Deckel FP4A / Hurco - Suppressor Bank Board damage

[ansgar]

Hello,

I got a 1987 FP4A with Hurco electronics about a year ago. It's been running great until recently when a few of the caps violently burned up in the last column of the Suppressor Bank Board (415-0118-001A)---I think the last column is connected to the coolant pump, which also stopped working at the same time.

I replaced the board, but when I turned on the machine (with the coolant pump off) the same few caps slowly started to heat up from 56F to 65F while the others stayed at 56F. The 65F wasn't the problem, but the trend and pattern of the heating was concerning. I stopped at this point and now I'm looking for some info and advice on how to proceed. In particular:

• What does the board do?
• Were these just aging caps or a faulty coolant pump (or other component) could cause the caps to fail?

Cheers,
Istvan

 

[ansgar]

I haven't found any answers yet, so I wanted to clarify that my question is not necessarily Hurco specific. Does anyone with general knowledge about similar parts / failures have suggestions on what should I do next?

 

[johansen]

Those are snubbers and they appear to be connected across the contactors. They are there as a stopgap measure to prevent the emi produced from causing errors on the circuit board.

Any semi competent person can locate new .5uf x2 rated capacitors and solder in a 220 ohm resistor in series. Or you may be able to find integrated components that are a close fit. I have seen 0.1uf plus 100 ohm (iirc) caps that are about 1/4” wide by 3/4” long.

They should not actually be needed. That particular manuf of capacitors are known for failing.

 

[ansgar]

Thanks for the reply!

I found a new board and replaced the burnt out one. However, the new board started to show a pattern of heating up that matched the burn pattern of the old one (see thermal image in the first post). I stopped after only 10F increase, since the temperature was increasing quickly.

I'd rather no have another board burn up. Is it possible there is some fault that causing the new board to heat up?

 

[johansen]

Is it actually new or new old stock.

RIFA Safety Capacitor Failures

RIFA Safety Capacitor Failures have been documented by many of us who restore and maintain vintage electronics equipment. One very spectacular failure was caught live here: courtesy Dave Jones of t…

shaunmerrigan.info

 

[ansgar]

It's new old.