Hello..my first TV

[Donj]

Hello to all.
Being a somewhat new member, this is my first post. I have been repairing/restoring radios and jukeboxes for many years but this is my first attempt at a television, so I have a few questions to get me on the right track.
First the hardware.... I picked this set up at a local auction. It is a Canadian General Electric model C2511. From the photos he posted, I believe that this is the same set that Tonyf had questions about in this post... http://www.videokarma.org/showthread.php?t=270485
The set appears to be in pretty good condition. Cabinet needs some work, but the chassis(s) look good with no rust or signs of rodent damage. The CRT (10fp4) tests good on my Sencore 465 with no shorts and an acceptable cut off voltage.
I figure that this set is a suitable candidate for restoration given the fact that I only have 30.00 invested and thanks to Mr. Covid, I'm going to be locked in the house with it for a while. I was able to obtain all print materials for this set from Radiomuseum as well as from Ronl.
I plan on replacing the electrolytics and all paper/wax capacitors to begin with which leads to my first question... must I use exact values for replacement or can I use the more modern equivalents? Such as .47 to replace a .5. I know that in most radio circuits this practice is acceptable, but never having worked on video circuitry, I just want to double check.
Once I get the capacitors done and have a chance to check resistors and make sure that everything else appears well, I will probably have some more questions prior to firing this beast up.
In the meantime, if anyone has something to add along the lines of things a beginner should know, please chime in..

Don

[old_tv_nut]

Originally Posted by Donj

... must I use exact values for replacement or can I use the more modern equivalents? Such as .47 to replace a .5.

Don

Really, the same general rules apply as for a radio, so yes, modern equivalents are fine unless you find something in the service literature that specifies a tighter tolerance.

Edit: Oh, and Welcome!

[Donj]

Finally got started on this beast. Being a Canadian model, it is set up for 25 cycle operation and has a separate chassis for the low voltage power supply. It is just a little thing .

First thing I noticed was that the two rectifier tubes were 5R4-GY rather than 5V4G as shown on the chart. I don't expect this is a problem. One of the two tubes tested dead. Digging a bit deeper, I found that one of the two 30 mfd filter capacitors associated with the dead tube displayed a pretty much dead short. The date code on the caps indicates that they are the originals. All windings on the power transformer and choke associated with the bad capacitor ohmed out fine, so it doesn't appear that the problem extended beyond the dead tube. Hopefully, this failure was the reason the set was retired many years ago.
Anyhow, will restuff the electrolytics and replace the few paper/wax caps and a few resistors in this chassis and that should take care of the low voltage chassis.Then on to the main one.
Since I have one dead rectifier tube, should I replace with the 5R4-GY as was there, or should replace with 2 5V4Gs as called for in the tube chart??

[Electronic M]

Both tubes have the same pinout and the same heater voltage and current so the transformer doesn't benefit from either one.
The 5R4 is rated for higher max plate voltage and plate current so I'd stick with it.

[Donj]

The task continues...
Main chassis is on the bench. Check the tubes, clean things up and get to work on the guts.
First thing I notice is the HV rectifier doesn't look right. All documentation calls for a 1B3. Pretty big tube. What's there is not. It is a 1X2B. Since I don't think this tube was even thought of when the set was made, it can not be original. The retrofit appears to be very well done and I suspect the set was probably functioning fine after the modification was made, so you think I should treat it as original and just continue on with the recap and other work?

[JohnCT]

Looks ham and egged (mmmmm...ham and eggs...).

It will work, but the 1B3 has more headroom in the peak voltage spec and a tiny bit more current than the 1X2.

In a B&W TV, the lower HV rating of the 1X2B may not be a problem. But I'm sure it did work fine.

Strange though that it was modified. The 1B3 is still plentiful even in the year 2020.

John

[Donj]

Other than pin locations on a different socket, I'll check and see if any other mods were required to accommodate the 1X2 sub. If nothing else has been drastically changed, maybe I'll re-change things back to original with the 1B3. Good idea? or a lot of unnecessary work for no gain? Will the octal socket mount as the present one is?

[old_coot88]

Originally Posted by Donj

... It is a 1X2B. Since I don't think this tube was even thought of when the set was made, it can not be original.

Here's an article about new tubes introduced in 1949, including 1X2. That'd be congruent with your set's vintage.

https://www.americanradiohistory.com...-Page-0027.pdf

It's obviously original to the set.

[bandersen]

I'm thinking it's original too. For example Admiral started using 1X2 in 1949 in their 20 series chassis.

[old_coot88]

The subject of this memorable thread was a Majestic set of about '49 vintage, and it used a 1X2. This feller started as a total noobie too, and cut his teeth on this set. Finally got it goin' like a boss.

http://www.videokarma.org/showthread...onarch&page=11

[Donj]

This is interesting.
Could this be an undocumented change? I have the complete service package , including revisions, from the General Electric Radio and Television Service Manual 1945-1949 courtesy of Radiomuseum, as well as copies of the RCC schematics of both the 1st and 2nd runs of production courtesy of RonL. Neither of these sources make any reference to the use of the 1X2B. This set has a serial number just into the range of run #2. R224581 started run 2 - mine is R224680. Would this qualify it for any possible undocumented late run changes?

[MadMan]

I think that back in those days, they just did whatever they had to do to make the sets work and keep the assembly line running.

[JohnCT]

Originally Posted by Donj

This is interesting.
Could this be an undocumented change?

They made changes all the time, some for cost, some for performance improvements, some for parts availability.

It's possible that there could have been a service bulletin issued but no subsequent reprint of the service data.

It would seem though that the tube complement chart inside the TV would at least reflect the change. On one of my TVs, the tube chart had the changes rubber stamped, but if yours had a sticker over the rectifier - maybe it dried up and fell off? Any sign of glue remnants around the rectifier position on the chart?

In any case, the tubes are close enough not to matter IMO.

John

[Donj]

Thanks for all the feedback. Looks like I'll just carry on and treat the alterations as original. Took a close look at the tube layout chart in the cabinet and there doesn't appear to be any changes or signs of changes ever made to it. As I said at the beginning of the post, this is my first attempt at a television, and I'm finding it an interesting effort so far.
About half way through the recap.. lots of drippy wax jobs to change, but there are numerous modern version under there as well. I expect this set was reasonably well serviced in its life before me. I have attached a photo. Should I need to replace these guys as well? They are over speced for the job being 1000 volt in place of 4 and 600 volt units

[JohnCT]

Is that ceramic across the line? If so, you should replace that with an "X" type capacitor.

But I remember back in the 60s when RCA had a recall because they had brown plastic caps right across the AC line that would fail and spew carbon and metal bits like a blowtorch. The cap RCA supplied looked like that ceramic, and I never saw one fail, but X and Y caps are now used for this purpose.

John