[Milsurplus] Harris RF 350K

[Peter Gottlieb]

Look on the web for the relay mod.  It puts a small amount of DC current through 
the RF path and works pretty well to keep the relays clean.  Bill Perry has the 
connectors for a reasonable price.  Oh yeah there is a guy who made up little PC 
boards to allow the use of available relays to replace the discontinued ones on 
the filter board.  He sometimes sells them on ebay, with and without relays.

I have a couple of these units and they work pretty solidly.  The only annoying 
thing is that the crystal oven is not powered when the radio is off.  Well and 
the fan in the power supply part which moves way too much air for non-continuous 
RTTY operation.  Find a power resistor to place in series with it to quiet it 
down.  Or ditch the power supply - I run one off of a 12 volt battery and float 
charger, have for years.



On 12/30/2017 9:05 PM, Ray Fantini wrote:
>
> One of the projects around the holiday was a Harris RF 350K transceiver. After 
> replacement of a half dozen shorted bypass capacitors on the + and – 15 volt 
> bus and repairs to the reset “auto start “on the controller have the mess 
> working. As typical for that family of radios the relays on the filter board 
> are shaky.
>
> Separated the power supply from the radio for working on this monster on the 
> bench and have been using the bench 12 volt power supply but decided now that 
> I want to put the two parts together and use the heavy  power supply that 
> comes with the radio.
>
> The issue is the power supply takes a weird connector. It’s a MS3106A 20-8S, 
> the 8S is because it has two huge sockets along with four small pins for the 
> AC and ground. The same plug is on the pigtail from the power supply to the 
> radio and although I have never seen it done may just ditch the huge, heavy 
> over built DC power supply and steel that connector to use the radio from 12 
> volts only.
>
> Looking at the amount of work to get this radio up and running and the 
> remaining issues with the filter board starting to think this family of radios 
> were hanger queens and perhaps that’s why so have been dumped by the 
> government although they somehow appear to sell for big money. This radio was 
> given to me by someone who sold it and then had it returned and never wanted 
> to see it again after that happened so that’s how I got it but the power 
> connector may be a big issue being that looking on E Bay I don’t see one.
>
> Ray F/KA3EKH
>
>
>
>
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