It reads "Model 5" on the front, and the switch positions are all Model 5.
(6 voltage ranges while the model 6 has one more position).
Where, how, can I get a Model 5 schematic? I would like to have a manual as well.
You need to remember the history of that 1951-1952 period at Heath.
When you stated the year 1952, in Guam -- that was a "key year".
Bob Eckweiler fills in the history details for you.
You actually have the Heathkit VTVM Model V-5A
====Heathkit VTVM History
courtesy of Bob Eckweiler, AF6Chttp://www.w6ze.org/Heathkit/Heathkit_019_V7a.pdfThe Heathkit V-5 VTVM
The V-5 replaced the V-4A in September of 1951.
Again the size of the meter was increased to 4-1/2" almost filling the width of the front panel. The cabinet itself also changed radically. Instead of a flat front panel that screws into a flange on the cabinet. the front panel, rear panel and cabinet are "formed" aluminum with rounded edges. There are no front panel screws; instead the front and rear panels and chassis are held to the cabinet by screws at the back of the cabinet, making a neater appearance and allowing the meter to fully extend from edge to edge. The jeweled pilot light remained on the front panel.
Internally the tube lineup changed; the octal 6SN7 tube was replaced with the smaller miniature 9-pin 12AU7 dual triode and the 6H6 was replaced by a 7A6 dual diode in an attempt to improve AC accuracy.
The 7A6 is a "loctal" based tube and has a different pin-out than the 6H6.
The tube socket and socket wiring were changed to accommodate the new tube.
In the Ohms circuit the two batteries (3V) were replaced with a single 1.5 volt cell,
and one of the Ohms divider resistors was changed to compensate.
Meter ranges remained the same as the V-2 through V4A.The Heathkit V-5A VTVM
The V-5A replaced the V5 in 1952. It remained on the market until replaced by the V-6 in 1954.
The V5A is almost identical to the V-5 except the 7A6 AC to DC circuit tube was changed back to a 6H6, as was the tube socket and wiring.Heathkit V-5A VTVM Manual (Assembly & Operation)http://www.ko4bb.com/manuals/22.214.171.124/Heathkit_V-5A_Vacuum_Tube_Voltmeter.pdfHeathkit V-5A VTVM Schematic Diagramhttp://www.ko4bb.com/manuals/126.96.36.199/Heathkit_V-5A_VTM_Schematic.pdf