What does +3v3a mean in a schematic - Page 6 - 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 30th December 2012, 07:46 PM   #51
srinath is offline srinath  United States
diyAudio Member
 
Join Date: Feb 2010
OK by process of elimination - I think -

The problem has to be in D453, r453, c465, r454, or d458uz5v1.

Why ?

I got 5.5v in pin 4, fed by the other side of the rectifier diode bridge, and that is regulated by the 7806 to 6v I believe.

The d453 etc is in the line straight off the fuse.
I will yank that out and see what it does to the voltage - or I may pull d458 first since the short is to ground.
Maybe also I need to look for a solder bridge, though the solder was all stock factory in that board.
Anyway your ideas welcome too.
Cool.
Srinath.
  Reply With Quote
Old 30th December 2012, 08:06 PM   #52
srinath is offline srinath  United States
diyAudio Member
 
Join Date: Feb 2010
I'll pull d458 out and see if the voltage @ pin 4 gets back to 6v dc.
If not, the next one would be the r454 followed by c465.
I think one if those has shorted to ground and got the voltage out from 7806 transistor to not get to 6v.
Cool.
Srinath.
  Reply With Quote
Old 31st December 2012, 04:52 AM   #53
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
Do noy pull out any zeners from the circuit e.g. d458. U will damage the circuits.

Gajanan Phadte
  Reply With Quote
Old 31st December 2012, 05:42 AM   #54
diyAudio Member
 
Join Date: Nov 2008
Location: Victoria,TX
Blog Entries: 1
Hi,
My advice is now to check for a short or a low resistance value to ground using the ohmmeter. I would check the resistance to ground at the point between R455 and C466. The D455 and D457 will isolate the reading from the transformer. Check the resistance and post the reading. D453 it is not the problem because it is follow by R453 4700 ohms resistor in series too high to loaded the PS. At this point you have to be careful because the IC451 feed voltage to the micro.
  Reply With Quote
Old 31st December 2012, 07:52 AM   #55
srinath is offline srinath  United States
diyAudio Member
 
Join Date: Feb 2010
Tauro0221: The r455-c466 junction to ground flashed a 120 ohm or so and went back to open. Sort of like a capacitor would.

Gmphadte: How would I damage it ? from heat ? I anyway would replace it with a new one. Desoldering takes more heat than soldering.

Cool.
Srinath.
  Reply With Quote
Old 31st December 2012, 08:44 AM   #56
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
No need for replacing the zener. U will damage if u remove and power on the circuit.

If u have voltage at pin 4 (5.5V, maybe 5.8V without load) and pin 2(5.1V), then look for the other circuit where from pin 1 returns. This pin 1 will be high(some + voltage near 5V) only when the power good detection and reset circuit works, and then only the relays will remain on.

Gajanan Phadte

Last edited by gmphadte; 31st December 2012 at 08:46 AM.
  Reply With Quote
Old 31st December 2012, 01:36 PM   #57
diyAudio Member
 
Join Date: Nov 2008
Location: Victoria,TX
Blog Entries: 1
Hi,
That means that there are no shorts. We need to go back. Check the resistance for the IC451 output pin to ground. Remove fuse F453 and check resistance from the fuse load side to ground and from T451 pin 2 to ground. Also check resistance across capacitor C462. Post reading.
  Reply With Quote
Old 31st December 2012, 02:33 PM   #58
srinath is offline srinath  United States
diyAudio Member
 
Join Date: Feb 2010
Tauro0221: I will get that checked tonight.

Gmphadte: I got these readings @ cp458 - Pin 1 was 0 vdc, 2 was 2.82 vdc, and 4 was like 5.5 vdc. Now I got that reading without anything connected to 458.

Ok If removing zener diode and powering up is bad, then I could replace it with a new one and try powering it up ?
Anyway I'll let you guys - Tauro in particular :-), tell me what to do, you have been great. What a learning experience this has been.

Cool.
Srinath.
  Reply With Quote
Old 31st December 2012, 02:41 PM   #59
diyAudio Member
 
Join Date: Nov 2008
Location: Victoria,TX
Blog Entries: 1
Hi,
just in case one more resistance check. With the fuse F453 remove check the resistance of the transformer winding between pin 1 and 2. Post the reading.
  Reply With Quote
Old 31st December 2012, 03:08 PM   #60
srinath is offline srinath  United States
diyAudio Member
 
Join Date: Feb 2010
OK cool.
Srinath.
  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
Linn "LINTO" MC Preamp Schematic without SMPS - Schematic for SMPS wanted tiefbassuebertr Analogue Source 40 14th July 2014 08:10 AM
Schematic needed panasonic RX-1230 schematic Buzzsaaw Analog Line Level 0 23rd April 2011 07:52 PM
who s got the best schematic? prorms Solid State 40 24th February 2011 12:29 PM
Schematic FABIO_IT61 Solid State 1 23rd September 2005 11:48 AM
P 1.7 schematic help MikeW Pass Labs 20 19th June 2005 07:36 PM


New To Site? Need Help?

All times are GMT. The time now is 09:46 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