Tinkling transistor!
Asa Cannell
amplifier, and it doesn't work. In the process of troubleshooting it,
I removed the power supply board and I noticed it made this odd
tinkling sound. I figured it was loose transistor hardware, but I
looked closer, and there were no loose washers are metal anywhere on
it. The tinkling seemed to be coming from both the large TO-3 2N456A
transistors. I couldn't tell for sure while they were on the board, so
I desoldered one, and indeed it tinkles. It sounds like there are
little bits of broken metal or glass inside the metal housing. Has
anyone had any experience with this? It definetly seems like its not a
good thing, but who knows, maybe 40 years ago they put scrap metal
inside the housings. The power supply where the transistors are isn't
catastrophically failing, but the output voltages do have alot of
ripple and I seem to be having intermittent problems. Is there a way I
can test this transistor?
Asa
Spehro Pefhany
Cannell) wrote:
>I just bought a ~40 year old princeton applied research JB-5 lock in
>amplifier, and it doesn't work. In the process of troubleshooting it,
>I removed the power supply board and I noticed it made this odd
>tinkling sound. I figured it was loose transistor hardware, but I
>looked closer, and there were no loose washers are metal anywhere on
>it. The tinkling seemed to be coming from both the large TO-3 2N456A
>transistors. I couldn't tell for sure while they were on the board, so
>I desoldered one, and indeed it tinkles. It sounds like there are
>little bits of broken metal or glass inside the metal housing. Has
>anyone had any experience with this? It definetly seems like its not a
>good thing, but who knows, maybe 40 years ago they put scrap metal
>inside the housings.
Maybe it's like those Chinese musical balls.
> The power supply where the transistors are isn't
>catastrophically failing, but the output voltages do have alot of
>ripple and I seem to be having intermittent problems. Is there a way I
>can test this transistor?
A multimeter on "diode check" range and see if you see the E-B and C-B
junctions (usually reads something like 650 on the meter) and that
they block in the reverse direction (overrange). If it passes that,
you can check the hFE if your multimeter has that function (almost all
inexpensive meters seem to have it these days).
Best regards,
Best regards,
Spehro Pefhany
--
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Embedded software/hardware/analog Info for designers: http://www.speff.com
John Popelish
I seem to have a vague memory of germanium power transistors that had
a bit of silica gel or some other humidity absorbing stuff inside the
case that rattled around. But I can't be sure this is not a fake
memory produced by suggestion.
If your transistor has low junction forward drops (less than .4 volts)
and is PNP, it is germanium. If it isn't I don't have a clue of what
is in there.
--
John Popelish
Pooh Bear
I'll add to that.
Different era but around 1980 I came across some *wickedly * well specced
Sanken power transistors.
Indeed Sanken still make excellent transistors for audio output stages.
I had some trouble understanding how they made them so well with Isb figures
that trounced Motorola or RCA's devices..
So I took a hacksaw to one and lifted the lid off a TO-3 device with a view
to examining the die.
It contained a large amount of a 'thermal compound'.
It might have been alumina - it might have been beryllia : see
http://www.azom.com/details.asp?ArticleID=263 ( hope not in the second
instance since it's carcinogenic ) !
I ditched the part in the trash very fast.
Modern semis don't use that trick. They also don't 'rattle'.
Graham
Winfield Hill
>
> Asa Cannell wrote:
>>
>> I just bought a ~40 year old princeton applied research JB-5 lock in
>> amplifier, and it doesn't work. In the process of troubleshooting it,
>> I removed the power supply board and I noticed it made this odd
>> tinkling sound. I figured it was loose transistor hardware, but I
>> looked closer, and there were no loose washers are metal anywhere on
>> it. The tinkling seemed to be coming from both the large TO-3 2N456A
>> transistors. I couldn't tell for sure while they were on the board,
>> so I desoldered one, and indeed it tinkles. It sounds like there are
>> little bits of broken metal or glass inside the metal housing. Has
>> anyone had any experience with this? It definetly seems like its not
>> a good thing, but who knows, maybe 40 years ago they put scrap metal
>> inside the housings. The power supply where the transistors are isn't
>> catastrophically failing, but the output voltages do have alot of
>> ripple and I seem to be having intermittent problems. Is there a way
>> I can test this transistor?
