I was taught Canada was part of the American continents, so technically Canadian broadcasts are American too, no?

No.

I guess that just goes to show how history is changing, and I'm Old :D

Technically Canada broadcasts in North America making their transmissions a North American broadsact. So Titan1 must think the USA is in South America...

I think what was being meant by the comment is that Canadian broadcasts and US Broadcasts while they are North American broadcasts, Canadian Broadcasts aren't "American" Broadcasts, as in USA broadcasts, (when one uses the word "American" generically like like what Kevin did in his post, you're not specifying which part of North America, because US broadcasts would be referred to as "American Broadcasts" whereas broadcasts in Canada would be referred to as "Canadian Broadcasts".

That's why you shouldn't use such broad sweeping terms when talking about something like that, because you can easily misidentify things (or countries or broadcast standards) by using such generic terminology like that.

What should of been said was: "Aren't Canadian broadcasts technically "North American Broadcasts"? rather than "Aren't Canadian broadcasts technically "American Broadcasts"?

It removes any ambiguity that could be there, especially when you have a country like the US that has the word "America" in its name ("United States of America") and the occupants of said country are called "Americans", and anything associated with said country is called "American", including its television broadcasts.

I hope that explanation was helpful.

The set and it's electrolytic capacitors are celebrating their 75th anniversary this year. This past week I sadly had to restuff the last wet electrolytic in my 1935 Scott AllWave 23. The wet electrolytic dried up and lost all its capacitance!

I am running the 721TS about five hours a day on weekdays and about four hours overall on weekends. That is about 30 hours per week. No sign of any problem with the original electrolytics.

Incidentally, CHCH TV in Hamilton Ontario is running Andy Griffith, I Love Lucy, Danny Thomas Show, My Three Sons and Bonanza between 10am and 1pm weekdays and the 721TS is on in the background as I work in my office.

Here is Bonanza photographed off air just now.

This my monthly update on the state of the original electrolytics. And the daily run of the RCA 721TS.

Still running fine. Here is a screen shot of a received morning broadcast just now of the Andy Griffith Show.

It has been about 5 months since I last reported on the 721TS. Still running fine on the original electrolytics after two years. Only problem with the set is the fine tuning backlash which is from what I see a common fault with the KRK2 tuner. Been running well over 1500 hours now.

Note it is sitting on top of my RCA AR88D receiver.

I just brought home a Crosley 9-408 tv that is all original with no repairs having been previously done. It looks nearly new especially the underside with it's numerous paper/wax capacitors. All the tubes are RCA with date codes ranging from the 11th-22nd week of 1948 with the exception of the two 5U4G's which are Sylvania.

I powered it up on a dimbulb tester with a 250 watt heat lamp and it passed that test. I also have an early RCA 630 TS that I electronically restored with the ever popular "shotgun" method of replacing all the Paper/wax caps and re-stuffing all the electrolytic caps. The set has been working quite well now for four years. While on the dimbulb tester I monitored the current draw with a kill a watt. The Crosley drew only a few watts less than the RCA.

The previous owner said the set worked and provided photographic proof. This mans father is a retired tv tech that fixed old tv's he is nearly 90.

I cautiously powered the set up on a power conditioner for a computer at a line voltage of 120 volts. I also hooked it up to a dvd player and applied a signal. After about 15 seconds I got a raster and after some fiddling with the brightness, horizontal, vertical and contrast I got horizontal and vertical sync and after a minute or so a fairly stable picture that looked quite good! Current draw was 295 watts, about 5 watts less than my RCA. I did not leave the set to run for more than a few minutes fearing that something might give out.

I was quite amazed that this was even possible! All the capacitors, resistors and even wiring looks nearly new. The resistors under the 1B3 have only a little dust and no carbon build up on them. I could even read the color bands easily after brushing the dust away. This set seems to have very few hours on it.

Unfortunately I don't have any tools for trouble shooting radio and tv other than a DMM which can measure resistance, capacitance, inductance, frequency and diode test. I do have a good digital soldering station.

The one job I enjoy the least is re-stuffing the electrolytic cans! After reading much of this thread I am convinced that it may not always be necessary.

Any suggestions? I will try to post some pictures of my set soon.

Thanks in advance!

Paul D.

I want to emphasize that I never power up electronic equipment of this age without first doing a full electronic assessment. As with the RCA 721TS, I assessed each electrolytic individually by isolating each electrolytic and reforming the dielectric.

I apply a power supply current limited to 10mA maximum and wait until the full rated voltage is met with less than 1 mA leakage. I typically aim for less than 500 uA. If the leakage after a day or so is 1 mA or higher, the capacitor will be replaced/ restuffed.

