, it does not seem to be any necessity to weld both sides). The input cap is welded only on the low part of the board, as it was the older cap.

I appreciate the help to verify if it is a stupid problem or if I fried some important component.

Thank you
Cosimo
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Old 16th January 2007, 02:11 AM   #2
EdT is offline EdT  Canada
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I don't fully understand what you did, but first check if your power supply is still working to start and replace the old parts step by step until it works again then you know what you did wrong.
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Old 16th January 2007, 09:04 AM   #3
ccereda is offline ccereda  Europe
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Thank you

The power supply works perfectly, is external and is the first thing I cheked.

What I did:
http://www.michael.mardis.com/sonic/start.html
Modification 3 "stealth"

Additional modifications:
Change the inductances with toroids, they are on the back of the board instead of the front.
Change the input cap wich is much bigger than the original so there is no room anymore for the toroids.

If somebody tells me How to insert an image I got the pictures of the front and back of the board.

Unwelding again the components is not an obvious solution because I would stress again the board with the risk of fatal damage (if this has not occured yet).

Thanks
Cosimo
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Old 16th January 2007, 11:33 AM   #4
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Location: NW UK
Where is your power fixed to the board?
Are you sure that those connections are good?


A picture would help if you can post one..
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Old 16th January 2007, 12:21 PM   #5
ccereda is offline ccereda  Europe
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Hi:

Since I am not able to put an image in this post I give you a link where you can see the front and back of the modified T Amp.

http://www.strub-company.com/tamp.htm

As you can see in the back I had to fix the connection of the cap, because it came off. I had a more skilled friend to weld the leg of the cap a little further on the path.
You may compare with the images of the Michel Mardis webpage.

BTW if anybody is able to tell me how to post images I will be thankful.

Cosimo
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Old 16th January 2007, 05:45 PM   #6
EdT is offline EdT  Canada
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Use this link to host your photos and use the link provided to post on here.

http://www.supload.com
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