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

Notification

Icon
Error

Login
2 Pages<12
Voltage drops of Placid HD after connecting load (BIII)
Options
View
Go to last post Go to first unread
Previous Topic Next Topic
niekos  
#21 Posted : Tuesday, January 1, 2013 7:12:31 PM(UTC)
niekos

Rank: Member

Groups: Member
Joined: 5/15/2012(UTC)
Posts: 19
Netherlands

Thanks: 5 times
Originally Posted by: avr300 Go to Quoted Post
Now, hand over to Russ and Brian. I can't debug the AVCC shunt without schematic ;-)

Something is wrong with your AVCC shunt module.


Brian and/or Russ can you help me out? And a happy new year of course :)
Back to top
Russ White  
#22 Posted : Tuesday, January 1, 2013 7:54:15 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)
Check your solder joint's - in the pics they look dry.
Back to top
WWW
niekos  
#23 Posted : Tuesday, January 1, 2013 10:00:55 PM(UTC)
niekos

Rank: Member

Groups: Member
Joined: 5/15/2012(UTC)
Posts: 19
Netherlands

Thanks: 5 times
I resoldered all joints, but it did not seem to make any difference so far.

SRA2 joints

new joints other side


I measured on the AVCC from the in/out/gnd joint to the first resistor/capacitor on the track and they were all ok.

I measured voltages again, the same as before (a bit higher):

On the side where SRA2 is printed in the board:

5,29V IN and 5,29 OUT

On the other side

5,29 in 2,4 V OUT.

I will resolder tomorrow once and measure all, just to be sure.


Back to top
Russ White  
#24 Posted : Tuesday, January 1, 2013 10:20:46 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)
please measure the voltage across D1, R4 and R5.
Back to top
WWW
niekos  
#25 Posted : Wednesday, January 2, 2013 7:02:28 AM(UTC)
niekos

Rank: Member

Groups: Member
Joined: 5/15/2012(UTC)
Posts: 19
Netherlands

Thanks: 5 times
D1 = 0,98V
R4 = 3 mV
R5 = 283 mV
Back to top
Russ White  
#26 Posted : Wednesday, January 2, 2013 1:46:22 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)
Sounds like you probably have a dead transistor or two - and possible D1 too.

Your best bet unless you feel like replacing parts until you find the borked one is to order a replacement. :)
Back to top
WWW
niekos  
#27 Posted : Wednesday, January 2, 2013 3:18:06 PM(UTC)
niekos

Rank: Member

Groups: Member
Joined: 5/15/2012(UTC)
Posts: 19
Netherlands

Thanks: 5 times
Thanks, what parts do you supect/advice to be replaced?
Do you have part numbers? I think it might be worth the try?
Back to top
Russ White  
#28 Posted : Wednesday, January 2, 2013 5:07:41 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)
Honestly - its probably more worth while to get the newer AVCC module anyway - it's a better circuit, but if you are intent on trying to fix it - I would say you might need to replace the following (in order of what to try first)

QP1-2 (BC856) (they are cheap so get a few extra in case QP3-4 are also dead)
D1 (once again order a few)

possibly the opamp (use OPA2209)
Back to top
WWW
thanks 1 user thanked Russ White for this useful post.
niekos on 1/2/2013(UTC)
avr300  
#29 Posted : Wednesday, January 2, 2013 6:19:56 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)
Originally Posted by: Russ White Go to Quoted Post
Honestly - its probably more worth while to get the newer AVCC module anyway - it's a better circuit,....


And it brings an increased sonic performance to the DAC. It's a very worthwhile upgrade.

(I'm not connected to TPA in any other way than being a satisfied customer).
Back to top
niekos  
#30 Posted : Wednesday, January 2, 2013 10:03:53 PM(UTC)
niekos

Rank: Member

Groups: Member
Joined: 5/15/2012(UTC)
Posts: 19
Netherlands

Thanks: 5 times
ok ok, you convinced me :-) I just ordered a new one :-)
Back to top
Rss Feed  Atom Feed
Users browsing this topic
GuestUser (24)
2 Pages<12
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