On 1/2/21 11:44 AM, seymour.shabow wrote:
>> Also not certain why two diodes are used on early Bally if the power
>> and hold windings lose power at the same time. And why not add caps
>> if the Bally is truly parallel.
> 2 coils collapsing in 2 different endpoints=needs 2 diodes to block
> voltage I would assume.
I think that early Bally and Williams flippers were wired the same way:
EOS switch shorts out the Hold coil. EOS switch opens and both Hold and
Power are energized. Flipper button releases and both coils collapse at
the same time.
One diode should be sufficient, unless there is something about winding
them differently that would require a second diode?
The Bally schematics seem to confirm the EOS Switch shorting out a
(hold) winding. So do early Williams SS. Both drawings make the coil
look like there is a center tap of a transformer.
Marco lists EB flipper coil as 25-500/34-5050.
Bally Strange Science 6803 shows a 0.05 cap on the flipper switch. It
shows a 0.01 cap on the EOS switch. Two diodes on the coil. EOS switch
shorts out a (hold) winding. Marco lists the flipper coil as
Jumping to a FP2, when Williams upgraded the power supply, they show the
same flipper schematic, with a the EOS switch shorting half the flipper
coil. No cap is present on any of the EOS switches.
Williams HS does not show the presence of a cap on the parts list of the
flipper. The schematic shows a cap on the flipper switch but not the
EOS switch. Schematic indicates EOS switch still shorts out the Hold
winding. Coil looks like a center tap. Coil is 23/600 - 30/2600.
F14 shows a cap on the EOS switch and flipper switch. Flipper schematic
shows a different connection with the EOS switch removing the Power coil
from the circuit. Coils are drawn as two separate coils (no 'center
tap') Hold is always on. Coil is 11630.
I too, don't want to sacrifice a good coil. Would like an early Bally
SS coil, early Williams SS coil and a later Williams WPC era.