[ICOM] IC-756Pro Linear amp SEND relay kaput

[Adam Farson]

Hi Charles,

The 76PA keying V/I rating is  25V/75mA. The voltage is a bit high, but
should not harm the relay. The IC-746Pro uses the same Tyco/OEG OMR-109F
reed relay as the IC-746 and many other Icom HF transceivers - so if your
746 was happy, the 746Pro should also be OK with direct keying.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Frost, Charles
Sent: 12 December 2005 09:54
To: ICOM Reflector
Subject: RE: [ICOM] IC-756Pro Linear amp SEND relay kaput

I am Keying my ALPHA 76PA straight from the keying jack on my IC764PRO just
like I did with my old 746 with no problems. It it different from the other
Icom rigs? Or is it the old ALPHA amp?

Charles Frost  K5LBU
Olle MS  K5OMS

-----Original Message-----
From: Kenneth D. Grimm, K4XL [mailto:kgrimm at adelphia.net]
Sent: Monday, December 12, 2005 11:40 AM
To: ICOM Reflector
Subject: Re: [ICOM] IC-756Pro Linear amp SEND relay kaput

Adam Farson wrote:

><snip>
>
>Required reading when connecting an Icom transceiver to an amplifier 
>whose keying V/I rating exceeds 16V/0.5A;
>
>http://www.qsl.net/icom/auxrelay.html
>
><snip>
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>
>
>  
>
I couldn't agree more!  Rather than spending "real" money for an IC-756ProII
relay to an Alpha 78 relay interface, click on the link at the bottom of the
above linked page labeled "Here."  This simple little circuit works like a
treat.  I've built several of them for myself and friends using "ugly bug",
vero board and printed circuit techniques.  How can you go wrong with one
transistor, one resistor and one diode?  

All of my amps, commercial and homebrew, use positive voltage keying on the
relays, so I used the diagram at the bottom of the page.  (Why would anyone
use negative voltage keying?)

Shopping at All Electronics you can find a TIP32C for .65, a neat little
Hammond plastic box for $1.20, 1K resistor .50 (you get 9 spares at this
price),  1N4002 $1.00 (11 extras), a 10' cable with RCA plugs on each end
for $1.00.  So, not counting the bit of pc board, vero board or whatever you
decide to mount this on, the total cost would be $4.35.  If you have any
kind of junk box at all, the cost might be much lower!  This is not rocket
science.  Anyone can build this gadget.  :-) 

All of the parts are available from other sources, I just happened to have
the All Electronics catalog here at the computer and checked on their
prices.

-- 

Ken K4XL
k4xl at arrl.net

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