I have a couple of voltage related questions regarding my 1973 Williams Gulfstream. This machine has DC pop bumpers and kickers that are powered from the output of the rectifier.

The label on the power supply says it provides 24VAC. In my machine, the AC voltage is reading 29.5VAC on the normal tap lug (and at the AC terminals on the rectifier).

Is it normal for a power supply to put out that much more voltage than what the label says?

What should the DC voltage be from the bridge rectifier on my machine?

Thanks in advance.

#2 2 years ago

Tuukka

Pinside member

Lempäälä

5y 78,350 1,762 16 18

It is normal that the 24VAC is a bit high when none of the solenoids are operated.

The DC voltage will be even a bit higher since without load, the capacitor at bridge output gets charged to about 1.4 times the AC voltage. It will drop when a bumper operates.

You could try (quickly) measuring the AC and DC voltages when a bumper is held on. Then they should be near 24V. But don't keep the bumper coil on for more than 10 seconds at a time or it will overheat.

#3 2 years ago

FLB

flb_gulfstream

Pinside member

Monticello, IL

3y 24,650 62 2

Thank you, Tuukkaa.

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