Discussion:
1958 Genco Fun Fair - Need help with Selenium Rectifier Info
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Corvette Bob
2021-10-17 21:34:52 UTC
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Hi Guys - Helping a friend restore the above pin and am running into trouble finding any information about the overall schematic and specific information about replacing the existing Fansteel selenium rectifier. The rectifier has the number P-1004 stamped on it but I can't find any data on it. I believe the transformer supplies 24 or 30 vac to it and not 120 volts. But, not positive about that. I've never worked before on one of these so am hesitant to just start poking around it. I see there is a 22 volt dc circuit breaker just below the large ac transformer so I have that at least. The three main glass fuses are listed as 110 vac, 7 vac, and 30 vac. The internet pinball database lists two documents that I tried downloading but neither worked. I found some older Genco forum notes for 40's era EM games which talked about these rectifier's and their replacement but nothing specific and they were all 120 vac input rectifiers. Could the rectifier in this Fun Fair be a lower voltage unit? BTW, this game does power up. Any help and assistance will be greatly appreciated. Thanks in advance - Bob
John Robertson
2021-10-17 23:08:09 UTC
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Post by Corvette Bob
Hi Guys - Helping a friend restore the above pin and am running into trouble finding any information about the overall schematic and specific information about replacing the existing Fansteel selenium rectifier. The rectifier has the number P-1004 stamped on it but I can't find any data on it. I believe the transformer supplies 24 or 30 vac to it and not 120 volts. But, not positive about that. I've never worked before on one of these so am hesitant to just start poking around it. I see there is a 22 volt dc circuit breaker just below the large ac transformer so I have that at least. The three main glass fuses are listed as 110 vac, 7 vac, and 30 vac. The internet pinball database lists two documents that I tried downloading but neither worked. I found some older Genco forum notes for 40's era EM games which talked about these rectifier's and their replacement but nothing specific and they were all 120 vac input rectifiers. Could the rectifier in this Fun Fair be a lower voltage unit? BTW, this game does power up. Any help and assistance will be greatly appreciated. Thanks in advance - Bob
Hi Bob,

You can replace the original Selenium Rectifier with a more modern
Silicon bridge rectifier, you jus thave to first identify the output
fuse on the original device and that will be replicated on a new fuse
and holder that you will add to one of the AC input terminals to the new
bridge.

How to identify the terminals on the original selenium rectifier:

There are usually five terminals coming radially out of the centre of
older selenium rectifiers. The centre most terminal is the positive
terminal. The next terminal on each side of the positive terminal is one
of the two AC terminals. The outermost terminals are normally shorted
together with a heavy solid wire and are the negative terminals.

You can replace this with any bridge rectifier rated at 25A or more, and
a minimum of 100VAC (for spikes),

You absolutely MUST add a fuse on the one or both AC terminals (both if
the secondary windings that feed the bridge is Centre-Tapped) and the
value of the fuse can't be more than the total of the original factory
recommended fuses for the DC output(s). It can be Slo-Blow. It is there
to protect the transformer in case the silicon rectifier shorts out...

I copied the above tip to my Rowe/AMI page in the hopes I would do some
more editing...

https://www.flippers.com/ami-rowe.html

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
Corvette Bob
2021-10-18 14:27:10 UTC
Permalink
Post by John Robertson
Hi Guys - Helping a friend restore the above pin and am running into trouble finding any information about the overall schematic and specific information about replacing the existing Fansteel selenium rectifier. The rectifier has the number P-1004 stamped on it but I can't find any data on it. I believe the transformer supplies 24 or 30 vac to it and not 120 volts. But, not positive about that. I've never worked before on one of these so am hesitant to just start poking around it. I see there is a 22 volt dc circuit breaker just below the large ac transformer so I have that at least. The three main glass fuses are listed as 110 vac, 7 vac, and 30 vac. The internet pinball database lists two documents that I tried downloading but neither worked. I found some older Genco forum notes for 40's era EM games which talked about these rectifier's and their replacement but nothing specific and they were all 120 vac input rectifiers. Could the rectifier in this Fun Fair be a lower voltage unit? BTW, this game does power up. Any help and assistance will be greatly appreciated. Thanks in advance - Bob
Hi Bob,
You can replace the original Selenium Rectifier with a more modern
Silicon bridge rectifier, you jus thave to first identify the output
fuse on the original device and that will be replicated on a new fuse
and holder that you will add to one of the AC input terminals to the new
bridge.
There are usually five terminals coming radially out of the centre of
older selenium rectifiers. The centre most terminal is the positive
terminal. The next terminal on each side of the positive terminal is one
of the two AC terminals. The outermost terminals are normally shorted
together with a heavy solid wire and are the negative terminals.
You can replace this with any bridge rectifier rated at 25A or more, and
a minimum of 100VAC (for spikes),
You absolutely MUST add a fuse on the one or both AC terminals (both if
the secondary windings that feed the bridge is Centre-Tapped) and the
value of the fuse can't be more than the total of the original factory
recommended fuses for the DC output(s). It can be Slo-Blow. It is there
to protect the transformer in case the silicon rectifier shorts out...
I copied the above tip to my Rowe/AMI page in the hopes I would do some
more editing...
https://www.flippers.com/ami-rowe.html
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Hi John, Thanks very much for your note and suggestions. I'll visit my friend soon and try to verify the terminals as you noted. I did see that solid wire so will start off with the notion that it's the negative terminals. I'll post my findings as well. Bob
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