[Heathkit] Advice with germanium transistors

[gregory.beat at comcast.net]

Doug -

A 2N3055 or 2N3771 are common pass trasnsitors for linear power supplies with LM723 regulators.  Double check the transistor specs (here is a good reference link) for your application.

http://www.kbt-dc-supplies.com/index.php

Spec sheets
http://www.kbt-dc-supplies.com/specs.php

Greg
w9gb


> > Message: 1
> Date: Tue, 18 May 2004 21:28:52 -0400
> From: "Doug Shields" <w4das at adelphia.net>
> Subject: [Heathkit] Advice with germanium transistors
> To: <heathkit at mailman.qth.net>, <HEATH at LISTSERV.TEMPE.GOV>
> Message-ID: <00af01c43d40$a5073210$fab4a145 at system1>
> Content-Type: text/plain;	charset="iso-8859-1"
> 
> Hello all,
>       I have done a lot of design with transistors and integrated circuits
> but not with germanium parts.  I just got a "working" Heathkit IP-27 power
> supply and found two of the three germanium power transistors are shorted
> (collector to emitter.)    Replacement germanium parts are available but
> VERY expensive.  I have thought about replacing them with modern silicon
> power transistors.  What should I watch for in the conversion?  Any help
> from the real semiconductor gurus out there?  Thanks very much.
> 
> Doug  W4DAS
> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Wed, 19 May 2004 03:19:23 +0000
> From: Ronald KA4INM Youvan <ka4inm at tampabay.rr.com>
> Subject: Re: [Heathkit] Advice with germanium transistors
> To: h <heathkit at mailman.qth.net>
> Message-ID: <40AAD23B.1040208 at tampabay.rr.com>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> 
>    No trick, try whatever you have that's close gain wise with a greater 
> current, Voltage and power rating. If you are in any closed loop operation, like 
> in the pass transistor area the transistor type it doesn't matter at all.
>    I have replaced all of the germanium transistors with silicon in many
> devices with no ill effects.  The only critical areas are where the bias
> point of a stage is critical.
> 
> >       I have done a lot of design with transistors and integrated circuits
> > but not with germanium parts.  I just got a "working" Heathkit IP-27 power
> > supply and found two of the three germanium power transistors are shorted
> > (collector to emitter.)    Replacement germanium parts are available but
> > VERY expensive.  I have thought about replacing them with modern silicon
> > power transistors.  What should I watch for in the conversion?  Any help
> > from the real semiconductor gurus out there?  Thanks very much.
> -- 
>         73 (= Best Regards) de: Ron ka4inm at tampabay.rr.com
>      100% LINUX, since July, 1997   SENT Time and Date are UTC
>         Visit my HAM Web SITE at: http://www.qsl.net/ka4inm
> 
> 
> 
> ------------------------------
> 
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> End of Heathkit Digest, Vol 4, Issue 483
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