>
> a bit of silica gel or some other humidity absorbing stuff inside the
> case that rattled around. But I can't be sure this is not a fake
> memory produced by suggestion.
> If your transistor has low junction forward drops (less than .4 volts)
> and is PNP, it is germanium. If it isn't I don't have a clue of what
> is in there.
The 2N456A is a Germanium PNP, rated at 40V, 7A and 0.5 C/W in its
TO-3 package (it must have had a large die). In recent history it was
made by GPD (Germanium Power Devices Corp), Semitronics and Advanced
Semiconductor, Inc. (who may still offer it). Asa, I'd try replacing
it with a large silicon PNP transistor, like a TIP34 or TIP36. These
have TO-218 cases, but will mount properly in place of your TO-3 part.
After you do this you can open up the 2n456 and tell us what you find.
--
Thanks,
- Win
Nicholas O. Lindan
> large TO-3 2N456A transistors. tinkles. It sounds like there are
> little bits of broken metal or glass inside the metal housing.
I suggest pro-forma replacement of all tinkling transistors.
Something's broke. It may or may not be what is causing the
problems you are seeing but dollars to doughnuts they
are/will cause problems.
When in doubt, throw it out.
--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/
Nicholas O. Lindan
> 2N456A transistors.
I just googled, the 2N456 is a power PNP Germanium.
From the days of my youth PNP Ge power transistors were not
very (at all) reliable, at least in teen-ager driven Hi-Fi
gear. Try a modern silicon unit -- ge is (normally) only
needed for battery powered equipment. Common in old car radios.
Is Oliver Germanium still around?
Pooh Bear
He would have to re-bias the amplifer to use a silicon device in the output.
May not be trivial.
Why not suggest a TO-3 can device btw ?
MJ2955 would do nicely. http://www.ampslab.com/trans_mj2955.htm for example
- can buy online
Better still, replace it with the same part and no re-biasing should be
required other than setup.
http://store.americanmicrosemiconductor.com/2n456a.html
Graham
Winfield Hill
>
> Winfield Hill wrote:
>
>> The 2N456A is a Germanium PNP, rated at 40V, 7A and 0.5 C/W in its
>> TO-3 package (it must have had a large die). In recent history it was
>> made by GPD (Germanium Power Devices Corp), Semitronics and Advanced
>> Semiconductor, Inc. (who may still offer it). Asa, I'd try replacing
>> it with a large silicon PNP transistor, like a TIP34 or TIP36. These
>> have TO-218 cases, but will mount properly in place of your TO-3 part.
>>
>> After you do this you can open up the 2n456 and tell us what you find.
>
> He would have to re-bias the amplifer to use a silicon device in the
> output. May not be trivial.
A lock-in amplifier is NOT an audio power amplifier. All the signals
are at low or very low power levels, including the output, which is
+/-10V into a 10k load. Therefore it's most likely the 2N456A TO-3
transistor was in the power-supply regulator. It's also likely the
regulator has sufficient voltage overhead to work with 0.65V base-
emitter drops instead of 250mV in its control feedback loop.
We will see.
> ...replace it with the same part ...
> http://store.americanmicrosemiconductor.com/2n456a.html
Looks like a good source, I didn't know about them.
Perhaps we won't see.
--
Thanks,
- Win
Rich Grise
> "Asa Cannell" <acan...@wwc.com> wrote
>
>> large TO-3 2N456A transistors. tinkles. It sounds like there are
>> little bits of broken metal or glass inside the metal housing.
>
> I suggest pro-forma replacement of all tinkling transistors.
> Something's broke. It may or may not be what is causing the
> problems you are seeing but dollars to doughnuts they
> are/will cause problems.
>
> When in doubt, throw it out.
But at least do us the favor of taking Win Hill's suggestion of opening
the tinklers, [carefully!] and tell us everything you find!
Thanks!
