hi all well i powered the set up but this stuff is to early for me but ill get to the point there is no induction at the fly at all no glow of the rectifier tube. tubes all new and there is voltages at the fly and the ho tube has a blue glow so i guess its putting out. any ideas from anyone that knows these old sets?

I'm amazed I understand this.

You changed all the paper caps and domino style caps in the horizontal circuit?

You're speaking my language too Timmy.

This brings back memories of every no-HV RCA set I ever worked on ...LOL

Keep up the good diagnostics

electrolytic and paper caps for now to get it up and running to see where im at.

Change any of those domino style mica or paper or maper or pica whatever they are if there in the horz circuit change them.

A glowing blue tube can be normal or can indicate excessive current. Its hard to tell without measuring the cathode current.

Im not a fan of working on the old sets either. Way to many caps and so easy to get a wrong value installed.
Im much more a fan of the 60s color stuff.

Check the HOT grid voltage and make sure its negative.

the blue glow is in the hot but when you take the wire off the top the blue glow is gone so you may think that its oscillating in the fly but the fly is total dead . all the important caps in the horiz were the wax paper caps and they are changed, the fly looks great no wax, burn marks, its clean just no noise or output,lol,lol. i really didnt want to get into something this old but my girlfriend brought it home so its mine now to get working.

Wow Timmy, I never had a girlfriend that would fetch a TV for me. They used to consider my hobby AS their competition!

Do a resistance check of your windings, maybe one is not soldered to the fly terminal, etc. One can only hope:scratch2:

I attached the pages from my book that may help you. I will be looking for the other volumes since I have pre-52 BW sets; Emerson, Motorola, Philco and RCA. No Zeniths though:tears:
173823

resistance checks in circuit? i dont know what they should be the sams dont show it. i left the set on for awhile and the fly is cold.

took all wires off the fly and went to the sams and checked all coil connections for contiuity and it has readings on all coils. its like the circuit is not oscillating but if it were not then with standing voltage the flyback should be hot but its cold.

Run some voltage checks on the HO tube base.....If the screen is too low or the cathode is open that will kill the HV and probably leave the fly with 0 current running through it regardless of the state of the oscillator stage.

the hot has 99 volts neg grid and 200volts screen and i was told that the voltage should be 35v and 250-300v. not sure what it all means lol,lol.... and the odd thing is that it appears the the wire on top of the rec tube has about 300 volts on it.

Measuring the rec tub cap when powered on was only possible because there is no AC going thru the fly, only DC that feeds from the Damper tube (6W4?)

Try this with Power off ; What is your resistance measured from the horizontal tube cap to the HV rect tube cap? Should be about 500 ohms or what the sams lists. Its probably OK, since you got DC there.

Then this: Lift the 6CD6 hor out cathode pin 3 off ground and put an ammeter between that pin and ground. Leave it there and start trouble shooting the output and oscillator stage. If you have -99 volts, the tube is probably completely cut-off (not conducting)

My guess FWIW is that the horizontal oscillator is way off frequency. Start there. Check everything. Disconnect AFC circuit in case sync signal is causing issue.

the hot in this set is 6bg6 so i dont know if pin 3 is the same to use and the sams lists nothing in the way of voltages. i dont think there is an AFC like the 60s sets. there is something said about cathode currant in these old sets and i dont know where to set it. the sams dont even list what the cathode currant should be. would the pin 3 be the same for the tube i have because i dont know? from both rec cap and hot cap is around 200 ohms since this this set dont use much hv 7-9kv and the fly is small so i dont think it would be the same for bigger and newer sets.

There were TWO AFC's in 60's sets....the tuner AFC (which is what I think you mistook Davgoodlin's comments to refer to), and Horizontal oscillator AFC (that dates back to the 40's).

The horizontal AFC is meant to compare the oscillator frequency to the synch, and pull the horizontal oscillator frequency to match the synch. If the horizontal AFC circuit is bad it can pull the horizontal oscillator waaaay off normal operating frequency. The horizontal AFC circuit comprises all tubes on the schematic that are between the synch tube and horizontal oscillator tube. Pulling the tubes in the AFC will disable it and make trouble shooting oscillator issues easier.

well there is a horiz sync discharge tube, horiz react, and horiz osc.

Keep yr chin up, Timmy, you'll get it !

pulling those tubes did nothing so back to the drawing board. and i really dont want to touch the micas as they say these sets usually dont need them and replacements cause more problems.

Try pulling the first two (not the osc tube) out and see if your cathode current goes up to 150 milliamps of so. Without the schemo, I'm not sure. Ill see if I have it.

The horizontal AFC is meant to compare the oscillator frequency to the synch, and pull the horizontal oscillator frequency to match the synch. If the horizontal AFC circuit is bad it can pull the horizontal oscillator waaaay off normal operating frequency. The horizontal AFC circuit comprises all tubes on the schematic that are between the synch tube and horizontal oscillator tube. Pulling the tubes in the AFC will disable it and make trouble shooting oscillator issues easier.
Its a primitive type of phase lock loop.

pulling those tubes did nothing so back to the drawing board. and i really dont want to touch the micas as they say these sets usually dont need them and replacements cause more problems.

