Strangely marked BUZ Mosfet
Gareth Magennis
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.
Phil Allison
"Gareth Magennis is a FUCKING MORON "
>
>
> I have a Trace Elliot 300W bass amp here
** I suppose you whole life is over if you tell us the fucking model number
?
> 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.
** The device is labelled " STUPID " ???
April 1st has gone you know.
> One BUZ901 is blown,
** I suppose your whole life depends of not telling us what YOU mean by the
word "blown" ??
Lateral MOSFETS fail ( if they fail) in a unique way - not like any
other power devices.
WHAT IS IT ???
.... Phil
Gareth Magennis
"Phil Allison" <phi...@tpg.com.au> wrote in message
news:903a2u...@mid.individual.net...
You do make me laugh, Phil.
If it matters, it is a 7215 combo, i.e. a GP7 300 Watt SM series, but I
believe all Trace Amps share the same 2 amplifier modules.
There's a Bi-polar Bear which is Bi-polar (you might like that one), or the
150/300W Mosfet board which is Mosfet. I guess the 150W one uses just 2
Mosfets and smaller PSU caps.
But the question is only about the markings on the output devices, and
whether this STUD1P device is the original Trace part or some numpty
repairman has retrofitted a dodgy part he manufactured himself in his
kitchen of took it out of a Studiomaster or summat.
Sigh.
Gareth Magennis
p.s. it has been repaired at a place I know about that is well known for
dodgy repairs, and the soldering is absolutely shocking.
Phil Allison
>
>>> I have a Trace Elliot 300W bass amp here
>>
>>
>> ** I suppose you whole life is over if you tell us the fucking model
>> number ?
>>
>>
>>> 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.
>>
>>
>> ** The device is labelled " STUPID " ???
>>
>> April 1st has gone you know.
>>
>>
>>> One BUZ901 is blown,
>>
>>
>> ** I suppose your whole life depends of not telling us what YOU mean by
>> the word "blown" ??
>>
>> Lateral MOSFETS fail ( if they fail) in a unique way - not like any
>> other power devices.
>>
>> WHAT IS IT ???
>>
>
** You make everybody puke.
You colossal TURD !!
> If it matters,
** Of COURSE it fucking matters !!!!!!!!!!
> it is a 7215 combo, i.e. a GP7 300 Watt SM series,
** So now folk can look up the thing in their files -
YOU FUCKING TENTH WIT !!!!!!!!!!!
> But the question is only about the markings on the output devices, and
> whether this STUD1P device is the original Trace part or some numpty
> repairman has retrofitted a dodgy part he manufactured himself in his
> kitchen of took it out of a Studiomaster or summat.
** Who fucking cares ?
If you do not know how to test it - you are an absolute ASS.
Now - answer my fucking QUESTION !!
Go back - read my posts ten times AND you just might see there IS one.
You steaming great pommy FUCKWIT !!
.... Phil
Gareth Magennis
I've already told you I tested the MOSFETS with a PEAK component analyser.
There, I've done it again, it says "P-channel MOSFET". The blown one says
"NO VALID PART FOUND".
You don't happen to know if this STUP1D Mosfet is a BUZ906 by any chance?
Phil Allison
>
>>
>>
>> If you do not know how to test it - you are an absolute ASS.
>>
>> Now - answer my fucking QUESTION !!
>>
>> Go back - read my posts ten times AND you just might see there IS
>> one.
>>
>> You steaming great pommy FUCKWIT !!
>
>
** You are one LYING POMMY CUNT !
QUOTE:
"One BUZ901 is blown, the other 3 check out OK on a PEAK component tester ".
So - SOMEHOW you think the BUZ901 is 'blown".
But you do not say WHY or how you know !!!!!!!!!
Do you own a fucking multimeter ?
Got the slightest fucking idea how to use it??
Obviously NOT.
.... Phil
Phil Allison
"Gareth Magennis is a Steaming Great TURD "
>
> You don't happen to know if this STUP1D Mosfet is a BUZ906 by any chance?
** You just changed the part number.
Stupid.
.... Phil
N_Cook
news:p-SdnRAdzr627QHQ...@bt.com...
While at it toroidal mains Tx ? any inrush limitation ? no ken those
markings.
