[Amps] Looking for picture of SB220 interlock switch

Thu Nov 7 20:27:58 EST 2013

Have it your way.

OTOH, since you obviously have a reading comprehension issue you missed my 
statement that I added a label on the top cover stating the shorting strap 
was deactivated. Plus I discussed it first with the customer.

For obvious reasons the shorting bar is a thing of the past in ham 
amplifiers and a chicken stick doesnt come as an accessory. This is not the 
broadcast industry so stick to the subject.

Carl
KM1H

----- Original Message ----- 
From: "Joe Subich, W4TV" <lists at subich.com>
To: "Carl" <km1h at jeremy.mv.com>; <amps at contesting.com>
Sent: Thursday, November 07, 2013 6:28 PM
Subject: Re: [Amps] Looking for picture of SB220 interlock switch

>
> No, recommending the removal of protective devices and removing them in
> amplifiers you service is ridiculous.  I know that any technician in a
> broadcast environment who removed crowbars or other safety circuits
> would likely find themselves without a job.
>
> I hope for your sake that none of your customers - or someone they sell
> the modified amplifier to - is ever injured by high voltage.
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 11/7/2013 5:39 PM, Carl wrote:
>> Now you are becoming ridiculous.
>>
>>
>> ----- Original Message ----- From: "Joe Subich, W4TV" <lists at subich.com>
>> To: "Carl" <km1h at jeremy.mv.com>; <amps at contesting.com>
>> Sent: Thursday, November 07, 2013 11:19 AM
>> Subject: Re: [Amps] Looking for picture of SB220 interlock switch
>>
>>
>>>
>>> On 11/7/2013 10:47 AM, Carl wrote:
>>> > Adding a roll cage into your Prius might also save your life.
>>>
>>> Yes, and putting a body around motorcycles would save thousands
>>> of injuries/deaths a year.  I'm not about to strip the body off
>>> my automobile and drive it on the interstate.  Saving a few
>>> minutes in changing spark lugs isn't worth the danger every day.
>>>
>>> Since you remove the crowbar from amplifiers you service, do you
>>> also remove the cover plates from your outlets/switch boxes and
>>> disconnect the green wire?   After all, those are only necessary
>>> if those using the house don't have enough personal responsibility
>>> to keep their fingers out of the boxes or maintain their electric
>>> powered equipment.
>>>
>>> 73,
>>>
>>>    ... Joe, W4TV
>>>
>>>
>>> On 11/7/2013 10:47 AM, Carl wrote:
>>>> Adding a roll cage into your Prius might also save your life.
>>>>
>>>> However many of us come from the concept of personal responsibility, a
>>>> bit of training, and the ability to read a warning label.
>>>>
>>>> Those that dont/cant are removed from the gene pool which may be a good
>>>> thing.
>>>>
>>>> Carl
>>>> KM1H
>>>>
>>>>
>>>> ----- Original Message ----- From: "Joe Subich, W4TV" 
>>>> <lists at subich.com>
>>>> To: <amps at contesting.com>
>>>> Sent: Wednesday, November 06, 2013 11:20 PM
>>>> Subject: Re: [Amps] Looking for picture of SB220 interlock switch
>>>>
>>>>
>>>>>
>>>>> > That "safety" device can easily destroy your PS and I always
>>>>> > disable/remove them and add a warning label.
>>>>>
>>>>> While it may destroy your power supply it can save your life.  The
>>>>> best solution is to *add* the primary interlock switches and leave
>>>>> the crowbar in place.  Disconnecting the primary before or at the
>>>>> same time as shorting the HV will protect the power supply -
>>>>> particularly if a properly sized glitch resistor has been installed
>>>>> in the HV lead between the HV terminal and the crowbar/cold end of
>>>>> the plate choke.
>>>>>
>>>>> Every one of the "big transmitters" I ever worked on had *both*
>>>>> primary interlocks *and* mechanical crowbars in addition to the
>>>>> "deadman stick" to be used before reaching into any place where
>>>>> high voltage could exist.  Some of those power supplies were capable
>>>>> of as much as 20 KV at 10A - they were nothing to take lightly.
>>>>>
>>>>> I would never disable a safety circuit - that is quick route to an
>>>>> early appearance in "Silent Keys."
>>>>>
>>>>> 73,
>>>>>
>>>>>    ... Joe, W4TV
>>>>>
>>>>>
>>>>> On 11/6/2013 11:00 AM, Carl wrote:
>>>>>> That "safety" device can easily destroy your PS and I always
>>>>>> disable/remove them and add a warning label.
>>>>>>
>>>>>> If you are that worried about safety then add a cover switch to
>>>>>> disable
>>>>>> the AC line as many other amps do.  Very simple and inexpensive.
>>>>>>
>>>>>> Carl
>>>>>> KM1H
>>>>>>
>>>>>>
>>>>>> ----- Original Message ----- From: "Geert Jan de Groot"
>>>>>> <pe1hzg at xs4all.nl>
>>>>>> To: <amps at contesting.com>
>>>>>> Sent: Wednesday, November 06, 2013 4:07 AM
>>>>>> Subject: [Amps] Looking for picture of SB220 interlock switch
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> I'm preparing to start on an SB220 renovation project:
>>>>>>> replace capacitors, update diode board, etc
>>>>>>>
>>>>>>> The previous owner has disbled the safely interlock by
>>>>>>> bending the brass strip away and removing the
>>>>>>> "tapped phenolic spacer". I'd like to restore them.
>>>>>>>
>>>>>>> I'm not sure what, and why, the machanical and electrical
>>>>>>> parameters are of the spacer as I'll need to find something else.
>>>>>>> I'd expected it to be a metal thing but according to the manual
>>>>>>> it isn't.
>>>>>>>
>>>>>>> Does someone have a detailed picture of the interlock in place?
>>>>>>> Why is it an isolator? What are the mechanical stresses on the
>>>>>>> spacer?
>>>>>>>
>>>>>>> 73,
>>>>>>>
>>>>>>> Geert Jan
>>>>>>>
>>>>>>> PS: I know the interlock doesn't make it safe, but 'safer'
>>>>>>> and that's still a good thing IMHO
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Amps mailing list
>>>>>>> Amps at contesting.com
>>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>>
>>>>>>>
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>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>> _______________________________________________
>>>>> Amps mailing list
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>>>>> http://lists.contesting.com/mailman/listinfo/amps
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>>>>
>>>
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>>
>
>
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