KIM-1 repair

[JimDrew]

@daver2 - I did read about the 1.0A to 1.2A requirement, but that seems excessive to me. Does anyone know what the actual current requirement is while up and running?

@Dwight Elvey - Yes, I do know quite a bit about the various interface adapter ICs and their pinouts. The XIA currently has support for:

6520 PIA
6521 PIA
6522 VIA
6523 TPI
6525 TPI
6526 CIA
6530 MIOT/RRIOT
6531 RRIOC (Vcc on pin 21 instead of 20)
6532 RIOT
6821 PIA
8520 CIA
8521 CIA

This is a project that I started before the pandemic, became a victim of the parts shortage, and then lost interest really. Now I am back on this project. For the 6530, I have a slew of masked ROMs that people have sent me, along with schematics to determine the state machine requirements.

Which pinball machine do you have? Allied used 6530-06 through 6530-11 for their pinball machines. There were also a couple Gottieb sound boards that used the 6530. I have the ROMs and state machine info for these. I can't provide ROM code (copyright reasons), so I have made the XIA so that you can upload the ROM to it and then select the state machine functionality. This is the same method used originally when ordering a new part from MOS, Rockwell, or Synertek (see attached example for the Rockwell order form).

RE: the KIM-1, I am going to have to change the sockets because there are literally some pins that are not soldered (move freely).

 

[daver2]

I can't help you with the actual current draw as I don't have a real KIM-1.

There are a couple of capacitors and a zener diode directly across the +5V and 0V power rails, so it would be worth checking these first.

Dave

 

[powerlot]

Interesting project @JimDrew , I hope you succeed.
My KIM-1's current draw was about 500-700 mA with all the ICs in. The large ICs U1-U3 and the display do consume a bit of power

 

[JimDrew]

Thanks for confirming your current consumption. I don't have a choice about changing the sockets, so I will do that and then try with 1A of current output and see what happens.

 

[JimDrew]

I have been sorta sucked down the rabbit hole repairing this KIM-1, so I ended up fully recreating the keypad (exactly like the original). I am having some samples made (hires SLA) and I might end up having these injection molded. I know there is probably not a huge demand, but this will also work with a different PCB I designed (no membrane overlay) for the replica KIM-1 boards out there as well.

 

[Hugo Holden]

Nice job !

Sucked down the Rabbit hole eh ? Welcome to vintage computing, I'm sucked down the Rabbit hole too on a vintage computer repair and I think I'm about to become the Mad Hatter.

 

[JimDrew]

Thanks! I am not exactly new to vintage computing.... this is just a new rabbit hole.