Kenwood A83 dangerous amp?? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 5th November 2003, 07:19 PM   #1
diyAudio Member
Join Date: Jun 2001
Location: Flanders, Belgium
Arrow Kenwood A83 dangerous amp??


I've just got an amplifier to repair...
The amp was dead, so I decided to look inside....
After some measurements I realised there was no DC power at the collectors of the output transistors, so I looked at the PSU...
It seems that the primary of the transformer is broken, however the primary is almost connected directly to the mains, without a fuse!! The only thing between is a "breaking" relais driven by a small circuit with a different (small) PSU. At the secondary windings there aren't any fuses too!!! The only fuses in this amp are there to connect the mains to other (external) devices.

Maybe I'm wrong, but isn't this a VERY unsafe way to work?? what happens if the rectifierdiodes are short circuited (primary of the transformer will burn??)
Does anybody know where to find some schematics of this amp??

best regards,

  Reply With Quote
Old 5th November 2003, 07:38 PM   #2
MarkMcK is offline MarkMcK  United States
diyAudio Member
Join Date: Aug 2003
Location: Ohio
Hi HB,

This is a simple one. To prevent owners putting in oversized fuses, most commerical amplifier transformers use a thermal fuse wound into the transformer.

Most likely this has opened. The manufactuerer would want you to replace the transformer to repair the unit (assuming there is no downstream problem to cause this thermal fuse to open). Usually these thermal fuses were not drawn into the schematics.

On some transformers you can get at the thermal fuse. If you can, then the transformer can be repaired.

Good luck,

  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
I know this is illegal but is it dangerous or cunning. inteificio Parts 5 9th January 2006 09:55 PM
Glass wool. Is it dangerous? sachi Multi-Way 15 20th March 2005 01:31 AM
416B dangerous tube? serengetiplains Tubes / Valves 8 16th March 2005 06:23 PM
dangerous hum with opa637 in a Cmoy style amp Garbz Chip Amps 7 19th March 2004 06:35 AM
215 decibel !! Could be dangerous massive Everything Else 10 29th August 2003 04:27 PM

New To Site? Need Help?

All times are GMT. The time now is 09:03 AM.

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