[ARC5] TCS Transmitter Tip - Snubber

[Dennis DuValll]

The TCS transmitter already includes snubbing circuits made up of R120 and capacitors C128A and 128B.  This setup protects the contacts
on both the “Power” and the “Send-Receive" relays.  Having said that, though I have encountered failures with C128 (A and/or B) and so on occasion have 
added additional components much as described by Dave.

Dennis L. DuVall, W7QHO
Glendale, CA





> On Nov 24, 2016, at 4:18 PM, David Stinson <arc5 at ix.netcom.com> wrote:
> 
> I've revived three TCS transmitters to original design
> and run them from original dynamotor supplies.
> Brad W.  take a look (had to replace a bearing):
> https://goo.gl/photos/p3SRrZ5Y2uomNdHe9
> 
> All three transmitters have had an issue with arcing across the High B+ contacts on the TR relay.  This causes the PA Current meter to stay above zero while key-up and you will hear the arcing in the receiver.
> If allowed to continue, the contacts will be destroyed
> and other damage will occur.
> 
> If  you remove the transmitter from its case, lay it
> on its back and remove the outside PA 1625, you can access the contact set.  Photo:
> https://goo.gl/photos/d4UuG29fZ6DCyFdH9
> 
> There is just enough room to install a "snubber,"
> which is a capacitor and resistor in series, across
> the contacts.  Values are not critical; the one pictured is .047 1KV in series with 240 Ohms.
> .1 and 180 Ohms will also work.  Reinstall the 1625
> and make sure you have clearance.  Photo:
> https://goo.gl/photos/h3XGqeCB78XtEXXN6
> 
> This will stop the relay arcing.
> 
> 73 DE Dave AB5S
> 
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