Trace Elliot GP12 SMX, 1998 300W bass amp last week PA was marked "Bipolar
Bear" on overlay and devices under spring clips, not seen , but checked out
as BCE npn & pnp devices
Meat Plow
> p.s. it has been repaired at a place I know about that is well known for
> dodgy repairs, and the soldering is absolutely shocking.
Why not just replace all 4 with known pairs? TT manufactures
a bunch of different audio mosfet devices
http://www.semelab.com/magnatec/alfet.shtml
--
Live Fast Die Young, Leave A Pretty Corpse
Gareth Magennis
"N_Cook" <div...@tcp.co.uk> wrote in message
news:ini43d$nfo$1...@dont-email.me...
Toroid, will get back to you tomorrow with the rest.
Gareth.
Gareth Magennis
"Meat Plow" <mhyw...@yahoo.com> wrote in message
news:pan.2011.04...@lmao.lol.lol...
Yes, that is my preferred option, and I could get them from Farnell
tomorrow.
However, that would cost me about £50 for the four, so perhaps £60 to the
customer, which is getting on for $100.
If there is any doubt what these oddly marked devices actually are I will do
just that.
Cheers,
Gareth.
Gareth Magennis
Not really my policy I'm afraid. If it blew up again I wouldn't have a leg
to stand on.
Cheers,
Gareth.
Ian Field
Philthy was raised by dingoes.
Michael A. Terrell
Gay dingoes.
--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.
Meat Plow
$100 isn't bad for a slayed output stage. Especially on previously bodged
repairs. For that combo and most others including vintage my minimum fee
is $100 before parts. I do more work on vintage than anything. People
drag in these Silvertone, Airline, Ampeg, Gibson etc.. from the late
1950's/60's all the time. If it's a small combo like a GA series
Discovery,Maestro,Explorer etc...I'll slide the $100 minimum fee unless
it needs a restoration. Last Silvertone 50 watt head I restored I charged
$200 labor and the customer never batted an eyelid.
I'd replace all 4 of those devices and take a hard look at the whole thing
probably before I ordered parts.
Phil Allison
"Gareth Magennis"
>
> If there is any doubt what these oddly marked devices actually are I will
> do just that.
** What does your PEAK say about the pin out and the Gate threshold
voltage ?
Should be Source on the case and about 0.5 to 1.0 volts.
.... Phil
Gareth Magennis
"Phil Allison" <phi...@tpg.com.au> wrote in message
news:904nfo...@mid.individual.net...
Doesn't display voltage information, it either says its a "* channel mosfet"
and identifies the pins, or "no valid part found". Its a PIC based device
I believe.
I bought it purely to check Mosfets go or no go, and it works well.
Gareth.
N_Cook
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?
Gareth Magennis
Toroid and no inrush limit device. The Bipolar Bear uses 2SA1695 and
2SC4468 devices.
Gareth.
Phil Allison
"Gareth Magennis"
>
>
> Doesn't display voltage information, it either says its a "* channel
> mosfet" and identifies the pins,
** IS THE *SOURCE* ON THE FUCKING CASE OR NOT !!!
You FUCKING MORON !!
.....Phil
Gareth Magennis
Gareth Magennis
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.
Phil Allison
"Gareth Magennis"
>
>>> Doesn't display voltage information, it either says its a "* channel
>>> mosfet" and identifies the pins,
>>
>>
>> ** IS THE *SOURCE* ON THE FUCKING CASE OR NOT !!!
>>
>> You FUCKING MORON !!
>
> Bye bye.
** FFS - asshole !!
What the FUCKING HELL is wrong with you ????
Is it gonna KILL YOU to post a simple, factual reply ???
The ANSWER to MY question is the ANSWER to YOUR question !!
Did your mom refuse to breast feed you ? ?
Did your dad fuck you up the arse when you were two?? ??
JESUS FUCKING CHRIST alive ...............
You gotta be the most RETARDED autistic pommy cunt ALIVE !!
..... Phil
N_Cook
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
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.
Gareth Magennis
Just realised I've got the old version of the Peak. The new one does more
things than mine, like gate threshold voltage.
Gareth.
Gareth Magennis
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.
Arfa Daily
"Phil Allison" <phi...@tpg.com.au> wrote in message
news:905njj...@mid.individual.net...
I thought you told me a couple of weeks ago, that that was me Philip ...
