pointers to transistor (semiconductor) curve tracer circuits/projects

Am 29.10.18 um 01:46 schrieb jjhudak4@gmail.com:
> 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.
> 
> 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 identical 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.
> 
> Basically what I am looking for is a curve tracer that has a micro attached to it that have some A/D's on them that can record the data of interest (e.g. Ib (vb), Vce, etc.
> I've considered an arduino based approach but they have the limitations of  5V max on the input for the A/Ds and don't want to scale it.
> I've looked for old Heathkit and Tek curve tracers that I could augment with a micro but they seem to be very scarce, in addition to having transistors in them that are NLA.
> I could design one myself but in all honesty, I'd prefer to find something where someone has 'plowed the ground' and at the very most, I'd have to augment it with a micro.  Yea, I am a bit lazy - the intent was to fix the amp, not develop a curve tracer....
> Thanks in advance


I have bought this one, since I don't want yet another boat anchor
and want the results on my disk. No more screen photos.
Price was so that I could survive the loss.

https://www.ebay.de/itm/112168145773?ul_noapp=true

It seems to work; the documentation is a hard to understand pidgin.

Sometimes there are unexpected results, like in one of the

plots where the drain current goes suddenly into saturation

for no reason.

Might be operator error, can't tell easily from the docs.

These plots have been done with it:

< 
https://www.flickr.com/photos/137684711@N07/42542542745/in/album-72157662535945536/lightbox/ 
     >  and left/right.


regards,
Gerhard

Am 29.10.18 um 22:57 schrieb John Larkin:
> 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.

He asked an on-topic question and got shitty, off-topic answers,
all of them but maybe 2 or 3.
Your's was none of the 3.

Gerhard

On Sunday, October 28, 2018 at 8:56:12 PM UTC-4, John Larkin wrote:
> On Sun, 28 Oct 2018 17:46:44 -0700 (PDT), jjhudak4@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.
> >
> >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 identical 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. 
> >
> >Basically what I am looking for is a curve tracer that has a micro attached to it that have some A/D's on them that can record the data of interest (e.g. Ib (vb), Vce, etc.  
> >I've considered an arduino based approach but they have the limitations of  5V max on the input for the A/Ds and don't want to scale it.
> >I've looked for old Heathkit and Tek curve tracers that I could augment with a micro but they seem to be very scarce, in addition to having transistors in them that are NLA.
> >I could design one myself but in all honesty, I'd prefer to find something where someone has 'plowed the ground' and at the very most, I'd have to augment it with a micro.  Yea, I am a bit lazy - the intent was to fix the amp, not develop a curve tracer....
> >Thanks in advance
> >J
> >
> >
> 
> Do you generally have schematics? That should be enough to pick a
> replacement part.
Right, schematics would help a lot.
GH
> 
> A curve tracer tells you nothing about thermal properties, namely
> power handling capacity.
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

John Larkin wrote:
> On Sun, 28 Oct 2018 17:46:44 -0700 (PDT), jjhudak4@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.
>>
>> 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 identical 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.
>>
>> Basically what I am looking for is a curve tracer that has a micro
>> attached to it that have some A/D's on them that can record the data
>> of interest (e.g. Ib (vb), Vce, etc.
>> I've considered an arduino based approach but they have the
>> limitations of  5V max on the input for the A/Ds and don't want to
>> scale it.
>> I've looked for old Heathkit and Tek curve tracers that I could
>> augment with a micro but they seem to be very scarce, in addition to
>> having transistors in them that are NLA.
>> I could design one myself but in all honesty, I'd prefer to find
>> something where someone has 'plowed the ground' and at the very
>> most, I'd have to augment it with a micro.  Yea, I am a bit lazy -
>> the intent was to fix the amp, not develop a curve tracer.... Thanks
>> in advance
>> J
>>
>>
>
> 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.

=================================================

There was an article in QST magazine (April, 2015) "Mini-CT: A Curve Tracer 
for the Ham Shack" by Veikko Kanto N7VK describing a curve tracer using a 
C8051F121 microcontroller.  The article is at 
http://www.arrl.org/files/file/QST%20Binaries/Apr2015/Expanded%20Text.pdf, 
however, the software seems lost to oblivion. I couldn't find it on the QST 
web site.  A thread on EEVBlog gives his location 
https://www.eevblog.com/forum/projects/minict-curve-tracer-zener-diodes-etc/. 
You might be able to contact him for a copy of the software and any further 
development of the project.
From a perusal of the article, it appears that he provided a data recording 
feature in the software.  Perhaps, if you could contact the author, some 
further development could give you a good portrtion of what you're after in 
a curve tracer.

