Graymark Micro-Museum

This poster of Graymark’s kits is about 3.5 x 2.5 feet.  It dates from the 1970’s and was intended to be displayed where students could see it and browse for a project.

The Graymark poster hanging in the radio shack.

The Graymark Micro-Museum includes 5 constructed kits that are fully restored and functional; additional constructed kits; a number of original kits that have not be constructed; and a number of manuals and documents.

A 501 Crystal Radio was one of the simpler kits.

The 506 radio has 5 tubes (follows the American 5 tube radio lineup – 50C5 35W4 12AV6 12BE6 & 12BA6).  It covers the standard AM broadcast band and a Shortwave band.  It also has a phono jack input to function as an audio amplifier

The 510 AM radio also uses the 5 tube American radio lineup

The 511 regenerative All Band Radio used 3 tubes and plug-in coils.  By placing the receiver slightly into regeneration, it was possible to receive CW and SSB signals.  However, stability & selectivity were very poor.  Detailed info is here:

The 515 micro-power AM transmitter used 3 tubes.

An unopened 505 AM transmitter kit

A Graymark 512 8-transistor portable radio kit that was never assembled.

The Graymark 525 table top radio came with a wooden cabinet.  It used a standard 5-tube American radio lineup like the 510.

The 509 audio amplifier had a bright red chassis.

The 502 is a 12 VDC power supply using a transformer, full wave rectifier and capacitor filter.

The 523 strobe light had psychedelic lettering.

The 802 was a 2-transistor radio similar to the earlier 508.

Manuals for some of the kits.