[volt-nuts] Crazy price

[Charles Black]

About 2 years ago I bought a Datron 4910 for about $950 on eBay. It 
arrived with three broken banana jacks (replacements must be very 
carefully chosen). It had too much electrical noise on all four of the 
the cells and the cell voltages were not stable.  It had several broken 
wires in the battery circuits. The original batteries needed to be 
replaced with a size  that is presently available and the new batteries 
have more capacity too ($160).

The noise problems were resolved  by replacing several faulty power 
supply electrolytic caps and a number of tantalum caps on the 
motherboard and in each of the cell assemblies. The banana jacks were 
obtained from a Datron 4912 that I bought for parts ($500). I moved the 
cell from the 4912 to the cell 1 position in the 4910 to take care of a 
slightly increased voltage instability over cells 2  through four.

At this point I ran the unit for many weeks using a 3458a and logging 
all the data to my computer one output at a time. The 4910 it remained 
well within specs so I sent the unit to Fluke for Z540 calibration with 
data. The Fluke tech found that I had an intermittent short from the LOW 
jacks to ground so I picked the unit up to repair it. It turned out that 
the screw for the M/B regulator was intermittently shorting to the 
anodized power supply case. It was a factory assembly problem that was 
duplicated in my 4912 as well!

I took the unit back to Fluke and this time the calibration with data 
went just fine. I just picked up my 4910 last week and am trying to get 
my switch software to do it's thing.. My short term goal is to be able 
to constantly monitor my 4910 and 4912 outputs and to be able to do 
accurate comparisons with other portable standards.

I have quite a bit of my time working on the 4910  and the data system 
as well as some outlay for calibration that can be reduced drastically 
if highest accuracy for the 4910 is not needed. I wanted to be able to 
calibrate my 3458a which should be linear to 0.1 ppm. I checked the 
3458a with my Fluke 720 to 0.2 ppm at many points so it is working quite 
well.

Charlie

On 3/7/2012 3:30 PM, Will wrote:
> The $4300 Datron went to India. Seems to be a hobbyist with very deep
> pockets rather than someone starting a cal lab. He has bought a huge
> amount of expensive (overprised?) stuff in just a few months.
>
> http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=manic_t&ftab=AllFeedback&myworld=true
>
> I don't know if there is a way to show all descriptions of his
> purchases on the same page. I just selected "wiew item" to see the
> details of each purchase. I should ask my friend who taught me Ebay
> basics (or at least tried). Now I know how to search current and ended
> listings...
>
>
> 2012/2/20, J. Forster<jfor at quikus.com>:
>> There was no bidding. It looks like a BIN or BO.
>>
>> I'd guess a Cal Lab needed it for a specific job and that item was speced
>> in a contract.
>>
>> FWIW,
>>
>> -John
>>
>> =================
>>
>>
>>> I friend e-mailed me this:
>>>
>>> http://www.ebay.com/itm/270897641120
>>>
>>> I have never bought anything from Ebay and I don't know the system
>>> very well, but it seems that someone really paid $4300. Maybe there is
>>> something that I am missing?
>>>
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>>
>>
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