:-)
Arfa
Ian Field
"Arfa Daily" <arfa....@ntlworld.com> wrote in message
news:WIknp.6238$2o1....@newsfe18.ams2...
There's one for every one of his split personalities.
Meat Plow
It's everyone who isn't Phil "fucking insane" Allison.
Meat Plow
I own a really old Sencore Cricket transitor/fet checker. You don't have
to identify BCE correctly because it has 6 pushbuttons on it. It's still
a useful tool to check leakage and gain.
Gareth Magennis
"Phil Allison" <phi...@tpg.com.au> wrote in message
news:905njj...@mid.individual.net...
Phil, if you want to tell us about Mosfet dv/dt failure or something, just
come straight out with it.
I don't know why you feel the need to set these traps.
But thanks for the heads up anyway.
Gareth.
>
>
Phil Allison
"Gareth Magennis"
> "Phil Allison"
>>>>> Doesn't display voltage information, it either says its a "* channel
>>>>> mosfet" and identifies the pins,
>>>>
>>>>
>>>> ** IS THE *SOURCE* ON THE FUCKING CASE OR NOT !!!
>>>>
>>>> You FUCKING MORON !!
>>
>>>
>>> Bye bye.
>>
>>
>> ** FFS - asshole !!
>>
>> What the FUCKING HELL is wrong with you ????
>>
>> Is it gonna KILL YOU to post a simple, factual reply ???
>>
>> The ANSWER to MY question is the ANSWER to YOUR question !!
>>
>> Did your mom refuse to breast feed you ? ?
>>
>> Did your dad fuck you up the arse when you were two?? ??
>>
>>
>> JESUS FUCKING CHRIST alive ...............
>>
>> You gotta be the most RETARDED autistic pommy cunt ALIVE !!
>>
>
> just come straight out with it.
>
> I don't know why you feel the need to set these traps.
** There is NO TRAP - you dopey wanker.
You want to know if that STUP1D device is a lateral mosfet like the BUZ906 -
right?
If it is, it will have the SOURCE connected to the case.
But if as is likely it is NOT like the BUZ906, the SOURCE will be on the
same pin that is the emitter of a TO3 transistor.
FACT:
All power mosfets have an internal DIODE between the Source and Drain
terminals that is reverse biased in operation.
So, you just need a multimeter to say which way the device in question is
connected internally.
.... Phil
Gareth Magennis
OK, thanks. This does have the Source connected to case (actually the tab
as these are TO247 versions, not TO3).
But in trying to decipher what I thought you were getting at, I investigated
the dv/dt failure mode which I think the "blown" mosfet may have, as there
is around 165ohms between gate and source and/or drain. (I can't stop the
SD from looking like a short circuit).
Interestingly the customer said that the amp went DC and fried his speaker -
the amp has no relay or DC protection. My little bit or research so far
indicates that dv/dt failure in industrial motor applications can be down to
pulling the power cable off a stalled motor, zapping the gate/substrate
connection in a nanosecond. Might this also apply to a faulty speaker in
this kind of audio amp which burns short then eventually self disconnects?
I also understand extremely electrically noisy environments can also induce
this failure mode. The customer is daisy chaining this amp with another one
via the FX send, I'm wondering if this has any chance of being the cause of
the failure.
Cheers,
Gareth.
Phil Allison
"Gareth Magennis"
> "Phil Allison"
>> You want to know if that STUP1D device is a lateral mosfet like the
>> BUZ906 - right?
>>
>> If it is, it will have the SOURCE connected to the case.
>>
>> But if as is likely it is NOT like the BUZ906, the SOURCE will be on
>> the same pin that is the emitter of a TO3 transistor.
>>
>> FACT:
>>
>> All power mosfets have an internal DIODE between the Source and Drain
>> terminals that is reverse biased in operation.
>>
>> So, you just need a multimeter to say which way the device in question is
>> connected internally.
>>
>
> as these are TO247 versions, not TO3).
** The ONLY maker in the world of lateral mosfets in TO3 or TO247 is
Semelab.
Their BUZ905P and BUZ906P types are available in TO247 packs.
But I very much doubt your " STUP1D " is one of them.
> But in trying to decipher what I thought you were getting at, I
> investigated the dv/dt failure mode which I think the "blown" mosfet may
> have, as there is around 165ohms between gate and source and/or drain. (I
> can't stop the SD from looking like a short circuit).