The 721TS electrolytics all showed leakage well under 500 uA at full rated voltage and tested correct capacity within 10%. I will say that surprised me. But with my six RCA TVs from the late 40's, I have only had to restuff/ replace three electrolytic cans in total.

The problem is suddenly powering them up after a long dormant period without reforming will place undue stress. But I would be game to monitor current leakage over say a week of full rated voltage to see if they survive and if so, I would not hesitate in leaving them in place.

My 721TS has been running on the capacitors for two years now with no sign of failing despite warnings from others.

It has been more than two years running regularly. The original electrolytics remain fine.

I was told the original electrolytics would eventually fail. Any suggestions when this will be?

Well it has been exactly two years and three months of regular operations. It was June 20, 2020 I first powered it up. It has been running fine ever since. And I am still waiting for those danged original 1947 vintage electrolytic capacitors to fail. There are five of them and they just won't go bad!

I am beside myself because I was sure they were going to fail by now.

Anyhow here is a photo I took a few minutes ago.

That's encouraging since I have an RCA 630TS that I purchased a few years ago. It is in great condition; the GE replacement CRT measures NOS. I guess I should bring it up slowly on my Sencore PR-57, monitoring the current and see what happens. I don't mind rebuilding the capacitors but if they hold good, why not???

Thanks for the encouraging update.

You could do it slowly that way. What I prefer is to put a current limited DC power supply across the electrolytics with power off. With the tubes not conducting and with a study of the schematic to see what bleeders are across the B plus, you can better gauge the condition of the electrolytics. In some cases I simply disconnect the electrolytics to better isolate to confirm the condition of the electrolytic.

I have restored set that must have been dormant for 50 years of more. My RCA 721TS the seller near Schenectady NY told me my 721TS was stuch in the attic in the early 60's and was not touched until they sold it to me in 2016. I cleaned out a mouse nest but didn't start to restore it until 2020. It absolutely had not been powered in the meantime so it likely sat unpowered for 60 years. Incredible when you think about it.

And that is what I think saved the electrolytics. I gently brought up the capacitors by limiting the current to no more that about 10mA per capacitor. If the set has sat for decades, the capacitors will be almost a dead short and it is almost certain the capacitors will be destroyed. Yhe key is to carefully monitor and ensure the current is strictly limited until the dielectric has properly reformed.

I would leave the DC supply on for the night and inch the voltage upwards while monitoring the current. When it reached close to the rated maximum voltage, the electrolytic, if healthy, it will draw only about 100uA. If the capacitors draw more than 1mA after reforming, then it must be restuffed.

To summarize, I do not like using a Variac to first power up. To me it is the lazy man approach to the problem and because you are more adequately monitoring the current, it is hit and miss. By using a high voltage DC supply with current and voltage monitoring, you can better decide whether the capacitor is a survivor or not.

Proof should be the 721TS which has lasted over two years on ALL the aluminum can capacitors. I am in the midst of restoring a CT100 color set (which when I have time again in a few weeks will get down to the final alignment) which I slowly reformed the capacitors with the DC supply. All have survived and work fine.

I have a Heathkit High Voltage Power Supply, IP-17 which I have totally restored. It has voltage and current meters so it would be easy to do.

I have a working T100 that came up on all original electrolytic capacitors. But I have not turned it on for about 8-10 years though. It was rather easy to get going.

8 to 10 years off, if the capacitors were previously good, I dont think will be a problem. I think it is a problem when it has been off for 40 or more years with a sudden power up..

If you use the DC HV power supply across the B plus line to reform the capacitors, I will be interested in your results.

The set has now been running faultlessly since July 2020. That is two and a half years still running on the original electrolytics. Still no sign of failure.

Great to see this update and you have given me an incentive. I have an RCA 630TS that is in excellent physical condition and has all of the parts. The GE CRT, no doubt a replacement, tests NOS. I will start with replacing the paper capacitors in the sweep sections and audio and see how the electrolytic capacitors reform. Carefully, slowly! Thanks.

It has now been three years since I resuscitated this set. Recall all of the original electrolytics except for a replaced 40uFd axial lead unit are original. Most of the paper dielcetric capacitors were changed. I left a few units which were bypassed by resistors less than 100Kohm. And a few resistors which I found drifted when it affected performance. I then decided to run the set regularly and report from time to time on it's performance over the years. It is well past 1500 hours.

