Bash Amp Power Supply Repair - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 10th July 2011, 11:26 AM   #1
diyAudio Member
 
Join Date: Aug 2008
Default Bash Amp Power Supply Repair

I have a couple Bash subwoofer amps that I would like to get up and running. They both seem to have failed from the typical problems associated with the SMPS power supplies. I have replaced the FET's and anything else burnt, but I have hit a wall. On the power input side what seems to be an inrush current limiting thermistor has failed and I cannot identify the component. The markings are DSP 104. Also the PDC board has what looks to be a failed diode. Unfortunatley the silkscreen is double marked so I cannot determine the proper direction. The diode is d11 in the upper right corner. It can be seen burned and black. Please have a look at the pictures.
Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.

Last edited by crazifunguy; 10th July 2011 at 11:29 AM.
  Reply With Quote
Old 10th July 2011, 06:57 PM   #2
! is offline !  United States
diyAudio Member
 
Join Date: Jun 2005
Location: Midwest
Thermistor is 10 ohm (@ 25C temperature), 4 amp type. Substitute equivalent value.

part # example from original 13DSP-104
Diing Tai Electronics Co. Ltd

As for the "diode" with dual polarity markings on the PCB, I can only guess it is a DIAC based on this forum topic:
Klipsch Promedia BASH amplifier
  Reply With Quote
Old 10th July 2011, 07:52 PM   #3
diyAudio Member
 
Join Date: Aug 2008
WOW Thank You for the fast reply. I searched and searched and posted on a few different forums about the DSP 104 and was coming up empty. Also in my years of playing with electronics I have never heard of a diac. Learn something new all the time. That would explain why when I used a diode the SMPS would not osciliate. When I replace the parts I will post updates and hopefully the amp will be alive!!
  Reply With Quote
Old 22nd August 2011, 07:18 AM   #4
diyAudio Member
 
Join Date: Aug 2008
I have decided to redesign this power supply here is my latest PCB
Click the image to open in full size.
  Reply With Quote
Old 26th April 2012, 03:09 PM   #5
diyAudio Member
 
Join Date: Apr 2012
Default Bash Amp Power Supply repair

can someone provide where to source Diing Tai Electronics Co. Ltd 13DSP 104 thermistor? our usual supplifiers do not carry this product. Equivalents acceptable. Further, what is the Root Cause (RCA) of this failure. we have seen this in many not only consumer self powered subs, but also with commercial self powered subs?
  Reply With Quote
Old 25th August 2012, 07:35 PM   #6
pdlemen is offline pdlemen  United States
diyAudio Member
 
Join Date: Jan 2011
The rubber cement used to adhere components to the pcbs and for sound deadning turns conductive.For instance in a Klipsch Sub 10 (Bash-Indigo of course) and in the Tannoy TS8's the smaller daughter/smps driver are adhered to C72 and C24 of the main pcb. This cement starts conducting on the back side of the driver and drastically changes the timing for Q3 and Q4 output transistors and then ka pow. Also remove this glue from the rail caps and any other location where it is applied over conductive surfaces like component leads and circuit traces. This stuff has been used industry wide since the early 80's and is a valuble tool for engineers who appreciate "planned obsolesence". It gives a one two punch in the fact that it turns conductive and it will also corode thru protective applications used over circuit traces. Once it corodes down to the metal it can then start shorting out anything and everything. Nasty stuff.
  Reply With Quote
Old 22nd April 2013, 01:24 AM   #7
rokoren is offline rokoren  United States
diyAudio Member
 
Join Date: May 2012
Default Exact same issue with an Episode C5 Sub12

Wow, I just got through troubleshooting an Episode 12" sub, 300 watt BASH amp Model C5 Sub12. I just came upon your post, and I am surprised the see that I had exactly the same failures and came to exactly the same conclusion that you had about root cause. Originally, I had found designator R400 had failed with a nasty burn mark. This part's markings, if any, were illegible after the burn, but I suspected it was a current limiting NTC thermistor. My measurements after grinding off the burnt half of the themistor and reading 20 ohms, the original part must have been a 10 ohm 13mm NTC thermistor. Then later, I found the IRF740 mosfet was failed short. The small control "daugher" board that manages the gate voltage to the failed Mosfet on the primary winding of the transformer, is glued to the transformer itself, presumably to avoid failures/stress due to sonic vibrations. This glue had browned due to heat and age, but was also leaching some greasy looking smelley fluid. I knew that could not be good, where critical timing / capacitances needed to be maintained, so I removed the board, cleaned it all off, and reinstalled this time using hot melt to provide the mounting means. I just ordered the mosfet and a similar NTC thermistor to complete the repairl
  Reply With Quote
Old 22nd April 2013, 01:43 AM   #8
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Sometimes when SMPS blows it wipes out a few components.

On my design the transistors all blew, the thermistor and the SMPS IC.
The SMPS IC voltage supply regulator often went too.

Once repaired I would definitely power up with light bulb in series to limit current, just in case.
__________________
PCBCAD50 software. http://www.murtonpikesystems.co.uk

Last edited by nigelwright7557; 22nd April 2013 at 01:45 AM.
  Reply With Quote
Old 4th September 2013, 06:26 AM   #9
Zeppy is offline Zeppy  United States
diyAudio Member
 
Join Date: Sep 2013
I'm new to this so I don't know how to post a question for the experts to read? I'm having issues with the thermistor.It was blowing the fuse.Since I didn't have the right thermistor on hand I put a couple of 5 ohms in series just to see if it would come up.Fuse quit blowing but still won't work.Do I have to use the original 10 ohm 4a 13dsp-104 for klipsh bash amp board
  Reply With Quote
Old 4th September 2013, 06:35 AM   #10
Zeppy is offline Zeppy  United States
diyAudio Member
 
Join Date: Sep 2013
Same klipsch sub woofer modelsub12 120v? The pdc board has a zener diode marked Z1 that checks two directions in circuit but out of circuit reads 653 on fluke diode scale.the diac d11 reads nothing either direction.I removed all conductive glue.q11 checked ok.Is the reason this amp won't turn on because I need a thermistor that is 10 ohms cold and rated at 4 amps? I ckd all the fets and high speed switch diodes on the secondary for shorts .All ok Replace pdc and thermistor?
  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
Help for repair or rebuild power supply from bass amp. Fredenando Power Supplies 1 14th December 2012 01:30 PM
Power Supply Problem/Repair ak_47_boy Power Supplies 3 7th July 2008 10:36 PM
klipsch bash amp repair anwaypasible Everything Else 1 12th September 2007 12:40 PM
HV power supply repair smoking-amp Tubes / Valves 1 17th February 2005 02:42 AM
Audio power supply repair tennisballg Car Audio 11 30th April 2004 12:12 AM


New To Site? Need Help?

All times are GMT. The time now is 08:35 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