[volt-nuts] HP3468A

Roy Phillips phill.r1 at btinternet.com
Mon Aug 29 11:03:12 UTC 2011

Is it possible that this  has been left in the "calibrate" mode ?   I seem 
to remember that there is a DIL switch at the rear (number 8), for this 
purpose. This is of course an instrument that is equipped with HP-IL, which 
makes it a little less attractive, but otherwise a very well made DVM. Good 

From: "Bob Smither" <smither at c-c-i.com>
Sent: Sunday, August 28, 2011 6:08 PM
To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
Subject: Re: [volt-nuts] HP3468A

> gbusg wrote:
>> Neil's suggestion (to check the power supplies) is a good one.
>> Make sure the +5V, -15V and +15V rails are correct - and use an 
>> oscilloscope
>> to check for excessive ripple.
> Done.  All the supply rails look good.
>> You didn't mention if you have the rechargable battery option (opt. 001),
>> but if so, that adds to the number of possible problems.
> The unit does not have that option.
>> I definitely would replace the 3 volt lithium cell (BT551) ASAP.
> I did this, but no change.  I wonder if the boot process is assuming
> something that has been lost from the RAM.
>> Also make sure that the front panel "Reset" button isn't stuck in the
>> pushed-in position.
> Reset button?  Don't see that.
>> If you're lucky, doing all the above will lead to a cure. If not, then it
>> sounds like some other fault is still causing the "RESET" line (at U501) 
>> to
>> keep cycling. It doesn't sound like you're getting through the turn-on
>> self-tests far enough to see possible further error codes (e.g., 
>> Calibration
>> RAM error, or RAM error, or ROM error, or A/D converter error).
> Agreed.
>> Let us know how you come-out on it.
> Will do.
> Thanks for the feedback!
> -- 
> Bob Smither, PhD                                   Circuit Concepts, Inc.
> =========================================================================
> Blessed is he who expects no gratitude, for he shall not be disappointed.
>   -- W. C. Bennett
> =========================================================================
> Smither at C-C-I.Com  http://www.C-C-I.Com  281-331-2744(office)  -4616(fax)

> _______________________________________________
> 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. 

More information about the volt-nuts mailing list