Good luck with the project.  It would make a great follow-up article for QST 
or another magazine.

Cheers,
Dave M 

On Mon, 29 Oct 2018 23:30:36 +0100, Gerhard Hoffmann
<ghf@hoffmann-hochfrequenz.de> wrote:

>Am 29.10.18 um 22:57 schrieb John Larkin:
>> 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.
>
>He asked an on-topic question and got shitty, off-topic answers,
>all of them but maybe 2 or 3.
>Your's was none of the 3.
>
>Gerhard

I answered first, and my response was civil and relevant. He didn't
answer my question about schematics. 

He apparently resents not getting free consulting, and resents
discussion drift. It's an unmoderated public forum; get used to it.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

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

On 10/30/18 00:42, John Larkin wrote:

> I answered first, and my response was civil and relevant. He didn't
> answer my question about schematics.
>
> He apparently resents not getting free consulting, and resents
> discussion drift. It's an unmoderated public forum; get used to it.
>
>

This is not facebook and and nothing like as controlled, or as PC,
thankfully...

Chris

On Monday, October 29, 2018 at 8:43:04 PM UTC-4, John Larkin wrote:
> On Mon, 29 Oct 2018 23:30:36 +0100, Gerhard Hoffmann
>  wrote:
> 
> >Am 29.10.18 um 22:57 schrieb John Larkin:
> >> On Mon, 29 Oct 2018 14:39:08 -0700 (PDT), three_jeeps
> >> 
> >>> @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.
> >
> >He asked an on-topic question and got shitty, off-topic answers,
> >all of them but maybe 2 or 3.
> >Your's was none of the 3.
> >
> >Gerhard
> 
> I answered first, and my response was civil and relevant. He didn't
> answer my question about schematics. 
> 
> He apparently resents not getting free consulting, and resents
> discussion drift. It's an unmoderated public forum; get used to it.
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> picosecond timing   precision measurement 
> 
> jlarkin att highlandtechnology dott com
> http://www.highlandtechnology.com

I did reply to your first post but I forgot and did it in my email and it didn't get posted.  To address your points:
1) I usually try to find schematics, sometimes not very successful. If I do have schematics, I try to model it to see how it performs (if it is something I am not familiar with).  I did answer the question of noise.
2) There are lots of reasons why curve tracers are no longer made by Tek, HP, etc.  My speculation is that as a business decision, it is not profitable because ppl solve the design problem with different technology rather than with discrete transistors.  That does not imply the use/application is useless. 
3) I know a curve tracer does not provide any insight as to noise characteristic, and I know that noise is a concern - especially in old clunky electromechanical beasts like cassette deck.  If you look at some of the designs and implementations, some of the low noise solutions are quite elegant.
4) Discussion drift - that is true, I resent it.  I ask a technical question on a technical group and expect the answers to be technical.  As one reader pointed out, most of it was not.  
5) free consulting - is appreciated, and thanked in kind. Just because an approach doesn't do something doesn't mean the approach is invalid for other things. Because curve tracers do not provide insight on noise characteristics doesn't me they aren't useful for their intended purpose.  I have a fairly solid academic background in EE but admittedly rusty in certain areas.  I  took extra courses in semiconductor physics even though it was not my major and that was many years ago.

6) unmoderated public forum.  Right - anybody can say anything on any topic.  My expectations for ppl to stay on topic was apparently incorrect.  My expectation of professionals providing feed back in a professional manner was not met by a number of the responses, to which I am unpleasantly surprised.  I am used to a higher standard, even in unmoderated groups.  My expectations have been 'recalibrated.'
I appreciate the helpful feedback from you and other.
Peace,
J


On Monday, October 29, 2018 at 8:43:04 PM UTC-4, John Larkin wrote:
> On Mon, 29 Oct 2018 23:30:36 +0100, Gerhard Hoffmann

> 
> >Am 29.10.18 um 22:57 schrieb John Larkin:
> >> On Mon, 29 Oct 2018 14:39:08 -0700 (PDT), three_jeeps
> >> 
> >>> @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.
> >
> >He asked an on-topic question and got shitty, off-topic answers,
> >all of them but maybe 2 or 3.
> >Your's was none of the 3.
> >
> >Gerhard
> 
> I answered first, and my response was civil and relevant. He didn't
> answer my question about schematics. 
> 
> He apparently resents not getting free consulting, and resents
> discussion drift. It's an unmoderated public forum; get used to it.
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> picosecond timing   precision measurement 
> 
> jlarkin att highlandtechnology dott com
> http://www.highlandtechnology.com