The set has developed two problems:
1. The original KRK2 tuner fine tuning has a bad back lash which make it difficult to fine tune. I believe it has to do with the slop in the shafte which I have to address. The second is a horizontal sync issue which causes the horiztal oscilaator phase to shift briefly and jump back. It is very momemtary and occurs rarely. Have no idea what it may be and keeping an eye on it.

But this set has been incredibly reliable and delivers a very good picture for a set which is 76 years old. Here are a few snapshots from over the air CHCH TV channel 11 this morning.

Latest update on the 721TCS.

From the original 2020 restoration:

All the original can electrolytics are still fine with no problem That makes them 76 years old!

I left many of the original wax capacitors which pose no threat due to leakage. The ones I left are shunted by resistances 1M ohm or less and pose no DC threat.

Only two resistors changed asthey affected performance (horizonal plate resistor and video amp plate resistor.

An axial lead 40uF capacitor changed due to leakage.

Recent service:

KRK2 tuner fine tuning problem - slop due to wear in the brass tuning wand worn making it hard to tune for best sound (recall this is a split sound set). I made a new brass wand and attached it to the original tuning shaft disc. The repair fixed perfectly the fine tuning issue.

Horizontal jumping. the picture would jitter horizontally due to what appearred to be a time constant change in the circuit. Changed 6SN7 oscillator tube which fixed the problem.

Set remains working fine after regular 3 1/2 years use on all original electrolytic capacitors.

Here is a screen shot from this morning with the signal from an over the air signal via an ATSC set top box.

Beautiful!

Interesting.

I recently restored (But did not align) my 630TS and found that half of the original electrolytic capacitors tested good (out of circuit) for leakage; the other half were no good. I restuffed the bad ones and reconnected those testing good. I could see that those which tested good were a different manufacturer (or design or whatever, just different). Sure made things easier.

I guess they may be from the same era/manufacturer?

The capacitors in this 721TS initially looked bad. But the set had been stored away and left dormant for 55 years when I bought it. I slowly reformed the capacitors over the course of four days. The key is to limit the current to just under 10mA and slowly bring up the voltage until it meets or slightly exceeds the maximum rated voltage. I would then let it sit at the maximum voltage for a few hours and notice the current continue to drop until it was no more than 200uA at maximum voltage. All of the capacitors came back that way.

However, I have a Canadian market RCA CTC5 color TV. The set was manufactured in Camden NJ and in Montreal it was modified for 25Hz power. The modification included replacing the power transformer on the main chassis with a 25 Hz filament only transformer and then adding a separate small additional chassis with a massive B supply transformer, an additional filter chole plus two Canadian mad Sprague 80uF 500v electrolytic capacitors. The main chassis had Camden installed Mallory capacitors.

When I restored the set in 2014, the Mallory capacitors reformed dielectrics were very low leakage 100uA or less. The Sprague's were close to 1mA leakage at 500v. I left them in and 8 years later one shorted and destroyed a pair of 5U4 rectifiers. I felt at the time the Sprague's were marginal. But the Malloys remain fine.

It has just reached four years since the restoration. The restoration preserved all the original chassis mount electrolytics and carbon resistors. Only the paper capacitors not shunted by resistors were replaced.

Sixteen paper capacitors and an axial lead 40uFd and capacitor were replaced. Two out of tolerance were replaced with identical type carbon resistors.

The only mechanical issue was a loose worn brass fine tuning shaft which I remade and replaced. A full IF RF alignment was done.

I switch on the set regularly and it remains in excellent operating condition. The snapshots are from an off air signal this evening.

The aim of this thread was to see if the original 77 year old electrolytics would stand up to modern use. As I pointed out earlier in this thread, I took care reforming slowly the original electrolytics.

Impressive. And equally impressive is the lifetime of these electros!

Looks good of course. I have a 630TS that still has one half of the can electrolytics original. The other half of them were leaky and were rebuilt (stuffed). I found that the ones that are still original were manufactured by the same company; the ones that were leaky were manufactured by a different company. I don't know who the companies were, only that I could tell by construction materials, technique etc. were the same.

Thanks for sharing!

That is what I found with RCA CTC5 Canadian chassis. The Camden installed Mallory's remained all good. But the Canadian Sprague capacitors mounted on the auxillary 25Hz chassis were bad and refused to reform without appreciable leakage.

Recall I spend a few days slowly reforming the capacitors after the TV sets and remained dorment and unused for many years. Most would come up fine but there are a few that will have a higher leakage. The Spragues becan with a leakage of about 1mA and that current leads to heat dissipation which propagates eventual catastrophic failure. I waited to see what would happen to the Spragues and they were warm in operation. If the capacitor is warm, it will go!

