ESCORT 3146A manual? [fixed]

[Harvs]

Hey Guys,

I've picked up a ESCORT 3146A with some issues (power outage during calibration stuffed it apparently.)  Anywho, have you got any idea where I can find a manual for it?  I can't even seem to find an operators manual for it online, let alone a service manual with calibration instructions.

Any help would be great.

Cheers

[vtl]

Hah small world, I bidded on that thing and tried to look for a service manual as well.

The only thing I found was the operator manual in german, and it didn't even list the fault codes. I believe the Agilent 3402A is a rebadged ESCORT 3146A and the operation manual is avaliable from Agilent's website. But the service manual doesn't appear to be floating around.

Theres some pictures on the unit's insides in this manual, maybe check if this is indeed a rebadged escort

https://docs.google.com/viewer?a=v&q=cache:QMAxd8BwYIsJ:cp.literature.agilent.com/litweb/pdf/U3402-90001.pdf+&hl=en&gl=au&pid=bl&srcid=ADGEEShyrB4W2xRl2JzSlIagS3Rt5fnDqSdQpoP2Fe-5KPFUFhz58RvtoEmoLsZfNlHFarbjgRV6TqtAj0KLIjS8YswIaao76OPyn7ePpG3syKDD4fHxKxn555teVQ65YkMVU4xVoT9R&sig=AHIEtbSI8DetLMGNb-L4s_tCIjnrB5lHEg

Will be interesting to see if you are able to fix it 

[Harvs]

Thanks mate, Oz is too small a place for there not to have been someone else on here bidding on it 

See how I go 

[Harvs]

The meter was sitting on my back doorstep when I got home last night, so I had the fun of playing around with it  .  It's had a few drops in its life, and I was surprised by the quite poor build quality of the case.  Just made very cheaply compared to the old HP and Tek gear I've got.  I guess they were considerably cheaper when they were made, I hope that the re-badged version Aglient has got some better (i.e. thicker) steel in the case.  I'll have to do a tear down some time.

Any how, as described in the eBay auction, the cal was all over the place, and some ranges were just dead, causing the meter to jump all over the place when in auto-ranging.  I trawled the net for an hour or so, converting all the Chinese forums to try and get a answer to the cal procedure.  The intriguing bit was, I found some half arsed instructions someone gave someone else on one of these chinese forums, and when I tried it, it replicated the sort of faults that the meter had (i.e. it made a previously working range dead.)

So I scraped that idea, and with nothing really to loose, I just systematically went through combinations of button pushes to try and work something out.  I certainly haven't got it all, as the meter can apparently be calibrated to a non-exact reference (i.e. you can measure a reference with a better meter and transfer that reading.)  However I worked out two cal buttons, one is the zero offset cal, and the other cals a 100,000 count on whatever range it's on (i.e. 100.000V, 10.0000V, etc.)

I did a very rough transfer from my HP 3456A using just a lab power supply dialed in as close as could get it on each range, the meter is now fully functional on all functions.

So, I'm left needing to build something to be able to dial in each of those voltages precisely.  I'm guessing a resistor divider network with some trim pots with be the easiest way, maybe powered from batteries through a voltage reg (I only want to transfer the cal from my 3456A.)  If anyone's got an easy method feel free to give advice.  I need 100.000V, 10.0000V, 1.00000, 100.000mV. I also need 10A and 100mA, but they're less critical and I've got the tools to do a pretty good job with those at the moment.

Having got it working, I don't for one minute believe what the guys said in the ebay auction.  I recon someone's just had a hack at trying to cal this thing without the procedures, has screwed it up, then couldn't work out what to do then.  Possibly the guy didn't understand how ADCs do a gain and offset calibration, because with that piece of information it only took about 30min of pushing buttons to work out the offset and gain cal buttons.

So I recon a pretty successful endevor, and now I have a second bench meter 

[ElektroQuark]

Maybe someone can find util those button sequences.
You may put them here for the community.
(I don't have one of those meters, but anyhow).

[Harvs]

Yeah I was going to do a tear down and put together some more detailed notes on this meter, but with work I'm probably not going to do that for a little while.

Basic details are as follows:

1 - In the top right of the display there's a hole, normally covered by a sticker, that says "cal" on it.  Stick a paper clip in there to enter cal mode.

* A quick note, there doesn't appear to be any way back once you hit one of the buttons in Cal mode.  I.e. there's no cancel that I can see.  So don't go entering Cal mode unless you really plan on doing it.

2 - Select the function and range.  The meter starts up in auto-ranging mode, DC volts, select the function and use the up-down buttons to select the range you're going to cal.  Also putting it into manual mode.

3 -  Cal the zero offset.  This effects the gain calibration so must be done first.  Short the input, then press the "Local" button.  The display should now read all zeros.

4 - Cal the 100,000 count. Apply the 100,000 count input (i.e. 100V, 10V, 1V, 100mV etc.), then press the "Rel" button directly below the "Local" button.  The display should now read 100,000.

5 - Exit cal mode. Just poke the Cal button through the hole again.