After loaning out my Dynacord powered mixer to a friend he in turn loaned it to a fellow sound engineer (I use the term loosely!) Who managed to blow it up on a local UK Council paid job (Glossop Remembrance Sunday)! The story even made a local UK Councillor's Blog. The audience were as disappointed as myself I suspect! And being the kind guy that I am.. I'm only charging for the destroyed parts, including 20 power transistors! I suspect that most engineers would have written the unit of..
Update: Not only has the clown who used my mixer-amp without my permission and then broke it, not yet apologised to me. But I believe he has actually complained at the cost of the parts for the free repair! The cheek of it! I already explained about complementary transistors and the need to use a matching set. I may just send him a bill for labour: So far 6 hours at let's say £60 per hour = £360
All done! 1 x service manual £20 16 power transistors, silicon diode, 3 x resistors, solder and heat transfer paste £130. Labour: 1 hour strip down time, 3 hours troubleshooting schematic, 2 hours fitting new parts, 2 hours following manufacturers service procedure and 1 hour rebuild = 9 hours @ £40 per hour £360. Total £510. Be very grateful Coco!
A rather frazzled power amp section!
Transistors Removed
Removing Through-Hole components from a double sided circuit board takes time and care.
New power transistors fitted
Before soldering the transistors in I cleaned up the heat sinks with isopropol alcohol and then applied heat transfer compound to the bottom of each transistor.
Repaired and ready for 'Rasputin's Younger Brother'..