Joined: Feb Thu 24, 2011 1:29 am Posts: 2801 Location: Dallas, TX - in the city but with bobcats and coyotes
Assuming that I remember the FM-3 schematic properly, the eye tube is solely used as an indicator. One beam (lower) is for tuning and the upper one for stereo indication. You can always leave a "dead eye" tube in place. It just won't look quite as cool. I normally tune "eyeless" FM receivers by ear. The high frequencies get clearest at proper tuning. Expect some minor drift as the unit reaches normal operating temperature.
If you go to "www.the-planet.org" you can find instructions on replacing the EMM801 with an EM84, which has only a single display. You'll lose the stereo indicator, but you'll have the tuning indicator. It's a fairly simple rework, a few wire changes at the socket.
Joined: Jan Thu 01, 1970 1:00 am Posts: 7871 Location: Warner Robins, GA
Could make a plug in adapter with wiring running toan external box then use an EM 84 and also wire up a circuit to use a neon bulb for the stereo indicator or a second EM84.
Try to find a donor "parts set" FM3 for a reasonable price, say, $50 - $60, it will include all the tubes and unobtanium components to keep your tuner in good order.
I normally tune "eyeless" FM receivers by ear. The high frequencies get clearest at proper tuning. Expect some minor drift as the unit reaches normal operating temperature.
