TDA2822M Oscillatiing in Grundig Receiver - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 3rd February 2016, 07:56 PM   #1
diyAudio Member
 
Join Date: Feb 2016
Default TDA2822M Oscillatiing in Grundig Receiver

I"m troubleshooting a grundig SW receiver with a low frequency output oscillation that's using a TDA2822M chip in bridge mode. The problem goes away with headphones plugged in and also with a 100 ohm resistor in series with speaker. Have subbed out the chip and bypass/filter caps in circuit as well as 8 ohm speaker. No luck. Any thoughts appreciated.

John
  Reply With Quote
Old 7th February 2016, 04:24 PM   #2
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
Grundig, TDA2822M? Probably a Chinese-built "Grundig" model then (rebadged Tecsun or something)?

Anyway, low-frequency oscillation sounds like you should turn your attention to power supply decoupling. I guess you'll find a few bad electrolytics with sky-high ESR. (Got something resembling a makeshift ESR meter?) Also check whether the voltage regulator still does its job.
  Reply With Quote
Old 7th February 2016, 04:43 PM   #3
nec3 is offline nec3  Turkey
diyAudio Member
 
Join Date: Jun 2005
Location: Ankara
Is the receiver operated on batteries or AC mains ?
It oscillates also in low volume levels or only when turned up max ?
What is DC voltage at the input and output of 2822M ?
When you short inputs to the ground, the oscillation stops?
  Reply With Quote
Old 12th February 2016, 10:53 PM   #4
diyAudio Member
 
Join Date: Feb 2016
Thanks for those suggestions. The radio is branded Grundig/Eton S350. I had never run it on batteries but when I tried that - problem gone. So I opened up the wall wart and there is no regulator in there or inside radio either - just some large electrolytics which I had already replaced. I was getting 8-10 volts out the supply even tho it's nameplate ssys 6 - have never seen that before. Swapped it out for a switch mode adjustable - set it for 6 volts and its back in business. Go figure.
  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
TDA2822M amplifier circuit questions junkmail Chip Amps 7 27th December 2014 08:01 AM
LA4450 and TDA2822M interfering danny92 Chip Amps 4 23rd August 2013 07:18 PM
tda2822m problems... pat allen Chip Amps 7 27th July 2013 02:01 PM
Strange problem with Grundig CS200 tube receiver Rodeodave Tubes / Valves 16 15th June 2011 03:21 PM
Buzz noise from DC brushless fan in TDA2822m enigmaticEntity. Chip Amps 11 21st March 2011 01:50 PM


New To Site? Need Help?

All times are GMT. The time now is 09:26 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki