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  #16  
Old 05-16-2018, 01:30 PM
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Quote:
Originally Posted by Electronic M View Post
My b&k 466 will show mid to upper bad on monochrome CRTs that produce reasonably bright pictures on a healthy chassis.... Cutoff is only important on color CRTs...As long as you don't get all or nothing cutoff response adjusting the knob( that indicates gas).

The good bad scale is accurate for color CRTs where a good portion of the emission is lost at the shadow mask before it can reach the phosphor.

If it is somehow dim with the chassis working right just throw a brighter on it.
This is, of course, very encouraging news. The cutoff definitely isn't all or nothing, it basically just does nothing, unless you ease off on the G1 voltage, in which case cutoff works more or less as it would with a stronger testing tube.

I'm okay with a reasonably dim picture, just so long as it doesn't blow out and lose focus whenever there's a bright scene, or text on the screen. I think that with the above info a basic recap is more or less justified, just to find out how well it works.
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  #17  
Old 05-16-2018, 08:01 PM
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If it is still dim once you get the chassis sorted out a mild rejuvenation should bring it back. I've had good results with B&W tubes after rejuvenation. They usually last quite well. Color tubes are much more difficult as you are trying to match three guns plus they don't seem to last as long after rejuvenation (less cathode material?)
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  #18  
Old 05-17-2018, 08:49 AM
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I've also seen this tube (17BJP4) available as NOS, periodically, when I searched for it. Will keep the rejuvinate plan in mind.

One thing which threw me about this set, was how to get into it! I started by taking the back off, then the screws which hold the chassis in place, then the front panel... Then there was no reasonable way to get the control panel out, but I managed to somehow contort my hand.

When all was said and done I realized the whole set is built on a flat piece of plywood, which forms the bottom, and the front, sides and top all unscrew from this, leaving only the bottom. This will be great for working on the set but I sure wish I figured it out earlier!

Now just waiting for the rainy weather to end so I can take the chassis outside, and detail it with an air gun. The component side is quite dirty. I am curious if the old British made Plessey electrolytic cans have any life left, or need to go.

Last edited by maxhifi; 05-17-2018 at 08:52 AM.
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  #19  
Old 05-18-2018, 10:23 AM
dieseljeep dieseljeep is offline
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Originally Posted by maxhifi View Post
I've also seen this tube (17BJP4) available as NOS, periodically, when I searched for it. Will keep the rejuvinate plan in mind.

One thing which threw me about this set, was how to get into it! I started by taking the back off, then the screws which hold the chassis in place, then the front panel... Then there was no reasonable way to get the control panel out, but I managed to somehow contort my hand.

When all was said and done I realized the whole set is built on a flat piece of plywood, which forms the bottom, and the front, sides and top all unscrew from this, leaving only the bottom. This will be great for working on the set but I sure wish I figured it out earlier!

Now just waiting for the rainy weather to end so I can take the chassis outside, and detail it with an air gun. The component side is quite dirty. I am curious if the old British made Plessey electrolytic cans have any life left, or need to go.
I thought Plessey had a plant in Canada!
If the CRT is aluminized the picture will be reasonably good. Makes a real difference.
More pictures of the chassis would be great.
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  #20  
Old 05-18-2018, 11:01 AM
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The chassis is full of British capacitors, hunts, plessey, and others. All the paper caps are from the UK. Canadian Marconi was British owned at that point. I have an earlier one with a round CRT which is in poor shape, but even has a British made focus coil on the CRT. That TV is unfortunately missing cosmetic parts, but is much older in design. One thing which seems to me a bit unique about Marconi sets is the IF sections are done in a straight line, they look a bit different from the US designed sets. The sets are a real mix of British parts and American design, sort of like our language and culture!

British Capacitors are quite common in the electronics which were made in Montreal in the 1950s and 1960s.

I got a new blow gun for my air compressor with a narrow tube at the end, this afternoon I plan to reassemble the set on its plywood base, and take a bunch of photos after I clean it more. One thing I noticed is the horizontal output tube is bad, the getter is white.

Last edited by maxhifi; 05-18-2018 at 11:07 AM.
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  #21  
Old 05-18-2018, 04:42 PM
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Here's some photos of the cleaned chassis.
Attached Images
File Type: jpg DSC_0547-1024x578.jpg (71.9 KB, 40 views)
File Type: jpg DSC_0550-1024x578.jpg (88.9 KB, 35 views)
File Type: jpg DSC_0555-1024x578.jpg (60.1 KB, 35 views)
File Type: jpg DSC_0548-1024x578.jpg (77.8 KB, 33 views)
File Type: jpg DSC_0552-1024x578.jpg (55.6 KB, 33 views)
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  #22  
Old 05-18-2018, 10:18 PM
Gregb Gregb is offline
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Hey Max, if you need a horizontal output tube I more than likely have a number of them.

