Do you pop your flashes at least once per month?

[Leigh B]

my flashes are used on a regular basis's,Yes ,that keeps them going

That is certainly the preferred methodology for any electronic equipment.

Realize that electrolytic capacitors are not in any way unique to photography.
They're used in every electronic product that exists, regardless of its purpose or function or power source.

And all such products will suffer capacitor degradation and potential failure if left unused over a long period of time.

- Leigh

 

[Theo Sulphate]

I have a mid-1970's minicomputer that was last used in 1987. It and its peripherals worked perfectly when last used. It's been in storage since the mid-1990's.

I've thought that I would use a Variac to apply low power at first (starting at 5v) and over many hours increase it slowly - eventually reaching the normal 110v.

Now this seems like a bad idea. Right?

In addition to the main power supply, there are the two processor boards, console boards, memory boards, peripheral controller boards, an external floppy drive, and disk drive, printer, and CRT, all with their own power supplies.

Do I need to replace all the electrolytics? Some are the large can type, some are the smaller cylindrical ones mounted flush on the board.

 

[Leigh B]

I have a mid-1970's minicomputer that was last used in 1987.
It and its peripherals worked perfectly when last used. It's been in storage since the mid-1990's.
...
Do I need to replace all the electrolytics? Some are the large can type, some are the smaller cylindrical ones mounted flush on the board.

I strongly recommend doing so.
Replace ALL electrolytics with modern 105 degree caps and sleep soundly.

The Variac idea works fine for older tube-type equipment.

It does not work at all well for solid-state gear, particularly any using integrated circuits.
The problem is that ICs are not really bistable devices.
They're analog devices biased to either full cutoff or full conduction.

Those conventions require a supply voltage within nominal tolerance, usually + or - 5% (not 10%).

If the supply voltage drops significantly below nominal, the devices are biased in a linear region.
When that happens, the current drain goes through the roof and the device burns itself up.

I have the first Altair 8800 (no suffix) in the state, from 1974.
This is how I would restore it if I wanted to power it up.

- Leigh

 

[Theo Sulphate]

I strongly recommend doing so.
Replace ALL electrolytics with modern 105 degree caps and sleep soundly.
...

Ok - thank you for the advice; I appreciate it.

 

[AgX]

Realize that electrolytic capacitors are not in any way unique to photography.
They're used in every electronic product that exists, regardless of its purpose or function or power source.

However there are special flash capacitators offered by the industry. Likely optimized for fast de-charging (short flash duration)n and for rapid cycle work. In case of searching for a substitute main capacitator one should have that in mind.

Thank you for that circuit diagram!

 

[AgX]

To put things into perspective:
At least compact flashes from the 80s/90s are so cheap by now that if a main capacitator fails it is likely better just to substitute the whole flash or to salvage another sample for the capacitator than trying re-viving it.

Keep in mind you are working with rather high voltages and large charges, these capacitors can be harmful, even if not exploding...