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  #1  
Old 05-13-2018, 12:35 AM
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maxhifi maxhifi is offline
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Canadian Marconi TV 102T17

Picked up this tv today, my favorite picture tube size, 17", going to make a project of restoring it.

One problem though.. Check out the asbestos around the yoke! Not sure how to handle this, for now just replaced the back.
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  #2  
Old 05-13-2018, 02:10 AM
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Yank it off, throw it in the trash and blast it in the backyard with the compressed air. It won't kill ya to handle it for three minutes.
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Old 05-13-2018, 02:20 AM
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Yup. Try to be upwind from it so you breathe in as little of it as practically achievable.
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Old 05-13-2018, 12:03 PM
Tom9589 Tom9589 is offline
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What was the use of this asbestos? Did they install it to reduce the heat on the rear cover of the yoke which was famous for crumbling with age?
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Old 05-13-2018, 12:31 PM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Tom9589 View Post
What was the use of this asbestos? Did they install it to reduce the heat on the rear cover of the yoke which was famous for crumbling with age?
That isn't original. Looks like someone put it on for some reason, maybe arcing.
Go to the dollar store and pick up some cheap dust masks, carefully sweep up the crumbs and the sheet and put in a plastic bag. It's not good to breath it, but the poor souls that died of Asbestosis were exposed to it, forty hours a week, for twenty or thirty years.
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Old 05-13-2018, 01:04 PM
fixmeplease fixmeplease is offline
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If you can spray some light water mist on it, it wont release dust at all when you remove it. Theres gonna be some fibers inside the tv left over to blow out. The cheap dust masks only stop the bigger sized particles and its the micro size fibers that cause most the problems with repeated long term exposure. There are masks made for asbestos or those air supplied hoods, but for a one time thing I wouldnt worry much about it.
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Old 05-13-2018, 01:11 PM
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The horizontal output and damper are in a cage directly under the yoke, I think it's kind of a fix for a bad thermal design.
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Old 05-13-2018, 03:17 PM
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I think I have a handle on how to do this, need to pick up a good dust mask first. I hope there isn't more asbestos inside the HV cage, but I will leave checking that until after what's there now is cleaned out.
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Old 05-13-2018, 08:07 PM
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I bought a P100 respirator at home depot, which is marked on the package as good for asbestos.... Thought it best to spend a few extra bucks to prevent future hypochondria about inhaling asbestos fibers.
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Old 05-13-2018, 09:59 PM
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You're really overthinking it. You could legit hold your breath for the two seconds it takes to pull the thing off and put it in the garbage can. But hey, whatever makes you feel better.

I'm with mips on this one, take it outside and blow all the dust out.
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Old 05-14-2018, 12:00 PM
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You're really overthinking it. You could legit hold your breath for the two seconds it takes to pull the thing off and put it in the garbage can. But hey, whatever makes you feel better.

I'm with mips on this one, take it outside and blow all the dust out.

I think you're likely right, I just think better safe than sorry, I can be a bit of a hypochondriac sometimes, and for the minimal effort involved in getting a proper mask, wetting it down, not rushing, etc. I'd rather not worry about asbestos later on, next time I get a cough.

I got the circuit to this TV from a forum member, and studied it a while. This is my first B&W chassis which is line operated (no power transformer). It doesn't even have a voltage doubler, only a half wave rectifier and a very low B+ of 130V! I do like that the sound detector is an actual discriminator, and not the nasty quadrature detector my RCA and Philco sets use.. Fingers crossed it won't buzz?

I do have a nice 500kVA isolation transformer to make working on it safe. Once I get the chassis cleaned out I'm looking forward to checking the CRT and making sure it's a viable candidate for restoration.
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Old 05-16-2018, 02:03 AM
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Got the set cleaned up and disassembled. Tested the 17BJP4 CRT on my B&K 466, not looking good... Cutoff almost nonexistent, and emission bad. On the other hand, early Canadian TVs aren't exactly common anymore, and I do like how this one looks.
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Old 05-16-2018, 12:50 PM
dieseljeep dieseljeep is offline
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Originally Posted by maxhifi View Post
Got the set cleaned up and disassembled. Tested the 17BJP4 CRT on my B&K 466, not looking good... Cutoff almost nonexistent, and emission bad. On the other hand, early Canadian TVs aren't exactly common anymore, and I do like how this one looks.
The CRT just needs waking up. Probably lying dormant for several years.
BTW, that quite an isolation transformer you have there!
I know you meant 500VA or .5KVA. I've made that same error.
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Old 05-16-2018, 01:02 PM
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The CRT just needs waking up. Probably lying dormant for several years.
BTW, that quite an isolation transformer you have there!
I know you meant 500VA or .5KVA. I've made that same error.
haha, I'm always specifying 500kVA transformers at work, I didn't even catch that

So far I ran the CRT for 8 hours at 6.3V, and I also tried running it for 30 minutes at 8V. At 8V, emission is well into "good" (75/100 on the B&K 466), but at 6.3V, it's at the high end of the bad scale.

Even after letting it sit all night long at 6.3V, it's still reading bad. Cutoff only occurs if I turn down G1 to a bit less than 40V.

I think this tube will make a picture, but do you think it's realistic it will wake up more than this? I've had them come to life before, but this isn't looking good to me. Then again, I haven't done as many as most people here.
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Old 05-16-2018, 02:16 PM
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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.
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