Reviving Test Equipment After A Long Storage Period

I have a number of pieces of test equipment (HP, Tek, analog/RF) that have been sitting in storage for a decade.

Time to apply the power and see if they work.

What is the recommended procedure to bring test equipment that has been stored for a long period?

Also is there a MIL document that relates to this subject?

Thanks for what info you can offer.


Reply to
Loading thread data ...

formatting link

Reply to

Old tube-based items should be brought up with a variac to 80-90% full voltage for up to a half an hour, and then up to full voltage if no smoke.. This allows the electrolytics to re-form; rare baddies will complain (smoke or explode). Battery powered equipment should have no problems unless the batteries are a part of an inverter to provide 120VAC..then try to bypass the inverter and use the variac scheme.

Reply to
Robert Baer

Borrow or buy a variac or poorman's version a lamp socket in series and variety of traditional bulbs 10W to 150W. Flickering bulb, like wavering variac ammeter, often indicates cap problem. remove cover and sniff while powering up.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to

And then if it doesn't work look for lithium batteries maintaining the calibration memory.

My HP 54542A digital 'scope died that way. No error message. It just wouldn't start up.

After replacing the lithium battery and going through the self test and calibration procedure it was fine.

Another potential problem is failing eproms. I bought a vector network analyzer from ebay which turned out to have one flipped eprom bit. I wrote this up on

The most common problem is probably dried up electrolytic capacitors in switching power supplies. A cheap esr meter is worth its weight in gold as there is often no visible sign of failure. I use a Peak ESR60.


Reply to
John Walliker

Depends on the equipment. In our shop we constantly use old test gear from the 70s (Fluke 9010, scopes) and they rarely need attention.

If you are worried about electrolytics exploding then you could run the equipment on a Variac and dial it up gradually - note that this is not going to work with switching supply machines.

On the other hand gear that uses tape or hard drives can have failures related more to moving parts seizing up. Tape drive equipment will likely have flattened capstans and melted drive belts, ancient hard drives may have turned into 'shake&bake' where you have to give them a snap to start the platters turning (don't do this if it DOES work!) - the bake part is to leave it on from then on until you can archive the data safely!

There are electronic replacements for old hard drives SCSI, MFM, and IDE you just have to do a little hunting and sometimes pleading.

I picked up a SCSI adapter that I am going to see if my IDE to SmartCard device can interface with so I can replace the drive completely on my Fluke 9100s. Might get to this project this summer...

With stuff only a decade in storage? I'd turn it on and see what happens

- most likely it will work if there is no corrosion.

John :-#)#

    (Please post followups or tech inquiries to the newsgroup)
  John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
 Click to see the full signature
Reply to
John Robertson

The big killer is electrolytic capacitors. Aluminum electrolytics often survive, but may take a while to reform their dielectric, drawing some current until that happens. Tantalum wet-slug caps are AWFUL, and have a TERRIBLE failure history in exactly this situation. What's worse, in some "mainframe" computer sort of systems with large power supplies, is they will burn holes in the circuit boards, leading to almost irreparable damage. I know slowly charging the aluminum electrolytics by bringing the voltage up slowly with a Variac is a time-honored method in the days before switching power supplies. Something I've tried since then is to blip the power on and back off immediately once, let the unit sit for ten minutes and then power up and see if it runs.

I think the military has been playing ostrich with this since the Vietnam war, but it keeps those techs busy replacing caps at the repair depots.


Reply to
Jon Elson

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.