So far the 77 year old units in the 721TS still run cool after an hours operation. So my suggestion before even plugging the set in is to do an assessment and dielectric refomation to ensure leakage is 100uA or less and then give them a try.

Yes, it is interesting.

I know that it's a PITA but if there are not a lot of connections on the electrolytic capacitor, I disconnect every lead and test the capacitor for value first and leakage at the working voltage next. If it passes, I put everything back and then monitor the temperature. Sometimes you win, sometimes you lose.

When I bought this set about 6 years ago, it had sat in an attic for nearly 60 years unpowered. Apart from a mouse nest, it was a pretty clean and intact set. When I began the restoration, I decided to first evaluate the electrolytics. As it had not been powered on for many years, the filter capacitors were extremely leaky. I believe had it been powered as I found it, the capacitors would have been most likely destroyed and the rectifier destroyed.

I proceeded to reform the electrolytics by simply removing the 5U4 rectifier and with power off, connecting my Sprague TO6 supply across the B+ supply line. I limited the current to a maximum of 10mA and left the TO6 running all night. The voltage across the capacitors began to rise from less than 10 volts @ 10mA. I had taken into account any shunt resistance across the B supply and I recall removing some divider resistances.

The next morning the capacitor voltage had reached nearly 100 volts with minimal leakage. I raised the voltage and keeping maximum leakage less than 10mA. By the end of the day the total paralleled capacitor leakage was well under 1mA. I disconnected a few capacitors I could not readily access to ensure leakage was no more than 100uA at full rated voltage.

The point I am making here is that the capacitors will be destroyed unless a more gentle approach is made waking them up. I never use a variac to power up an old device. I will instead immediately look at the electrolytics and evaluate and see if they will reform. Then if the TV set dates prior to 1960, I will replace almost all the paper capacitors.

I have rebuilt a sizable number of electrolytics which will not reform. But with all 5 of my late 40's RCA Televisions, I have only replaced one chassis mount multiple section electrolytic. My CT100 had two bad chassis mount electrolytics and my CTC5 set has retained all the original electrolytics. Curiously, a 1961 CTC 11 RCA color I restored a decade ago required replacement of every chassis mount electrolytic. All but one the dielectric would not reform and the one that did suddenly failed in service. (The failure was not a short but went totally open.)

So there is no hard and fast rule. It is easy to reform the things and to test leakage and capacitance. And the experience I have had has been very good up to now.

And that's the key. No two are alike.

Just an update after 4 1/2 years of regular use. Only problem in the last 4 1/2 years was the KRK2 fine tuning shaft. I made a new one out of brass riveted to the original fine tuning disc.

Still using all of the original chassis mount electrolytics. 78 years and still fine. The restoration entailed only replacing the wax caps that needed replacing eg subject to a a large DC across them. A three resistors had drifted affecting operation. Tested transconductance on all tubes and replace a few with original period NOS RCA tubes.

The main point is the originality of the electrolytics. They survived because the set was not plugged in after the set sat unpowered for over 50 years. Slowly reformed the capacitor dielectrics and they are all still fine. One axial lead electrolytic was bad and was replaced.

Here are a couple of snapshots off air made this afternoon. Can you name the film?

Thought I should resurrect this old thread considering the significance of the originality of my 1947 721TS. I resuscitated this set nearly 5 1/2 years ago and this was to be an experiment to see if a fairly well preserved set could be reliably operated replacing parts only what were absolutely necessary.

In the resuscitation of this set, it retains all but two of it's carbon resistors. About 95% of the paper dielectric capacitors were changed. The ones that were retained were shunted by resistances which swamped the leakage resistance of the capacitors. It retains some of its original tubes. I carefully selected RCA period tube for replacement so it is a fully RCA tubed set. When I received the set 10 years ago, it had sat in a heated attic in a house near Schenectady for just over 50 years. Upon pulling it apart I found a small mouse nest under the chassis and fortunately it caused almost no damage. The set was not powered from the early 1960's until after it's resuscitation in 2020.

However, of major consideration is this set retains all of it's original electrolytic capacitors. This thread describes the extra effort I took to preserve the capacitors. I am not averse to changing the electrolytic ic they test bad. But slowly reforming the dielectric on each electrolytic in this set brought them all back with very low leakage.

So the bet was on as to how long they would last? I power the set on average once a week and let it run for a couple of hours. I decided to check the capacitors this evening and can report that they all appear fine.

Here after 5 1/2 years, after the careful reforming of all the original electrolytic cans, are some off air shots. (I did replace the original 40uF axial lead electrolytic but all the chassis mounted cans are now 78 years old.

Gorgeous pics!

Thanks.