Talk:Bally/Stern

re: Diodes on bally stern - I think you should revert it back, there's no more investigation needed. Bally used it from the factory. Stern used it interchangeably. While I usually put 1n4004's back on because I have a ton of them due to their universal use in wpc etc. and on coils, the issue raised by the RGP discussion of this is completely wrong..... you're not pumping more than 5 volts through it (the PIA is driving it) and you're not putting more than 0.2 amps through it, either. I forget the spec offhand for the PIA's max current output capability, but I doubt it's getting anywhere near 0.2 amp, and there's current limiting resistors on the mpu board anyway on the strobes and returns.

Also, not sure that changing pinwiki to mirror what some random chatter on RGP speculates on is a good idea. You're taking the authoritative source (the machines themselves, and the documentation provided with them) and changing it to suit the opinions (dead wrong, in this case) of a couple individuals who either didn't think through what they were posting or flat out don't understand ratings of parts. You could just as easily sub a 1n4001, 4002, 4003, 4005, 4006, 4007 diode across the switch matrix and it will work fine in this applicaiton. Ditto with other small signal diodes (although I have not seen the 914 specified in bally or stern's documentation).

re: Diodes - SC, it was not a knee jerk reaction to a discussion on RGP. It was a matter of observing the discussion, and then referring to the Stern and Bally documentation. Both Bally and Stern consistently state "1N4004 diodes are used". There were no statements in the docs regarding 1N4148s. Now, if you've physically seen 1N4148s (you are much closer to this era of games than I), then that's a different story. On a similar note, it has been recommended to use 1n4004s on GTB sys1 and sys80 games. GTB explicitly states ion docs that 1n270s can only be used on their games. That was the kind of info I was looking for from Stern or Bally in their docs. - jpal

Re: replacing inductors L1/L2 on mpu boards with a jumper - there's a reason those inductors were added to the circuit in the first place - anyone know what it is? -scochar

MPU Jumpers

http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Bally_AS-2518-35_or_AS-2518-133_Jumper_Info

I would change this myself, but I want to make sure I am correct: In changing the jumpers to use 2732's, it says to cut E-13-15. Shouldn't it also say to cut 2-6? 9316 uses 9 jumpers while 2732 uses 7, so 2 jumpers should be cut. The rest have one end moved. The Hammer

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Sorry for the slow response. I finally had time to sit down and study this.

I don't have a -35 to look at, one that is strapped for dual 2732s, and I don't use or modify the -35 boards that often in general. However, after looking at the schems., I don't see how the state of jumper 2-6 and / or 1-4 would matter. Both of these jumpers tie address lines A11 and A14 to U1 and U4. Neither U1 or U4 are used in this dual 2732 or 2732 / 2716 combination. --Jimpal (talk) 06:59, 24 August 2016 (CDT)

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Thanks for investigating this. I am not sure what to do with this, if anything. If following the instructions exactly as written, both those jumpers should be cut. But you are saying this does not matter since those wires address U4 which is empty. I wonder if that deserves some sort of asterisk or footnote. Most, like myself will just be following the instructions like a cookbook, in which case, both wires should be cut. I guess I would make the 'cookbook' foolproof and cut the jumpers. The Hammer (talk) 17:31, 24 August 2016 (CDT)

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The only thing I'm confused with is where does it state to cut these jumpers? I could not find that statement. --Jimpal (talk) 19:09, 24 August 2016 (CDT)

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In the table, with what jumpers should be installed, isn't the right hand column the jumpers to be cut? The Hammer (talk) 21:20, 24 August 2016 (CDT)

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Yes, but it makes no mention of 7 jumpers versus 9 jumpers either. --Jimpal (talk) 08:42, 25 August 2016 (CDT)