I have a BASH amp that needs repair. Not sure if this should go in the class D section or not (BASH class D-ish? 
) It comes out of a Klipsch SUB-12. From what I've diagnosed so far, one opamp is bad (easy fix), and some part of the digital converter/drain voltage modulator. It appears that both sets of output transistor pairs (IRFZ14 and IRF9Z14) are OK (tested with DMM, verified gate signal looks OK on oscilloscope). The FET that controls the drain voltage (IRF530) seems to test OK, but without the digital converter working correctly I can't be 100%. One part certainly seems to be missing, (R61) which is a series resistor going to the current sense line. The UC2842A VCC line only goes to 2V when it is installed, but without will go to 22V. I had tried multiple UC2842A chips, and all do the same thing so I assume that isn't the problem. Solving both of these problems seems to be first on the list to getting this amp up and going. I can't really identify where the +22V is sourced from either. One pin on the module goes from a cap to ground and that's the only trace I can see connected to the main PCB.
Does anybody have a schematic (long shot) or at least have a high quality picture of the board so I can identify a missing part vs a DNI? Any help or guidance on this amp would be helpful.
) It comes out of a Klipsch SUB-12. From what I've diagnosed so far, one opamp is bad (easy fix), and some part of the digital converter/drain voltage modulator. It appears that both sets of output transistor pairs (IRFZ14 and IRF9Z14) are OK (tested with DMM, verified gate signal looks OK on oscilloscope). The FET that controls the drain voltage (IRF530) seems to test OK, but without the digital converter working correctly I can't be 100%. One part certainly seems to be missing, (R61) which is a series resistor going to the current sense line. The UC2842A VCC line only goes to 2V when it is installed, but without will go to 22V. I had tried multiple UC2842A chips, and all do the same thing so I assume that isn't the problem. Solving both of these problems seems to be first on the list to getting this amp up and going. I can't really identify where the +22V is sourced from either. One pin on the module goes from a cap to ground and that's the only trace I can see connected to the main PCB.Does anybody have a schematic (long shot) or at least have a high quality picture of the board so I can identify a missing part vs a DNI? Any help or guidance on this amp would be helpful.
Thanks!
The information you provided will certainly help lots of people - thanks a bunch!
The information you provided will certainly help lots of people - thanks a bunch!
Hi I have a BASH amp that needs repair. I just acquired a Klipsch Sub-10 Subwoofer (BASH) amp and was looking for a schematic for troubleshooting. By any chance has anyone in here figured out what was shorting out causing the 2 amp fuse to blow? I had read somewhere it was a thermal design issue? Anyone..Thanks
Hi all,
Rank newbiphile here with a question. I have a Klipsch Sub-12 with a dead plate amp. The progression was that I found a blown fuse, replaced it, and lots of smoke and sparks emanated from the "thermister"? next to the main AC bridge rectifier (D6? on the schematic). From what I read these BASH plate amps blow all the time. At one point Klipsch was exchanging them for about $60 but I hear that number has now grown to over $200. There is an Ebay guy in AZ who repairs these for $125, and you buy new BASH plate amps for I think $160. But my question is, given the reliability of these, and other factors, is it worth fixing or would a DIYer just replace the amp with something else? I was actually thinking of converting it to a passive speaker box and plunking the amp on top or bolting it to the back. I was hoping to spend as little as I can but I also don't want to throw good money after bad. I suppose one advantage to repairing is this amp was designed for this speaker. Or can't I even make that assumption? I have a scope and a meter, and I have some experience, but I have never been very good at troubleshooting.
Rank newbiphile here with a question. I have a Klipsch Sub-12 with a dead plate amp. The progression was that I found a blown fuse, replaced it, and lots of smoke and sparks emanated from the "thermister"? next to the main AC bridge rectifier (D6? on the schematic). From what I read these BASH plate amps blow all the time. At one point Klipsch was exchanging them for about $60 but I hear that number has now grown to over $200. There is an Ebay guy in AZ who repairs these for $125, and you buy new BASH plate amps for I think $160. But my question is, given the reliability of these, and other factors, is it worth fixing or would a DIYer just replace the amp with something else? I was actually thinking of converting it to a passive speaker box and plunking the amp on top or bolting it to the back. I was hoping to spend as little as I can but I also don't want to throw good money after bad. I suppose one advantage to repairing is this amp was designed for this speaker. Or can't I even make that assumption? I have a scope and a meter, and I have some experience, but I have never been very good at troubleshooting.
Just to add a quick note:
In addition to the thermistor I found one of the MOSFET's has a nice big hole blown out of it and a smoke trail across the board. The amp power transistors appear to be heat sinked to the large outer mounting plate, but the power supply MOSFET's are not. They just have a medium sized aluminum plate that sits inside with no air flow. Anybody know the likelihood that various electrolytics in this thing have dried out and may be a problem? I think I'll take a trip to Fry's and if the parts are cheap enough I may just replace the stuff I see and hope the circuit powers up well enough to probe around for other issues. I will replace both MOSFET's at least.
In addition to the thermistor I found one of the MOSFET's has a nice big hole blown out of it and a smoke trail across the board. The amp power transistors appear to be heat sinked to the large outer mounting plate, but the power supply MOSFET's are not. They just have a medium sized aluminum plate that sits inside with no air flow. Anybody know the likelihood that various electrolytics in this thing have dried out and may be a problem? I think I'll take a trip to Fry's and if the parts are cheap enough I may just replace the stuff I see and hope the circuit powers up well enough to probe around for other issues. I will replace both MOSFET's at least.
Hello
I too have a sub 12 with the burnt board.
do you remember how you solved this problem? thank you
denis6gallo@gmail.com
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