[volt-nuts] A Fluke 732A: Return it or keep it?

Thu Jun 12 12:18:13 EDT 2014

Hi Roy,

I would like to second Todd's advice about leaving the Fluke 732A's 
output voltage adjustment alone. You already have stable outputs and 24 
microvolts high is very acceptable. My Datron 4910 (four output supply) 
has predictable digital output level settings that doesn't have any luck 
involved so it is a better candidate for resetting the standards than 
the Fluke 732A. I had Fluke reset them last calibration because I had 
just repaired the Datron 4910 and my voltages were all over the place 
but stable.  Also I would expect your Fluke 732A to about as temperature 
stable as my Datron 4910. In my experience my 3458A needs to be at 23C 
to calibrate. Also it should have the fan filter freshly cleaned and 
record the 3458A's internal temperature. I have recorded (over several 
days) each Datron 4910 output with my 3458A and a switch and can say 
that the Datrons are temperature stable but not my 3458A.

Charlie

On 6/12/2014 7:54 AM, Bill Gold wrote:
> Roy:
>
>      I use a ( General Cement ) GC 8276 adjustment tool to make the pot
> adjustments in the 732A.  I use the end that has the recessed metal blade.
> The pots are about 3.5 inches back from the front panel.  It sometimes is
> very difficult to engage the tool slot in the pot.  It helps to look through
> the front panel hole with a small flashlight and observe the position of the
> slot in the pot ( i.e. 9, 10, 11 o'clock for example ).  Then when you
> insert the adjustment tool you can get close to the point when you can
> engage the adjustment pot.  Sometimes it will seem impossible to engage the
> tool into the slot, but with patience it can be done.  Once you do engage
> the pot do whatever adjustment you want, don't pull the tool out, just leave
> the tool engaged with the pot so that if you want to make another small
> change you won't have to go through the same problem of trying again and
> again to engage.
>      I have found that turning the pots may cause a drift which will show up
> days later due to the pot being "dirty" or whatever.  So what I usually do
> is to turn the pot back and forth over several revolutions so that I can
> "clean" the contact wiper.  I usually make an initial adjustment and then
> turn the pot about 1/32 of a turn in the opposite direction just to relieve
> any "stress" that might be there and cause a small change in the output
> voltage.  I usually have very good results with these methods.
>      But I will agree with Joe that sometimes it is better just to leave
> things alone and just use the known offset from 10 volts when checking or
> doing cals.
> Bill
>
>
> ----- Original Message -----
> From: "Todd Micallef" <tmicallef at gmail.com>
> To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> Sent: Thursday, June 12, 2014 7:20 AM
> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>
>
>> Roy,
>>
>> The 732A uses the 3059Y-1-101 type cermet pot for the 10V adjustment. You
>> can use a simple plastic tweaking tool for adjustment. I believe you will
>> need a fairly long tool. You can shine a light into one of the other holes
>> to see the orientation of the pot. However, many people may prefer to
> leave
>> the pot as is and just record the readings. It is going to drift anyway
> and
>> won't stay adjusted for long. The drift may worsen once the pot position
>> has changed too. I have adjusted mine, but only after the broken pots were
>> replaced.
>>
>> Todd
>>
>>
>> On Thu, Jun 12, 2014 at 9:57 AM, R.Phillips <phill.r1 at btinternet.com>
> wrote:
>>> Hi Joe
>>> Sorry if I am retracing steps, but I have recently had my 3458A
>>> restored/recal'd  by Agilent - its good to have it back. I also have a
>>> Fluke 732A which I can now check. Currently it is 10.000024 volts, I now
>>> feel confident to trim it to the 3458A. I have tried to see the trimmers
> in
>>> each of the three holes - they appear to be some way within, and I am
>>> wondering if you could confirm the type of pot. that is used and just
> how
>>> long a trimming device is required. Is this a special tool only
> available
>>> from Fluke ?
>>> Regards
>>> Roy Phillips.
>>>
>>>
>>> -----Original Message----- From: J. L. Trantham
>>> Sent: Saturday, March 08, 2014 10:09 PM
>>>
>>> To: 'Discussion of precise voltage measurement'
>>> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>>>
>>> Charles,
>>>
>>> What size batteries did you use for your external pack and where are you
>>> located?  In other words, how long can your external battery pack
> 'survive'
>>> keeping the 732A 'hot'?  Is the external pack recharged at Fluke or does
> it
>>> have to make a round trip on the initial charge?  Once I am convinced my
>>> unit is stable (which will probably be another six months or so, after I
>>> get
>>> my 3458A's re-calibrated by Agilent), I hope to be able to send it to
> Fluke
>>> for calibration.
>>>
>>> Fluke made a transit case (732A-7002) and a Battery Charger and
> Auxiliary
>>> Battery Case (732A-7003).  However, I have never seen a picture of
> either
>>> of
>>> these.  Does anyone have any information on these?
>>>
>>> How did you make your case?  Did you include a charger?  Combination of
>>> battery pack and shipping container or separate battery pack and
> shipping
>>> container?
>>>
>>> I was thinking of building a case with built-in charger, fuse, and AC
>>> connector and cord such that when the unit arrived at the CAL facility
> all
>>> that would be needed would be to plug it in and allow the external
> battery
>>> pack to recharge while the unit being calibrated was plugged in,
> recharge
>>> the internal batteries, and calibrated.  Or does the 732A also charge
> the
>>> external battery pack along with the internal batteries?
>>>
>>> The connector you need (complete with female contacts) is a Hypertronics
>>> P/N
>>> D01PB306FSTAH and is in stock at Kensington Electronics at $8.96 each
> (plus
>>> tax and shipping).  Only problem is their $50 minimum order.
>>>
>>> The 'shell' only is P/N D01PB306NT and the female contact is P/N
>>> YSK006-010ANH (three needed).
>>>
>>> http://ecommerce.keiconn.com/hypertronics/D01PB306FSTAH
>>>
>>> I ordered two of the connectors from Fluke using a P/N that one of the
>>> Fluke
>>> folks in their eCal facility gave me, noting that someone else had asked
>>> the
>>> same question a couple of weeks earlier, with Fluke Item# 2181497,
>>> described
>>> as '100-166, PLUG - MALE, HYPERTRONICS'.  They were $12.31 each (plus
> tax
>>> and shipping) and arrived as the shell only, no contacts.
>>>
>>> If Fluke solves their supply chain problem, I sure would like to get the
>>> six
>>> female contacts I need to make my connectors 'complete'.  When I got on
> the
>>> phone with Fluke, I could never find anyone that had any knowledge about
>>> this.  Is there anyone there I should ask for that might understand my
>>> question?
>>>
>>> I look forward to your posting the update from Fluke.
>>>
>>> Thanks.
>>>
>>> Joe
>>>
>>>
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