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Found these inside a non-working 71B
03-11-2018, 06:09 PM (This post was last modified: 03-11-2018 06:28 PM by MikeSD.)
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RE: Found these inside a non-working 71B

Yes i'll post label and back side of F/A, if that is what it is. The chip p/n above U9 is shown above.


it's out. that chip above U9 seems soldered ok. Just thin wires so it moves. Buzzes ok top to bottom.

Now to the cleanup. Step by step.

[Image: its_out.jpg]

[Image: wires.jpg]

My original problem: Calc wouldn't power on. No LCD content displayed at all.

My assumption was it might have had something to do with broken wires in these new chips. Assuming that the broken wires didnt touch something else it shouldnt, can not being able to configure these chips break the chain so that nothing would show on display?

I'm now wondering if these mods might not have anything to do with tbe lack of LCD.

The repair label said the original problem in 86 was CPU lockup. That appears to have been repaired. If the 71B doesnt run after removing my RAM and FORTH, I might switch 71B.

Question on replacing flex cable. There are two pins connected together on one end on bottom board, but on the display side the outside pin doesnt have a trace or via to it. But does have a trace in the flex for it. Why is that? and/or what is that pin for?
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RE: Found these inside a non-working 71B - MikeSD - 03-11-2018 06:09 PM
What's U10? - Dave Frederickson - 03-15-2018, 03:43 PM

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