[ARC5] command set bench psu

[Meir WF2U]

Thanks for the good information!

I got a couple of those; I never realized they were for the ARC-5/SCR-274N
and later type receivers! I picked up 2 at a hamfest a long time ago for $25
for both. I used them as general bench supplies, for the plate voltage. I
never used the 24VDC output...
Since they haven't been used for a while, it's time to dust them off and
replace the rectifiers and mod them per Mike!

73, Meir WF2U
Landrum, SC

-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Mike Hanz
Sent: Friday, January 11, 2013 4:35 PM
To: Darryl Sage
Cc: ARC5 at mailman.qth.net
Subject: Re: [ARC5] command set bench psu

On 1/11/2013 2:52 PM, Darryl Sage wrote:
> I saw a command set bench psu . i had to have it more mony than brains.I
> guess i can retire a few dynos  I have never seen one before are they
rare?
> I will have to make room for it now. 73  darryl    ve3cpo

I'm assuming that you are referring to 
http://www.ebay.com/itm/ARC-5-Power-Supply-SCR-274N-Receiver-OEM-/1409024993
34 


I've had a few cycle through here.  I've used them for a while, then 
pass them on to someone who's wanting one.  They have some drawbacks, 
one of which you can see in the photos - the voltages tend to be on the 
high side rather than the low side as we are more and more trying to 
provide for our dwindling supply of command sets.  The selenium 
rectifier used for the low voltage supply should be replaced before it 
replaces you, and the HV bridge diodes could be replaced by four modern 
HV diodes.

You can fix the voltages with a bucking transformer, but if I was 
keeping one, I'd put in a 6082 (24v filament) series regulator on a 
3"x3" outboard chassis on the back, and design the circuit so that the 
HV switch steps started at maybe 50v and ended up around 220v. There are 
plenty of those circuits in the manuals.  Then it would be pretty 
useful.  It's a shame the nifty cable with the dynamotor connector was 
retained by the seller, but you can cobble one up fairly easily, if not 
as elegant looking.

Congratulations on your purchase - I'm sure you'll enjoy using it!

73,
  - Mike
______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:ARC5 at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html