Hello,
a couple of us on the pinball newsgroup have been wondering about a design for an over voltage protection circuit we would like to add to our games.
Here is the problem: On some pinball games there is a pcb dedicated to providing the +5.0 DC volts for the logic boards. Apparently when this board fails, it fails and then sends anywhere between 10-12 VDC to the circuit boards. On some of these circuit boards there are ancient (read obsolete and expensive) TTL and CMOS chips, that this novice suspects would not tolerate 10-12 VDC very well.
- Should I be worried about sending 10-12 VDC to these dinosaur chips?
- If so, are there any websites or ideas you could share in regards to designing an over voltage protection circuit for this power supply pcb? I know I won't be competent with an ASCII drawing; I could certainly fax the schematic if you so desired.
Thank you in advance for any and all thoughts you may have.
Regards, Dan