Zenith ZKB-2 - Broken Screw Shaft

[daja689]

Hello all,

I am not sure if this is the right place to post this.

I recently began buying vintage keyboards out of interest for ALPS switches, and I fell in love with ALPS SKCL Green after getting a Zenith ZKB-2, which has become my favourite keyboard to type on (thankfully the switches were in good condition).

When trying to remove the screws from the back plate of the Zenith ZKB2 in hopes I could lube the stabs easier, I noticed a loose screw shaft in the top-middle hole.
I tried to move it around for it to line up; it snapped off when I heard it rattling around in the board.

I pried the bottom open to release the broken screw shaft. I gently pried opened the bottom of the keyboard to release the broken-off screw shaft and don't know how to open the top portion. I put the screws back on  (except the broken-off one) fearing that I may damage the keyboard further if I tried to take the plate off completely for now, since I am new to basic vintage keyboard maintenance.

So the I wish to ask the following:

1. How to get the back plate off the keyboard without damaging anything?
2. What should I use to rejoin the broken screw shaft? Should I use hot glue? superglue? ABS cement?

The keyboard is still fine to use as of now, but there's just an empty screw hole that I taped over which bothers me a little.

Any input is appreciated!

Attached are the pictures of the keyboard and the broken-off part.

[daja689]

Here is the image of the part that broke off, since it somehow dropped from the original post.

[chyros]

Ah, the ZKB-2. One of my all-time favourite keyboards .

The shaft was probably already damaged and just snapped off. I doubt you did any more damage to it; you can take the back plate off by just undoing the bolts and that should be enough. You can try gglueing or chemically welding it back into place but obviously you need to make sure that the shaft is in the right angle when youu put it back so I'd have the bolt and shaft alreeady fixed to the plate when you glue it back.

As for loosening the toop plate, it's held together with bolts in the PCB (and maybe the side), as I recall . Undo those and you can just take them apart. It's MUCH easier to service vintage keyboards than modern ones, so it's preetty straightforward, really .

[TomahawkLabs]

I actually have one of these keyboards coming today (I also am trying to collect the SKCM/SKCL switches) with yellows. I think gluing it and using the screw to line up the holes is the best idea. How are you using these old Alps keyboards? Are you buying them as donor boards or do you have a method to use them on modern systems?

[daja689]

I actually have one of these keyboards coming today (I also am trying to collect the SKCM/SKCL switches) with yellows. I think gluing it and using the screw to line up the holes is the best idea. How are you using these old Alps keyboards? Are you buying them as donor boards or do you have a method to use them on modern systems?

My plan is when they (unfortunately) break, they will be used as donors. Right now all the ALPS boards I have are working. When I got the ZKB-2 it came with a passive AT to PS/2 adapter attached to it, which is excellent since I have an active PS/2 to USB from a long time ago when my friend sold me his Model M.
Though soon enough I realized that not all keyboards with a 5-pin DIN can be used with a passive AT adapter since you can't use XT keyboards with it. I learned that the hard way when I got a black badge Zenith Z150 off eBay. I had to buy a converter for it and it works wonderfully now.

Ah, the ZKB-2. One of my all-time favourite keyboards .

The shaft was probably already damaged and just snapped off. I doubt you did any more damage to it; you can take the back plate off by just undoing the bolts and that should be enough. You can try gglueing or chemically welding it back into place but obviously you need to make sure that the shaft is in the right angle when youu put it back so I'd have the bolt and shaft alreeady fixed to the plate when you glue it back.

As for loosening the toop plate, it's held together with bolts in the PCB (and maybe the side), as I recall . Undo those and you can just take them apart. It's MUCH easier to service vintage keyboards than modern ones, so it's preetty straightforward, really .

Thanks, Thomas! I looked back at your video on the ZKB-2 and noticed when you disassembled the keyboard, the flip-out feet was removed as well, and I did read somewhere you had to remove them to disassemble. What's the best way to remove the feet without having it snap off, cause with age the plastic might be a bit brittle.

My concern with glue is that I have heard superglue (which I currently have) is not recommended for ABS. I did order a small bottle of plastic cement to hopefully weld it on through chemical means, but I was wondering if ordinary glue like Elmer's glue or Gorilla Glue would work as a less invasive method that also lasts.