** Melted mosfet chips always go low resistance Gate to Source.
TO3 versions of *lateral* types often go open on the drain pin when the
internal bonding wire fails after the chip has melted and shorted.
> Interestingly the customer said that the amp went DC and fried his
> speaker - the amp has no relay or DC protection.
** Blowing MOSFETS in that amp means the owner is abusing it - likely by
using an extension speaker cab with a dodgy or shorted jack lead.
Your wacky theories on the failures are just as off the planet as everything
else you post.
... Phil
Gareth Magennis
Yeah, well, I'm just trying to ensure I end up treating the cause rather
than just the symptoms. I don't want this to come back again needing more
very expensive Mosfets.
In fact I'm thinking of not doing it at all now.
Cheers,
Gareth.
Phil Allison
"Gareth Magennis"
> Yeah, well, I'm just trying to ensure I end up treating the cause rather
> than just the symptoms.
** Repairers are not in a position to do investigations into mysteries -
like Sherlock Holmes - so can only make guesses at what really happened to
cause a given failure, at best.
Some owners repeatedly damage their own amplifiers by the grossest of
stupidity - and then lie about it.
Egs:
1. Plugging two amps into the same speaker cab.
2. Running a jack lead from one amp's output to another amp's output.
3. Using broken, home made and plain faulty jack leads with speaker cabs.
4. Loaning their amp to a mate or other person who is an idiot.
5. Letting fuckwit roadies muck about with and set up their amps when they
are absent.
6. Hiring their amps out for profit and never telling the repair tech about
that.
In all the above cases, serious amp damage is a near certainty and most
owners will never admit to doing it.
>I don't want this to come back again needing more very expensive Mosfets.
> In fact I'm thinking of not doing it at all now.
** With the history being as you described - that may well be the best
move.
I have a particular aversion to dealing with DJs under any circumstances.
... Phil
Gareth Magennis
I know its going to go badly wrong - Wooooo, I see, I see, um, blown
Mosfets and another melted speaker.
Gareth.
Meat Plow
> Interestingly the customer said that the amp went DC and fried his
> speaker - the amp has no relay or DC protection. My little bit or
> research so far indicates that dv/dt failure in industrial motor
> applications can be down to pulling the power cable off a stalled motor,
> zapping the gate/substrate connection in a nanosecond. Might this also
> apply to a faulty speaker in this kind of audio amp which burns short
> then eventually self disconnects?
>
> I also understand extremely electrically noisy environments can also
> induce this failure mode. The customer is daisy chaining this amp with
> another one via the FX send, I'm wondering if this has any chance of
> being the cause of the failure.
Slaving another amp via the send isn't likely but a failing speaker or
poorly wired/connected load might be the reason.
Gareth Magennis
"Meat Plow" <mhyw...@yahoo.com> wrote in message
news:pan.2011.04...@lmao.lol.lol...
Check this out, if just for educational purposes. Quite interesting.
http://www.4qd.co.uk/serv/MOSFETfail.html
Gareth.
Meat Plow
Mostly pertaining to motor control applications. My experience is limited
to audio applications. Some similarities exist thought. Still a good read
for failure modes.
Phil Allison
"Gareth Magennis"
> Check this out, if just for educational purposes. Quite interesting.
>
> http://www.4qd.co.uk/serv/MOSFETfail.html
** Got nothing WHATSOEVER to do with LATERAL mosfets !!!
These are completely different animals to switching mosfets.
Originally invented by Hitachi and sold in TO3 packs as 2SK ( N ch) and 2SJ
( P ch) numbers as the perfect output devices for audio amplifiers. Power
amp makers in the UK, Australia and NZ pounced on them and for a while in
the mid 1980s, MOSFET amps were the industry standard.
Later, Hitachi supplied plastic pack ( TO3P) versions too - then stopped
making the TO3 devices completely in the late 1980s. There was shock, horror
and nashing of teeth until it was discovered that an obscure semiconductor
maker in Scotland ( of all places) was making very similar lateral devices
to Hitachi ( under licence?) - this was Semelab.
Initially, all Semelab devices had SML part numbers on them, but later this
changed to BUZ part numbers. The exact same devices are also sold under the
Exicon brand and Magnatec. Magnatec also supply dual chip versions of the
same devices - this simply doubles the max current and max power
dissipation ratings.
