M0110 keyboard no input on 512k

[wottle]

Recently picked up a 512k from Facebook marketplace as a non-booting machine. After pickup, quickly removed the battery (which had started leaking and actually corroded the battery holder metal tab to the point where it broke off when I removed the battery.

Anyway, I inspected the inside of the machine (once I figured out there is a 5th screw on the 512k under the battery cover) and things looked pretty good. So I fired it up to see how it was doing. It initially made some clicking noises when powered on, so I tried unplugging the floppy drive as it sounded like it was trying to load or eject a floppy. Fortunately, with a couple other power on / offs, it actually booted to a chime.

I didn't have a 400k floppy and I didn't really trust the floppy drive at this point, so I flashed the ROM in my FloppyEmu and crossed my fingers. Fortunately, it booted up and I could move the mouse cursor on startup. So far, I was very excited to have done so little work and have it functional.

Unfortunately, I quickly realized the keyboard was not working. I did verify the cord was a straight-through 4P4C, not just a phone cable. I also checked that the pins in the connectors look fine, and all 4 on both the keyboard and the computer look fine. I opened up the keyboard because honestly it felt hollow and I was worried there might not be a board inside, but it all looked fine, and I didn't see anything wrong with any of the components on the board.

Any ideas of what to check? Unfortunately, I don't have any other Mac 128k/512k/Plus to test the keyboard with, nor do I have a known working keyboard to compare with.

 

[PacNPal]

My understanding is that these keyboards were easily damaged if the wrong cable was used. Unfortunately, the keyboard could be dead as a result. Best of luck.

 

[Stephen]

Recently picked up a 512k from Facebook marketplace as a non-booting machine. After pickup, quickly removed the battery (which had started leaking and actually corroded the battery holder metal tab to the point where it broke off when I removed the battery.

Anyway, I inspected the inside of the machine (once I figured out there is a 5th screw on the 512k under the battery cover) and things looked pretty good. So I fired it up to see how it was doing. It initially made some clicking noises when powered on, so I tried unplugging the floppy drive as it sounded like it was trying to load or eject a floppy. Fortunately, with a couple other power on / offs, it actually booted to a chime.

I didn't have a 400k floppy and I didn't really trust the floppy drive at this point, so I flashed the ROM in my FloppyEmu and crossed my fingers. Fortunately, it booted up and I could move the mouse cursor on startup. So far, I was very excited to have done so little work and have it functional.

Unfortunately, I quickly realized the keyboard was not working. I did verify the cord was a straight-through 4P4C, not just a phone cable. I also checked that the pins in the connectors look fine, and all 4 on both the keyboard and the computer look fine. I opened up the keyboard because honestly it felt hollow and I was worried there might not be a board inside, but it all looked fine, and I didn't see anything wrong with any of the components on the board.

Any ideas of what to check? Unfortunately, I don't have any other Mac 128k/512k/Plus to test the keyboard with, nor do I have a known working keyboard to compare with.

If you have a logic analyzer or oscilloscope you can observe the central two pins — one is clock and the other is data. The data line will pulse high or low with the clock line.

If you're seeing a clock and data then your keyboard is fine. Could be something on the Mac side. If you're seeing power but no clock / data then your keyboard is ready to be bought by me.

 

[JeffC]

I had the same problem and had done a number of checks. I had checked continuity between the solder joints of the cord connectors on the AB and keyboard and it looked fine. This made me think there was no connection issue anywhere in the plugs or cables.

Finally after following @JDW suggestion to clean the contacts inside the female plugs with alcohol, it works great. It didn't make any sense to me since my continuity checks already showed a good connection from end to end, but it worked. Might be worth a shot.

My understanding as stated above is that if someone had attempted to use a standard phone cord at some point it could have fried the keyboard, but I also remember reading that the chip that gets damaged is not proprietory and can be replaced. Others probably have better info on that.

 

[wottle]

I had the same problem and had done a number of checks. I had checked continuity between the solder joints of the cord connectors on the AB and keyboard and it looked fine. This made me think there was no connection issue anywhere in the plugs or cables.

Finally after following @JDW suggestion to clean the contacts inside the female plugs with alcohol, it works great. It didn't make any sense to me since my continuity checks already showed a good connection from end to end, but it worked. Might be worth a shot.

My understanding as stated above is that if someone had attempted to use a standard phone cord at some point it could have fried the keyboard, but I also remember reading that the chip that gets damaged is not proprietory and can be replaced. Others probably have better info on that.

I had also tested the continuity of the cable, and from the contacts in the connection in the female jack to the boards and it seemed fine. I also tried to push back the wires inside the female jack to their original position (some of them had been pushed down and were siting further back than others).

However, as a rule I always listen to @JDW's advice, so I got some DeoxIT out and sprayed the cable and the jacks on the machine and the keyboard. Fired it up and... The keyboard is working fantastically!

I'm kind of disappointed with myself for not doing that when I cleaned everything when I first got the machine. Will certainly be adding "dioxit any external connectors that may have gotten corroded over the years" to my list of Vintage machine intake procedures. Thanks for reminding me that often the simplest answer it the one I should try first. However, maybe someone else in the future will see this post and it will help them! Thanks!

Unfortunately for @Stephen , no new keyboard is headed his way (this time).

 

[Stephen]

And I would have got it too if it wasn't for that meddling JDW!

 

[wottle]

And I would have got it too if it wasn't for that meddling JDW!

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Your photoshop skills are unmatched!