Toshiba Transistor question - 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 5th February 2009, 01:11 AM   #1
diyAudio Member
 
Join Date: Sep 2008
Default Toshiba Transistor question

Hello all, I am working on an onkyo receiver and found a shorted output transistor mounted to the heatsink. The number on in is Toshiba B1558 and then a small 5G, I bought what I though was the correct one B1558 but it has a small 5E It is square also and the original is tapered at the top. I cannot seem to find the B1558 original anywhere, is the one I bought the same you think?

Thank you very much for your help
  Reply With Quote
Old 5th February 2009, 01:15 AM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
It is probably a batch group code, so you should be OK
  Reply With Quote
Old 5th February 2009, 01:31 AM   #3
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
that's 2SB1558

Si-P Darl

140V/8A/80W
Attached Images
File Type: jpg 2sb1558.jpg (63.9 KB, 211 views)
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 5th February 2009, 03:33 AM   #4
diyAudio Member
 
Join Date: Sep 2008
I installed the one I have and the unit keep blowing the mains fuse, befor it would turn on for a moment and then turn off, now this, any ideas, Thanks again.
  Reply With Quote
Old 5th February 2009, 03:56 AM   #5
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Those codes sometimes are sort codes for beta ranges in the Japanese transistors I have worked with. (Mainly Sanyo)

The fact that it keeps blowing the fuse is an indication that you have not found the entire problem. You should use a variac and/or ballast lamp which may help you to troubleshoot the amplifier. You should assume until you prove otherwise that since you blew the fuse again more damage has occurred - generally application of full power after an untested repair is not a good practice.

I bet you have got a bad driver transistor or two as well, and generally it is a good idea to replace drivers and outputs in pairs.

The diode test function on a dmm is not always conclusive that a transistor that tests ok is actually good. I have been stung more than once by this assumption. (When they test bad using this technique they generally are.)

Check the bias string (diodes, vbe multiplier, pot, whatever) - in most output stage configurations if this goes open the output transistors turn hard on shorting across the supply.

Higher beta replacements in critical locations sometimes results in the amplifier becoming unstable if the design was predicated on transistors of not higher than some specific beta. You will need a scope to diagnose the issue if this turns out to be the case.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 8th February 2009, 02:13 AM   #6
diyAudio Member
 
Join Date: Feb 2009
Send a message via ICQ to chaida_ic Send a message via MSN to chaida_ic
Default Re: Toshiba Transistor question

It is 2SB1558, many TOSHIBA transistor just ignore 2S
This is the datesheet http://www.alldatasheet.com/datashee...A/2SB1558.html

B1558, the TOSHIBA has stopped producing it.

Quote:
Originally posted by litezoner
Hello all, I am working on an onkyo receiver and found a shorted output transistor mounted to the heatsink. The number on in is Toshiba B1558 and then a small 5G, I bought what I though was the correct one B1558 but it has a small 5E It is square also and the original is tapered at the top. I cannot seem to find the B1558 original anywhere, is the one I bought the same you think?

Thank you very much for your help
  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
Transistor sub for Toshiba 2SA561 PJdiy Vendor's Bazaar 1 21st April 2008 09:57 PM
Comparison Of Onsemi Vs Toshiba Transistor fotios Solid State 18 23rd August 2007 11:23 PM
Carver Preamp and the Toshiba 2SC2878 transistor EchoWars Solid State 33 8th May 2005 05:14 PM
TOSHIBA 2SC4793 and 2SA1837 medium power transistor pspice models? mikek Solid State 1 24th September 2002 08:14 AM


New To Site? Need Help?

All times are GMT. The time now is 07:56 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