UK – Wanted - Loan or Purchase – Faulty Logitech Z906 Subwoofer and Control Unit

[Chris56000]

Hi!
Is there anybody in the UK got a faulty Logitech Z906 Subwoofer & Control Unit they're willing to loan or sell me cheap for drawing out and documenting please?

There are so many problems and threads about these going defective, that I'd like to make some proper drawings and parts list for them to help Members with faulty units!

(I will investigate whilst drawing out and let any Member who loans me these what the fault is so they can decide whether a repair is worthwhile!)

Chris Williams

[DavidAlfa]

Not what you're asking for, but I found this folder with plenty of internal pics of the Z906:
https://drive.google.com/drive/folders/1hneUEiCzSagL9xqY97EnEmZD2zfqwrbj

[Chris56000]

A folder of pictures will serve as a "placement guide" and a record if parts have to be removed from a PCB but it is is useless for circuit tracing purposes – you cannot trace a circuit built with SMD out from a photo – you have to be prepared to remove components like i.c.'s from the PCB to see the tracking underneath the integrated circuit devices themselves!

The only way to do this correctly is by continuity and component–value measurements from the actual units themselves – this is a point I will be emphasizing in the "Circuit Tracing" chapter of my T & M Theory and Repair Book now being written!

(I won a set on eBay about eighteen months ago for this purpose but the seller refused to honour the sale and sent me a nasty note saying "did you think I was going to let this go for £27?!")

Chris Williams

[Nominal Animal]

Amazon UK is selling them new for 300 UKP as of 2023-06-19, with used complete sets for sale on eBay and elsewhere for 180-260 UKP.

If you cannot find anyone willing to borrow/borrow+fix/sell theirs to you, you could always consider buying one new, and then putting it on sale at eBay or elsewhere, to recoup some of the cost.  If it is also hardened/fixed against the most common issues affecting them, mentioning it was used to reverse-engineer and fix the issue, and fully tested but not otherwise used, should let you recoup most of the original price, I think.

It is what I would do, having very minimal budget for my hobbies, but knowing how liberating and stress-reducing actually owning the device to be dissected is: in my book, certainly enough so to warrant the financial risk.

[Chris56000]

I've got no problems with buying one, either a full set or just the parts I want to draw out, but the prices on eBay, even for non–workers have been verging on the obscene in recent months, often up to FIVE fumes the new price on Amazon – how do they expect to sell at those over–inflated prices?!

Can anyone confirm that it would only be the Control Unit and Subwoofer I need for the circuitry components?

Chris Williams

[Old Printer]

Ambitious. First thing that strikes me is if this thing is that bad, and they have made a bunch of them, it is likely Logitech has revised the boards/components trying to sort it out to cut down on warranty claim expense. Kind of like trying to hit a moving target. Do the pictures of the boards show revisions?

[Chris56000]

No, I can't see any revision numbers on any of them, and there are no signs of after–design modifications, (e.g., added thro' hole components attached to the boards, "mod–wire" links, obvious track–cut mods, etc., etc!) that I could spot on those pictures!

When I draw anything out I always mark the PCB revision/copper number, etc.,in a prominent place on my diagram and mark "added" components in light blue, and "unpopulated" positions using light pink dashed–line symbols and red component reference numbers!

Chris Williams