transistor problem - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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
Reply
 
Thread Tools Search this Thread
Old 23rd March 2013, 07:45 AM   #1
diyAudio Member
 
Join Date: Feb 2011
Default transistor problem

Hi and thanks for reading this post.

My amplifier has been playing up on me and i noticed a swollen capacitor which i replaced with a new one of the same voltage and capacitance.

When reassembled the amp would not work at all, after a few hours of experimentation i noticed a row of transistors which are clipped onto the metal chassis of the amp, obviously this was done by the manufacturer to keep the transistors cool and i had to unclip these to get the board out.

When the transistors are clipped onto the chassis of the amp so in effect they are all sharing one large heatsink the amp does not work, i gave each transistor its own heatsink and now the amp works fine.

Can anyone tell me what is going on.

Many thanks in advance. John.
  Reply With Quote
Old 23rd March 2013, 08:16 AM   #2
diyAudio Member
 
Join Date: Feb 2009
did you remember the electrical insulation between each transistor and sink?
  Reply With Quote
Old 23rd March 2013, 09:05 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by goodsguys View Post
........ i noticed a row of transistors which are clipped onto the metal chassis of the amp,..........
This does not sound like a chipamp.
Are you in the correct section of the Forum?
__________________
regards Andrew T.
  Reply With Quote
Old 24th March 2013, 07:44 AM   #4
diyAudio Member
 
Join Date: Feb 2011
Hi. Thanks for the replies.

The only thing between the transistors and the chassis was a layer of thermal paste.

When i reassembled the amp i did not put on a new layer of paste, just thought i would power it up for a few seconds to see if the recap had fixed the problem, the power supply made a high pitched whining noise.

So i applied the paste and the whining noise went away but now there is no sound, perhaps the paste was having an insulating effect and separating the transistors from each other and the new paste i am using does not do that.

Can you tell me anything about the electrical insulation between each transistor and sink you mentioned, what is this, is it something i can buy?.

Many thanks. John.
  Reply With Quote
Old 27th March 2013, 11:35 PM   #5
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
You need to buy some SIL pads to electrically isolate the transistors from the heat sink.

It could be you blew some transistors by shorting them to the heatsink.
  Reply With Quote

Reply


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
soldering a TO-3 transistor technique ? (problem for me) guitar89 Construction Tips 26 8th August 2013 05:53 AM
problem in transistor test seifi Solid State 3 23rd May 2010 09:21 AM
SMPS flyback, transistor problem Archion Power Supplies 4 13th May 2010 04:13 PM
Soundstream Rubicon 702 Output transistor Problem? tyu527 Car Audio 10 29th August 2008 06:37 AM
nightmare transistor problem!! fatboy Parts 7 4th November 2004 05:44 PM


New To Site? Need Help?

All times are GMT. The time now is 02:27 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2