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Marconi TF 791D cannoblization; appropriate?

PostPosted: Mon Dec 15, 2014 10:33 pm
by Proschuno
So I just purchased not to long ago from the flea market a set of radio stuff; got a Marconi TF 791D deviation meter. I'm considering ripping the deviation meter to harvest all the parts from it; it comes with nearly all English tubes, Brimar and Mullard (3 out of 19 are american; two from GE and one from Raytheon), and almost everything else looks fine (no rust, corrosion, etc.).

Problem is, one, it's from a flea market so god only knows what it went through,

And two, like an idiot I removed a tube from it (6CD6G) and blew a cap; don't know what it goes to, but it looks like something relate to the power supply part of it (which is all tucked away in a big metal box by itself). Hence, I might have destroyed something else anyway; only the cap was destroyed, all else looks fine, but you never know.....

basically I'm asking all radio guys if anybody knows if this is really a precious piece of radio equipment to try and repair someday (although I'm completely without any knowledge of radio equipment), or if it wouldn't be an offense to rip the daylights out of it?

Re: Marconi TF 791D cannoblization; appropriate?

PostPosted: Tue Dec 16, 2014 9:43 am
by DeathRex
Radio????? I thought the government used these to keep everyone in line.

Re: Marconi TF 791D cannoblization; appropriate?

PostPosted: Tue Dec 16, 2014 9:48 am
by DeathRex
It looks military, so I would rather keep it as a deviation meter. To me it would be worth more together than parted out. Don't appear to be particulary rare.

Re: Marconi TF 791D cannoblization; appropriate?

PostPosted: Tue Dec 16, 2014 9:43 pm
by EWBrown
These were used to measure the frequency deviation of FM transmitters, and are not of particular usefulness unless you are building / repairing VHF FM transmitters.
No "audio" applications. Chances are that it has some rather interesting (and useful) tubes inside.
I liken them to the Heathkit color TV dot / bar generators, which are nearly useless given today's digital / flat panel TV technology. However, they are available for cheap money (and for free) , and contain lots of nice Mullard or Telfunken 12A*7 dual triodes, and other very useful parts. Most that I've found had very little use,
and the tubes tested on my Kickok 539 tube tester, measured as new, and not "worn out".
Back in the 1950s & 1960s, the Mullards and Telefunkens were considered as being "cheap imports", and cost less than the US made RCAs, GEs, etc. $) [:) (banana)

/ed B

Re: Marconi TF 791D cannoblization; appropriate?

PostPosted: Sun Dec 21, 2014 9:50 am
by azazello
EWBroun, you have PM.

Re: Marconi TF 791D cannoblization; appropriate?

PostPosted: Sun Dec 21, 2014 4:24 pm
by Geek
What Ed said (y)

Also they have very useful iron for tube audio hobbiests. Probably not enough for anything more than a 5W total SET or SEP power amp, but lots of preamp uses [:)

Cheers!