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KIM-1 repair

@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).
 

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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
 
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
 
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. :)
 
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.
 

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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.
 
Thanks! I am not exactly new to vintage computing.... this is just a new rabbit hole. :)
 
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. :)
Jim, did you make any progress on the 6530 replacements? As predicted by Dave, it's hard finding one
 
Yes and no. Yes, the design is great but there is a race condition in the hardware emulation (for most chips that the XIA emulates) that I am working through... it's been an interesting dilemma because I need a logic analyzer with at least 38 channels. So, I got a HP/Agilent 16702A and a slew of cards for it. I have friends who also got the same setups. All of our setups are bad because the cards are all bad. The 3M adhesive that is used to hold plexiglass runners on the cards (to prevent them from scraping into the motherboard) has eaten through the soldermask and copper traces! These are nearly impossible to fix. After searching for something affordable (and giving up) I found out about the Pico based analzyer and I am getting ready to build and test the latest version that can be daisy-chained together to give you up to 120 channels, supporting 200MHz on each channel which is way more than I need for this. So, the project is in limbo until I can look at the line states with a LA. I should have the design files literally any day for the new Pico analyzer, and I will rush to get boards made.
 
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That sounds great, and sorry to hear about your logic analyzers... It seems like those Picos are a real saviour in the vintage computing world
 
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