Polk Audio PSW 110 subwoofer

[batch85]

Re: Polk Audio PSW 110 subwoofer

Thanks again sir frankusb, and thanks also sir budm for that detailed photo of the filter cap and the SMPS IC.God bless both of you.

[frankusb]

Re: Polk Audio PSW 110 subwoofer

Well I've been using this subwoofer since the summer and it recently developed a hum. I decided to take budm's advice and replace the remaining capacitors. After doing that, the subwoofer no longer powers on. The LED blinks once a second or so. I've checked multiple times that the replacements were installed correctly observing polarity and that the voltage/capacitance matched the replacement parts. I am inclined to swap back to the previous parts and then install and test incrementally.

Any better ideas on how to approach this?

[R_J]

Re: Polk Audio PSW 110 subwoofer

This is a double sided board and you likely pulled the feedthru's out when you removed the capacitors, have a close look at the leads on the original capacitors, if their is a piece of the circuit board remaining on the lead thats your problem.
Post good clear pictures of the boards so we can have a look.

[frankusb]

Re: Polk Audio PSW 110 subwoofer

Thank you, I did damage a trace during removal. I found it on the first capacitor I pulled and had to make a small bridge out of a copper wire.

The subwoofer is powered on without any hum.

[ben2talk]

Re: Polk Audio PSW 110 subwoofer

Thank you, I did damage a trace during removal. I found it on the first capacitor I pulled and had to make a small bridge out of a copper wire.

The subwoofer is powered on without any hum.

OK, my turn now... ordered a 5-bag of 47uF 64V Panasonics (stated 10,000 hours lifespan... let's see). Sadly my eyes even with glasses gave me a headache (I left college in 1986 - I wasn't too bad then, but things got smaller and tighter since then!) so I'll be popping out to a local mobile phone repair guy to do my soldering.

[Kadro Correa]

Re: Polk Audio PSW 110 subwoofer

q14 and q15 are burst I can't identify them in my circuit
Can someone help me

[Kadro Correa]

Re: Polk Audio PSW 110 subwoofer

q14 and q15 are burst I can't identify them in my circuit
Can someone help me

I know they are the same of Q20 and Q21, but i dont know the order

[fabio_rm]

Re: Polk Audio PSW 110 subwoofer

I know they are the same of Q20 and Q21, but i dont know the order

They are the power mosfet on the right of the pcb, near the speaker output

[fabio_rm]

Re: Polk Audio PSW 110 subwoofer

I have part of amplifier schematic, lack the schematic of oscillator/comparator little pcb mounted vertical and seems nowhereto by found. Anyway on the schematic there are not voltage reference, i think voltages on the transformer output are too low , nobody know something about what need to be these voltages after the rectifier diodes over filter suplpy capacitors?

[fabio_rm]

Re: Polk Audio PSW 110 subwoofer

I try again. Nobody can measure the voltages on the secondary of the transformer after the rectifier diodes, when the sub is running and in the ON state?

[bfarnam]

Re: Polk Audio PSW 110 subwoofer

Thread Revival -
@Kadro Correa Q14 is IRF9Z24 and Q15 is IRFZ14 and they drive the SPK + wire from Vcd+ and Vcd-.

@fabio_rm the voltages on the secondary after the full wave rectifier should be the same as the mains minus any voltage drop from the full wave bridge rectifiers. This circuit is ALWAYS LIVE as there is no on/off switch.

If you voltage is low, I would suggest looking at the primary voltage ripple cap, C24, 150uF 400v. This is likely underrated and this is the same for the PSW110, PSW111, and PSW225. Also check continuity on D15, D16, D19 and D20 (full wave bridge). If one of these is open the voltage will be low.

When replacing C38/C39 it is important to keep the rated ripple current at 90mA or higher. A higher rated cap will prolong it's life.