transistor for CROWN amplifier - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 11th November 2007, 12:27 AM   #1
diyAudio Member
 
Join Date: Dec 2006
Default transistor for CROWN amplifier

Greetings,

I am repairing a CT800 Crown amplifier. I have found a bad transistor that Crown calls a C 8187-4. A number of power transistors are in parallel, with emitter ballast resistors, but even so I think they pre-sorted for matching since there is a "3" stamped on the case for all of the devices that are in parallel.

My search on this site suggests that some wold use the MJ21193 from ON sumiconductor (and its complement) for this application, but it is not clear that the person posting was replacing exactly the same part as I need to replace.

Does anyone know of a generic number to replace this transistor? (it is in a TO-3 case). I would obtain a few transistors and then hand match to the good ones that will be re-used.

this transistor is an NPN power transistor. If you also have any information on the PNP parts, I'd be interested in that also, since I haven'c checked all the PNPs yet.


thanks !

Tom
  Reply With Quote
Old 11th November 2007, 12:42 AM   #2
diyAudio Member
 
Join Date: Dec 2006
I just noticed that the MJ21193 is the PNP; of course the NPN MJ21194 is under consideration for replacing the CROWN C 8187-4.

thanks,

Tom
  Reply With Quote
Old 11th November 2007, 04:57 PM   #3
taj is offline taj
diyAudio Member
 
taj's Avatar
 
Join Date: Feb 2005
Do you have a schematic? I'm not familiar with that amp, but it's probably worthwhile to look at the schematic to at least ensure it doesn't use FET's before recommending a replacement BJT.

MJ21193/94 are very good BJT's, as are MJ15024/25. Chris ('Anatech') would probably have the answer for you in 2 seconds.

..Todd
  Reply With Quote
Old 12th November 2007, 04:44 PM   #4
diyAudio Member
 
Join Date: Dec 2006
Thanks, Tod.

Yes, it is a BJT. I was able to find a schematic online. I usually just check BJTs to see if they look like two diodes, and this one has a very low-resistance junction that conducts in both directions, so its bad.

I'm beginning to think that if I don't have access to the CROWN specifications, and I replace with a new type part, I should replace all three paralleled transistors with hand-matched parts of the new type.

We'll see if anyone else adds to this thread, otherwise, that's what I'll do.

Tom
  Reply With Quote
Old 13th November 2007, 03:44 AM   #5
taj is offline taj
diyAudio Member
 
taj's Avatar
 
Join Date: Feb 2005
Yes, yes, yes. If you have to change part numbers, you will need to change all of them, including its complementaries. That much I do know.

..Todd
  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
Crown amps, transistor replacement (long) Eaulive Solid State 17 17th August 2011 02:28 PM
MIMPS? crown Transistor matching Zero Cool Solid State 0 8th May 2009 09:50 PM
Crown Com-Tech 210 Power Amplifier Crown Com-Tech 210 tyler477 Solid State 1 31st October 2008 04:24 AM
RCA 3626 power transistor from Crown amp delapoer Parts 6 3rd June 2004 03:02 PM


New To Site? Need Help?

All times are GMT. The time now is 01:33 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