OLD-COMPUTERS.COM : The Museum

OLD-COMPUTERS.COM : The Museum • The all-in-one (H/Z-120) version actually had three screen color options -- Amber, Green and white. However, in ten years of working at Heathkit, I have NEVER seen the white screen in operation, however I have two white tubes from the kit, new in the box (from our first shipment of Z-120! We got two green, two amber, two whites. The whites never sold...and are probably the best screen!). Going to have to install 'em one of these days in one of my H-120s. :)

• The Z-100 didn't run at 4.77MHz. because they were to freaking cheap to put more crystal oscilators in the PC, so they picked one frequency that could be divided down into all the frequencies needed on the board. The H/Z-100 had something like ten or so crystals and crystal oscilators in the box. The original machine ran at a flat 5.000MHz, the later one ran at 8.000MHz, and more than a few of the old ones were upgraded to 8MHz simply by replacing the processor and the processor crystal. Zenith later had an official upgrade to the later rev of the main board (which took 256K memory chips) which replaced a number of parts with "high-speed" versions, but my experience was that it wasn't needed.

• The keyboard was INCREDIBLE on these things. Several friends of mine consider it the best keyboard on a mass-market machine ever.