"N_Cook" wrote in message
...
Gareth Magennis wrote in message
...

"N_Cook" wrote in message
...
Gareth Magennis wrote in message
news Hi,

I have a Trace Elliot 300W bass amp here that uses 2 pairs of
BUZ901/906
mosfets. All output devices have been resoldered or replaced at some
point,
and the amp now contains 2 x BUZ901 (SML) and 2 marked STUD1P.

I've repaired a few of these in my time but never come across this
marking.
Is it a Trace internal number, or have these been substituted in from
elsewhere? Are they actually BUZ906?

(One BUZ901 is blown, the other 3 check out OK on a PEAK component
tester).


Cheers,



Gareth.




perhaps obtained from these people
http://www.autogarduk.com/stock%20list%2027.htm
41 P and 274 N

What are the test parameters of a Peak?



Don't have a clue. It runs on a 9v battery.

It does claim to measure hfe, but again I don't know with which
parameters.
I don't think its meant to be a precision instrument but I find it very
useful, mostly for finding dead mosfets and possible good ones, and
identifying pinouts of bipolars.

I once had terrible problems with a C-audio amp that I just couldn't get
working. They had loads of BC184 (I think) doing the bias and stuff. I
replaced the lot with BC184L, not realising that the "L" meant the pinout
was different. Took me a looong time to suss that one out.
Now I always double check with the Peak when replacing any signal
transistor, just in case.

Likewise Farnell once sold me some resistors that were a decade lower
than
marked on the packaging. Again took me a while to suss out the problem,
and
I now always meter EVERY resistor before soldering it in.

Cheers,

Gareth.



If mains fuse is designated T3.15 amp, it wil probably need an inrush
fitting sometime in the near future , see thread here last week T-E GP12
SMX
and Studiomaster comparison


I contributed to that thread. I'll be sticking a T4 in it instead. ;-)
4 new Mosfets and labour is almost an uneconomical repair as it is.





Dealt with a heap of C-audio Pulse 2 1100 last year. Stored outdoors (open
sided barn) with the thinking that plastic tarpaulin over the rack with a
pack of silica gel (as found, not activated) inside it in the autumn would
keep them ok over a GB winter.

Except for a few colateral damage burnt out 1/3W R , all the problems were
those TO92 , gone slightly ohmic presumably from damp ingress. Throws out
the bias and then amp always goes into protect.



I looked inside 2 of these C audio pulse (nothing to do with C audio really)
and quickly put them back together again and gave them straight back. Fist
time I'd ever done anything like that.



Gareth.