Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Login
Placid BP Power Supply R1 smoked
Options
View
Go to last post Go to first unread
Previous Topic Next Topic
noodles  
#1 Posted : Friday, September 10, 2010 9:29:20 AM(UTC)
noodles

Rank: Member

Groups: Member
Joined: 9/10/2010(UTC)
Posts: 3
Location: Tasmania
Hello Brian/Russ,

I got a spark and smoke when measuring the R1 to adjust to ~ 0.25V (i think I may have come in contact with one of the QN1 transistor legs, the voltage over R1 is 0.007V and will now not bias at all. All LEDs work, and I’m still getting 15v over both rails. Both QN1 and QP3 are cold. The board was working fine, until the spark and smoke incident. Where’s the best place to troubleshoot.
Back to top

Wanna join the discussion?! Login to your Twisted Pear Audio Support forum accountor Register a new forum account.
Back to top  
avr300  
#2 Posted : Friday, September 10, 2010 12:54:11 PM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
See http://www.twistedpearau....aspx?g=posts&t=1180

Properly your potentiometer has lost it..
Back to top
noodles  
#3 Posted : Friday, September 10, 2010 4:20:04 PM(UTC)
noodles

Rank: Member

Groups: Member
Joined: 9/10/2010(UTC)
Posts: 3
Location: Tasmania
avr300, thanks for that, it has not been tested under load it may be the VR1, how do I test to make sure, it was working fine before the spark, and I did not over wind it? I got the spark from R1, I thought QN1 may be the culprit.
Back to top
noodles  
#4 Posted : Friday, September 10, 2010 9:02:41 PM(UTC)
noodles

Rank: Member

Groups: Member
Joined: 9/10/2010(UTC)
Posts: 3
Location: Tasmania
OK I get no resistance adjustment from VR1 when I turn the trimmer, I’ll replace it and see.
Back to top
avr300  
#5 Posted : Friday, September 10, 2010 11:54:00 PM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
I think your probe while touching either end of R1 slipped and hit the ground plane ontop of the PCB simultaneously touching R1. If so, you will kill the pot.
Back to top
johnwmclean  
#6 Posted : Tuesday, September 14, 2010 5:16:32 AM(UTC)
johnwmclean

Rank: Member

Groups: Member
Joined: 5/1/2009(UTC)
Posts: 8
Location: Australia
Thanks avr300, that worked a treat! Psu is up and running.
Back to top
avr300  
#7 Posted : Tuesday, September 14, 2010 7:53:28 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
Applause
Back to top
Russ White  
#8 Posted : Tuesday, September 14, 2010 5:04:11 PM(UTC)
Russ White

Rank: Administration

Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 3,979
Location: Nashville, TN

Thanks: 25 times
Was thanked: 89 time(s) in 83 post(s)
I just have to say thanks to AVR300 for stepping in an helping out. We have the best users ever. :)
Back to top
WWW
avr300  
#9 Posted : Wednesday, September 15, 2010 4:20:37 AM(UTC)
avr300

Rank: Member

Groups: Member
Joined: 6/17/2008(UTC)
Posts: 921
Denmark

Thanks: 1 times
Was thanked: 70 time(s) in 69 post(s)
Anytime, Russ.
Back to top
Rss Feed  Atom Feed
Users browsing this topic
GuestUser (3)
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Youtube
Copyright © Twisted Pear Audio