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(Topic ID: 333712)

Great Plains System 1 power supply

By ACDNate

1 year ago



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  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 1 year ago by ACDNate
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#1 1 year ago
OP
 
NLJ

ACDNate

Pinside+ Frequent

1y 34,050 202 13

Does anyone have any documentation or information on the Great Plains Electronics Gottlieb System 1 power supply?

Working on a Charlie's Angels that has an audio issue of some sort. On startup i get a few sounds but once a game is started I don't get very many sounds. Periodic and not consistent with the youtube play videos I watched.

I went to look at the PSU to verify voltages and I'm getting 15.4v on test point 1 that should be 12v. Test Points 2 and 3 show correctly 5v and -12v. The post labeled "+5v" tests 5v. Test Point 4 isn't labeled and reads 94.5v.

The 15.4 is off obviously and may have a role in my audio issue. Anyone have a manual for the PSU or guidance on what i need to look at to correct the hot 12v?

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#2 1 year ago
 
JWK

sparky672

Pinside member

US Manhattan, IL

11y 55,050 1,730 1

Ed from Great Plains is on Pinside. G-P-E

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#3 1 year ago
 
GPE

G-P-E

GPE

US Omaha, NE

13y 76,800 2,778 4

Don't worry about the 12V reading at 15.4V. The 12V is an unregulated input so the voltage is an approximation and is often a bit high.
Also, sound boards don't use voltage associated with TP1 (it isn't passed to any header pins), it is only used by the onboard 5V regulator.
5V and -12V sound fine.

TP4 is your high voltage input and is used by your VFD display regulator. Also an unregulated voltage at this point so the 94V is fine.
For some reason - the designer, whoever that may be , forgot a few voltages when adding test points to the board. 60 and 42V for VFDs can be measured at J3 Pin 1 and J3 Pin 3. These two are regulated but have a pretty big tolerance of about 5% (if I remember correctly). If your VFD displays are working then don't worry about this.

Is the sound board the original three tone board? And are the caps on him original?

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#4 1 year ago
OP
 
NLJ

ACDNate

Pinside+ Frequent

1y 34,050 202 13

Quoted from G-P-E:

TP4 is your high voltage input and is used by your VFD display regulator. Also an unregulated voltage at this point so the 94V is fine.
For some reason - the designer, whoever that may be , forgot a few voltages when adding test points to the board. 60 and 42V for VFDs can be measured at J3 Pin 1 and J3 Pin 3. These two are regulated but have a pretty big tolerance of about 5% (if I remember correctly). If your VFD displays are working then don't worry about this.
Is the sound board the original three tone board? And are the caps on him original?

Displays are erratic at times. Hard to photograph but my assumption has been they are dying. Haven't dug into them yet.

Looking at the 3 tone board I believe you may be on to something. Looks rough.

Anyone sell a kit?

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#5 1 year ago
OP
 
NLJ

ACDNate

Pinside+ Frequent

1y 34,050 202 13

So I was able to get a pic of displays.

The p1/p2 do display more digits when scoring begins but the 1st digit tends to sort of ghost in and out. Like I said it's not consistent though

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