Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Crossover makes amp go into protection mode
Crossover makes amp go into protection mode
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 22nd April 2019, 05:02 PM   #31
Mark Tillotson is offline Mark Tillotson
diyAudio Member
 
Join Date: May 2018
Location: Cambridge UK
An internal short in a coil will be hard/impossible to see normally - trying to run it at high power may provoke visible arcing, but may also damage the amp and speakers.


Close visual inspection (ie with a magnifier) might throw something up (perhaps one coil
got scrapped by a sharp metal object?).


There might be an intermittent capacitor or solder joint that only shows up with higher voltages/currents than a multimeter will provide.


[ postings overlapped! Good to hear its figured out now - the cap is either shorted, open or intermittent, whatever it just needs replacing with a non-polar equivalent ]
  Reply With Quote
Old 22nd April 2019, 06:09 PM   #32
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
We don't know yet something is wrong with the cap.
A quick test would be to temporarily fix the 'good' cap to the 'bad' board, to get confirmation it is the cap and not the associated wiring.

Jan
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.

Last edited by jan.didden; 22nd April 2019 at 06:20 PM.
  Reply With Quote
Old 22nd April 2019, 06:09 PM   #33
stevebogus is offline stevebogus  United States
diyAudio Member
 
Join Date: Nov 2010
Quote:
Originally Posted by Defo View Post
Eureka! Disconnected the big cap for the woofer and now all is good! This begs the question tho, what is wrong with the cap?


My guess is an intermittent short in the cap, sensitive to either vibration or temperature. Electrically, there are two conductive "plates", separated by a dielectric material. Sometimes a metal film is deposited directly to the dielectric, or a layer of metal foil alternates with the dielectric film. To save space this is wound in a tight little bundle. One plate could short against the other if there is physical damage or a defect.


Once the short circuit begins there will be a sudden spike in current through the cap, which would generate heat. This might be enough to maintain the short circuit until it cools down, or the short occurs frequently enough that the protection circuit is retriggered.
  Reply With Quote
Old 22nd April 2019, 06:17 PM   #34
BigE is online now BigE  Canada
diyAudio Member
 
BigE's Avatar
 
Join Date: Aug 2008
Location: Toronto
The big cap for the woofer??? Isn't that for the tweeter? You could be driving the tweeter with full music signal... a sure way to fry it.

I would do as Jan said. Very good idea.
  Reply With Quote
Old 22nd April 2019, 08:37 PM   #35
Defo is online now Defo  Norway
diyAudio Member
 
Join Date: Nov 2008
Quote:
Originally Posted by jan.didden View Post
We don't know yet something is wrong with the cap.
A quick test would be to temporarily fix the 'good' cap to the 'bad' board, to get confirmation it is the cap and not the associated wiring.

Jan
Just did this, and it's not the cap Now I really have no clue...
  Reply With Quote
Old 23rd April 2019, 01:42 AM   #36
Old'n'Cranky is offline Old'n'Cranky  Australia
diyAudio Member
 
Join Date: Aug 2009
Well you've swapped one cap.
Now keep going with the other parts.
One at a time, then test both crossovers.
  Reply With Quote
Old 23rd April 2019, 07:08 AM   #37
Defo is online now Defo  Norway
diyAudio Member
 
Join Date: Nov 2008
Quote:
Originally Posted by Old'n'Cranky View Post
Well you've swapped one cap.
Now keep going with the other parts.
One at a time, then test both crossovers.
Isn't it possible to deduce something from the fact that removing the big woofer cap fixes the issue?
  Reply With Quote
Old 23rd April 2019, 08:09 AM   #38
wolf_teeth is offline wolf_teeth  United States
diyAudio Member
 
wolf_teeth's Avatar
 
Join Date: Mar 2006
Location: Indiana
If we knew what the circuit was, then yes. Since it's of proprietary nature, we don't know this information.

Later,
Wolf
__________________
Photobucket picture pages: http://photobucket.com/Wolf-Speakers_and_more
Writeups/thoughts/blogs: http://techtalk.parts-express.com/blog.php?u=4102
  Reply With Quote
Old 23rd April 2019, 08:41 AM   #39
Defo is online now Defo  Norway
diyAudio Member
 
Join Date: Nov 2008
Quote:
Originally Posted by wolf_teeth View Post
If we knew what the circuit was, then yes. Since it's of proprietary nature, we don't know this information.

Later,
Wolf
See attached pics. Pretty sure its correct.

First is board layout.
Second is schematic based on board layout.
Third is re-arranged to make it easier to read.

Hope that brings some value!
Attached Images
File Type: jpg crossover-schematic-0.jpg (81.4 KB, 93 views)
File Type: jpg crossover-schematic-1.jpg (38.6 KB, 95 views)
File Type: jpg crossover-schematic-2.jpg (37.8 KB, 97 views)

Last edited by Defo; 23rd April 2019 at 08:44 AM.
  Reply With Quote
Old 23rd April 2019, 09:07 AM   #40
avtech23 is offline avtech23  Australia
Certifiably addicted to DIY.
diyAudio Member
 
avtech23's Avatar
 
Join Date: Dec 2017
Location: South 'straya
Crossover makes amp go into protection mode
Is this connection correct (marked in blue)
Attached Images
File Type: png capture.png (301.3 KB, 87 views)
__________________
The ever growing project list.. :NAP140 Clone, NAD 3020i & 3225PE, JLH1969, TDA2050, Fender 5F2A Princeton, NE5532 Pre, SHPA, B1 Korg. : VSQC Phunk Style, Retro 50W, Filmosound 601. : Apex AX-14, TGM-10, TDA7265, LM4780 (Last in line)...maybe
  Reply With Quote

Reply


Crossover makes amp go into protection modeHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Nad 304 Protection Mode sirhenry Solid State 2 14th May 2009 09:46 AM
amp protection mode ? chrissy14xsi Car Audio 40 14th March 2009 02:00 AM
Amp Protection Mode sseabrook07 Car Audio 3 29th October 2006 02:26 PM
protection mode won't go off Darkcrusher Solid State 5 2nd February 2006 02:10 PM


New To Site? Need Help?

All times are GMT. The time now is 07:51 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki