Burnt out transistors - replace with same or something better? Rotel RB-991 - 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 18th November 2012, 02:59 PM   #1
diyAudio Member
 
Join Date: Dec 2004
Location: York
Smile Burnt out transistors - replace with same or something better? Rotel RB-991

Hi,

One of the transistors in my Rotel RB-993 has shorted.

A toshiba 2sc5200

Easy to swap in a replacement.

However had a thought, it has been a while since this amp was designed, surely there must be something better out there now.

So what's your thoughts?

This amp is used to power the centre and surrounds in music/movie set up.

The front amps are Tag 8000p.

Current amp schematic attached:

https://docs.google.com/open?id=0B0W...0p0blFpaENQZjg
  Reply With Quote
Old 18th November 2012, 04:01 PM   #2
diyAudio Member
 
Join Date: Jan 2011
Location: Fosser, Aurskog-Holand, Akershus, Norway.
Why should there be any better transistors than the near legendary 2SC5200?

It's better to find out what made the short for You, than trying to replace with "a stronger device".
And why so? Well, neither of them will withstand a shortcirquit anyway.

And the 2SC5200 is still a very, very good transistor.
__________________
Sooner or later you end up with TANDBERG
  Reply With Quote
Old 18th November 2012, 04:23 PM   #3
diyAudio Member
 
Join Date: Dec 2004
Location: York
I should have added I know very little about transistors. If this one is great, will stick with it.

Now I just need to find out what caused the issue.

Thanks
  Reply With Quote
Old 18th November 2012, 04:26 PM   #4
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
I'll second TANDBERGEREN's reply.

Rebuild the faulty channel but use a bulb tester for powering up to save any mishaps. You need to be methodical and check for any damaged parts.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 18th November 2012, 04:42 PM   #5
diyAudio Member
 
Join Date: Dec 2004
Location: York
Even with no load connected both board protection fuses go pop spectacularly.
Am very basic with electronics, but a shorted transistor is my guess.

Eventually I will remember to bring my multimeter home to give it a look over.

The main protection circuits do not detect a fault, it is just the 1 amp board.
  Reply With Quote
Old 18th November 2012, 05:50 PM   #6
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
You cannot just drop in "better" transistors and get better performance. The circuit would have to be tailored to them, or problems such as oscillation will result.

There's nothing wrong with the 2SA1943/2SC5200. They are obsolete now, mainly due to rife copying and counterfeiting - Toshiba replaced them with TTA1943/TTC5200. There are some third party manufacturer clones made by Magnatec and Fairchild.
  Reply With Quote
Old 18th November 2012, 06:16 PM   #7
diyAudio Member
 
Join Date: Dec 2004
Location: York
Quote:
Originally Posted by jaycee View Post
You cannot just drop in "better" transistors and get better performance. The circuit would have to be tailored to them, or problems such as oscillation will result.
Said I was basic =-)
  Reply With Quote
Old 18th November 2012, 09:17 PM   #8
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
You say "both protection fuses blow". Which ones ? There are 2 pairs of fuses per channel.
  Reply With Quote
Old 19th November 2012, 07:03 AM   #9
diyAudio Member
 
Join Date: Dec 2004
Location: York
F301 and F302.

There are only two fuses I can find on each amplification board. There are other protection circuits on the shared, but these fuses are on the amp board itself.

Any tips?
  Reply With Quote
Old 19th November 2012, 07:22 AM   #10
diyAudio Member
 
Join Date: Dec 2004
Location: York
To save you looking around.

Page 1 bottom board.
  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 RB 850 and Marantz 5002 both burnt out, please help! dmbartender Solid State 2 27th October 2009 08:42 PM
Matching Output Devices Rotel RB-991 dtm1962 Solid State 7 17th August 2006 12:18 PM
Can I use MJL0281A & MJL0302A in place of Sanken FN1016 & FP1016 in my Rotel RB-991 dtm1962 Solid State 23 31st July 2006 08:08 AM
POLL:ROTEL RB-991/990 Owners- Output devices your Amp have? FP/N1016 or 2SA1492/c3856 dtm1962 Solid State 7 23rd July 2006 09:10 PM
Rotel rb-991 in class A appelkoos Solid State 8 25th May 2006 09:32 PM


New To Site? Need Help?

All times are GMT. The time now is 09:10 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