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.
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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:
http://www.diyaudio.com/forums/class-d/47401-klipsch-promedia-bash-amplifier.html
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:
http://www.diyaudio.com/forums/class-d/47401-klipsch-promedia-bash-amplifier.html
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!!
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?
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?
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.
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
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
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.
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.
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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
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?
Hey Zeppy,
I was working on my bash amp and totally forgot which orientation of which FET went where.
I was working on my bash amp and totally forgot which orientation of which FET went where.
I bought the NTE67 and NTE2374 which respectively were suitable replacements for the FETs but since I removed them from the board I forgot which one went where.
Thanks for this thread
I replaced the 2 IR730s and removed the crispy adhesive from the back of the SMPS control board and all is well again.
I replaced the 2 IR730s and removed the crispy adhesive from the back of the SMPS control board and all is well again.
The thermistor can be bypassed temporairly for testing. Just use a 100W lightbulb in series with the power to limit the current. Always check the gate resistors to the mosfets also. Klipsch should offer a free replacement for all amps that use this bad glue. They are well aware of the problem.
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Hello crazifunguy and others, id like to know if anyone would sell a complete amplifier board plate made by yourself?
I have a dead amplifier board for my Synergy SUB-10 subwoofer, it is a Klipsch variant, also with that same Bash card. Could anyone help me?
I have a dead amplifier board for my Synergy SUB-10 subwoofer, it is a Klipsch variant, also with that same Bash card. Could anyone help me?
Hi, I also have a dead amp from a SVS PB12-Plus. I suspect it's also the SMPS. Does anyone offer repair services or know if someone who does? I'd like to not have to replace the entire sub.
Thanks,
Chris Seymour
Thanks,
Chris Seymour
Thank you so much for this information. I was able to fix my Polk Audio PWS-111 after replacing the switching FETs twice I scraped the adhesive off the back of the daughter board. No more blown FETs of fuses.