[AMPS] Icom 756
David B. Ritchie
dbr@alumni.caltech.edu
Wed, 19 Mar 1997 14:58:21 -0800 (PST)
This is a common problem -- especially with all recent Icom Equipment --
if you want to use such equipment with older amps (Collins, Heathkit,
Drake, etc.) be sure to understand the rating of your switching relay (or
transistor circuit) in the transceiver as well as the voltage and current
present in the switching circuit of the amp -- not all amps just take 12V
to ground at nominal current! The SB220 will rapidly fry an Icom IC738
switching relay (Omron low voltage part) with its -115VAC. If you have
this problem there are all sorts of elegant and non-elegant solutions --
the best I've heard of is to put a heap big transistor in the transceiver
that can deal with anything likely to ever be seen -- its quiet, but it
requires some work, especially with surface mount technology boards.
Good luck
Dave N7UE
On Wed, 19 Mar 1997, JOHN BASILOTTO wrote:
> I have an Icom 756. I was using it with a Drake L4B. At first everything was
> fine; after about 30 days the reed relay in the Icom froze stuck. The Icom
> relay is rated at 16volts@2amps. The Drake amp has a 12 volt relay but has a
> potential of 26volts with no load. Consider using an aux. relay; otherwise
> you too may have to replace an Icom relay.
> 73, John w5GI
>
>
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David B. Ritchie, Esq.
D'Alessandro & Ritchie, P.C. -- Intellectual Property Lawyers
3521 E. Yorkshire Road, Pasadena, CA 91107-5432
818-683-8800 (TEL) 818-683-8900 (FAX) dbr@alumni.caltech.edu
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