Storing a 'scope, a cautionary tale

[AncientBrit]

A cautionary tale that others might benefit from.

I've got an Hitachi V422 'scope and was in the habit of storing it vertically on its base, tube face / controls face up, when not in use to save bench space.

Recently I started to experience problems with intermittent contacts on the push/pull switches and pot switches.

On investigation I discovered that the shaft lubrication had migrated downwards onto the switch contacts and formed a non conducting barrier.

It was a devil's own job to re-assemble the switch contacts after cleaning, you needed 4 hands.

So the solution to the problem is only ever to store the instrument in the operational position, ie with scope face and controls facing forward.

If you are ever offered a s/h unit it's worth checking the operation of these controls.

If it's suffering from this problem they will not self-clean despite repeated operation.

Switch cleaner might work, but getting into the switch bodies will be a problem.


Cheers,

Graham

[Steve Anderson]

I too used to store and operate my old analogue scope on the floor with the CRT facing the ceiling. But after some 10 years in this position it developed the same sort of symptoms, primarily in the vertical attenuator controls (the most used probably). I assumed it was just plain old wear and tear, by this stage it was getting to be 16 years old. I did also curse the pollution here in Bangkok too.

So a dose of contact cleaner on said controls and all was well...for a few months. Eventually I lashed out and bought the Tek I have now which doesn't take up any bench space to speak of, it's only about 10cm (4") deep.

So perhaps your cautionary tale is what happened to my old Goldstar scope, I still have it but it hasn't been switched on in 2-3 years and is still stored upright. I've often looked at it hinking, "What am I gonna do with you?"...and moved on. It was my first 'real' scope and just like my first laptop that recently went to that big skip in the sky at eight years of age I would hate to just chuck it away.

If I could usefully reincarnate its 100MHz internals somehow that would be a compromise.

Steve A.

[AncientBrit]

Steve,

Quote "What am I gonna do with you?"...

Well you could always convert it to a dedicated NBTV display... just a thought.

Cheers,

Graham

[Steve Anderson]

Well you could always convert it to a dedicated NBTV display... just a thought. Cheers, Graham

I have pondered that, but a few things have prevented that happening, firstly the CRT has an internally etched graticule which gets in the way. Second I have a bunch of flat screen CRTs of the same size without the graticule, third, it seems a crying shame to use all that bandwidth for a few dozen kHz, and finally to modify it (with DC correct cathode drive and all the rest) I may just as well build a monitor from scratch.

Your suggestion is very valid though. If there were a fellow NBTVer locally who wanted to have a bash at it I would be happy to pass it on. It's just cluttering up the top of our stairwell here.

Steve A.