The Canton family of speakers are very popular and good value for money for things like a home cinema.
This one came into the bench dead on arrival. It simply made no noise at all. So my amplifier was hooked up to it to reproduce the issue. This is always a good idea, as it rules out a possible issue with the customers amplifier and allows me to ensure the fix has actually worked.
Once opened, the circuit board was immediately visible. A search on the internet showed there were various mods of the Canton PCB out there and finding the exact one would be a challenge. I finally settled on this one, as it matched my version of what was infront of me most.
I used my vintage Heathkit signal tracer to follow the input signal and see where it was being lost.
Why? Well, this is a set I had purchased in USA years ago and had refurbished and overhauled and brought back to life. So it was fun to get a chance to use it again. It is an old tube operated amplifier, that allows and engineer to trace a signal using the probe and to work out on which component, the signal stops and goes no further. In this case, the signal was being lost at the cross-over potentiometer.
A good strong signal was going in but absolutely nothing as coming out. A test with my meter showed open circuit no matter where the potentionmeter was positioned. So any easy fix is to join the output of Op-Amp IC1A to the input of IC1B.
This is what the potentiometer looks like.
There is only one seller on ebay currently selling this item used, removed from an older device. However, the cross-over setting is rarely used anyway and the potentiometer can be bypassed. Should the user wish a full repair later, we can look into that option. So for now the R-3 to R2 legs of the potentiometer were bridged using solder.
The subwoofer was back to life and operating as normal. Time to screw everything back together and return it to it's owner.
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