This page outlines the parts used by Harmony during the "lost" period, and goes into them in more detail. This is meant as sort of a "terminology help guide" of sorts to help people understand what I mean by "diamondback tuners" and "no-foil" pickups.
Antifoil or No Foil Pickups - The "Anti-Foil" pickup or "No Foil" as some call them, are sort of like a later variant on the old Goldfoil design. These pickups consist of a 1"x3.5" metal casing, with six flat head "pole pieces", and 2 ceramic magnets. They measure in at around 5.5-6.5K Ohms, and have a "smoother" sound from a strat pickup. These pickups were used on the H801/802, and a bass version on the H805 bass, as well as various early sears 57-xxxx model guitars. They continued to be made and used until around 1985-1986 when the H803 came out and they were replaced with the Samick X13 and "X13 Style" pickups for a time, before going to a Plastic-Strat type.
Diamondback Tuners - Diamondback Tuners refers to the generic "budget" tuners used on most entry level guitars going back to the late 1970's. These machine heads have a diagonal stamped base, with a brass drive gear, and a pot metal worm gear, which has plastic chrome plated buttons attached to the top. The capstans are turned pot metal with a single hole through them for the string and a index to keep the strings wound. The "diamondback" comes from the stamped back cover which has a "X" pattern stamped into it giving it an almost "diamond-like" appearance. These were used on pretty much all Harmony models except the very cheap models (H802/3/4, early 57 models, etc).
Samick X13 Single Coils - The Samick X13 style single coil, was an inexpensive "strat-type" pickup design created in the 1970's by Samick for various Hondo/Kramer/Memphis/Harmony guitars. They continued to be used up through the 2000's and copied by other makers. The pickup, from the top, looks like a regular Fender Strat type pickup, with six blank polepieces sticking out of the top. These pole pieces go into a casing that features a ceramic magnet, sideways, placed into a nylon bobbin (or sometimes loose) wound with wire. The pickups are taller than Strat pickups by almost a third the height, and can come in both standard (6.4K Ohm) or "Hot" (11.5K) varieties, with some variation in between.