The Current Cost of Chasing PPM's (Fluke 732b price list)

[Awesome14]

My experience with used 732s: In the last five years we have purchased 4 732As and 2 732Bs. 2 of the 732As had unacceptable drift (3ppm/wk or more). The other 2 were nice units, with drift far below the spec of 0.6ppm/mo.

One of the 732Bs was bad, but it was the power board, so replacement was a snap. Both 732Bs drift about 0.1ppm/90 days, currently.

The problem is when you buy the first standard used. You have no way to check it. So, you really have to take it to a lab and have them check it.

[VintageNut]

My experience with used 732s: In the last five years we have purchased 4 732As and 2 732Bs. 2 of the 732As had unacceptable drift (3ppm/wk or more). The other 2 were nice units, with drift far below the spec of 0.6ppm/mo.

One of the 732Bs was bad, but it was the power board, so replacement was a snap. Both 732Bs drift about 0.1ppm/90 days, currently.

The problem is when you buy the first standard used. You have no way to check it. So, you really have to take it to a lab and have them check it.

Have you left the "bad" 732As running for years? I would think that they may settle down after 2 or 3 years.

[MisterDiodes]

732's on the used market - especially from eBay or the so called "equipment dealers" can be a real problem if the unit has been cold for years, or sitting in a cold / hot warehouse for years.  But they can come back to life.

Restoring a cold 732 takes time and patience.  When you buy a used unit it might take months to discover if you have a drifter or not - so you just pays your money and takes your chances.  Expect the worst and hope for the best.  Avoid the shady dealers (especially the ones that sell test equipment and then claim "have no means to test" Really?).  Avoid the units that claim to have traceable calibration but are missing the stickers from Fluke.  Ask for a calibration drift history record...if you find one of those for sale hot with current Fluke calibration expect to pay much, much more than a new unit and that's worth every penny if time is money to you.  That would be a rare sale but possible.

After a few years of being warm and cozy that used 732 may just stabilize and be perfectly fine.  And when they they settle down they can be very, very good and lowest noise of any Vref you could hope for. Look at what Fluke uses in their primary cal lab, right alongside their JVS: 732a's to this day.