T amp not working, Help please - diyAudio
Go Back   Home > Forums > Amplifiers > Class D
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 15th January 2007, 06:08 PM   #1
ccereda is offline ccereda  Europe
diyAudio Member
Join Date: Nov 2006
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
  Reply With Quote
Old 16th January 2007, 02:11 AM   #2
EdT is offline EdT  Canada
diyAudio Member
Join Date: Dec 2006
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.
  Reply With Quote
Old 16th January 2007, 09:04 AM   #3
ccereda is offline ccereda  Europe
diyAudio Member
Join Date: Nov 2006
Thank you

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

What I did:
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).

  Reply With Quote
Old 16th January 2007, 11:33 AM   #4
diyAudio Member
Lostcause's Avatar
Join Date: Aug 2005
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..
  Reply With Quote
Old 16th January 2007, 12:21 PM   #5
ccereda is offline ccereda  Europe
diyAudio Member
Join Date: Nov 2006

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.


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.

  Reply With Quote
Old 16th January 2007, 05:45 PM   #6
EdT is offline EdT  Canada
diyAudio Member
Join Date: Dec 2006
Use this link to host your photos and use the link provided to post on here.

  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Amp non working covik Solid State 0 12th November 2006 09:12 PM
WTB Krell KSA Mk2- working or non working Jozua Swap Meet 0 20th March 2006 12:14 PM
sub amp not working felzi Chip Amps 0 28th July 2005 06:29 AM
p3a not working, help! benmanf Solid State 9 27th May 2005 02:02 PM

New To Site? Need Help?

All times are GMT. The time now is 10:52 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2