Rich
Rich Grise
> "Asa Cannell" <acan...@wwc.com> wrote
>
>> 2N456A transistors.
>
> I just googled, the 2N456 is a power PNP Germanium.
>
> From the days of my youth PNP Ge power transistors were not
> very (at all) reliable, at least in teen-ager driven Hi-Fi
> gear. Try a modern silicon unit -- ge is (normally) only
> needed for battery powered equipment. Common in old car radios.
>
> Is Oliver Germanium still around?
Har-dy har har! ;-)
Cheers!
Rich
Winfield Hill
>
> Nicholas O. Lindan wrote:
>
>> From the days of my youth PNP Ge power transistors were ...
>>
>> Is Oliver Germanium still around?
>
> Har-dy har har! ;-)
Too young to remember joly old Oliver, a bear of a man?
Date: 04 Aug 2004 18:12:53
From: Spehro Pefhany
Subject: Re: Unusual Characteristic [LOL]
Anyone know if that Oliver dude from the ad campaign of the
<mumble >ties is still kicking?
Best regards,
Spehro Pefhany
Date: 04 Aug 2004 19:39:28
From: John Larkin
Oh, Oliver Germanium. Dunno. I'll ask next time I contact them.
Nowadays they mostly make GaAs photodiodes. Last time I bought
a TD from them, some years ago, it was about $80.
John
What about it John?
--
Thanks,
- Win
Pooh Bear
Winfield Hill wrote:
> Rich Grise wrote...
> >
> > Nicholas O. Lindan wrote:
> >
> >> From the days of my youth PNP Ge power transistors were ...
> >>
> >> Is Oliver Germanium still around?
> >
> > Har-dy har har! ;-)
>
> Too young to remember joly old Oliver, a bear of a man?
I recall the ads featuring him !
Graham
John Popelish
>
> Rich Grise wrote...
> >
> > Nicholas O. Lindan wrote:
> >
> >> From the days of my youth PNP Ge power transistors were ...
> >>
> >> Is Oliver Germanium still around?
> >
> > Har-dy har har! ;-)
>
> Too young to remember joly old Oliver, a bear of a man?
I kept waiting for him to announce germanium devices passivated with
germanium nitride and doped with ion implantation. I would love to
see what .5 volt germanium CMOS would look like. Still waiting.
--
John Popelish
Robert Baer
That diode drop test will also tell you if it is Germanium (i call it
flower power from "geranium"), or Silicon (i call it sand power); prolly
Germanium.
You may be able to get away with using sand power replacement.
Don Klipstein
>
>I seem to have a vague memory of germanium power transistors that had
>a bit of silica gel or some other humidity absorbing stuff inside the
>case that rattled around. But I can't be sure this is not a fake
>memory produced by suggestion.
I remember these also, fairly clearly. Power transistors that tinkled
when shaken or moved did exist!
- Don Klipstein (d...@misty.com)
Robert Baer
Actually, i had designed and built a 3V 100A regulated DC power supply
using two power Germanium transistors for the pass; never had problems.
Ran from 1K load to full load for years.
I found that used properly, they were more reliable that tne
"replacement" silicon power transistors (same power level).
Winfield Hill
>
> Actually, i had designed and built a 3V 100A regulated DC power supply
> using two power Germanium transistors for the pass; never had problems.
> Ran from 1K load to full load for years. I found that used properly,
> they were more reliable that tne "replacement" silicon power transistors
> (same power level).
That may be because the GPD devices had very large dies, and thus
very low thermal resistance. OTH, one was supposed to keep their
junction temps lower than for silicon, right? I don't recall.
GPD's power trannies would have been well suited for low-voltage
high-current linear regulators. They had 100A transistors with
beta = 125 (min, 25A), and Vce(sat) = 0.3V at 100A, beta = 10.
--
Thanks,
- Win
Rich Grise
> Rich Grise wrote...
>>
>> Nicholas O. Lindan wrote:
>>
>>> From the days of my youth PNP Ge power transistors were ...
>>>
>>> Is Oliver Germanium still around?
>>
>> Har-dy har har! ;-)
>
> Too young to remember joly old Oliver, a bear of a man?
