pointers to transistor (semiconductor) curve tracer circuits/projects

On 10/29/2018 01:47 PM, Johnny B Good wrote:
> On Sun, 28 Oct 2018 23:09:46 -0700, Jeff Liebermann wrote:
> 
>> On Mon, 29 Oct 2018 01:34:41 -0400, bitrex <user@example.net> wrote:
>>
>>> On 10/28/2018 11:00 PM, Jeff Liebermann wrote:
>>>> On Sun, 28 Oct 2018 18:33:48 -0700 (PDT), jurb6006@gmail.com wrote:
>>>>
>>>>>> ""youth", in quotes I'm just shy of 40"
>>>>>
>>>>> Wow, that explains why you're not conservative. You will be in about
>>>>> ten years, and don't worry, it doesn't hurt.
>>>>
>>>> Y're right.  I'm just short of 71.  I started out as a radical
>>>> leftist, commie pinko, anti-everything, chronically protesting, hippie
>>>> freak:
>>>> <http://www.learnbydestroying.com/jeffl/pics/jeffl/slides/
> jeffl-06.html>
>>>> Fast forward about 40 years, and today I'm an arch conservative,
>>>> somewhat reactionary, right leaning, registered Republican, member of
>>>> the establishment:
>>>
>>> Woah, how unusual.
>>
>> Not really.  Many of my friends followed approximately the same path.
>> Some saw the problems with the idealism of the 1960's and switched
>> early, while others got the clue after they accumulated some
>> responsibilities.  I know a few that still look like they're protesting
>> something, but vote and put their money on conservative candidates and
>> policies.  My transformation was rather unusual:
>> <http://www.learnbydestroying.com/jeffl/pics/jeffl/slides/jeffl-
> wolf.html>
>>
>> Patience.  Your turn will come.  Best you prepare yourself for the
>> inevitable metamorphosis.
>>
>>>> <http://www.learnbydestroying.com/jeffl/pics/jeffl/slides/
> jeffl-08.html>
>>>> It can and probably will happen to you.  Resistance is futile.
>>
>>> You don't have to explain to us that the "baby boomer" generation were
>>> sellouts with no real values who'd gladly hawk their souls for ten
>>> bucks. We know, already ;-)
>>
>> Ok, I won't explain.  You already have all the answers.  I'll give you
>> credit for recognizing that us baby boomers had "real values" to sell,
>> while your generation seems to lack any values worth selling.
>>
>   You seem to be impuning 'his generation' for the 'lack of "real values"
> to sell', forgetting that it was our generation's responsibility to
> install those "real values"  for them all to sell in the first place. :-(

My late father was a WW2 combat veteran (I'm the youngest of four) not 
some shit-talking fake ass "tough guy" never-served as the leadership of 
the Right appears to be full of now. I think I'll be okay.

>   It's not entirely our fault but it's a complex story involving
> technological developments that allowed our "Golden Rulers" to shape
> society through commercial and political propaganda so as to turn the
> consuming masses into the cash cow resource that it is today.
> 
>   As I said it's a *complex* story but that's what seems to be at the core
> of Humanity's problems today. I have my own hypothesis as to how
> Humanity's problems will ultimately be resolved but since it's in that
> class of hypothesis known as "Conspiracy Theory", I shan't bore you with
> its gory details. :-)
> 

On 10/29/2018 01:47 PM, Johnny B Good wrote:

>   It's not entirely our fault but it's a complex story involving
> technological developments that allowed our "Golden Rulers" to shape
> society through commercial and political propaganda so as to turn the
> consuming masses into the cash cow resource that it is today.
> 
>   As I said it's a *complex* story but that's what seems to be at the core
> of Humanity's problems today. I have my own hypothesis as to how
> Humanity's problems will ultimately be resolved but since it's in that
> class of hypothesis known as "Conspiracy Theory", I shan't bore you with
> its gory details. :-)
> 

the hustle such as it is is not particularly sophisticated, Trump is the 
best friend the military-industrial complex has ever had, his role is to 
transfer as much money to billionaires as possible and in turn they will 
spend millions and billions to keep him, or a guy like him, in power as 
long as possible.

All you have to do to impress about 50% of Americans is just tell them 
you're going to give their money to billionaires instead of a black man 
and they'll love you forever. Easily-played dupes and rubes, like taking 
candy from a baby, really.

