I would NOT recommend the Harbach SB-220 replacement T-R relay. The one I
bought worked reliably for less than six months before beginning to exhibit
very poor contact pressure in the receive (normally-closed) position,
requiring almost continuous attention (cleaning/burnishing). I finally got
sick of it, pulled it out, and threw it in the trash. I then designed a T-R
system (after considerable research on the internet) using Kilovac vacuum
relays and a small reed relay to switch the operating bias on. Works great,
super-fast, now I have QSK CW.
A second caveat on the Harbach relay is that it is NOT a direct pin-for-pin
clone of the Heath relay. You will need to analyze its pinouts carefully.
Wires will end up going to different places on it.
Your mileage may vary. The Harbach might end up working fine for you, but I
can't recommend it.
Having said that, my converted 6m SB-220 has numerous other Harbach products
in it, and they are all working fine. Just not the replacement T-R relay,
which is now in a landfill somewhere in Rio Rancho, New Mexico.
Bill W5WVO
--------------------------------------------------
From: "Steve Katz" <stevek@jmr.com>
Sent: Wednesday, April 07, 2010 3:31 PM
To: "JayKay" <pcb4u@verizon.net>; <amps@contesting.com>
Subject: Re: [Amps] SB220 SICK...RELAY
> Model RY220 from Harbach Electronics. $22 I think.
>
> http://www.harbachelectronics.com/main/page_products_sb220__sb221.html
>
> WB2WIK/6
>
>
>
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of JayKay
> Sent: Wednesday, April 07, 2010 2:27 PM
> To: amps@contesting.com
> Subject: [Amps] SB220 SICK...RELAY
>
> Thanks to all for your inputs. I am going to try cleaning the relay
> contacts and watch alignment, etc.
>
> If I can't get it going (contacts beyond repair), I would like to
> replace the relay but a quick Google shows the KA-3702 relay by PB
> doesn't exist.
>
> My thinking is to grab the 120VDC present in the rig and regulate it
> down to 5VDC or 12VDC (once I know the resistance of the coil) and then
> get a 10 amp 3PDT relay. It will also make it easier to interface with
> newer rigs that don't like 120V switched to ground through their
> internal relays.
>
> I could use a series resistor (with the R of the coil) to step it down
> but I don't want to hot switch 120V (at T = 0) to any external relays
>
> 1) Anyone have the KA-3702 relay or a source?
>
> 2) Additional comments?
>
> 3) Relay recommendations?
>
> Thanks
>
> Jay
>
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>
>
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