[MRCA] T-195 Power Supply Options

[Steve]

Dennis,
	I believe that many military radio officiandos have their eyes wide
open looking for one of those old battery charges like Ted's.  Have to 2nd
Mike's comment that the supply is very worthy and is happy running most of
the 28V equipment up and down the bench the MRCA meets!!

Steve, kd3ht

-----Original Message-----
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On
Behalf Of Mike Murray
Sent: Sunday, November 01, 2009 1:54 PM
To: mac
Cc: MRCA at mailman.qth.net
Subject: Re: [MRCA] T-195 Power Supply Options

Hi again, Dennis!
Well, your supply of Ted's worked great on my T-195, and it was a very nice
piece of craftsmanship. Well done!

For my T-195, I have a good ol' fashioned mechanical dynamotor. At least, I
am 99.999% sure I do.
Is that good or bad, I wonder? Have thought about conversion to solid state.
Possible?

OK on the batteries. This sounds like what I should do.
Will keep you all updated as we formulate our next steps.

TNX es 73!
Mike
KW4HF


--- On Sat, 10/31/09, mac <w7qho at aol.com> wrote:

> From: mac <w7qho at aol.com>
> Subject: Re: [MRCA] T-195 Power Supply Options
> To: "Mike Murray" <mmurray377 at yahoo.com>
> Cc: MRCA at mailman.qth.net
> Date: Saturday, October 31, 2009, 5:42 PM
> Mike,
> 
> First of all, which power supplies do you have in your
> T-195, i.e, mechanical dynamotors or the later solid state
> replacements.  If the latter your switcher may work OK
> without any capacity or other assist.  Many T-195s I've
> seen have one of each, usually solid state HV and mechanical
> for +250, -45 & 115V-400 cps. which still requires some
> surge capability but not as much as the 1000 volt unit.
> 
> DO NOT try to hang a bunch of caps across the output of
> your switcher.  Better way is to shunt  a couple
> of seriesed 12 volt car batteries across your supply through
> an isolating diode to prevent a reverse current flow back
> into your PS.  Adjust your PS voltage to give 2-3 amps
> charging current to the battery under no-load condx and
> connect the -195 across the battery terminals.  The
> diode should have a rating of 200 A or so, no problem these
> days.
> 
> You can  also use a pair of smaller power supplies to
> run the T-195.  The load is split almost perfectly
> 50-50 at the primary power input connector, see your manual
> for the pin-out.
> 
> I built the supply that Ted uses.  It's simply an old
> garage Hot-Shot charger with the selenium rectifier replaced
> by a solid state bridge and something more than 100,000 mfd
> (I don't remember exactly) hanging across the output. 
> No regulation but not needed with the -195.  Have since
> duplicated this circuit in a nice cabinet with a variac,
> meters, etc. and use this for my GRC-19s.
> 
> Dennis D. W7QHO
> Glendale, CA
> 
>


      
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