LM3886T Problem, I think - 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 28th December 2005, 01:39 AM   #1
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Default LM3886T Problem, I think

I recently had a failure in an using a LM3886T chip. The amp about blew up my eardrums on one channel. It was a real loud buzz.
After disconnecting it I found almost the full positive rail voltage on the output. It was disasembled to check for problems, and nothing wrong was found. Check the chip and it was not shorted on either rail.
Powered back up, and the chip acted up a little and finally stabilized. It even amplifed. Operated fine for about an hour. But then started passing dc again.
This is not how I expected a LM3886 chip to fail. I always thought they either work, or they do not. This seems intermittant.
When I have time, I will clip it out and try to install another in the circuit board. Hopefully this problem will not still be there.
Have others seen these chips act up, settle down, and start acting up again?

George
  Reply With Quote
Old 28th December 2005, 01:50 AM   #2
diyAudio Member
 
Join Date: Feb 2005
Location: Watertown, NY
do you have a loose solder somewhere or a connection touching something it shouldnt??
  Reply With Quote
Old 28th December 2005, 03:08 AM   #3
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
indeed you should check connections in your power supply
  Reply With Quote
Old 28th December 2005, 06:16 AM   #4
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Since you were using the uninsulated "T" version, was the insulation 100%?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 28th December 2005, 10:07 AM   #5
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Default Good news

I have double checked all connections and the status of the mica insulator. But the come and go nature made me think that clipping out the LM3886T would only be a lot of work for nothing.
Guess I need to dig back into the circuit board again and see what has caused this. It acted up after playing one morning for a couple of hours. It had been sailing along for a couple months.
I was sitting about 10 feet away when the 32 vvolts hit that speaker. My ears rang for a day. My wife was downstairs and she thought something blew up. Lowther drivers are tougher than most think.

George
  Reply With Quote
Old 28th December 2005, 10:08 AM   #6
diyAudio Member
 
sagarverma's Avatar
 
Join Date: Feb 2005
Location: NEW DELHI
Quote:
It even amplifed. Operated fine for about an hour. But then started passing dc again.
check all the solder joints carefully.dry joints cause probs.
__________________
Never Underestimate The Bandwidth of A Station Wagon Full Of Magnetic Tapes Hurtling Down The Highway...................Andrew S Tanenbaum
  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
10 pcs LM3886T daedalus Swap Meet 3 28th March 2009 03:39 AM
Wtb :- LM3886T PCB poynton Swap Meet 7 6th September 2007 04:18 AM
Fs: Lm3886t Lm3886tf elementx Swap Meet 2 14th July 2006 04:18 PM
LM3886T/TF for sale elementx Swap Meet 1 3rd June 2006 10:13 PM
Lm3886t Nobodysfool Chip Amps 10 22nd May 2006 06:26 AM


New To Site? Need Help?

All times are GMT. The time now is 04:11 AM.


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