On Monday, October 29, 2018 at 8:38:36 PM UTC-4, Dave M wrote:
> John Larkin wrote:
> > On Sun, 28 Oct 2018 17:46:44 -0700 (PDT),  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.
> >>
> >> 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 identical 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.
> >>
> >> Basically what I am looking for is a curve tracer that has a micro
> >> attached to it that have some A/D's on them that can record the data
> >> of interest (e.g. Ib (vb), Vce, etc.
> >> I've considered an arduino based approach but they have the
> >> limitations of  5V max on the input for the A/Ds and don't want to
> >> scale it.
> >> I've looked for old Heathkit and Tek curve tracers that I could
> >> augment with a micro but they seem to be very scarce, in addition to
> >> having transistors in them that are NLA.
> >> I could design one myself but in all honesty, I'd prefer to find
> >> something where someone has 'plowed the ground' and at the very
> >> most, I'd have to augment it with a micro.  Yea, I am a bit lazy -
> >> the intent was to fix the amp, not develop a curve tracer.... Thanks
> >> in advance
> >> J
> >>
> >>
> >
> > 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.
> 
> =================================================
> 
> There was an article in QST magazine (April, 2015) "Mini-CT: A Curve Tracer 
> for the Ham Shack" by Veikko Kanto N7VK describing a curve tracer using a 
> C8051F121 microcontroller.  The article is at 
> http://www.arrl.org/files/file/QST%20Binaries/Apr2015/Expanded%20Text.pdf, 
> however, the software seems lost to oblivion. I couldn't find it on the QST 
> web site.  A thread on EEVBlog gives his location 
> https://www.eevblog.com/forum/projects/minict-curve-tracer-zener-diodes-etc/. 
> You might be able to contact him for a copy of the software and any further 
> development of the project.
> From a perusal of the article, it appears that he provided a data recording 
> feature in the software.  Perhaps, if you could contact the author, some 
> further development could give you a good portrtion of what you're after in 
> a curve tracer.
> 
> Good luck with the project.  It would make a great follow-up article for QST 
> or another magazine.
> 
> Cheers,
> Dave M

Looks very interesting and applicable.  I'll check it out.
TYVM
J

On Monday, October 29, 2018 at 6:14:50 PM UTC-4, Gerhard Hoffmann wrote:
> Am 29.10.18 um 01:46 schrieb 
> > 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.
> > 
> > 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 identical 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.
> > 
> > Basically what I am looking for is a curve tracer that has a micro attached to it that have some A/D's on them that can record the data of interest (e.g. Ib (vb), Vce, etc.
> > I've considered an arduino based approach but they have the limitations of  5V max on the input for the A/Ds and don't want to scale it.
> > I've looked for old Heathkit and Tek curve tracers that I could augment with a micro but they seem to be very scarce, in addition to having transistors in them that are NLA.
> > I could design one myself but in all honesty, I'd prefer to find something where someone has 'plowed the ground' and at the very most, I'd have to augment it with a micro.  Yea, I am a bit lazy - the intent was to fix the amp, not develop a curve tracer....
> > Thanks in advance
> 
> 
> I have bought this one, since I don't want yet another boat anchor
> and want the results on my disk. No more screen photos.
> Price was so that I could survive the loss.
> 
> https://www.ebay.de/itm/112168145773?ul_noapp=true
> 
> It seems to work; the documentation is a hard to understand pidgin.
> 
> Sometimes there are unexpected results, like in one of the
> 
> plots where the drain current goes suddenly into saturation
> 
> for no reason.
> 
> Might be operator error, can't tell easily from the docs.
> 
> These plots have been done with it:
> 
> < 
> https://www.flickr.com/photos/137684711@N07/42542542745/in/album-72157662535945536/lightbox/ 
>      >  and left/right.
> 
> 
> regards,
> Gerhard

Looks useful but deciphering its documentation might be an equation with too many unknowns...I'll contact him for more details, or you if agreeable to it.
Thanks
J

On Monday, October 29, 2018 at 6:03:58 PM UTC-4, John Larkin wrote:
> 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
> > 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

Thank you.  A bit pricey for my needs but if they come down to <= $200 USD, I'd consider it.
J