We bought the SPC 10 subwoofer as part of a Diamond 5.1 speaker set around 10 years ago – was a lot of money. Noticed the other day the bass sounded a little flat. Turned out the SPC 10 ‘power cube’ was not coming on (no little green light on back).
Started by checking fuse which is mounted in main input on back of unit (New Zealand version anyway) – that was fine.
Ignoring warning on the back I opened the unit to see if I could see anything obviously wrong:
- The IC connected to big aluminium heat sink on high voltage side of power board was blown. I was unable to read lettering on chip since burnt off/ blown away.
- The power unit was not supplying low voltage (15V) to the processing board.
What Google said
- Wharfdale website wholly unhelpful. Kind of disappointing. I know it’s an old product, but still.
- A local hi-Fi place sells new (‘deleted stock’) units for NZD$759. Not going to happen.
- Did not have much luck finding replacement power board nor circuit plans to attempt a repair (id blown chip).
A saviour – Silvestron Bits and Bytes video
Resigned to the thing being totalled and that I would be having to lob into the sea (has a symbol on back warning against putting in dustbin) I came across video below.
The chap had same issues as I (blown IC and no low volt power) but was able to identify the blown IC chip: a TOP261YN by Power Integrations.
I ordered both from Mouser Electronics, which I think is a US company (though my bits came from Hong Kong). Components were a couple of cents each (if you are in NZ – hit me up, I bought spares). Shipping was going to be $20 or sommin to New Zealand so I got sucked into Mouser’s free fast DHL delivery if you spend over $60.
Anyway, here are the parts:
The problem I ran into
I was a little heavy-handed removing the Zener diode and ripped hair-thin trace off top of board that connects across cathode of Zener. Dohhhhh! So: Be super careful removing the old diode!
Actually. Just be careful generally.
I managed to jerry rig a fix by splicing in some copper wire with Teflon tube (a trick I learnt on video below). The trace runs to an IC labelled ‘U3’ (could not read label on chip) and somewhere else (I soldered to broken trace and used some heat shrink tube to secure).
Anyway – it worked. Thanks, Silvestron.