Mesa Mpulse 600

[xtian]

Rich at Mesa also pointed to profusionplc.com for replacement FETs--cost including shipping is about $275. Additional parts from mouser, plus about four hours of my time is causing client to reconsider sending the amp to Mesa for service, because they promised to cap the repair at $400 because client is a Camp Fire survivor. Cool, that's smart, because who knows what else is burnt up. Even the insulator behind the FETs was burned clean thru.

[J M Fahey]

Rich at Mesa also pointed to profusionplc.com for replacement FETs--cost including shipping is about $275. Additional parts from mouser, plus about four hours of my time is causing client to reconsider sending the amp to Mesa for service, because they promised to cap the repair at $400 because client is a Camp Fire survivor. Cool, that's smart, because who knows what else is burnt up. Even the insulator behind the FETs was burned clean thru.

WTF?

I just simuated ordering *ten* of each (because itīs cheaper than ordering 6 each)and my shoppingb cart at Profusion shows U$98.

Shipping to US is U$39 (to Argentina a whopping U$48)

Not sure about VAT, it "should" not be charged to International orders butb thatīs not a deal killer anyway.

My numbers show less than U$150, including US sourced micas and nuts/bolts.

Not sure where the U$267 bill can come from.

Replacing all 12 , turning amp on and testing with a load to check itīs working fine should be doable within 2 hours.

Just sayinī

Sorry, I forgot, include a few 5W 0.22 ohm resistors.
In any case, quite doable.

[xtian]

Am I shopping the same place as you? Here are the N-channel ones:

https://www.profusionplc.com/parts/ecw20n20-s

Listed at Ģ85.70 for ten, that's $112.10, times two plus $30 shipping is $254.

Please show your math, JM!

--

also, for labor, I've already got an hour into the job. And there are at least 7 x 12 = 84 solder pads that need to be desoldered. Plus time for disassembly/reassembly and testing. I don't own an electric desoldering station. How would you manage all this in two hours?

[J M Fahey]

Am I shopping the same place as you? Here are the N-channel ones:

https://www.profusionplc.com/parts/ecw20n20-s

Listed at Ģ85.70 for ten, that's $112.10, times two plus $30 shipping is $254.

Please show your math, JM!

Easy.



So the grand total is $98+$30=$128 if you want it within 1-3 days or $98+9=$107 if you can wait 10 days (I would).



--

also, for labor, I've already got an hour into the job.

WHY?
Seeing transistors *cracked* and shorted does not take more than 15 minutes, if that much.

And there are at least 7 x 12 = 84 solder pads that need to be desoldered.

???????
I count 3 pads per transistor and 2 per resistor ... IF they are open, which I doubt all are.

Plus time for disassembly/reassembly and testing. I don't own an electric desoldering station.

Nor do I.
But a plain solder pump + a plain soldering iron means I can desolder 2 per minute, at a leisurely pace.

How would you manage all this in two hours?

How?: easily.
Including assembly/disassembly and 15 minutes testing.
But then I do this a living; going too slow is not bad, I appreciate being careful and safe, but then I canīt bill overtime to the customer, can I?
Itīs my problem, not his.

In any case, you are not *forced* to do that repair, at a competitive price, and within 2 hours bench time, you can always lose the job and send it away if not comfortable with it.

[nosaj]

Easy.
[ATTACH=CONFIG]53040[/ATTACH]
[ATTACH=CONFIG]53041[/ATTACH]
[ATTACH=CONFIG]53042[/ATTACH]
So the grand total is $98+$30=$128 if you want it within 1-3 days or $98+9=$107 if you can wait 10 days (I would).



--


WHY?
Seeing transistors *cracked* and shorted does not take more than 15 minutes, if that much.

???????
I count 3 pads per transistor and 2 per resistor ... IF they are open, which I doubt all are.

Nor do I.
But a plain solder pump + a plain soldering iron means I can desolder 2 per minute, at a leisurely pace.

How?: easily.
Including assembly/disassembly and 15 minutes testing.
But then I do this a living; going too slow is not bad, I appreciate being careful and safe, but then I canīt bill overtime to the customer, can I?
Itīs my problem, not his.

In any case, you are not *forced* to do that repair, at a competitive price, and within 2 hours bench time, you can always lose the job and send it away if not comfortable with it.

Juan running the smackdown. All valid points, Juan is one of those people I'd love to work under. He would make me a much better technician,

nosaj

[xtian]

I would be happy to send the job to you, JM!

Thanks for showing the part numbers. I was sourcing ECW20N20-S -- much more expensive parts.

[J M Fahey]

If I only we were closer
But I guess 6000 miles would add a little to cost

In any case, BUZ90* are single die, same as most 2SK/J , so you donīt need to specify very expensive double die ones.

Your choice; if Factory flat fee is ok to you, so be it.

Not sure in this relatively conventional amplifier but I would choose Factory any day of the week with modern Class D amplifiers.

Yet Markus Bass deals with them routinely .... as with everything else, practice makes perfect.

[drewl]

Didn't take me long to rebuild one of these in similiar condition.
Another had that FET board totally fried beyond repair.

Replacement from Mesa came fully populated and wasn't too expensive.
Dropped it in, biased it up and it never came back going on like eight, ten years.

Call Mesa, see what they get for the board now, if they have any left.

[xtian]

Mesa no longer offers the boards.