The Potemkin village will eventually collapse, however, and the Trumps 
and Waltons and Peter Thiels will get while the getting's good. And if 
you thought Hillary Clinton was bad wait until you see the true terror 
of the New Left that will drop in to fill the void; any duffy old 
MAGA-boomer without the scratch to escape to New Zealand with the 
billionaires and unfortunate enough to remain behind will be torn to pieces.

And probably me too, by association. Thanks assholes I kinda liked it here.

On Sun, 28 Oct 2018 21:08:18 -0400, bitrex <user@example.net> wrote:
\
> 
>
>for "high end" audio amps and cassette decks the parameters you'd also 
>want to know the noise specifications a curve tracer won't tell you that 
>either.

Cassette decks? Why?


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On 10/29/2018 02:55 PM, John Larkin wrote:
> On Sun, 28 Oct 2018 21:08:18 -0400, bitrex <user@example.net> wrote:
> \
>>
>>
>> for "high end" audio amps and cassette decks the parameters you'd also
>> want to know the noise specifications a curve tracer won't tell you that
>> either.
> 
> Cassette decks? Why?
> 
> 

Don't ask me man, I went completely solid-state ages ago I don't even 
own any CDs anymore. People are peculiar about their dumpy ol' Onkyos 
which need constant maintenance with their very-impressive-for-the-time 
75dB SNR or whatever. I assume that some of them have critical sections 
in say the pickup amps which require low noise or matched transistors 
but it's also been ages since I've worked on one

There's some stuff from the past that's worth preserving but some shit 
is best left in the past like vinyl and cassettes they were never that 
great.

On 10/29/2018 03:11 PM, bitrex wrote:
> On 10/29/2018 02:55 PM, John Larkin wrote:
>> On Sun, 28 Oct 2018 21:08:18 -0400, bitrex <user@example.net> wrote:
>> \
>>>
>>>
>>> for "high end" audio amps and cassette decks the parameters you'd also
>>> want to know the noise specifications a curve tracer won't tell you that
>>> either.
>>
>> Cassette decks? Why?
>>
>>
> 
> Don't ask me man, I went completely solid-state ages ago I don't even 
> own any CDs anymore. People are peculiar about their dumpy ol' Onkyos 
> which need constant maintenance with their very-impressive-for-the-time 
> 75dB SNR or whatever. I assume that some of them have critical sections 
> in say the pickup amps which require low noise or matched transistors 
> but it's also been ages since I've worked on one
> 
> There's some stuff from the past that's worth preserving but some shit 
> is best left in the past 

Oh and Newt Gingrich is another example

@bitrex
You are either a troll or had way too much coffee.  GIve it a rest man.I have some high end audio gear from the 80s and I do some repair for friends/clients.  I also do format conversions for myself and other ppl. 
I posted a question and 60% of the drivel that flowed is totally unrelated or begged the question about usefulness.  I always thought that an IQ test should be given to ppl before they got an on-ramp to the net.  Most would fail the test.
I don't care about your technology views, your likes/dislikes, or your perspective on audio or electronics, your political view, or what your father did or did not do.  Mine was a WWII vet - fighter pilot but has nothing to do with the question I asked.

Why a cassette deck? I am repairing one for a friend.  He and I both have a Nakamichi 1000ZXL.  It appears his preamp died.  I didn't challenge him as to why he *still* uses it...to each their own.
take a back seat, shut up, and enjoy the ride, or leave.

On Sunday, October 28, 2018 at 8:56:12 PM UTC-4, John Larkin wrote:

> 
> Do you generally have schematics? That should be enough to pick a
> replacement part.
> 
> A curve tracer tells you nothing about thermal properties, namely
> power handling capacity.
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

Thank you, I know that.  Thermal properties arnt my concern.
J

On Sunday, October 28, 2018 at 9:38:33 PM UTC-4, Phil Allison wrote:
> jjhu...@gmail.com wrote:
> >
> >
> > I find myself in a situation where I am repairing some high end
> > audio amps and cassette decks that have house numbered semiconductors,
> > mainly transistors as well as JDEC p/n that are NLA.
> > 
> 
> ** It's " JEDEC " =  Joint Electron Device Engineering Council.
> 
> The full specs for JEDEC semis are always published and Google can search that for you.  Also this page has a few more clues.
> 
> https://www.elexp.com/Images/Reading_Transistor_Markings.pdf
> 
> 
> > I have found a few transistors that are dead and need to be replaced.  
> > Fortunately, they are in parts of the amp where the other channel has
> > an identic transistor.
> > Having one transistor as a base will allow me to match something close
> > to the original.
> > 
> > I have made (in the past)  the typical transistor curve tracer that shows
> > the curves on a scope - cute but not precise enough for my intentions. 
> > I am more interested in a lab type instrument. 
> > 
> 
> ** You are wasting your time, that is no way to even get close. 
> 
> I have a LOT of experience with substituting transistors found in all brands of hi-fi and pro audio electronics. There are plenty of clues to be found & used in choosing suitable replacements for obsolete and code numbered parts. 
> 
> Sometimes devices need to be Vbe and/or Hfe matched - circuit topology is the big clue there. 
> 
> Hint: watch out for TO3 devices that seem like ordinary power transistors but are in fact Darlingtons.
> 
> 
> .....   Phil

