AMC CVT3030a Help for repair - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 23rd January 2011, 03:55 PM   #1
diyAudio Member
Join Date: Jul 2008
Default AMC CVT3030a Help for repair

Hello !
I've got this amp new in, say 1993/94. It has had some issues over the years :
When in warranty, one channel stop working, the importer's repairer did a terrible job, removing some connector and doing bad soldering job. But it worked.
Some years ago the B+ diode bridge went out and I repaired it changing the big filter electrolytic.
A week ago, one channel went out, blowing the fuse on the B+ supply. I thought that the diodes had gone south again. Alas, it was one of the left channel EL34 has lost it's vacuum (soldering a tube is not a good idea, but it worked for years).
I bought a couple of ElectroHarmonix Sovtek EL34EH and soldered them. This channel runs fine now.
But the other channel arced on one of the EL34 I thought it was caused by the opening having disturbed dirt and dust inside the box. I scratched the PCB between the two pins which smoke, and the put things back in. The bias was impossible to get on this channel : The 0V is impossible to get becase I get around the bias voltage..... So I suspect one of the FET (BS592 and it's associated PN2222A) to have blown. I cant source them anywhere.
So All your thoughts and help will be *vastly* appreciated !
Many thank in advance for your help and advice !
  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
What do you think about the AMC DAC8 D/A converter? chops Digital Source 14 15th July 2010 05:43 PM
AMC DAC8 Question 3357 Digital Source 1 29th September 2009 08:53 AM
Need help to identify potentiometer in amc 1030 milen007 Parts 13 27th May 2008 05:28 PM
AMC 25100 repair chris737 Solid State 0 5th January 2008 11:22 AM
Help on AMC CVT 3030 wuffwaff Tubes / Valves 8 26th May 2006 07:09 PM

New To Site? Need Help?

All times are GMT. The time now is 06:41 PM.

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