Issue While Rehabbing an STA-2100, What To Do? - 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 6th September 2014, 10:03 PM   #1
diyAudio Member
 
Join Date: Nov 2009
Default Issue While Rehabbing an STA-2100, What To Do?

I posted this yesterday on AK but haven't received a serious response, so I thought I try here.

I'm in the process of rehabbing this Realistic I've had for a couple of years. I played it a bit after I bought it but it sounded a bit off so I stowed it away until I was ready to do a full recap. Now that I've started I found one channel must have failed because there were a lot of replacement components. Since none of the components were the same as stock I decided to follow the EW's advice in this thread and go with On Semi replacements.

http://www.audiokarma.org/forums/sho...d.php?t=556573

While doing the amp board I noticed some reconstruction and replacement of the Sanyo 2SD400P (TR506A) that's mounted to the heatsink (left photo). The replacement is not a TO-92 package and there is no stock mounting clip like the other channel (right).

At this point what would you do? Leave the transistor that's there? Order a 2SD400 replacement and DIY a clamp? Are the clamps available anywhere? I couldn't find any.
Attached Images
File Type: jpg STA-2100_1.jpg (158.2 KB, 22 views)
File Type: jpg STA-2100_2.jpg (153.8 KB, 20 views)
File Type: jpg 2SD400.JPG (14.7 KB, 20 views)
File Type: jpg Diagram.JPG (111.3 KB, 20 views)
  Reply With Quote
Old 6th September 2014, 10:32 PM   #2
diyAudio Member
 
jerluwoo's Avatar
 
Join Date: Feb 2006
Location: Ashland,Ky U.S
Using a different transistor affects the thermal compensation. The larger to220 has a larger thermal mass and will compensate differently than the to92, adding the Vbe change with temperature, this could be a large difference. Using the device the amp was designed for is the best for ensuring it's continued operation. The clamp would be easy to reproduce if you can't find a new one. VR502 in the schematic should also be carefully inspected or replaced, this was a poor design choice, if the wiper goes open the output transistors will self destruct.

Last edited by jerluwoo; 6th September 2014 at 10:48 PM.
  Reply With Quote
Old 6th September 2014, 10:55 PM   #3
diyAudio Member
 
Join Date: Nov 2009
Thanks Jerluwoo, I'll plan on changing VR502.

Rather than trying to find a transistor replacement I'm thinking of finding a donor. That transistor seems pretty common.

Mike
  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
STA-500 Power Amp protect issue XsamuraiX PA Systems 9 4th June 2014 10:23 PM
Just got me a realistic STA 2080 srinath Solid State 16 19th May 2012 09:50 PM
Pioneer STA-2100 Volume Control Knob gouldtv Parts 1 9th September 2008 01:04 PM
Genexxa STA-2170 John Ball Chip Amps 0 22nd December 2007 01:15 PM
Realistic STA-7 receiver rpapps Solid State 8 17th May 2005 02:49 AM


New To Site? Need Help?

All times are GMT. The time now is 07:40 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