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#61
09-24-2012, 09:49 PM
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I hope you are still planning to variac this to life!
__________________
My current "holy grail" is trying to get enough parts together to get a Singer TV6U going. Been kicking my ass for nearly a year now :-P 
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#62
09-25-2012, 02:10 AM
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 I new this was a common point of failure and even bought some replacement sockets. Unfortunately, the break didn't reveal itself until after I wired the PCB back in   I globbed a little solder on the break and it's restored continuity through the PCB (for now). If I ever need to pull the PCB for some reason, I'll replace the socket. I still don't have continuity through to the AC plug though. There seems to be another break somewhere between the CRT and tuner tubes. Last edited by bandersen; 09-30-2012 at 02:16 PM.
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#63
09-25-2012, 03:00 AM
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I fixed a loose tube in the tuner and finally have filament continuity
 Here it is powered up with the fusistor pulled out so there's no B+.I'll try a full power up after I get some sleep. 
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#64
09-25-2012, 03:13 PM
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Startup filament current
I checked the filament current when the set is turned on and found it peaked at about 1 amp then settled down to 600mA after 10 seconds. That's with a single CL-90 (120 ohms cold) in place of the original thermistor (400 ohms cold).
I then tried it with two CL-90s in series and got a peak or around 850mA before settling down to 580mA. I checked in my RCA tube manual but couldn't find any data about permissible cold filament startup currents. Does anyone know if it's OK to have 1A (or more) running through a 600mA tube for a few seconds every time a set is turned on ? If not, I could go with three CL-90s in series to really keep that current surge down.
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#65
09-25-2012, 03:56 PM
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I did some searching on the web and discovered Ametherm has a nice line of thermistors including these with a cold resistance of 220 ohms.
1 Amp max, 2.2 ohm hot http://www.digikey.com/product-detai...873490?cur=USD 2 Amp max, 0.9 ohm hot http://www.digikey.com/product-detai...873476?cur=USD
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#66
09-25-2012, 05:17 PM
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I hooked up a test speaker, popped in a fusistor and slowly bright it up on a variac until I achieved full B+.
Only the tubes weren't lit up until I wiggled that tube in the broken socket again. I'm definitely going to have to replace it! After fiddling a bit with the tuner, I heard our LPTV channel 6 coming through the speaker   I removed the screw locking down the CRT and popped it off the chassis. I'll lay down some padding on my workbench so it doesn't get damaged and hook it up next. 
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#67
09-25-2012, 07:08 PM
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I hooked up the CRT and powered it up again. That got me a nice bright horizontal line
I quickly turn the brightness down to avoid a burn. Wiggling the 10DE7 vertical osc. and output tube produced some vertical deflection so I'll start checking there. 
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#68
09-25-2012, 10:46 PM
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Ugh, another broken socket pin.
 I globbed some solder on that break too and achieved vertical deflection After a bit of tweaking, I got a watchable picture. The hor. linearity is off, vertical hold touchy, channel oscillator slugs are off and it needs an alignment, but it's progress   
Last edited by bandersen; 09-25-2012 at 10:55 PM.
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#69
09-25-2012, 10:51 PM
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After all that.... ALIVE is GOOOOOOD!!!! and a picture too??? BONUS ROUND!!
 SR
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#70
09-25-2012, 10:52 PM
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Wow! That looks great so far!
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#71
09-25-2012, 11:41 PM
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And what's the first thing we see? Mr Death!
 Maybe you should have gone ahead and replaced all the sockets! 
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#72
09-26-2012, 12:00 AM
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Quote:
I swear all these 9-pin sockets looked fine when I inspected them. I'll be pulling the PCB back out and replacing them. Better order up some more for my other sets too
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#73
09-26-2012, 12:10 AM
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That's funny, as I read this post, that episode of TZ is on right now.
__________________
"It's a mad mad mad mad world" !! http://www.youtube.com/user/mwstaton64?feature=mhee
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#74
09-26-2012, 04:15 AM
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its alive ! you sure took that tv a long way back to the living .
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#75
09-26-2012, 07:00 AM
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Quote:
because they seem to catch my eye. Can you post a picture of a new tube socket and tell who can supply them? If I find a Predicta, might as well replace all the tube sockets with the recapping. Thanks Carl
__________________
CW 1950 Zenith Porthole - "Lincoln"
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