I’ve been working on this old audio amp and learning lots in the process.
It’s a Sugden A48 which came in along with an old Pioneer Turntable. Both needing some tlc. The amp was first powered on with isolation transformer, dim bulb tester and Variac to ensure we didn’t have a short circuit or appliance that couldn’t cope with 240v AC after years of being in an attic unused. Next we checked the dc voltage on the speaker outputs to ensure we were not going to destroy any speakers fitted. Then the covers came off, caps were checked to be discharged and a new power cable was fitted.
The cover has been painted with a paintbrush with no primer coat and was flaking off so that needed fixed too.
So far we’ve tested the amp with a signal generator and oscilloscope and run for a short while with a cd player hooked to the tape input. Next will be phono circuit once we get the turntable working.
So far so good, but it’s also been a steep learning curve. There’s always a risk that once the customer starts using it electrolytes may leak from the caps, and other components may fail. But one step at a time.
Amazingly the service manual is still available and the company is still making audio products in the uk.
Essential is H&S. Lots of large capacitors, mains voltages. Tips like keeping one hand behind you back while working on the unit with covers off are excellent for increasing safety.
Would be great to hear of other tips to protect the repairer, the item being repaired and the customer. Oh and it had the wrong fuse in the plug. Pays to check and not assume.
