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Silvercrest CT2116 (uk)

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Turnip:
Hi Andy,

You've prob sussed it but attach my 11AK30 file - Chris

Restorer79:
 :c017: Chris, much obliged all info on this is handy. It's the other halfs set & she likes it. Noticed in your notes that it says about a special version of BU808DFI for this set, have you ever had problems fitting a standard replacement ?


Andy

Keith:
Ahhh the AK30! Nothing special about the BU808DFI, repaired 100's of these for hotels when I was working in Greece.
Replace the BU808, the main cause of the failure is C613 (line drive coupling), also worth changing C810, C848,C826, C623. Check for dry joints on the line drive transistor and associated components. Some models of the AK30 seemed to have a badly moulded rear case that pressed on the LOPTX pins, so check for dry joints on the LOPTX too and cut the pins a little shorter.
I got bored fixing these! But I was on commission, so when 10 arrived at once I knew cool beer would be waiting for me at the Jolly Roger.

Discharge the main smoothing block before working on it, they bite!

Keith

Restorer79:
Hi Keith: Thanks again for the reply, appreciate it. Yep smoothing cans can certainly bite the unwary, my Daughter saw me clipping a 100k across the can yesterday & wanted to know why. She's nearly finished her 1st year in College learning Industrial Electronics & Robotics, but when they've been taught about SMPS faults, nobody appears to have told them about Discharging the caps. I always clip a 100k across even if there is already a bleed resistor fitted, always change the line drive coupling caps when i've got a blown output transistor (Once bitten twice shy) & will change the others as well to be on the safe side. Your right about the LOPTx being dry jointed by the way it certainly was, also the chopper transformer was pretty bad.
Will check the other things you mention as well, when it's back up on the bench.
Gotta be fair working on this re-inforced why I hate working on modern equipment, everything is just so flimsy. Give me a dozen Vintage set repairs over 1 of these anyday.

Cheers: Andy

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