[Amps] Vacuum relay replacement - now grid reading

[Gary Smith]

Thanks to all for the replies both to say the relay is fine and on 
how to deal with the issue when it crops up again.

Now I see there's something else; theres a change in the grid meter 
reading that wasn't there before, it reads much less vigorously than 
before and shows no sharp defined peaks as the load/tune is adjusted. 
It doesn't appear to reflect what the readings should be and I don'e 
get full scale deflection, at most maybe 1/3 scale deflection. I'm 
getting full output however and no problem getting full output, but 
switching between the plate amp reading and grid reading I see little 
difference in the needle deflection. 

Also, I don't see the ALC light come on as I tune so ALC likely isn't 
working. Wasn't like this before so it's most likely related to 
something that happened when the relay locked in the transmit 
condition. Need to figure this one out.

One of the nice things about getting an old amp that's been pried 
into before by one or more previous owners is you & the amp get to 
know each other much better. Usually this acquaintance develops more 
sooner than later. 

Heh,

Gary
KA1J

> Finding the bugs in my newly acquired amp. Today I found I could 
> transmit but couldn't receive & I tracked the problem to amp and the 
> with further inspection, to the Kilovac T/R. I think Jennings RJ1A 
> relays were in the original Alpha PA-77 so I think it's been changed 
> before.
> 
> Discovered the relay was locked in the transmit position and there 
> was continuity between COM & NO and none between COM & NC. the K3 
> received properly when shorting COM & NC. Took a screwdriver and 
> placed that on the NO terminal & gave it a light whack & that freed 
> the relay and it's back to working. I'm guessing this relay has been 
> a problem before and it'll surely fail again so I'm going to replace 
> it with a different one. 
> 
> I've been looking at the specs on different 8ms relays that fit and 
> the RJ1A-26N969 which is the RJ1A with a silicone coated top is 
> supposed to be rated for 10kv as opposed to the RJ1A at 5kv, other 
> than that they are the same relay. Seems like it would be an ideal 
> replacement but anyone know a reason I shouldn't use this one?
> 
> Thanks,
> 
> Gary
> KA1J