Re: {Collins} Collins 30L-1 Arcing at interlock switch

Hi Mike,

There are really only two things that could cause arcing at this switch
(assuming the wire to the switch isn't shorting through the insulation, or
dangling loose): the most likely is that the phosphor bronze arm is bent so
that the contact screw isn't centered in the hole when the cover is on the
RF compartment.  The fix is to bend the arm to position it more carefully.
Typically, the flat part of the arm should be vertical with the enclosure
lid secured.

The other (less likely) possibility is a carbon or dust track on the ceramic
standoff. The fix is to clean the ceramic. 

And, of course, make sure the shield cover is tightly installed, so that it
presses down on the phosphor bronze arm.

The 30L-1 only operates at 2 kV, so arcing is almost never a problem.

Jim W8ZR

> -----Original Message-----
> From: collins-bounces@xxxxxxxxxxxxx [mailto:collins-bounces@xxxxxxxxxxxxx]
On Behalf
> Of mike mackin
> Sent: Tuesday, June 16, 2009 7:16 AM
> To: collins@xxxxxxxxxxxxx
> Subject: {Collins} Collins 30L-1 Arcing at interlock switch
> I have a nice working 30L-1 amplifier. All original except for new
rectifier diodes about a
> year ago. Recently It has developed an issue with arcing at the top cover
interlock switch.
> The first time it happened right at power up. I immediatly shut off and
checked everything
> out finding no problems. The interior is clean and interlock hardware is
tight and looks fine.
> After reassembly and power up, all seemed ok until the next day. About 2
minutes after
> powering up the 2nd time, it happened again. This is happening when the
amp is idle and
> not during tune up or transmit.
>  Any ideas or suggestions would be greatly appreciated. I am a new member
here and am
> glad to be part of the group
> Thanks.
> Mike Mackin
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