Gregb
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  #23  
Old 05-18-2018, 10:25 PM
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Originally Posted by Gregb View Post
Hey Max, if you need a horizontal output tube I more than likely have a number of them.

Gregb
Hey Greg, I managed to find a couple of NOS horizontal outputs with my tubes, however I am far from done with this project, there's 17 other tubes that could be bad, among other stuff.
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  #24  
Old 05-20-2018, 05:30 PM
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I got all of the paper capacitors changed, and started measuring resistors. I'm surprised how many are 20-50% off, I've never had to order so many new resistors for a TV before. I am sure it would work as-is, but certainly not like new.
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  #25  
Old 05-20-2018, 06:22 PM
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Decided I wanted to check if the flyback and other critical components work, before ordering any parts.

I replaced all the paper caps except two I didn't have on hand. I reformed the electrolytic filter capacitors without incident. Then I installed the CRT and powered on.. Up came a nice raster, and the blasting audio of a TV which isn't tuned into a station. It's even reasonably bright.. A rewarding sight after all the work so far.

High voltage measures 12kV, but the meter I used is always low, on every TV I work on, so I think it's probably right on 13.5 as the manual wants.
Attached Images
File Type: jpg DSC_0557-1280x722.jpg (82.9 KB, 25 views)
File Type: jpg DSC_0556_crop_633x391.jpg (29.3 KB, 27 views)

Last edited by maxhifi; 05-20-2018 at 06:26 PM.
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  #26  
Old 05-20-2018, 08:28 PM
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That's a great start. Youv'e even got a full raster. A few Australian sets had the IF's arranged in a straight line like yours (PYE, Astor). Some had them on a sort of sub chassis suggesting they were all pre aligned then simply dropped in during chassis assembly.
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  #27  
Old 05-20-2018, 11:41 PM
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Quote:
Originally Posted by irext View Post
That's a great start. Youv'e even got a full raster. A few Australian sets had the IF's arranged in a straight line like yours (PYE, Astor). Some had them on a sort of sub chassis suggesting they were all pre aligned then simply dropped in during chassis assembly.
Were there any transformerless sets in Australia? 240V seems like a lot of filaments.

I really, really like my new isolation transformer. It's so luxurious to be able to work on a line powered device without being paranoid about safety.
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  #28  
Old 05-21-2018, 01:06 AM
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There were a few transformerless models, Ekco being one of them but they were not popular in Aus at all since 240V is quite lethal and the possibility of contact with the chassis with Active and Neutral reversed scared a lot of people. I had an isolation transformer until very recently when It went up in a cloud of smoke and oozed black goo everywhere. It was a pull from an old Sony color set and had served me well for many years but didn't like being connected to a laptop charger (I was using the laptop to play audio at a party and had a ground loop causing digital noise in the background so used the iso tranny to get around it). Power factor correction in Chinese power supplies is non existent. As all the Transformerless TV's in Aus are long gone I don't think I'll worry about replacing it.
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  #29  
Old 05-21-2018, 11:05 AM
dieseljeep dieseljeep is offline
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Originally Posted by irext View Post
There were a few transformerless models, Ekco being one of them but they were not popular in Aus at all since 240V is quite lethal and the possibility of contact with the chassis with Active and Neutral reversed scared a lot of people. I had an isolation transformer until very recently when It went up in a cloud of smoke and oozed black goo everywhere. It was a pull from an old Sony color set and had served me well for many years but didn't like being connected to a laptop charger (I was using the laptop to play audio at a party and had a ground loop causing digital noise in the background so used the iso tranny to get around it). Power factor correction in Chinese power supplies is non existent. As all the Transformerless TV's in Aus are long gone I don't think I'll worry about replacing it.
The NEC and the CEC does not allow any voltage higher than 120 volts from live to earth ground in residential and smaller commercial installations. I always thought it was a safer approach than using a higher voltage for general usage. Copper wire is expensive here as well, but we never sacrificed safety for reduced expense.
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  #30  
Old 05-21-2018, 11:19 AM
dieseljeep dieseljeep is offline
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Originally Posted by maxhifi View Post
Were there any transformerless sets in Australia? 240V seems like a lot of filaments.

I really, really like my new isolation transformer. It's so luxurious to be able to work on a line powered device without being paranoid about safety.
Paranoia runs deep, into your life it will creep!
The sets built in the 240 volt areas used valves (tubes) that had a higher heater voltage at lower current. Many times they added up to more than 120 volts, so they only had to drop less voltage from 240 volts. The mains dropper was a high wattage item and still a common failure item.
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