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  #31  
Old 12-22-2013, 09:46 PM
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Quote:
Originally Posted by holmesuser01 View Post
I'll look and see what I have tomorrow. (It's dark here.)
Ok, i'll be on here again tomorrow.
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  #32  
Old 12-23-2013, 07:24 AM
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I dug out the manual for the cheep model
of that year. Same basic design but lacking features
like comb filter, jack pack, better audio etc.

Start process.
Relay closes, applies 150 VDC to HOT & that little board.
The little board has a multivibrator that drives the HOT base.
This gives some HV.
A winding on the flyback ( FBT ) is rectified by CR3473 &
gives 25 volts to the hoz drivers.
Also goes through R3464 12 ohm 10 W to Q3437 the 12V regulator.
As the 12 V comes up it starts the hoz osc & the set
is in the run state.
If any of the chain breaks that 2 K resistor usually will burn.

Like most sets this one has two grounds for measuring DC.
HOT GROUND used for HOT & multivibrator. Use the anode
of CR3205 on HV board for measurements.
COLD GROUND use the CRT ground or IF shield for measurements.
This is for almost all other DC grounds.

For now check for 150 VDC at C of HOT using the hot ground.
Then turn off set, wait a few minutes, hang the meter on cathode
of CR3473 & cold ground. Turn on WHILE WATCHING meter.
It will either go up & stay up, never go up, or go up then
quickly down.

73 Zeno
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  #33  
Old 12-23-2013, 12:50 PM
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Quote:
Originally Posted by pac.attack76 View Post
Label on the insife of the cabinet shows high voltage horizontal sweep module as 9-454. If that's not it, let me know.

I had this module, but used the last one I had in a set that sat unused for almost 25 years. The CRT tested like new, so in went the module. Set is working great.

Sorry I can't help you. I also checked my used stash.
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  #34  
Old 12-24-2013, 12:54 AM
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I found CR3205. I should hang off that to check for 150 vdc at c of hot? What is c of hot? Sorry, just can't think straight. Also, i can't locate CR3473. Wanted to mention a blue wire coming down from the yoke with a red wire has burned at the end where it plugs onto the HV board. red is fine. trying to test today and smelled burning.
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  #35  
Old 12-24-2013, 07:07 AM
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Yes for 150V use anode of CR3205 as ground.
CR3473 on main board ( 9-214 ) ??? Left of main filter cap
& a stand-up power resistor. Use cold ground for that.
Fix zorched yoke wire now, if you are lucky its causing shut-down.

73 & merry Christmas
Zeno
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  #36  
Old 12-24-2013, 09:14 PM
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I found CR3473. Clipped off that and metal corner mount of crt and got from 0 to 4 but realized i had left the ribbon cable off the main board that runs up to the crt board. when i put that back on, meter never went up at all. as for the blue yoke wire, i had to relocate that on up the trace to another location on the back side of the HV board as it had burned the board around that immediate area and the pin where the cable used to mount on had fell off. the smell i get now is just from the instance where i first turn the set on. it sparks there at the burnt area one second. what next?
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  #37  
Old 12-25-2013, 06:59 PM
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Blue wire is low end of yoke. If you havent cut out all
the burned PCB & replace etch with wire. Also remove the
burned connector & be sure the red wire is clean.
Path of yoke is through LX3262 lin coil,
LX3261 width coil, C3261 coupling cap, then TX3251 pin transformer.
Also give the board a real good visual for bad PC cons etc.

73 Zeno
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  #38  
Old 12-25-2013, 07:19 PM
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Ill let you know what happens. would this be why the 12v loss?
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  #39  
Old 12-26-2013, 07:49 AM
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The arc hopefully is causing the shut down circuit to kill
the set. Everything but the 150 V goes dead.

good luck
Zeno
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  #40  
Old 12-26-2013, 12:22 PM
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Well, last time i worked on this, i placed that blue wire on the back of LX3262. Why is it arcing out at the old location? It burned a hole big enough for maybe a pencil to go through. how do i correct this? Everthing else looks ok including the 2 K resistor.
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  #41  
Old 12-26-2013, 02:00 PM
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The arc is due to carbon build-up there at the contact point. You've got to get rid of the carbon. Cut it away, as necessary.
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  #42  
Old 12-26-2013, 02:08 PM
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Originally Posted by holmesuser01 View Post
The arc is due to carbon build-up there at the contact point. You've got to get rid of the carbon. Cut it away, as necessary.
Ah, ok. then everything should work afterward? I'll clear away the bad area and post again.
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  #43  
Old 12-26-2013, 02:55 PM
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Success! All it was carbon buildup whete it was arcing. apparently, the whole failure was the blue yoke wire arcing and causing the burned area. i had fixed the wire last year and didn't know about the carbon causing this. cleaned with a brush and cut away the affected srea and she started right up. been running about 10 minutes now. gonna hook up a vcr and see how we look. thanks to all those who helped. awesome people on here. ill also pist up ics when i can and update on the cabinet repairs as well.
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  #44  
Old 12-26-2013, 03:35 PM
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Yay! Zenith!!!
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  #45  
Old 12-26-2013, 03:47 PM
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The knowledge on this website is fantastic!
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