Krell KSA-150 Repair and Restoration - avoid Trevor Lees Audio...

[Sirflatch]

WoW U do such an AWESOME JOB !!!! PLEASE FIX MY KSA 250 Signature Series Beast !!!

[mikefitzman]

@Sirflatch Thanks, would be happy to fix yours, I am in Perth, Western Australia.

[overkillaudioinc]

How did you repair the damaged circuit board areas where the PCB substrate was charred?

[mikefitzman]

@overkillaudioinc Hi, yes this was something a took a bit of time with. As these are very low impedance areas of the circuit, I removed as much carbon as possible with a toothbrush and solvents, and then measured the resistance in the burned areas. After cleaning, the damaged areas had essentially the same resistance per mm as undamaged board, and so were good to go. I then installed new parts on both damaged and undamaged boards and she has been perfect ever since.

[overkillaudioinc]

@mikefitzman I have repaired many crest amplifiers that burn holes through the board when the PSU caps fail. I grind away all charred areas of the PCB with a dremel tool, then grind up some old PCB and mix with epoxy and fill in the hole or charred area and grind down flat once fully cured. this works well but I was curious if you had other techniques or methods. always looking to improve.

[mikefitzman]

@overkillaudioinc This is a good method and if I had not been able to remove the carbon, or if the burns had been deeper, I would have needed to do this myself. Luckily I was able to remove what the previous 'tech' had left behind and there was enough good board remaining.

[fireplace911]

It costs nearly $1000 to send an amp to your house and back?

Where do you live the south pole?

[mikefitzman]

@fireplace911 Yes, a 50kg amp worth $3000 + double boxed packaging does cost nearly $1000 to send twice across Australia, a distance of 3500 km x 2, using a reputable shipping service!

[mikefitzman]

@fireplace911 Speculation is always dangerous. What occurred is exactly as I described it. Paypal did not and would not offer any partial refund for repairs. I took it to the highest level of review in Paypal and had full documentation. Even with the seller's fraudulent listing, all they would offer was a refund of purchase price minus two-way shipping, potentially leaving me nearly a grand out of pocket for trusting a seller - way worse than keeping the amp and restoring it. Sad, but true.

[incyphe]

I don't know you, but you are a genius, and a true craftsman.

[mikefitzman]

Thanks for those comments guys, much appreciated.

[apogeediva]

Kudos on the work you did. You're certainly a perfectionist!

Shame on dealers like Trevor Lees - 99% of the end users don't have your expertise and would have had to scrap this lemon.

I'll contact you separately about a KSA-200S I own.

[freemanslim]

PROS mate!! oh and a great music taste by the way :)

[mikefitzman]

@zozanday I agree that there are some bad eggs out there but overall, my experience has still been excellent and I have had some wonderful deals on eBay - just not this one!!!

[fragglan]

OMG ! This person you bought it from is for sure a monkey !!!!!!!! Should i laugh or cry? To repair with this kind of parts in equipment like this is unbelievable... Thank good it's in your hands now, and you've gave it a proper repair, to last many years to come. Nice video, i have made a similar work to a KSA-250 and i was lucky if i compare to your hidden problems. NICE WORK !!!

[mikefitzman]

@fragglan Thanks very much for the kind words. I saw your KSA-250 video and it is excellent. You make some great points about the slow start board. The one in my KSA-150 is laid out differently and those ceramic resistors get hot, but nothing else is quite so close by. I love your solution to the issue - very nicely done.