I've been interested in vintage keyboards for a few years (but only really dove deep into the rabbit hole maybe 9 months ago? One day I'll find an excuse to post some other stuff I got!), and I got a Zenith Z-150 recently. For now, I just wanted some place to post some of this measurements, in case this helps other people with their Zeniths.
I disassembled my Zenith Z-150 (because I was initially having trouble with getting this keyboard working with my custom converter that has a reset line) and looking to see if I needed to replace any capacitors (turns out I didn't, I got this keyboard working using TMK pretty easily). However, whilst I had the board disassembled (and after getting some nice digital calipers to play around with), I decided to post this info online so that other people with Zeniths can easily find replacements for stuff.
There's two electrolytic capacitors that I was looking at (C6 and C14).
The value of C6 is 33 microfarads (33 µF) and 16 V, whilst C14 was 4.7 µF and 35 V.
As for the screws; the metal backplate used screws with a standard Phillips #2 bit - but the keyboard assembly was attached in a top-mount system using 6 bolts - 3 on each side; with 3 different lengths - the bolts are 1/4" (6.1mm, barely didn't fit with a 6mm metric nut driver, but fit with the 1/4" driver from the same cheap driver set that came with metric and SAE drivers). I've seen other Zeniths use Phillips drivers - if it matters, this board seems to be from late 1986 (top case dated 26 November 1986, PCB dated the 49th week of 1986).
Below are the measurements for all of the bolts - from largest to smallest. The bolt used for the grounding wire has same measurements to the bolt closest to the back edge of the top case (as labeled in the diagram above).
Largest:
Spoiler:
Spoiler:
Spoiler:
P.S. If y'all want me to grab values for the ceramic capacitors (since I heard those *could* break via cracking?), let me know, I'll have to see what I can do....