Tinkling transistor!

A

Asa Cannell

Guest
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?

Asa
 
"Asa Cannell" <acannell@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.
Click to expand...
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/
 
"Asa Cannell" <acannell@wwc.com> wrote

2N456A transistors.
Click to expand...
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?

--
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/
 
On Sat, 27 Nov 2004 12:35:56 +0000, Nicholas O. Lindan wrote:

"Asa Cannell" <acannell@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.
Click to expand...
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
 
On Sat, 27 Nov 2004 12:45:12 +0000, Nicholas O. Lindan wrote:

"Asa Cannell" <acannell@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?
Click to expand...
Har-dy har har! ;-)

Cheers!
Rich
 
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! ;-)
Click to expand...
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
 
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?
Click to expand...
I recall the ads featuring him !


Graham
 
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?
Click to expand...
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
 
In article <41A81F13.16FA302@rica.net>, John Popelish wrote:
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.
Click to expand...
I remember these also, fairly clearly. Power transistors that tinkled
when shaken or moved did exist!

- Don Klipstein (don@misty.com)
 
Robert Baer wrote...
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).
Click to expand...
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
 
On Sat, 27 Nov 2004 14:53:04 -0800, 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'd rather remember Oliie than rest on my Laurels. ;-)
Click to expand...
 
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.
Click to expand...
I thought beryllia was harmless in chunk form. (Powder from
machining is very nasty.)

--
The suespammers.org mail server is located in California. So are all my
other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited
commercial e-mail to my suespammers.org address or any of my other addresses.
These are my opinions, not necessarily my employer's. I hate spam.
 
On Sun, 28 Nov 2004 19:18:21 -0600,
Hal Murray <hmurray@suespammers.org> wrote
in Msg. <y9OdnfcdioBA5TfcRVn-pw@megapath.net>

I thought beryllia was harmless in chunk form. (Powder from
machining is very nasty.)
Click to expand...
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)
 
On Mon, 29 Nov 2004 11:30:49 -0800, Asa Cannell wrote:

I cut the transistor open and took a picture! You can see it at:

http://www.exoticelectron.com/tinkle.jpg
Click to expand...
So, it was their first attempt to put silicon into a transistor!

;-)
Rich
 
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