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Old 4th May 2019, 2:24 am   #12
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 497
Default Re: 1940's Motorola VT 71 tv

Originally Posted by Lloyd 1985 View Post
I’ve got the Bakelite cased 7VT2, very similar inside to your set! Before I could get anything sensible from mine I had to replace the wax paper caps rated 6KV, the ones connected to the centering controls and the EHT smoother. I still have the selenium rectifiers fitted in mine, and although they are working they do occasionally let off a bit of a bad smell! Normally when the set is switched on from cold. Might be worth pulling the ballast tube out and checking that all the sections are OK. What I did with the filter caps was to cut them open carefully and remove the innards and replace them with a new capacitor, then stick the can back on. Although if new twist lock cans are available, I’d go with that instead!

Just Radios have all the 6KV rated capacitors for sale, good quality film caps too.
There's a lot of really solid advice in this entry!
First thing, you have to make sure you are using the proper schematic for this chassis, as there is several variations of this chassis. The voltage divider used for the B+ source is different from the various versions.
Another thing to note is the B- is floating and not tied to the chassis.
More later, as I read more entries from this thread.
Dave, Midwest USA.
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