[TomahawkLabs]

My plan is when they (unfortunately) break, they will be used as donors. Right now all the ALPS boards I have are working. When I got the ZKB-2 it came with a passive AT to PS/2 adapter attached to it, which is excellent since I have an active PS/2 to USB from a long time ago when my friend sold me his Model M.
Though soon enough I realized that not all keyboards with a 5-pin DIN can be used with a passive AT adapter since you can't use XT keyboards with it. I learned that the hard way when I got a black badge Zenith Z150 off eBay. I had to buy a converter for it and it works wonderfully now.

I applaud you for using the original hardware with converters. Are you a big linear fan because I tried SKCL Greens and I am not sure if the boards were just extra dirty or what, but I put them at the bottom of the list. Yellows, while boring, felt very smooth. I am a big Alps clicky person with tactile being a very close second.

[daja689]

My plan is when they (unfortunately) break, they will be used as donors. Right now all the ALPS boards I have are working. When I got the ZKB-2 it came with a passive AT to PS/2 adapter attached to it, which is excellent since I have an active PS/2 to USB from a long time ago when my friend sold me his Model M.
Though soon enough I realized that not all keyboards with a 5-pin DIN can be used with a passive AT adapter since you can't use XT keyboards with it. I learned that the hard way when I got a black badge Zenith Z150 off eBay. I had to buy a converter for it and it works wonderfully now.

I applaud you for using the original hardware with converters. Are you a big linear fan because I tried SKCL Greens and I am not sure if the boards were just extra dirty or what, but I put them at the bottom of the list. Yellows, while boring, felt very smooth. I am a big Alps clicky person with tactile being a very close second.

Most the time when I have used mechanical keyboards I used linear switches. I do game a lot and linear switches feel the best. Now with that being said, when it comes to alps switches, anything goes as long as it isn't too heavy. I really love the greens and oranges so far. I also have a SKCM white board and they feel very nice to type on.

Regarding the smoothness, here is my anecdote:
I have two green boards - ZKB-2 and Z150. The ZKB2 came in relatively clean, and they feel stellar to type on. The Z150 came in a bit grungy with dust bunnies hanging out on the plate. The switches are a bit scratchy but still feel good to type on. I have never tried yellows though. I could have snagged a board with yellows when I bought the ZKB2, but due to monetary constraints I decided not to.
 

[chyros]

I actually have one of these keyboards coming today (I also am trying to collect the SKCM/SKCL switches) with yellows. I think gluing it and using the screw to line up the holes is the best idea. How are you using these old Alps keyboards? Are you buying them as donor boards or do you have a method to use them on modern systems?

My plan is when they (unfortunately) break, they will be used as donors. Right now all the ALPS boards I have are working. When I got the ZKB-2 it came with a passive AT to PS/2 adapter attached to it, which is excellent since I have an active PS/2 to USB from a long time ago when my friend sold me his Model M.
Though soon enough I realized that not all keyboards with a 5-pin DIN can be used with a passive AT adapter since you can't use XT keyboards with it. I learned that the hard way when I got a black badge Zenith Z150 off eBay. I had to buy a converter for it and it works wonderfully now.

Ah, the ZKB-2. One of my all-time favourite keyboards .

The shaft was probably already damaged and just snapped off. I doubt you did any more damage to it; you can take the back plate off by just undoing the bolts and that should be enough. You can try gglueing or chemically welding it back into place but obviously you need to make sure that the shaft is in the right angle when youu put it back so I'd have the bolt and shaft alreeady fixed to the plate when you glue it back.

As for loosening the toop plate, it's held together with bolts in the PCB (and maybe the side), as I recall . Undo those and you can just take them apart. It's MUCH easier to service vintage keyboards than modern ones, so it's preetty straightforward, really .

Thanks, Thomas! I looked back at your video on the ZKB-2 and noticed when you disassembled the keyboard, the flip-out feet was removed as well, and I did read somewhere you had to remove them to disassemble. What's the best way to remove the feet without having it snap off, cause with age the plastic might be a bit brittle.

My concern with glue is that I have heard superglue (which I currently have) is not recommended for ABS. I did order a small bottle of plastic cement to hopefully weld it on through chemical means, but I was wondering if ordinary glue like Elmer's glue or Gorilla Glue would work as a less invasive method that also lasts.

Yeah you just pinch the feet and then they come out very easily. There's a nonzero chance they'll break of course but I've taken mine out plenty of times and they never broke on any of my ZKB-2's.

The best, and at the very least cleanest way, to glue ABS is to use acetone or something similar. It's called chemical welding, basically you dissolve the ABS surfaces and rejoin them as the acetone dries off. Basically you'll be reforming the material from scratch.