>
I'd rather remember Oliie than rest on my Laurels. ;-)
Hal Murray
>
>It might have been alumina - it might have been beryllia : see
>http://www.azom.com/details.asp?ArticleID=263 ( hope not in the second
>instance since it's carcinogenic ) !
>
>I ditched the part in the trash very fast.
I thought beryllia was harmless in chunk form. (Powder from
machining is very nasty.)
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Marc H.Popek
part ought to do the trick.
I have a collection of electronics materials for auction, as well. let me
know if you need these GE power transistors...
Marc
http://search.ebay.com/_W0QQgotopageZ1QQsassZlvmarcoQQsorecordsperpageZ50QQs
osortorderZ1QQsosortpropertyZ1
"Asa Cannell" <acan...@wwc.com> wrote in message
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Good luck
Marco
"Marc H.Popek" <LVM...@worldnet.att.net> wrote in message
news:sOuqd.69783$7i4....@bgtnsc05-news.ops.worldnet.att.net...
Robert Baer
The "older" germaniums had problems at "high" temperatures, due to the
use of Indium for doping.
However, the "newer" germanium transistors withstood high temperature
better than silicon transistors (do not remember what was used for
doping).
What that meant was one could dissipate more power at heatsink temp
approaching 100C and not have reliability problems.
Daniel Haude
Hal Murray <hmu...@suespammers.org> wrote
in Msg. <y9OdnfcdioB...@megapath.net>
> I thought beryllia was harmless in chunk form. (Powder from
> machining is very nasty.)
Yes, but after you open a beryllia-filled case "with a hacksaw", do you
expect all of it to still be in chunk form?
--Daniel
--
"With me is nothing wrong! And with you?" (from r.a.m.p)
Asa Cannell
http://www.exoticelectron.com/tinkle.jpg
To recap:
The power supply board in a 40 year old PAR JB-5 lock in amplifier has
lots of ripple on the output. Two of the large TO-3 power transistors
on the board (TI 2N456A's) and all the diodes (GE 1N1692's) make
tinkling noises when you shake the board. I desoldered the transistors
and diodes and confirmed it was they who was tinkling and not the
board/solder joints/evil spirits. I cut one of the 2N456A's open with
a dremel, and took a picture.
I have a feeling the white chunks inside are deadly beryllium oxide.
Can someone confirm this for me?
Win, thanks for the replacement suggestions. I was able to replace the
2N456A's with TIP34B's. The replacement seems to work okay on the
secondary -24V to -20V regulator, but not on the rectified AC to -24V
regulator. I think there are other problems on the board (like those
rattling diodes).
Asa
acan...@wwc.com (Asa Cannell) wrote in message news:<51ca721c.04112...@posting.google.com>...
Rich Grise
> I cut the transistor open and took a picture! You can see it at:
>
> http://www.exoticelectron.com/tinkle.jpg
>
So, it was their first attempt to put silicon into a transistor!
;-)
Rich
John Popelish
>
> I cut the transistor open and took a picture! You can see it at:
>
> http://www.exoticelectron.com/tinkle.jpg
>
> To recap:
>
> The power supply board in a 40 year old PAR JB-5 lock in amplifier has
> lots of ripple on the output. Two of the large TO-3 power transistors
> on the board (TI 2N456A's) and all the diodes (GE 1N1692's) make
> tinkling noises when you shake the board. I desoldered the transistors
> and diodes and confirmed it was they who was tinkling and not the
> board/solder joints/evil spirits. I cut one of the 2N456A's open with
> a dremel, and took a picture.
>
> I have a feeling the white chunks inside are deadly beryllium oxide.
> Can someone confirm this for me?
>
> Win, thanks for the replacement suggestions. I was able to replace the
> 2N456A's with TIP34B's. The replacement seems to work okay on the
> secondary -24V to -20V regulator, but not on the rectified AC to -24V
> regulator. I think there are other problems on the board (like those
> rattling diodes).
Looks like desiccant to me. Germanium and moisture do not get along
well at all.
--
John Popelish