[1000mp] MPV Driving SB220

[Cecil Acuff]

Mike I'd be interested (off list) in your QSK conversions.  I'm currently 
rebuilding a Clipperton L and might want to include that..

Thanks & 73

Cecil...
----- Original Message ----- 
From: "Mike Schatzberg" <cherokeehillfarm at earthlink.net>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Tuesday, October 24, 2006 10:25 AM
Subject: Re: [1000mp] MPV Driving SB220


> Hello Jim:
>
> Heathkit part number 69-55, is a TPDT relay, with a 110 VDC coil.  It is
> indeed driven by switched DC voltage from the simple half wave power 
> supply
> circuit off of one of the transformer windings.
>
> Perhaps Heathkit produced more than one version of the switching, which
> handles both antenna transfer duties and bias switching.
>
> I have changed many of these amps to QSK using vacuum and reed relays, and
> usually have several pulls in the junk box here.  They are all DC relays.
>
> 73 and Happy DXing,
>
> Mike
> W2AJI
> ----- Original Message ----- 
> From: "Jan Erik Holm" <sm2ekm at telia.com>
> To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
> Sent: Tuesday, October 24, 2006 11:06 AM
> Subject: Re: [1000mp] MPV Driving SB220
>
>
>> I see, then I do know what it is.
>>
>> Well now, the SB-220 has a AC operated relay, need
>> I say more?
>>
>> 73 Jim SM2EKM
>> ------------------------------------------------------------
>> Bill Gode, Sr. wrote:
>> > Snubbing Diode (From Wikipedia):
>> >
>> > When the current flowing is dc, another often seen form of a snubber is
>> > a simple rectifier diode placed in a circuit in parallel with an
>> > inductive load (such as a relay coil or electric motor). The diode is
>> > installed in the direction that ordinarily does not allow it to 
>> > conduct.
>> > When current to the inductive load is rapidly interrupted, a large
>> > voltage spike would be produced in the reverse direction (as the
>> > inductor attempts to keep current flowing in the circuit). This spike 
>> > is
>> > known as an "inductive kick". Placing the snubber diode in inverse
>> > parallel with the inductive load allows the current from the inductor 
>> > to
>> > flow through the diode rather than through the switching element,
>> > dissipating the energy stored in the inductive load in the series
>> > resistance of the inductor and the (usually much smaller) resistance of
>> > the diode (over-voltage protection). One disadvantage of simple
>> > rectifier diode used as a snubber is that because the diode allows
>> > current to keep flowing, the relay may stay picked-up slightly longer;
>> > some circuit designs must account for this delay in the dropping-out of
>> > the relay.
>> >
>> > 73,
>> >
>> > Bill, W9NHQ
>> >
>> >
>> > ----- Original Message ----- From: "Jan Erik Holm" <sm2ekm at telia.com>
>> > To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
>> > Sent: Tuesday, October 24, 2006 8:34 AM
>> > Subject: Re: [1000mp] MPV Driving SB220
>> >
>> >
>> >> What is a snubbing diode? I have never heard that
>> >> expression before.
>> >>
>> >> /Jim SM2EKM
>> >> ---------------------------
>> >> Pete Smith wrote:
>> >>> You can also play safe by putting a 220-ohm resistor in series with
>> >>> the switching lead to limit the current through the relay contacts;
>> >>> that device was published in QST many years ago, when relays in
>> >>> TS-930s like mine were being fried by the relay current - the stock
>> >>> SB-220 relay has no snubbing diode, which may be part or all of the
>> >>> problem.
>> >>>
>> >>> 73, Pete
>> >
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>>
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