Perkin-Elmer 7300 Clean Up and Teensy

User avatar
OldIsNew

12 Oct 2019, 20:39

I thought this was an interesting looking board. The switches are Hi-Tek High Profile, but I figured what the heck. Couldn't find any date stamps.
orig_SM.jpg
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back_orig_SM.jpg
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Case_label_SM.jpg
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Opened it up. A very roomy, mostly empty case.

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PCB:
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KeysOff_SM.jpg
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PCB_back (2)_SM.jpg
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PCB_label1_SM.jpg
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PCB_label2_SM.jpg
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The Main IC was unusual:

Main_IC_SM1.jpg
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Main_IC2_SM.jpg
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Main_IC3_SM.jpg
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Traced out the rows and columns:
IC_Labeled_SM2.jpg
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This is the matrix I came up with:
PE_Matrix_SM.jpg
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Wired up the Teensy. I put it on the front because of the room and just personal preference, but PLENTY of empty space for it on the back too.

Wired_SM.jpg
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I hooked up the buzzer for key clicks. There is a potentiometer dial on the board that controls the volume, so can turn it off!


Finished (I may retrobright the keys, but haven't decided for sure yet). I'm not a big fan of the Hi-Tek High Profile switches, but did brush on some plastic safe silicone spray lube and that helped!
Final_SM.jpg
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Video of typing on board (Sorry about the cut off view, but I can't seem get my videos to upload rotated properly in landscape mode anymore!):

User avatar
User101

13 Oct 2019, 08:04

Lookin good, btw, how heavy are these switches? Those in my TI Terminal are very light

User avatar
OldIsNew

13 Oct 2019, 20:45

User101 wrote:
13 Oct 2019, 08:04
Lookin good, btw, how heavy are these switches? Those in my TI Terminal are very light
Thanks! I'd say the switches on this board are on the heavy side. They do actuate pretty high up but feel fairly heavy when bottoming out. Swabbing on a plastic safe silicone spray lube did help with the famous scratchiness of these switches.

User avatar
User101

Today, 07:15

OldIsNew wrote:
13 Oct 2019, 20:45
User101 wrote:
13 Oct 2019, 08:04
Lookin good, btw, how heavy are these switches? Those in my TI Terminal are very light
Thanks! I'd say the switches on this board are on the heavy side. They do actuate pretty high up but feel fairly heavy when bottoming out. Swabbing on a plastic safe silicone spray lube did help with the famous scratchiness of these switches.
Strange, those in my TI are exceptionally smooth and pleasant. Maybe the smoothness of these switches heavily depend on condition. The Ti terminal is virtually unused.

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