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

Notification

Icon
Error

Login
Strange problem with PlacidBP
Options
View
Go to last post Go to first unread
Previous Topic Next Topic
bishopoz  
#1 Posted : Saturday, July 3, 2010 12:35:13 AM(UTC)
bishopoz

Rank: Member

Groups: Member
Joined: 1/28/2010(UTC)
Posts: 25
Location: Sydney
Hi guys,

I have had a PlacidBP set to 12v powering the crossover for my active speakers. It was working fine for a number of weeks then after suddenly after being powered up for some time it would drop down to ~2v on one side. The time it takes to drop from 12v to 2v has progressively shortened so it is now almost instant. Still reads 12v with no load attached though.

Any suggestion greatly appreciated.

Thanks

Paul
Back to top

Wanna join the discussion?! Login to your Twisted Pear Audio Support forum accountor Register a new forum account.
Back to top  
Russ White  
#2 Posted : Saturday, July 3, 2010 2:17:41 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)
Perhaps it not set for enough current?
Back to top
WWW
bishopoz  
#3 Posted : Sunday, July 4, 2010 1:33:02 PM(UTC)
bishopoz

Rank: Member

Groups: Member
Joined: 1/28/2010(UTC)
Posts: 25
Location: Sydney
Hi Russ,

I cannot get a stable voltage measure across R1 or R13 on bad side, it moves about from a couple of mV to 19v. The good side is dead stable at 250mV across R2. Does that give any pointers?

Thanks

Paul
Back to top
Russ White  
#4 Posted : Sunday, July 4, 2010 9:44:45 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)
What is the voltage across C3?

250mv across R2 is OK if there is no load, but is a bit high if there is one.
Back to top
WWW
bishopoz  
#5 Posted : Monday, July 5, 2010 3:51:55 AM(UTC)
bishopoz

Rank: Member

Groups: Member
Joined: 1/28/2010(UTC)
Posts: 25
Location: Sydney
Hi Russ,

C3 is ~2v, same as good side. The 250mV is without load BTW.

Have tried to understand the schematic and traced the supply from C3 to output and both channels align until c7/c8 where the good channel reads ~7v & bad ~16v. I'm guessing it would be c7 and/or corresponding IC?

Thanks for your help.

Paul
Back to top
bishopoz  
#6 Posted : Tuesday, July 13, 2010 6:10:57 AM(UTC)
bishopoz

Rank: Member

Groups: Member
Joined: 1/28/2010(UTC)
Posts: 25
Location: Sydney
Hi Russ,

Any pointers on where to look? I haven't replaced any components yet as I stuffed my last placid by being too gung-ho.

Thanks

Paul
Back to top
Russ White  
#7 Posted : Tuesday, July 13, 2010 9:17:22 AM(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)
Possibly a bad current adjustment pot?
Back to top
WWW
avr300  
#8 Posted : Tuesday, July 13, 2010 12:35:20 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 would try a fixed resistor approach.
Back to top
Russ White  
#9 Posted : Tuesday, July 13, 2010 5:00:45 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)
Me too :)
Back to top
WWW
Rss Feed  Atom Feed
Users browsing this topic
GuestUser (5)
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