On 11/14/2016 3:15 PM, Ralph Mowery wrote:
In article ,
says...

"Old pinballers never die, they just flip out."
I found 220 mfd 450 caps at JustRadio.com. I'm not sure if these will

The 220 mfd will work fine where the 200 mfd caps are used. Many of
them have a large tolerance of 20 to 50 %or more.


Might be helpful to take a peek below the obvious.

Take a close look at the pix of the capacitors at the mouser link.
Compare the solder pins to the size of the buss bars in the welder.
At least you'll be able to say you thought about the consequences
of tiny pins and dubious solder connections. That compounds if you
go with fewer larger caps. All that energy into the weld
came from the caps. It's just as easy to melt the solder at that
end.

Don't go too crazy with the cap values. My spot welder is calibrated
to deliver energy based on the voltage and cap value.
If the cap is different, the calibration can be off by that ratio.
If your meter has a square-law scale, that can make a significant
difference in calibration at one end or the other. You can't
just add a resistor to fix it. But you can put a post-it note
on the panel and do the scale factor in your head.

If you don't have a schematic, create one. It only takes one
wrong assumption to make a lot of smoke.

Beware saturation in the output transformer. Mine has a core reset
pulse between firings. If that part of your system is broke,
you can saturate the core. At best, that can take your diagnostics
down the wrong path. At worst, more smoke that takes out the parts
you just fixed.

Are we having fun yet?