[volt-nuts] Solartron 7071 vs 7081

[J. L. Trantham]

Dave,

Is it possible you have a 7081 that has been converted to a 7071 by
replacing the front panel?  How difficult is it to remove and replace the
front panel?

Joe

-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Robert Atkinson
Sent: Wednesday, April 04, 2012 6:13 AM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Solartron 7071 vs 7081


Hi David,
It sounds like you just have to close the circuit for the missing "8 nines"
button.
 
Robert G8RPI.


________________________________
From: David C. Partridge <david.partridge at perdrix.co.uk>
To: 'Discussion of precise voltage measurement' <volt-nuts at febo.com> 
Sent: Wednesday, 4 April 2012, 1:50
Subject: Re: [volt-nuts] Solartron 7071 vs 7081

Bill

Here's an extract from an email from one of the guys who worked at Solartron
for a long time and is still there now that it is Ametek:

>Incidentally did you know that the 7081 and 7071 are essentially the 
>same instrument? The reference zener diodes were soaked for several 
>weeks in an oven which temperature cycled them and each diode was 
>checked regularly for stability. The very best ones were selected to go 
>in the tighter specified 7081. The not so good ones went in the 7071. 
>Otherwise the only difference is the front panel and the contents of 
>the EPROMS. The 7081 has an 8 x nines (51 seconds integration time) 
>button. On the 7071 this button is not present and the firmware limits 
>the integration time to  3.2 seconds (7 x nines display). Both units 
>can go down to 3 nines (1.56mS integration time, 100 readings per 
>second when under remote control although of course this rather defeats 
>the object of having such an long scale instrument.

Hence my surprise to see ROMs clearly labelled 7081 in a 7071 meter, and it
does not think it is a 7081.  Apart from the front panel and external
labelling there's sweet little visual difference between it and my 7081
(internally as well as externally).  I've not found any candidate jumpers
thus far, and I have looked.

So yes, I do realise that even if it were possible to fool the firmware that
wouldn't magically turn the 7071 into a 7081.

Dave


_______________________________________________
volt-nuts mailing list -- volt-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
_______________________________________________
volt-nuts mailing list -- volt-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.