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Old 04-25-2018, 11:18 AM
Tony F Tony F is offline
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Canadian Sylvania Halo Light 1954-55

Hello, I picked up a (I believe a 1954-55 ?) 21" Sylvania Halo Light set. It is made by Northern Electric for Sylvania in Canada. I found an ad on Google search of a Life magazine (page 71) dated 1954. The model number on the back panel is C401W. It looks like the lower set in the ad (The CROYDEN) rather plain cabinet. I got it for next to nothing with hopes of getting it going. The Halo Light works ( The guy I got it from was not aware he should not power it up without changing the caps.) I'm going to test the picture tube for emissions. I was wondering if anyone would know if this set would cross to a U.S. model for schematics ?

Thanks in advance
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Old 04-27-2018, 10:27 AM
Tony F Tony F is offline
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After a little research, it looks like this set crosses to a Sylvania 21C401. (I'm only going by photos of the cabinet layout). Although I'm not quite sure if Northern Electric made any changes electrically. It looks like Sams schematics Dated 12-56, Set 341, Folder 15. Does anyone know if the schematics can be uploaded from somewhere ? Models listed seem to include 21C401, 21C404, 21C405, 21C508, 21C509, 21T101, 21T102, 21T104, 21T105, 21T106, 21T110, 21T207, 21T208, 24T101, 24T201, (Ch. 1-532-3, -4, -5, -6, -7).
Yesterday I hooked up my B&K 466 and the picture tube (a 21" universal model dated 1965) tested midway in the BAD section for emissions. I tried a restore (1 press of the button) and it now tests 3/4 of the way into GOOD. What can I expect as far as life of this tube, provided I get around to re-capping the set ?

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Old 04-27-2018, 11:30 AM
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Electronic M Electronic M is online now
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Location: Pewaukee/Delafield Wi
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Pro tip: Tubes that have been dormant for ~10+ years will have contaminates bond with the surface of the cathode blocking emissions...Collectors refer to it as the CRT being sleepy. A sleepy CRT will typically wake up if you leave in in emissions test mode for 10-45min...Sometimes increasing the heater voltage by 40% will be needed to wake it up...Once it wakes up it should stay if you give it use within a few months...The wake-up process is much gentler than a rejuve and should be done first.

If it was asleep as I suspect (assuming you did not damage it with the rejuve) it is probably still a fairly good tube for the long haul. One additional check is to switch off the heater or reduce it's voltage signifficantly and see how long it takes for emission to hit bad. If it drops instantly there is not much life left 3-10 seconds is a tube with plenty of life.

If you have not done a TV resto before don't sweat CRT lifespan too much...If it don't have much life left it makes a good set to learn on since if you screw it up bad it won't feel as bad if you know the CRT life was limited...Also if you do get it working you can run it into the ground and get the most of the CRT while it lasts.
Tom C.

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Reading between the scan lines since the mid 2000's.
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