PowerBook 180 - some keyboard keys don't function

[luRaichu]

Today I tried to setup RAM Doubler on my PowerBook 180 only to discover I couldn't type my name on the keyboard. When opening Key Caps it says there's "no description for this keyboard" (the built-in one). external ADB keyboards work fine.

I tried reseating the interconnect cable and the keyboard's FPC cables. I'll check the connectivity of the daughterboard as well. And will furnish a video of the problem soon...

 

[luRaichu]

I cleaned the keyboard FPC contacts with alcohol, still no effect. maybe I should try zapping the PRAM.
Here's a video of the problem:

 

[luRaichu]

I cleaned the keyboard FPC contacts with alcohol, still no effect. maybe I should try zapping the PRAM.

Hah! can't even zap PRAM as the P key doesn't work. Can't do this with an external keyboard either.

 

[croissantking]

It may be your interconnect cable. Common problem.

How to repair a Powerbook 140-180 interconnect cable

This guide shows the process for a PowerBook 160/165/180, but it should be similar for a 140/145/170. The main difference is that the earlier PowerBooks have a narrower 50(?)-pin connector rather than 72-pin on the later ones. I carried out this repair on two of my interconnect boards after...

68kmla.org

 

[luRaichu]

It may be your interconnect cable. Common problem.

The interconnect cable is visually fine.

 

[demik]

The wire can break inside the cable on theses. Common problem indeed. One of mine does that, cable is definitively broken
It can be the keyboard which is broken as well. Interconnect is just more likely

 

[croissantking]

The wire can break inside the cable on theses. Common problem indeed. One of mine does that, cable is definitively broken
It can be the keyboard which is broken as well. Interconnect is just more likely

Exactly this. You will not be able to see the damage visually. Some keys not working is indicative of a defective interconnect cable.

Here's another thread discussing the issue: https://68kmla.org/bb/index.php?threads/powerbook-145b-repair-attempt-needs-help.45592/

 

[croissantking]

Also - as an alternative to zapping the PRAM you can disconnect the interconnect board from the processor daughtercard. It will lose settings when you do this as the PRAM battery is on the interconnect board.

 

[luRaichu]

Just tried with a multimeter- the interconnect cable seems OK. Unless there's one pin broken because I didn't test all of them.

 

[halkyardo]

The only way to know for sure if the interconnect cable is good is to test every single pin - it only takes one broken connection for problems to occur - and even then the fault can be intermittent.

 

[luRaichu]

Yeah I'm almost certain the interconnect cable is trash now. There's only garbage on-screen now.
Where can I get a replacement flex cable on DigiKey?

 

[croissantking]

If you obtain a replacement interconnect board, just be super careful when handling it - try not to bend or flex the cable.

The benefit of doing a rebuild though, if you’re able, is that you can select stranded ribbon that will not be as vulnerable to the same problem.

 

[demik]

Just tried with a multimeter- the interconnect cable seems OK. Unless there's one pin broken because I didn't test all of them.

That's tricky because sometimes some lines looks OK outside, and with the angle inside the powerbook the broken wire doesn't have continuity anymore PITA to find out

 

[luRaichu]

Best solution for new ribbon cables I've found is to buy one of these. Cut to desired length and double up so you've got 80 pins, then throw away 8 so you've got a 72 pin cable. PLUS it's stranded.

https://www.digikey.com/en/products/detail/3m/3756-40-100/8256295

A footlong of cable should be plenty.

 

[croissantking]

I linked to my guide to do this above - perhaps you missed it. You may find it helpful.

 

[luRaichu]

I linked to my guide to do this above - perhaps you missed it. You may find it helpful.

I read this thread before I started having PowerBook pain and after. Thank you for making it, it'll sure come in handy

 

[croissantking]

You’re welcome. I hope it goes smoothly for you.

Thanks for sharing the link to the flex, I couldn’t tell from having a quick glance if it is high density (like a wide SCSI cable/80-pin ATA cable).

 

[luRaichu]

I don't know what you mean by "high density" but the ribbon I linked to is 0.025" pitch and should fit the original socket.

 

[croissantking]

I don't know what you mean by "high density" but the ribbon I linked to is 0.025" pitch and should fit the original socket.

Yeah the pitch. Sounds like you’re good to go.

 

[halkyardo]

A footlong of cable should be plenty.

I'm imagining a 'two box' PowerBook with the top and bottom cases sitting separately on a desk

Best of luck! I'm a bit terrified of having that happen to my 180c any time I open it up. Certainly still possible to repair, but a bit of a pain for sure. Good on you for giving it a go.