View Single Post
  #24  
Old 11-16-2004, 01:10 AM
Jeffhs's Avatar
Jeffhs Jeffhs is offline
<----Zenith C845
 
Join Date: Feb 2003
Location: Fairport Harbor, Ohio (near Lake Erie)
Posts: 4,035
Sony AM/FMs

I have several vintage transistor sets here, but the best ones, IMO, are two Sony AM/FM radios. One is a rather large 18-transistor AM/FM/FM stereo portable (model MR-9700W), the other a smaller AM/FM 3-volt portable (model TFM-7720W). The AM/FM/FM stereo radio sounds like a console, and has incredible bass for a portable mainly because of its large solid wood cabinet (the sound quality is great, second only to my 1963 Zenith K-731 seven-tube AM/FM receiver).

The smaller three-volt portable works well, but has an intermittent somewhere as the sound will cut in and out at random. I can bring it back simply by tapping the volume control, so I suspect either the control itself is defective or noisy or else there is a bad connection on the PC board it is soldered to. I hope the problem is just a noisy control, though, as I don't look forward to tearing the set apart to resolder bad connections around it. That is, I can do it if need be, but I'd rather not if I can possibly avoid it.

I also have a late-1960s vintage Aiwa AM-FM portable that works very well; the only problem is, I can't find it--yet, anyhow. Probably stored away in a box somewhere around here. Liking radio as much as I do, and since the set works, I wouldn't dream of putting it (or any of my vintage radios) out with the trash.

The power supply for the TFM-7720W receiver seems sorta' odd (to me, anyhow). The set will work on AC or two 1.5-volt size D flashlight cells; the latter is why I say this set's power source is unusual. Most larger portables use at least four C or D cells (my late-'60s Aiwa portable, mentioned above, uses four C's for 6 volts; the MR-9700W stereo receiver uses four D-size flashlight cells, also for a total of six volts). How did Sony manage to design the TFM-7720 to operate on just three volts? The set has a tuning indicator (most likely a small, perhaps grain-of-wheat bulb behind a small rectangular red lens on the tuning dial--I doubt very much it's an LED, given the radio's vintage) which I'm sure eats up power like crazy when it is on (this would explain why this radio has been designed to use D-size batteries, as these are capable of higher current output than C or penlight cells).

BTW, at my former home, some 20 years ago, I had a small Japanese-made portable (AM, FM, and two shortwave bands) that looked an awful lot like one of Zenith's Interoceanic models. I was reminded of this when I saw a pic of a later-vintage Zenith Interoceanic in one of Doug's posts, earlier in this thread.

Also, Heathkit offered an AM/FM/SW set in the early '80s, IIRC, which looked like a knockoff of one of Zenith's later solid-state TO sets. The Heathkit set, I swear, was a dead ringer for the Zenith, as the Heathkit had the same rotating drum dial, front-panel layout, etc. as Zenith's solid-state TO. I think Heath may have offered their version of this set after Zenith bought out Schlumberger in the early '80s or thereabouts.
__________________
Jeff, WB8NHV

Collecting, restoring and enjoying vintage Zenith radios since 2002

Zenith. Gone, but not forgotten.

Last edited by Jeffhs; 11-16-2004 at 01:15 AM.
Reply With Quote