Hitachi lateral mosfets in plastic packs are now sold under the brand "
Renesas " .
A lateral mosfet will always have the source connected to the case or
heatsink tab, have a threshold voltage of about 0.7 volts, come in P and N
channel versions and be found in audio amplifiers and very little else.
OTOH - switching mosfets have the drain connected to the heatsink tab, are
almost all N channel types ( no genuine P ch compliments exist) have
threshold voltages of 2 to 5 volts and are found mostly in switching PSUs,
motor drives and class D amplifiers.
.... Phil
Gareth Magennis
Isn't a speaker a motor?
Gareth.
Phil Allison
"Gareth Magennis"
>
> Isn't a speaker a motor?
** And chaulk an cheese are the same too.
Fuckwit.
... Phil
Ian Field
Maybe the "speech coil" head actuators in old 5&1/4 FH HDDs blur the
distinction a bit.
Meat Plow
It can be perceived as a sound motor.
Meat Plow
> "Gareth Magennis"
>
>> Check this out, if just for educational purposes. Quite interesting.
>>
>> http://www.4qd.co.uk/serv/MOSFETfail.html
>
>
> ** Got nothing WHATSOEVER to do with LATERAL mosfets !!!
>
> These are completely different animals to switching mosfets.
>
> Originally invented by Hitachi and sold in TO3 packs as 2SK ( N ch) and
> 2SJ ( P ch) numbers as the perfect output devices for audio amplifiers.
> Power amp makers in the UK, Australia and NZ pounced on them and for a
> while in the mid 1980s, MOSFET amps were the industry standard.
I cried the day Hitachi quit manufacturing the 2SK49 / 2SJ135 pairs. I
have one old SCS 350w/ch power amp that uses them. I acquired it with a
blow channel back in the late 90's. It wasn't easy back then to find
replacements. I imagine it's probably a lot easier these days to find NOS
replacements. Maybe even a sub is made today?
Gareth Magennis
"Phil Allison" <phi...@tpg.com.au> wrote in message
news:909l0u...@mid.individual.net...
Oh and there's me thinking a motor is a device that converts electrical
energy into mechanical energy.
Fuckwit.
David Nebenzahl
>>> Mostly pertaining to motor control applications. My experience is
>>> limited to audio applications. Some similarities exist thought.
>>> Still a good read for failure modes.
>>
>> Isn't a speaker a motor?
>
> It can be perceived as a sound motor.
It *is*, in fact, a motor. Which, technically speaking, is anything that
converts electrical energy to mechanical motion. So by this definition,
even solenoids and piezo transducers are motors.
Now, it's not a motor in the conventionally-understood sense--something
that produces rotary motion--but it is, nonetheless, a perfectly good motor.
--
The current state of literacy in our advanced civilization:
yo
wassup
nuttin
wan2 hang
k
where
here
k
l8tr
by
- from Usenet (what's *that*?)
Meat Plow
My reference was to the failure modes of motor speed control mosfets.
They aren't the ideal comparison to the failure modes found in audio
power amps using lateral or bipolar mosfets. None the less the 4QD read
was enlightening.
Lots of things can be considered motors if you think outside the box.
Anything that conveys motion can be considered a motor.
Phil Allison
"Meat Plow"
>
> I cried the day Hitachi quit manufacturing the 2SK49 / 2SJ135 pairs. I
> have one old SCS 350w/ch power amp that uses them. I acquired it with a
> blow channel back in the late 90's. It wasn't easy back then to find
> replacements. I imagine it's probably a lot easier these days to find NOS
> replacements. Maybe even a sub is made today?
** Finding NOS for those numbers is nigh impossible now.
But the Semelab BUZ900 and BUZ905 lateral mosfets are near identical.
Where devices operate in parallel, best not mix the numbers up -
particularly if there are no source ballast resistors.
.... Phil
Mike Tomlinson
<mhyw...@yahoo.com> writes
>It's everyone who isn't Phil "fucking insane" Allison.
That's the product of transportation of thieves, rapists and murderers
to van Diemen's land and 200 years of enthusiastic inbreeding since.
--
(\__/)
(='.'=)
(")_(")
Mike Tomlinson
<sound....@btconnect.com> writes
>Decision is made, I'm not touching this.
Think you're right. Not worth the comeback if it fails again.