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Spellman DXM70N600X3547 power supplies on ebay -70kV 8.56MA

Posted: Mon Nov 14, 2016 1:52 am
by Andrew Seltzman
A number of -70kV power supplies have showed up on ebay:
Spellman DXM70N600X3547 115V-AC 0-70KV-AC 8.56MA Power Supply X3547

The seller sold one to me for $200, and 2 to Conrad Farnsworth for $200ea via best offer, you may be able to get them for a lower offer. The seller has 24 of these supplies for sale. These have negative output and analog/serial/Ethernet/USB control. I would strongly recommend buying one of these while they are available. Don't push up the price for the rest of us by using "buy it now", the seller responds promptly to the best offers and there are plenty of supplies available.

http://www.ebay.com/itm/152315510338?_t ... EBIDX%3AIT


Here is the product manual:
http://www.spellmanhv.com/Products/DXM

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Mon Nov 14, 2016 2:07 am
by Grigory_Heaton
Damn that's a good deal. Shame I can't justify the cost at this point. Congratulations to anyone that picks one of these up.

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Mon Nov 14, 2016 5:57 pm
by Kuba Anglin
Can you verify the HV connector type? I know these units sometimes have specialized connectors and it is difficult to tell by the picture.

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Mon Nov 14, 2016 7:03 pm
by Jim Stead
In a previous post, Andrew said they used a Claymount CA11 mini connector. See viewtopic.php?f=6&t=10294&p=70621&hilit ... 547#p70621

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 12:34 am
by William Kelly
Update: I just purchased the last one, also for $200. Thanks for letting us know about this! What a snag!
- William

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 12:50 am
by Dan Knapp
I just purchased one also. They went quickly. Thanks Andrew for letting us know about these.
I checked the National Instruments web site to see if there was a LabView driver for this power supply posted, but there doesn't seem to be one. If anyone has or plans to write one, it would be nice if it was shared with others here.

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 1:00 am
by Andrew Seltzman
Here is a matlab driver I wrote for the supply, It should ramp the supply up to 5kV over 5 sec, then back down to 0v

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 2:58 am
by Rich Feldman
Thanks for the tip, Andrew, and for suggesting that readers avoid the BIN button. Reminds me of those $99 turbopumps that came up on ebay a few years ago. One has to wonder what fraction of the sales began at this forum.

I am among the fortunate buyers.

Just discovered that ebay's Offer History page shows more detail when one is logged in.
We can see which offers expired without a response, and which ones were countered by the seller.
Capture.JPG
The only money value shown is mine.

I admire Andrew's finely tuned ebay searches. He spotted and announced that set of three "Hc-3" detector tubes a few weeks ago, which (by coincidence) I had stumbled upon and was exchanging messages with the seller.

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 6:27 am
by Andrew Seltzman
Bern Bareis actually tipped me off to these supplies. Did you end up buying those He3 tubes?

Re: Spellman DXM70N600X3547 power supplies on ebay -70kV 8.5

Posted: Tue Nov 15, 2016 7:08 pm
by Jim Kovalchick
I picked up one of these too. The manual has lots of good info on how to use various interfaces and how to create your own software controls like Andrew has done.

I hope everyone's units comes through in good shape. I probably won't tinker with mine until I'm back at our lab in York PA and Mike is home on break. I'm assuming the biggest challenges will be rigging up an alternate connector and dealing with arc tripping of the supply when new grids arc and spark during burn in.

I recommend that people add a kill switch at the interlock pins.

Many thanks to Andrew for his insights on these. I saw these show up on Sunday in my normal followed searches, but I resisted the urge to BIN until I did some research. A forum search showed that Andrew had one. Not only did Andrew answer my quick questions, but he saved me a couple hundred with a recommendation on the buy it now price. :)

If folks have operating experience I hope they share here.