Help needed Output Transistors blown - Page 2 - 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 14th February 2007, 11:59 AM   #11
Rossy is offline Rossy  United Kingdom
diyAudio Member
 
Join Date: Feb 2007
Location: Scotland
Hi this is the left Channel that has blown
thanks
there is a 220R resistor (fuesable) that has blown and will need replacing all other componants check out apart from the 4 transistors
But i am having dificulty finding compliments for the MJE15031 here in the UK

Click the image to open in full size.
  Reply With Quote
Old 14th February 2007, 12:10 PM   #12
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
Are all the output transistors A940?
Also, please post a picture of the underside of the PCB.

/Hugo
  Reply With Quote
Old 14th February 2007, 12:17 PM   #13
Rossy is offline Rossy  United Kingdom
diyAudio Member
 
Join Date: Feb 2007
Location: Scotland
Hi thanks for Helping me

Ok all 8 Transistors are A940 4 for each channel
i circled the 4 that have been blown and the 1 resistor

Click the image to open in full size.
  Reply With Quote
Old 14th February 2007, 12:46 PM   #14
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
So all you need is MJE15031.
Replace the 2SC1815 as well just above the 220R resistor.
Check the other small transistors, all are 2SC1815 and 2SA1015.
I don't know of any suppliers in the UK, you could try Farnell. They sure have the MJE15031 and 2SC1815.
As for the 2SA1015, you could replace it with BC212, also available at Farnell but not pin compatible.

/Hugo
  Reply With Quote
Old 14th February 2007, 12:54 PM   #15
Rossy is offline Rossy  United Kingdom
diyAudio Member
 
Join Date: Feb 2007
Location: Scotland
Thats great i will order them up

just a couple of things will i be ok with the MJE15031 although the Mhz is 30 rather than 4

and the resistor 220R what wattage would you expect it to be 1watt? colour code is red red black black brown

thanks
  Reply With Quote
Old 14th February 2007, 01:06 PM   #16
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
I would try. Some frequency compensation could be added to prevent oscillation (you'll need the experts for that).
As for the resistor, 3611127 from Farnell will do fine as you only have to buy in quantities of 5.

/Hugo
  Reply With Quote
Old 14th February 2007, 01:20 PM   #17
Rossy is offline Rossy  United Kingdom
diyAudio Member
 
Join Date: Feb 2007
Location: Scotland
Hi thanks for the help
i found this web site that hass all componants i think?

could you check the resistor for me?

thanks

also could you check 2SA839

thanks
  Reply With Quote
Old 14th February 2007, 01:25 PM   #18
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
Also, check the resistor near the burned one. 4k7?
All emitter resistors - the ones on the 2SA940 rightmost pins - need checked together with the 33R base ones.

/Hugo
  Reply With Quote
Old 14th February 2007, 01:27 PM   #19
Rossy is offline Rossy  United Kingdom
diyAudio Member
 
Join Date: Feb 2007
Location: Scotland
Hi pulled all the legs up for the resistors all seem fine apart from the one that i took out

thanks for all your help

great guy
  Reply With Quote
Old 14th February 2007, 01:28 PM   #20
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
2SA839 will do fine if you can get it.
I gave you the part# of the resistor at www.farnell.co.uk.

/Hugo
  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
Musical Fidelity P170 Blown Transistors rigel9999 Solid State 35 4th January 2013 11:03 PM
Yamaha M-45 Blown Output Transistors gni Solid State 35 29th July 2008 09:47 PM
Blown output transistors crest amp mechaboy1 Solid State 28 9th January 2007 11:17 PM
Xtant 1001DX Output transistors needed Stooo Car Audio 17 20th October 2004 02:33 AM
SPICE models for power amp output transistors needed... ergo Solid State 9 22nd March 2001 07:31 PM


New To Site? Need Help?

All times are GMT. The time now is 04:46 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