Yes, I know, I mistyped - thanks
I agree with you about the circuit clues.  Since my background is math/control theory and hardware/digital architect (as in design of CPUs), my analog skills have gotten a bit rusty. If I have some questions, perhaps I can bounce them off you privately?
Thanks
J

On Mon, 29 Oct 2018 14:39:08 -0700 (PDT), three_jeeps
<jjhudak@gmail.com> wrote:

>@bitrex
>You are either a troll or had way too much coffee.  GIve it a rest man.I have some high end audio gear from the 80s and I do some repair for friends/clients.  I also do format conversions for myself and other ppl. 
>I posted a question and 60% of the drivel that flowed is totally unrelated or begged the question about usefulness.  I always thought that an IQ test should be given to ppl before they got an on-ramp to the net.  Most would fail the test.
>I don't care about your technology views, your likes/dislikes, or your perspective on audio or electronics, your political view, or what your father did or did not do.  Mine was a WWII vet - fighter pilot but has nothing to do with the question I asked.
>
>Why a cassette deck? I am repairing one for a friend.  He and I both have a Nakamichi 1000ZXL.  It appears his preamp died.  I didn't challenge him as to why he *still* uses it...to each their own.
>take a back seat, shut up, and enjoy the ride, or leave.

You sound obnoxious. This is an unmoderated newsgroup, and we discuss
electronics. If you want paid consultants, you'll have to pay for
them.

If power doesn't matter, there are generic gumdrop NPNs and PNPs and
they are all pretty much the same. Casettes are noisy all by
themselves, so the transistors won't matter.

I think there is a reason that people like Tek used to sell curve
tracers and transistor testers, and don't any more.

I'd like a box that characterizes RF fets (phemts, SiC, GaN) for both
DC specs and capacitance, but we do that other ways now, and wouldn't
pay a lot for a dedicated box.




-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Mon, 29 Oct 2018 14:57:20 -0700, John Larkin
<jjlarkin@highland_snip_technology.com> wrote:

>On Mon, 29 Oct 2018 14:39:08 -0700 (PDT), three_jeeps
><jjhudak@gmail.com> wrote:
>
>>@bitrex
>>You are either a troll or had way too much coffee.  GIve it a rest man.I have some high end audio gear from the 80s and I do some repair for friends/clients.  I also do format conversions for myself and other ppl. 
>>I posted a question and 60% of the drivel that flowed is totally unrelated or begged the question about usefulness.  I always thought that an IQ test should be given to ppl before they got an on-ramp to the net.  Most would fail the test.
>>I don't care about your technology views, your likes/dislikes, or your perspective on audio or electronics, your political view, or what your father did or did not do.  Mine was a WWII vet - fighter pilot but has nothing to do with the question I asked.
>>
>>Why a cassette deck? I am repairing one for a friend.  He and I both have a Nakamichi 1000ZXL.  It appears his preamp died.  I didn't challenge him as to why he *still* uses it...to each their own.
>>take a back seat, shut up, and enjoy the ride, or leave.
>
>You sound obnoxious. This is an unmoderated newsgroup, and we discuss
>electronics. If you want paid consultants, you'll have to pay for
>them.
>
>If power doesn't matter, there are generic gumdrop NPNs and PNPs and
>they are all pretty much the same. Casettes are noisy all by
>themselves, so the transistors won't matter.
>
>I think there is a reason that people like Tek used to sell curve
>tracers and transistor testers, and don't any more.
>
>I'd like a box that characterizes RF fets (phemts, SiC, GaN) for both
>DC specs and capacitance, but we do that other ways now, and wouldn't
>pay a lot for a dedicated box.

Keysight has a curve tracer, the B1505A Power Device Analyzer. It's
around $80K.

We have a couple of their SMUs, which can be programmed to do curve
tracing, and lots more.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com