Help! Marshal MG50DFX Anybody Anyideas - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 10th August 2005, 09:43 AM   #1
diyAudio Member
 
Join Date: Aug 2005
Unhappy Help! Marshal MG50DFX Anybody Anyideas

My marshal amp recently stopped working so I decide to fix it. I replaced the main amp chip a TDA 7293 along with all of the other pre amp chip including many TL027`s when I put the amp on now it works all of the time but is very quiet? Can anybody shed light on my problems? I also noticed two leds in the amp one green and one red, are they for test purposes? should they light up?
Cheers for any help offered
  Reply With Quote
Old 11th August 2005, 02:29 AM   #2
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
Look at pin 4 of the module ribbon, or pin 9 of the 7293 itself. This is the standby pin. There should be a positive voltage there - maybe 3-5v or something. When the big chip fails sometimes it damages the mute circuit.

On the main board somewhere is a small transistor and a zener that control this line. Shorted zener will leave the chip muted.

Something to check.
  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
Marshall MG50DFX Schematic wanted... fuzzy Solid State 1 12th February 2009 03:35 PM


New To Site? Need Help?

All times are GMT. The time now is 07:03 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