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Keypad identical to TI 1250?


davidbrit2

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I opened up my Astrocade to clean out the keypad contacts (gotta have bounce-free input for entering BASIC programs), and it looks like the keyboard is identical to that of the TI 1250 calculator. I don't know if that's the case for all production runs of the Astrocade, but mine has that distinctive TI keyboard design that I've seen from repairing a Radio Shack EC-4000 (TI-57 OEM clone), TI-30, and TI MBA, i.e. a layer of black tape covering rows of metal domes, and vertical row and column wires set into white plastic plastic.

 

Looking at this x-ray photo of the 1250, you can even see the second keyboard row has its bottom edge hanging off further to the right, and its left edge slightly inset, due to being welded to the rightmost row line - exactly how my Astrocade keypad is constructed:

 

http://www.datamath.org/XRAY.htm#Texas Instruments TI-1250

 

So, if you've got an Astrocade with a completely broken keypad, a TI 1250 might be a good cheap donor.

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17 minutes ago, ballyalley said:

Wow-- I've never heard anyone say this before: a TI calculator keyboard can be swapped-in for an Astrocade keyboard?  That sounds too good to be true.  Unless TI calculator are as expensive as Astrocade's nowadays.

 

So, you're gonna be entering in a BASIC program...?

 

Adam

 

Yeah, it looked exactly like what I'd expect a TI 1250 keypad to look like, based on my experience with other TI keyboard internals and the x-ray photo of the 1250. It looks like the 1250 can be had for about $10-20 on ebay these days. It's just a basic 4-function calculator. Heck, you could probably replace the ribbon cable with a longer one and use the calculator shell itself as a "remote" keypad. :D

 

My Astrocade is a "Bally Professional Arcade", and the board for the keypad had a label on it showing a 1978 date - presumably the manufacturing and/or assembly date. I don't know if later machines use a different keyboard design.

 

I've got AstroBASIC arriving in the mail tomorrow, with manual and overlay, and I wanted to clean the contacts to make sure the keyboard response would be acceptable for typing in 1,800 byte programs on a 24-key keypad. :)

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10 minutes ago, ballyalley said:

 

Yes, please post those photos.  And, where and when did you get  new old stock keypads for the astrocade?!?

 

Adam

From that collection I acquired back in 2004 from a former Bally employee. 

 

The same collection with the chips, controllers, steering wheels, BalCheck etc.

 

-Michael

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Shoot, I could have sworn I had a TI 1250 I could open up and photograph to compare, but I must have been confusing it with the 1000 I have (which uses an entirely different keyboard). Maybe I'll grab one on ebay since they're so cheap, then I can add it to the collection and get some photos of the internals.

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10 minutes ago, davidbrit2 said:

I could have sworn I had a TI 1250 I could open up and photograph to compare, [...] Maybe I'll grab one on ebay since they're so cheap, then I can add it to the collection and get some photos of the internals.

 

A side-by-side comparison of the keypads would be great!  After that, you can port Tiny BASIC to the calculator and play "AstroBASIC" games on there too.

 

Adam

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10 minutes ago, ballyalley said:

 

A side-by-side comparison of the keypads would be great!  After that, you can port Tiny BASIC to the calculator and play "AstroBASIC" games on there too.

 

Adam

That might be a stretch since the 1250 is a basic 4-function calculator with no programming capability. ;)

 

I just ordered a 1250 to add to my collection. I'll get some pics of the internals when it gets here, and if the keyboard contacts need cleaning, I'll do a deep tear-down of that too. Should be exactly the same process I used on my Astrocade earlier today!

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