[R-390] R-390 Break-In Relay - Do I have a problem?

[Barry]

Not sure.  The DC resistance for the Break-In relay's coil is 8 ohms so that may be close(?)

Barry - N4BUQ

> Thanks Barry.  Does the 1/2 amp current sound right?
> 
> Sent from my iPhone.  Apologies in advance  for the typo’s
> 
>> On Nov 27, 2024, at 10:21 PM, Barry Scott <72volkswagon at gmail.com> wrote:
>> 
>> Since there's no filtering, you're reading the full ripple voltage.
>> 
>> Thanks,
>> Barry - N4BUQ
>> 
>>> On Wed, Nov 27, 2024 at 7:46 PM <k1jos at att.net> wrote:
>>> 
>>> I finally got my R-390 RF and audio working well with outstanding advice
>>> from Don Heywood.  I just put it into the rack with help from a young strong
>>> neighbor and I was setting up a TR switch/sequencer to use the radio with my
>>> low power AM transmitter.  The TR/sequencer relays can handle up to 400V @
>>> 120mA.  I measured the current across the rear terminal 9 (Break-in) and 16
>>> (GRND) with the Break-In switch ON.  I read about 500-600mA with a DMM
>>> across 9-16 and the relay works without chatter.  However, looking at the
>>> manual I see that the coils of the break-in relay K602 and the antenna relay
>>> K101 are in parallel and are fed from the selenium bridge rectifier CR801.
>>> I'm not 1200% certain but I believe the selenium was replaced about 10-12
>>> years ago with a silicon bridge.
>>> 
>>> 
>>> 
>>> From the manual:  " The low-voltage secondary (terminals 8 and 10) of T801
>>> supplies 25.2 volts ac to all filament, dial lamps, and oven-heater
>>> circuits. A tap (terminal 9) on this winding provides 12 volts for dry-disk
>>> rectifier CR801, to supply 6 volts dc to antenna relay K101 and break-in
>>> relay K602."
>>> 
>>> 
>>> 
>>> However, with Break-In switch turned ON but rear terminal 9 and 16 NOT
>>> shorted, I read 12VAC not DC across 9 and 16 on my DMM.   The break-in relay
>>> is working and I don't think it would work well if it was a DC coil.  I hate
>>> the thought of pulling the receiver out again but I am more concerned about
>>> damaging the relays coils.
>>> 
>>> 
>>> 
>>> Any advice appreciated.
>>> 
>>> 
>>> 
>>> Happy Thanksgiving to All,
>>> 
>>> 
>>> 
>>> Jerry NY2KW
>>> 
>>> 
>>> 
>>> 
>>> 
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