Can Anyone Identify This Component in Meridian 103/5 Power Amps Please? - 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 19th April 2010, 06:49 PM   #1
Thomo is offline Thomo  United Kingdom
diyAudio Member
 
Thomo's Avatar
 
Join Date: Nov 2006
Default Can Anyone Identify This Component in Meridian 103/5 Power Amps Please?

I have a Meridian 103 power amp that doesn't work, and was wondering if anyone could identify this component that is superglued (or similar) to the heatsink.

Click the image to open in full size.

I'll post a pic of the schematic shortly once I've drawn on where this part is connected.

Lee.
  Reply With Quote
Old 19th April 2010, 06:56 PM   #2
Thomo is offline Thomo  United Kingdom
diyAudio Member
 
Thomo's Avatar
 
Join Date: Nov 2006
Here's the schematic for the 103 with arrows drawn to show where it's connected.

Cheers, Lee.

http://www.diyhi-fi.co.uk/pdf/Servic...cuits_edit.pdf
  Reply With Quote
Old 19th April 2010, 07:06 PM   #3
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
can you identify the 2off 10V Zeners on the PCB, or is that them glued to the heatsink?
__________________
regards Andrew T.
  Reply With Quote
Old 19th April 2010, 07:12 PM   #4
diyAudio Member
 
PhaseLockLoopy's Avatar
 
Join Date: May 2008
Location: On a mushroom
Is that not just a thermal cut out? -- the wires are both the same colour and go back via two rails that come up through the centre of the PCB on fairly hefty track
__________________
Hum likes to have a nice "Noise to Signal" ratio
To "Hum" is to be noticed Quality hum is when it pours out of Electrostatic speakers
  Reply With Quote
Old 19th April 2010, 07:16 PM   #5
diyAudio Member
 
Join Date: Sep 2004
Location: UK
Quote:
Originally Posted by PhaseLockLoopy View Post
Is that not just a thermal cut out? -- the wires are both the same colour and go back via two rails that come up through the centre of the PCB on fairly hefty track
But if that were the case it would short out the rails, which is a bit drastic ....

It would work though!
  Reply With Quote
Old 19th April 2010, 07:32 PM   #6
diyAudio Member
 
Steve Dunlap's Avatar
 
Join Date: Sep 2008
Location: Here
I may be missing one transistor in the picture, but the schematic seems to have 19 and I see only 18 on the board.
  Reply With Quote
Old 19th April 2010, 07:39 PM   #7
diyAudio Member
 
Join Date: Nov 2005
It has to be a normally open thermal switch. (or a big NTC thermistor, you'd have to look much closer into the circuit to see what that would do, but measuring the part is easy) When the sink rises to the trip point it clamps off the supply to voltage stage through the isolating resistors.

Last edited by Andrew Eckhardt; 19th April 2010 at 08:09 PM.
  Reply With Quote
Old 20th April 2010, 12:23 AM   #8
tvi is offline tvi  Australia
diyAudio Member
 
tvi's Avatar
 
Join Date: Apr 2001
Location: Moonee Ponds, Vic, Australia
Can you post a pic of the copper side of the board,
might help?

Rgds
James
__________________
The small part of ignorance that we arrange and classify we give the name of knowledge.
Ambrose Bierce
  Reply With Quote
Old 20th April 2010, 12:30 AM   #9
diyAudio Member
 
Join Date: Nov 2005
I tried to edit that post 15 times. It's the input stage left after the resistors, the stage that handles voltage gain is before it, and those aren't just isolation resistors, they're dropping resistors for the zeners. An NTC on there would have to seriously drop the supply to the input section before the bias regulator dropped out, so it probably wouldn't be any more effective than a thermal switch. An ohm meter will give you the answer.

Last edited by Andrew Eckhardt; 20th April 2010 at 12:32 AM.
  Reply With Quote
Old 20th April 2010, 09:34 AM   #10
Thomo is offline Thomo  United Kingdom
diyAudio Member
 
Thomo's Avatar
 
Join Date: Nov 2006
Hi guys, thanks for your answers. I too thought it was a thermistor or some sort of thermal cutout. I've measured it with an ohm-meter, and it's open circuit. I'll try heating it slightly with a hot-air blower and see if that changes anything.

Cheers, Lee.
  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
Can someone identify this component? teemuk Parts 6 29th February 2008 12:54 PM
Meridian 103 - bdy56 Transistor Alternatives? Thomo Parts 11 25th February 2008 02:26 PM
Help Identify this component! DoomPixie Parts 10 28th August 2006 03:01 PM
Help me identify this Surface mount component jives11 Parts 6 8th December 2005 02:50 PM
Help to identify component aeon845 Parts 1 19th May 2004 04:35 PM


New To Site? Need Help?

All times are GMT. The time now is 04:43 PM.


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