[time-nuts] HP 5061B

EWKehren at aol.com EWKehren at aol.com
Sat Sep 3 14:46:53 UTC 2011

Jeff from your description it is not clear wether the noise is due to the  
UPS or 5061B. The 5061 transformer most likely will complain with a crappy  
signal input.I do not trust the output from UPS since many have a crappy 
output  which is ok if your PC does not have PFC on the input.
I have in the past always used and recommended to run the units from 28  
Volt direct, not even using the AC input. Batteries do not have to be deep 
cycle  since power failures are not that prevalent and batteries will die from 
chemical  deterioration rather than cycle use. Low voltage cut out is 
mandetory since car  batteries will fail after a few full discharges.For instance 
Costco car  batteries have long warranties and combined with a Guest dual 12 
V 5/5 charger  makes a perfect set up for less than $230 and run time will 
be about 24 hours.  If you do not mind making small changes to the A2 
charger board you can get the  same result for half the price supplying power from 
the 5061B. I prefer the  Guest approach and I have noticed a price 
escalation on Guest chargers but you  can still get one for $110 shipping included.
Bert Kehren
In a message dated 9/3/2011 6:32:19 A.M. Eastern Daylight Time,  
w3kl at w3kl.com writes:


We lost power for several days after the hurricane  last weekend.  As a 
precaution I pulled the AC plug for my 5061B from the  UPS it's attached to 
since I was pretty sure that we would be without power  for a while and didn't 
want to have the unit plugged in when the power came  back in case there was 
a surge.

Power was restored on Tuesday but  I only got around to powering up the 
system  this  morning.

When  I plugged it in, it immediately started  making a buzzing sound - 
alomost like an alarm.  The system appears to be  working normally otherwise - 
alarm LED on, clock advancing,  etc.

I've never heard this buzzing  before during power  up.

Not knowing what the issue was, I powered the system  down.

Anyone have any clue before I start tearing it  down?

BTW - I don't see any mention of this in the  manual.

Thanks in  advance.

time-nuts  mailing list -- time-nuts at febo.com
To unsubscribe, go to  
and follow the  instructions there.

More information about the time-nuts mailing list