[volt-nuts] 7061 On Board Clock and Battery

J. L. Trantham jltran at att.net
Mon Jun 25 12:22:09 UTC 2012


Fred,

Your 7061 appears to be identical to mine, including the same versions of
firmware in the EPROM's.

I tried installing a 3 V lithium battery for B101 and a 47K resistor for
R117.  The current load brought it to about .5 volts.  I placed a 'short'
across R117 and the voltage rose only to about 1 volt.  I hooked my current
limited power supply to the points and it drew in excess of 150 mA from
'B101'.  At that rate, it would take a two D cell batteries to have any
duration of powering the point with the external power off.  The high
current draw prompted me to abandon any further testing.  No harm done
though as the meter still works properly.  Too bad it does not have battery
backup for the clock as does the 7081.

Thanks for the pictures.

Joe

-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Fred Schneider
Sent: Monday, June 25, 2012 1:13 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 7061 On Board Clock and Battery


http://www.pa4tim.nl/?p=2456 here is a picture of the inside of my 7061. No
second battery.

Fred PA4TIM

Op 25 jun. 2012 om 03:23 heeft "J. L. Trantham" <jltran at att.net> het
volgende geschreven:

> My 7061 has a single battery installed, B501, a 3.6 V Ni-MH 
> Rechargeable 3 pin battery.  My 7081 has two batteries installed, the 
> same 3.6 V Ni-MH Rechargeable battery and a ½ AA Lithium Battery that 
> serves as the onboard clock backup battery.  It is connected with its 
> negative pin to a 47K resistor to ground and its positive pin to a 
> diode that feeds a connection that is also fed by another diode from 
> the main power supply.  The common connection of these diodes feed the 
> clock chip.
> 
> 
> 
> On my 7061 there is a location, B101 that appears to be for the same 
> type ½ AA Lithium Battery.  The + pin connects to a diode, in a manner 
> similar to that described above, and the – pin connects to a ‘space’ 
> for a resistor, R117, with the other end of the resistor going to 
> ground.  Both the battery, B101, and the resistor, R117, are missing.
> 
> 
> 
> My questions are:
> 
> 
> 
> 1.    Does anyone have a 7061 with this battery and resistor installed?
> 2.    If so, what is the value of the resistor, R117, and what type is the
> battery?
> 
> 
> 
> It seems that this would be an easy addition to get a live clock 
> without the need to restart the clock each time the meter is turned 
> on.  Or, perhaps there is a reason why this in not a good idea.
> 
> 
> 
> Thanks in advance.
> 
> 
> 
> Joe
> 
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