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

1 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)

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Right. But it lists just one jumper to cut. I think two should be cut. It lists E13-15 to be cut, which is correct. But I think that 2-6 should be cut also. But as you point out, from a functional perspective, 2-6 does not have any effect. If one counts the number of jumpers in the first setting, there are 9 jumpers. In the 2732, there are 7. Cut one from 9 and I get 8. Yet there are 7 jumpers listed. That could lead to confusion. The same discrepancy is on several different setups (rows of the table), too. The Hammer (talk) 17:58, 25 August 2016 (CDT)

Those tables were probably lifted from "Clay's guide" a LONG time ago. As written, they are correct, although as you point out, there is a small gap in the info. Nothing to worry about. Either Jim or I will take a look and see if there is a good reason to clean it up. -- Chris Hibler

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Thanks Chris. I had no problem making the jumper changes on a MPU using the guide as instructions. But with the minor discrepancy, I thought I might have missed something. I would have made the edit myself if I was sure I was correct. The extra set of eyes are appreciated. The Hammer (talk) 07:26, 26 August 2016 (CDT)

2 First Things First

I started a new section in the classic Bally / Stern repair guides called "first things first". This section will eventually make it into all of the individual guides. Please keep this in mind when creating / removing / or editing higher level subsections under this section. Portability is key here. I figured Bally / Stern would be a good one to create a primer / outline for all other sections. I added some subsections and added some initial ideas under those subsections. Feel free to add anything left out.--Jimpal (talk) 12:44, 28 August 2016 (CDT)