Logitech R20 (Model No. S-0153B) 2.1 Sub not working

[Joe Black]

Ok, here goes.

I got these 2.1s from a friend as non-working after pot replaced. Whoever replaced pot did some damage to board and SMDs around, and I was able to somehow jump-wire the pot to work again.

Now, the satellites are working ok, but the sub is completely dead. Supposedly
sub worked fine.

I have no clue about these systems, so if anyone can shed some light or has a (similar) schematics it would be splendid.

I don't know which one is the sub IC, or the pinout or the expected Vin (cant google because coolers cover IC numbers). When I touch some SMD caps with tweezers sub is buzzing, so I figure wiring is OK.

So again, I+m totally lost here, and thanks for any input.

sorry, first pic uploaded accident, not sure how to remove

[budm]

Re: Logitech R20 (Model No. S-0153B) 2.1 Sub not working

You need to remove the heatsink to see the IC P/N.

[Joe Black]

Re: Logitech R20 (Model No. S-0153B) 2.1 Sub not working

I did, and the IC in question is an UTC8227. I will try to post what happens.

On pins 1 and 12 I have 12V DC when system is ON.

Same on pins 2,3,10 and 11 - 12V DC!?

On pin 7-3,5V DC.

Pin 8 - 1,5V DC.

Since I don't have a scope, I tried to check for V (AC) on inputs and outputs :

Pin 7 - around 3,5V AC.

Pins 2,6, and 11 all in mVs AC.

Also, I just measured resistance between pins

1 and 2 - OL
11 and 12 - 4 ohms.

Guess the IC is dead?