Restoration Commences on 1947 RCA Victor 721TCS

[Penthode]

I actually bought the set in central NY near Schenectady. The was no TV in Canada until 1952 and the first available TV dighna l here was from WBEN TV Buffalo NY in 1948. Muy RCA 8T243 was allegedly the first Canadian built TV manufactured in Montreal Quebec.

I bought the 721TS from the house it was purchased for and sat in for over 65 years. The attic was insulated so I guess it did not get too warm in the summer nor too cold in the winter. The set is interesting as it was quite dirty but typical he chassis was not corroded.

I bought an RCA 8T271 which included survivor electrolytics from a home just outside Philadelphia 7 years ago. The original owner bought the set just after he left the US Army with a bonus and he retained it until his death at the age of 91 in 2013. His family sold it to me and despite it not working and sitting in a corner in ther house for nearly 60 years unused, the electrolytic capacitors all came back fine and are still okay after hundreds of hours. This set, having sat indoors its whole life, had a pristine chassis. It looks like new.

So you have to take each case as it comes, I guess.

[Penthode]

The 721TS is currently running and has reached 52 hours. Running some Popeye cartoons.

I grabbed a couple of electrolytics from a rusty old Fada 630TS chassis (cabinet dissolved into shards). Looks like it was stored in a wet shed outside. So the electrolytic will have suffered wide climatic changes.

I started reforming it at 4pm today. It is now 10:30pm and at 450 volts the 10uF and 40uF capacitors in the can connected in parallel show a leakage of 200uA. This shows the capacitor is good. The 40uF measures 45uF and the 10uF measures 15uF.

I have been told I am lucky. Maybe so but I never have won a contest or even a book at the local raffle. So this baffles me why I have so much success and everyone else has horror stories to relate.

With the reformed electrolytic with such low leakage at full capacitor rated voltage, before tearing it apart, I would like to leave it at the full 450 volts for a day to see what happens. I maybe will after over voltage by say 5% to see what happens. Fortunately the failure mode is predictable: when it starts to go, like the paper capacitors, there will be a thermal runaway where the leakage increases creatingvheat which further accelerates the leakage and so on. In a paper capacitor, there is little thermal lag so the paper capacitor thermal runaway is fairly fast. The larger electrolytic thermal runaway is slower and more manageable.

Here is a picture of the reformed 630TS capacitor. Notice the VTVM reads 450 Volts DC and the Sprague TO-6 reads 200uA on the 0.6 mA full scale range. And a picture off the 721TS on the weak 10BP4.