[ICOM] FW: Info on Icom PS-55 Needed

[ve4xt at mymts.net]

The PS-55, stock, pushes AC through Pin 6 to the radio, where it comes back via Pin 3 and heads to the primary of the transformer. It's similar to the design of the internal supplies ICOM made for radios such as the IC-740 and IC-745.
Newer ICOM supplies (PS-126, etc.) merely put DC to the connector to the radio, and have their own switch for AC. With these, you need both the PS and radio switches to be on.
Likely what happened is the modder put the toggle switch across the lines running to Pins 3 and 6 of the connector and disconnected them from the connector. I suspect the IC-735 switch is a multi-pole switch that turns on both AC to the supply, when needed, and DC to the radio. Which would explain why you need both to be on.
The redundancy of the AC contacts on the radio's switch and the contacts in the added toggle switch isn't important, so if you wanted to reestablish the ability of the radio to turn on the supply but retain the function of letting the new toggle turn on the supply (when you don't have an IC-735 connected, for example), you could simply parallel the toggle switch to the connector.
You'd just have to be careful in the future if using the same connector on other radios to not fire AC towards those radios!
73, kellyve4xt



> From: k2gkk at hotmail.com
> To: icom at mailman.qth.net
> Date: Thu, 18 Jun 2015 16:18:14 -0500
> Subject: Re: [ICOM] FW: Info on Icom PS-55 Needed
> 
> I'm going to have to dive into the P.S. to figure out what's going on.  Both the added toggle on the P.S. AND the IC-735 power switch have to be on to power up the radio.  I suspect, but have not checked, that the 735 power switch MAY activate a relay that switches the 13.8 VDC as well as applying AC power to the P.S.  As it is, the P.S. WILL power the 735. 
>  
> In checking the PS-55, I find that the added toggle does get 13.8 VDC to the six-pin power plug. 
>  
> I also discovered that the P.S. output is running about 14.6!  I believe it to be advisable to reset the voltage to the specified 13.8 for safety of my 735.
>  
> * * * * * * * * * * * 
> * 73 - Mac, K2GKK/5 * 
> * (Since 30 Nov 53) * 
> * k2gkk hotmail com * 
> * Oklahoma City, OK * 
> * USAF & FAA (Ret.) * 
> * * * * * * * * * * * 
>  
> 
> > Date: Thu, 18 Jun 2015 14:08:05 -0700
> > From: gfiber at comcast.net
> > To: icom at mailman.qth.net
> > Subject: Re: [ICOM] FW: Info on Icom PS-55 Needed
> > 
> > So far as I remember the AC for the PS-55 did indeed go through the 
> > IC-735 power switch. The PS-55 6 pin connector has 6 wires, 4 are the DC 
> > and the other two are the AC. Some over the years did wire a separate 
> > switch into the PS-55 since there was no other way of powering up that 
> > supply with out connection to an Icom product or installing a switch or 
> > at least jumping the 2 AC wires together.
> > 
> > Gary K8IZ
> > 
> > On 6/18/2015 11:40 AM, Jim Hargrave wrote:
> > > Sounds like someone wired the toggle switch in series with the 735
> > > power switch.
> > > If you leave the toggle switch ON, does the 735 switch power the
> > > supply ON/OFF?
> > > Another thought. The 735 power switch is small and should not be
> > > wired directly to the AC input.
> > > Perhaps someone has wired a relay circuit to turn on the primary.
> > >
> > > 73, Jim - w5ifp at gvtc.com
>  		 	   		  
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