Hi guys
I'm a total newbie here, but a hobbyist and in need of a little desperate help with my AA0509 subwoofer amp which died today. It's been working perfectly for the past couple of years without a hiccup. I've checked the mains fuse and it's fine.
Have now disassembled the amp but can't see any obvious signs of burnt out resistors or power transistors. I DO know,however,after testing with the multimeter,there's no power from the supply rail, so it's more than likely something in that circuit. Has anyone had any experience with these or know of a common fault I may be able to work with?
Thanks in advance.
I'm a total newbie here, but a hobbyist and in need of a little desperate help with my AA0509 subwoofer amp which died today. It's been working perfectly for the past couple of years without a hiccup. I've checked the mains fuse and it's fine.
Have now disassembled the amp but can't see any obvious signs of burnt out resistors or power transistors. I DO know,however,after testing with the multimeter,there's no power from the supply rail, so it's more than likely something in that circuit. Has anyone had any experience with these or know of a common fault I may be able to work with?
Thanks in advance.
Just an update to this post. Upon further examination, I've discovered a badly burnt out resistor in the power supply module. I can see evidence of burn out on accompanying signal transistors underneath so I'm wondering if there's a source of replacement modules for these. I have no idea what the resistor is as it's totally burnt. Or any ideas??? Thanks
If this unit is 20 years old like my digitech (of utah) effects unit, probably the electrolytic filter capacitors shorted out. this then would take out the power rectifier (bridge) after the power transformer. If your "module" has two terminals with wiggle symbols (AC) and a + and a -, then it is a diode bridge. commonly available, but check with meter from each AC to each plus and minus.
Manufacturers tend to use resistors as "fuses", as without the liability insurance they are a lot cheaper.
If your module is not a diode bridge, you'll have to find a schematic with google or bing. Digitech of Australia, and digitech of Utah are not the same company, IMHO.
Manufacturers tend to use resistors as "fuses", as without the liability insurance they are a lot cheaper.
If your module is not a diode bridge, you'll have to find a schematic with google or bing. Digitech of Australia, and digitech of Utah are not the same company, IMHO.
Thanks for your reply Indianajo. Much appreciated. There is a burnt out resistor,which I suspect has been used as a fuse but I think it's taken out a couple of transistors along with it. Probably not worth chasing up and cheaper to just replace the whole thing I reckon.
Thanks again
Thanks again
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