[time-nuts] Re: 5061A HV Supply, et al. {External}

[Jim Muehlberg]

OK, after an 11 day hiatus, there is no change in ion pump current.  
Still very low (1 uA?) in "CS OFF". Switching to another mode (any) 
causes the pump current to increase and the A18 output to fold over, 
then it recovers and keeps doing this at about a 5 second period.  The 
monitor point reaches about 1.2 V before folding back.

So, I found a little laser HV supply that puts out 1250V at 4mA.  So, I 
thought I'd attach that.  On my homemade 172 MOhm Divider, the voltage 
turned out to be much higher, around 7kV!  Which I only found out after 
connecting to the tube.  Hopefully, that didn't kill it.  It drew about 
50 uA at this voltage.  I ended up leaving for a few minutes before I 
realized what was going on, since I couldn't believe the reading from my 
divider.

In any event, after reconnecting the A18, ion pump current is very low 
again, but this time the monitor point stays up at around 4V with the 
clock in "LOOP OPEN".  It no longer folds back at all.

Recall it has no divider module so I'm not sure monitor points are 
useful, but most are dead, except Supply, Ion Pump I, Osc Oven, CS 
oven.  There is a tiny bit of Beam current.

Next steps?  Did I kill it?  I may have access to a divider module...

Jim

On 2022-11-09 11:07 AM, Jim Muehlberg via time-nuts wrote:
> I've recently come into possession of a 5061A.  It is claimed that the 
> tube is exhausted, but I'm unwilling to scrap it (horrors!) yet. I'm 
> not well equipped for HV measurements, but it appears the +3500 V 
> supply is not working.  So, I'm hoping the tube just needs to be 
> pumped since it hasn't been powered for years.  Also missing the A3 
> assembly, but I'll worry about that later...
>
> Anyone willing to part with their A18 or loan it to me?
>
> Thanks!
>
-- 
Jim