ROTEL RA-820BX3 not working - 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 9th February 2012, 01:37 PM   #1
diyAudio Member
 
Join Date: May 2009
Location: Berlin
Default ROTEL RA-820BX3 not working

I got a broken ROTEL RA-820BX3 pretty cheap.
When I started to measure voltages I discovered that they are about 4 volts lower then they should be, according to the service manual.

I measured now the voltages at the rectifier and found out that instead of 41 volt they have 37 volt. I assume that the power supply does not work properly now, or?

Last edited by sangeet2; 9th February 2012 at 05:40 PM.
  Reply With Quote
Old 10th February 2012, 05:28 PM   #2
diyAudio Member
 
Join Date: May 2009
Location: Berlin
In the service manual is a voltage selector. But it is not on my amp...
Do I have the right service manual?
  Reply With Quote
Old 10th February 2012, 05:38 PM   #3
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
Very old. You may have high leakage of the main supply caps loading it down.
Your measurement is in idle. Correct? No input.
Low rails should not make much difference in it working as an amp, so I think you are not looking att eh correct problem first. What is the bias set at?
  Reply With Quote
Old 10th February 2012, 05:41 PM   #4
GoranB is offline GoranB  Poland
diyAudio Member
 
GoranB's Avatar
 
Join Date: Mar 2010
Location: Poland
Those 4V cant make a big difference. Whats the problem with your amp? Maybe you should be more precise.
  Reply With Quote
Old 10th February 2012, 05:43 PM   #5
diyAudio Member
 
Join Date: May 2009
Location: Berlin
Quote:
Originally Posted by tvrgeek View Post
Very old. You may have high leakage of the main supply caps loading it down.
Your measurement is in idle. Correct? No input.
Low rails should not make much difference in it working as an amp, so I think you are not looking att eh correct problem first. What is the bias set at?
Yes I measure without input.
Then I took out the fuses which appear after the Transformer. Then I measure an AC of around 25 Volts. So I guess no problem with the caps...
Bias I have not measured yet...
  Reply With Quote
Old 10th February 2012, 05:45 PM   #6
diyAudio Member
 
Join Date: May 2009
Location: Berlin
Quote:
Originally Posted by GoranB View Post
Those 4V cant make a big difference. Whats the problem with your amp? Maybe you should be more precise.
So far I only put a sine tone on the input and I don't get any signal from speakers output. Only on the record output.
Nothing seems to be obviously damaged, no smoky resistors or similar...
  Reply With Quote
Old 10th February 2012, 05:58 PM   #7
GoranB is offline GoranB  Poland
diyAudio Member
 
GoranB's Avatar
 
Join Date: Mar 2010
Location: Poland
Check F601/602
  Reply With Quote
Old 10th February 2012, 06:10 PM   #8
diyAudio Member
 
Join Date: May 2009
Location: Berlin
They are working
  Reply With Quote
Old 10th February 2012, 06:19 PM   #9
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
Check RY601 is switching. If it doesn't engage, the power amps will be muted. If in doubt you may remove it and connect jumpers in its place.
  Reply With Quote
Old 10th February 2012, 06:24 PM   #10
GoranB is offline GoranB  Poland
diyAudio Member
 
GoranB's Avatar
 
Join Date: Mar 2010
Location: Poland
Looking at the schematic i cant see a circuit for the speaker protection, but if the service manual is not the right one, maybe you have those circuit in your amp. If that is a case check if there is a DC voltage on the output, measure at the meeting point of 0.22 ohms ressistors.
  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
Rotel RA-920AX tooch Solid State 31 15th May 2011 07:36 PM
Rotel RA 931 argonrepublic Chip Amps 0 20th April 2009 02:26 AM
Rotel RA-820BX3 set quiescent method? cpemma Solid State 8 1st March 2006 07:16 PM
schematics of Rotel RA-971mk11 / RA-971 digitaldiablo Solid State 0 12th June 2003 05:03 PM
Rotel RA-820B jean-paul Solid State 0 9th December 2002 09:00 AM


New To Site? Need Help?

All times are GMT. The time now is 04:58 PM.


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