ANY MICAS IN THE HORIZONTAL SECTION MUST BE CHANGED!!!! AND YES I AM YELLING THAT.

They are ALWAYS bad, the only ones that dont need to be change are the ones in the IF that dont have much dc voltage across them.

well just now im hearing that the micas are infact not bullet proof and i guess they should be changed. are there any substitute caps to use in place of the values of the micas like mylar caps?

Even though it wont be popular, I use disc caps to replace micas. Keep them away from any heat source and they work great.

If you look at newer sets they all use discs where the old ones use micas.

well changed the micas in the horiz circuit and still no drive on the hot. i have been working with don lindsly and we checked voltages and it seems that there is a frequency but its to low to drive the hot. and now we cannot do anything else unless i have a scope which i dont have so im in the dark now with this set. i checked all the resistors in and around the horiz circuit and and found nothing out of tolarance. dont know where to go from here. tried other tubes and nothing. simple b&w is turning into a nightmare.

What is the screen voltage on the hot and what is it spost to be?

well i got the chassis out now but the voltages were close to what they spost.. to be but the neg voltages were high. i dont remember what they were as i was on the phone with don doing this. he thinks the problem is around the horiz discharge tube but cant find anything wrong. the only thing i have left to try is i had to sub the horiz reactance tube 6ac7 for a 6ab7 which is said to be a match for a sub but maybe i should get the right tube rather then the 6ab7 maybe they are different.

with the chassis on bench no crt control grid pin 5 of hot is neg 101 vdc and screen grid 205 vdc. pin 5 should be neg 94 vdc pin 8 should be 165 vdc.

with the chassis on bench no crt control grid pin 5 of hot is neg 101 vdc and screen grid 205 vdc. pin 5 should be neg 94 vdc pin 8 should be 165 vdc.

If the screen should be 165 and is measuring 205..

The tube is weak or there is excessive plate current.
Some kind of overload in the output like shorted fly, bad linearity coil, bad yoke, bad caps, bad damper, something causing the fly to be overloaded.
I guess if the frequency was way off it could cause that but if it was low you should hear it squeeling

the fly dont even get warm neither does the yoke and the cathode currant is 110ma. the 6ac7 tube is a sharp cutoff where the 6ab7 i am using is a remote cutoff as i am thinking maybe this could be a problem? and no squealing going on. and i tried 2 other tubes.

Timmy flavored jelly beans.

Im looking at a schematic for a TV30 cuz thats all I can find, where are you getting a TV125 schematic? What are you looking at?

The TV30 has a very confusing damper/output side of the flyback.

this fada set is called tv 125 because it dont have channel 1 and its got the rca clone 630 chassis. i have the sams photofact for rca 630 chassis.

does it match?

what are the tubes in your set, not on the schematic but the tubes in the horizontal circuit in the set.

I will look at the tv 30 and the 630ts later tonight today or tomorrow yesterday morning.

tubes are, 5v4 damper,6bg6 hot, 6k6 horiz oscillator,6sn7 horiz discharge,6al5 horiz sync disc. the tubes match the sams as well as the tv cover.

later today i will be checking voltages on the horiz tubes again and the damper as well to make sure they are close to the sams specs.

well the voltages are close on the rec tube from 350v i have 309 so this may suggest that there is no short and no crt in the set and the chassis is not running as it should as there is no load on the power supply .the ac volts off the sec transformer to rec tubes is fine. damper tube pin 2 and 8 are to be 350 but i am getting 274 pin 4 and 6 are to be 290 and im getting 287.

does it have 6ac7 hor osc control?

it has a 6ac7 but i have a 6ab7 in place of it which i am waiting for the right one since the 2 tubes have different cutoffs,6ac7,sharp cutoff and 6ab7 remote cutoff so i dont know if this is a problem but ill find out when i get the 6ac7 and try it. it also has a 6k6 tube for the oscillator and has a syncro loc in the rear and i checked ohms against the sams and its right on so the coils are good. the 6ac7 is the horiz reactance tube.

I will try and scan the riders when i get somewhere

:tears:well got the 6ac7 but i was told by don linsly that it wont work because this problem is with the frequency or oscillator circuit. now i just have to find out what is stopping the oscillations from doing its job and i dont have a scope. so back to the drawing board..............

If you plan to do much TV servicing a decent scope is a must!

i dont do much just mostly the round screen colors , when i find them.

Timmy, I started with an RCA WO-91 scope (1964?). It can be had for $50 or so...and its very easy to use. You do need a scope once in a while, especially when you need to "see", rather than measure, the voltage.

I recently picked up a 20 MHZ dual-trace Leader LBO-? for $80

there has to be something here im overlooking as i went over everything ,i think. i subbed a resistor for a higher value and got some hv but cannot figure out why, a 680k that measures .730 meg.

.730 meg=730K within 10% of 680k

well this project is now on hold because the power transformers primary is sizziling and burning, dont know why. i took out the 2 5u4 rec tubes to rule out anything in the circuit but its still burning up so thats it for now, and it is over 60 years old probably the original.