Repairing My Penultimate Zen V4 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 February 2010, 10:34 AM   #1
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Default Repairing My Penultimate Zen V4

Hello

Last Year I built myself this lovely sounding amp, pics can be seen here
Rixsta

I had it running for about a year, then when i blew one channel up and was too lazy to fix it untill last night. It was the input i thought that caused it to blow as i have no voliume control so if the amp is on and i plug things in it can be sensitive to the buzz or static at the input,which is what seemed to have done it . am i right in saying that if i put in a Volume coltrol and have the amp turned down wheni plug things in i will no longer have this problem of blowing the thing up ? lol

Here is the schematic
http://www.passdiy.com/pdf/zen-v4.pdf
Well anyway to my surprise i open it up and ill tell you which parts have gone
Z1 - Z5 totaly blown and possibly D1 not sure yet
R7 burnt out compleately
R0 slight burn marks
and one of the mosfets was blown i think Q5 the others were ok but i replaced them so far anyway.

So anyway im just about to replace the Zeener stack which i didnt do last night and fire her up again.

When i fire her up i just charge the power supply then connect it to the amp powering from the charge in the capacitors, it's a good way of testing and if all is good you get sound for about 10 seconds untill the capacitors have discharged.

brb
Im no electrician btw lol

Last edited by Rixsta; 19th February 2010 at 10:37 AM.
  Reply With Quote
Old 19th February 2010, 12:14 PM   #2
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Ok, replaced the parts, fired her up just from the charge in capacitors, working channel still ok and the channel im fixing, well powers getting thru all the board but as the music fades away on the working channel the music slowly comes in on the broken channel lol of corse it's distorted becuase im running of capacitors for testing purpose.

is it possible a capacitor needs replacing ? i might just replace Q4 now altho it seems ok

If i had the gut's id just wack the power right in but i dont have a variac to slowly bring it up, so dont want to risk it going up in smoke again.

Last edited by Rixsta; 19th February 2010 at 12:23 PM.
  Reply With Quote
Old 19th February 2010, 12:19 PM   #3
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Try a bulb tester.

Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 19th February 2010, 12:38 PM   #4
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Thankyou, ill have to rig that up, always meant to lol
basicly it's taking ages for power to get thru the circuit ? i hear the music come thru about 10 seconds after power up and i know thats not right !

am very confused now lol

Last edited by Rixsta; 19th February 2010 at 01:05 PM.
  Reply With Quote
Old 19th February 2010, 03:11 PM   #5
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Ok The 4V thats meant to be on Q2 is like 0.5 and ive replaced R7

all transistors but Q4 have been replaced, im realy thinking a capacitor is at fault now
any help apreciated, Time for a break i think lol

Last edited by Rixsta; 19th February 2010 at 03:26 PM.
  Reply With Quote
Old 19th February 2010, 09:27 PM   #6
diyAudio Member
 
Join Date: Feb 2006
Location: peak district, england
Might be worth looking at this thread!
Fail Safe Power Supply
  Reply With Quote
Old 20th February 2010, 12:53 AM   #7
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Cheers, ive got something setup now
am feeling happy with my troubleshooting stuff
am now at the point where everything works, however

The only reading thats right is the 46Volt after that point it's pretty much half voltage on the whole circuit hmmm
  Reply With Quote
Old 20th February 2010, 09:45 PM   #8
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Ok am realy actualy stuck now lol

I am about to look one more time to see if i missed anything daft, ive check near enoth every component on the board, it works but is just not as loud as it's meant to be because half of the circuit is running on too low power, but i cant figure out how or why thats happening.
  Reply With Quote
Old 20th February 2010, 11:01 PM   #9
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Novice electrician almost sorts it out lol Ok dont laugh
i didnt have it biased right, so i learn something new (bias efects almost whole circuit!)
now it looks like only problem is theres no .66 Voltage drop over R0

it's about .002

the investigation continues think im nearly there, hopefully

Last edited by Rixsta; 20th February 2010 at 11:24 PM.
  Reply With Quote
Old 21st February 2010, 11:57 PM   #10
Rixsta is offline Rixsta  United Kingdom
diyAudio Member
 
Join Date: Feb 2004
Location: Barrow-In-Furness, Cumbria
Send a message via Skype™ to Rixsta
Im Judging by the amount of reply's i must have done something dumb!
it's just realy odd i now have 0V over the bias resistors, yet i still hear sound.
how can this be that all voltages check right apart from the 0.66 ?
  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
The Penultimate Zen Part 4 gchrist Pass Labs 7 26th August 2008 08:07 AM
Penultimate zen psu arlekin Pass Labs 1 30th January 2006 10:07 AM
Penultimate Zen V4 Parts for sale Coulomb Swap Meet 12 10th February 2005 03:41 AM
Help with Penultimate Zen amp. Panelhead Pass Labs 3 30th December 2002 03:26 AM


New To Site? Need Help?

All times are GMT. The time now is 09:07 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