Notice pin 8 of V6 on the 6HS8, it gets power from 640v boost via R92, if the horizontal oscillator is NOT working, then this voltage is obviously not there for the plate to use, making the tube NOT happy, it will try to get power from someplace else, like the grids, this can overload and damage the tube.

From what I understand, V6 is not needed in the set for horizontal oscillation to take place, can be removed while you debug the horizontal oscillator circuit, it IS needed to sync it to incoming video however.

And as been stated many times by many here, an oscilloscope, even a crappy $35 one, would be a great aid to you at this point.

What if the ohms on the flyback were out to a degree would this prevent the oscillator from running. With the 6hs8 out the 190 rail is dropping bad down to 35 v. I think it’s obvious that whatever the problem was has now disabled the oscillator for good which is a good thing maybe now I can somehow track it down so now it’s a dead short probably between a resistor otherwise it would burn the fuse wire.

Possible short/ bad part, there are 8 connections to the 190v line, all must be checked, starting with both sides of R215, if 275V is OK, then R215 is suspect, or C2c, or anything that connects to 190v.

But, that is the reason for loss of horizontal oscillator, it needs 190v to work, find why you lost 190v, and it should work again.

Most likely suspects are, soldering errors, opens or shorts.
or
C61 , R215 ,C2 section c

All other links to that line are via 2k or higher resistors, and would be getting quite hot if shorted.

I had subbed another cap c2 c and the 15k resistor checks 18k so on to the next.

18k is just on the outside edge of tolerance (20%) and very out of 10%.

You may wanna change it with a new 1w 15k one.

Cap cap c2 c subbed with 10uf 350v?

Any chance that the 190 and 145 volt supplies are swapped on the schematic? The 15k resistor appears to be too high a value for the current that it must supply. The 190 supply as shown appears to be very weak!

:scratch2: jr

The 190v I never had a problem with that rail until now and the 15k resistor is getting warm like there is a draw and I pulled half the tubes and the cap I subbed was not 350 10 it was bigger voltage and uf

And yes that would have made more sense for it to be the other way around since there is only 2 connections and 190 having 8.

You will have to track down what the draw is, I would still suggest replacing that 15k with a new 1w one, then follow the 190v line to every place it goes, it has to be something, if it's feeding a resistor that's shorted on the other end, then that will be getting warm. As mentioned, 18k is a tad bit high, you have nothing to lose by replacing it with a same value 15k 1w resistor, it will just be more durable.

I have a 15k 1 watt wire wound I could put in but I know that won’t fix it I will have to trace down all 8 locations that feed 190v.

Chances are the problematic end also has a resistor on it's side and is getting warm as well, an IR camera would be handy for this such thing.

For a number of years as a teenager, I worked on TVs without an oscilloscope. When I finally got one, I couldn't imagine working on TVs without one. Even a cheap one with low bandwidth would make it a lot easier for you to troubleshoot this set. An oscilloscope will tell you whether an oscillator is running and if the waveform is correct. You just can't do that with a DVM. You should be able to find something on eBay. I got my last one from eBay and it was a high end Tektronix for a very good price.

If my house were to catch fire, the Tektronix oscilloscope is the first piece of gear I would remove. 'Nuff said.

Well there are several 2 and 3 watt resistors that normally get hot and up until now I had all tubes out and still a draw and the 275v is around 250v so if one goes down all are going to be low as well. So at this point I’m still thinking it may be a ceramic cap that may have been a problem and now is possibly shorted. How to find I don’t know it means turning this chassis into spaghetti with all clipping and checking and resoldering. Omg what a headache.

Running raw w/o tubes is not recommended, UNLESS you limit input voltage with a variac.

Reason is, the power supply is non regulated, and dependent on load, the tubes in the set ARE that load, w/o the tubes in the set, the voltage generated can exceed the ratings of the filter electrolytic capacitors and damage them (internal shorts), when you run w/o tubes one must be very careful not to let the bias voltage spike above the rate the capacitors can tolerate, or it can be really bad.

I only tried it for a moment and was watching voltage either way it’s still a disaster.I don’t want it to run to long and stress the fuse wire and or the power transformer or anything else for that matter.just prior to the voltage drop off I think the flyback was buzzing I know they don’t do that but the buzz was from the flyback area.

Here is how I see this set working ( my take on it ), you have the thermistor R211, cold at 26.5 ohms, as it heats up. It gets lower, they put this in as a protect timer to keep the bias low as the tubes warmed up as not to shock the caps with overvoltage until the heaters were warm enough to load the circuit down enough.
Without tubes in the set, this feature is defeated, and the bias out of X2 at C1 can easily reach over 400v or more and may have damaged the new electrolytic capacitors you have put on there, of course there is no way to know for sure if this is what has happened, but it is possible.

I have been thinking the same thing about the caps not being able to handle ripple. But without the tubes I only did it for around 10 seconds and I did watch the voltage.

As for the caps if one it shorting then it could effect the b+ network since they all go to ground except for one section but I’ll be checking them.

Changed the caps still 190v pulling down I didn’t change the 2 250 160 uf being the initial voltage is little over 400v but slowly drops because of the 190v dropping. Still the dark.

Put in the 1w wire wound 15k resistor you have for R215, then check on the other end for warm resistors that they are giving power to.

And, if you have not done so at this point, replace disc capacitor C61, that is the only one that is NOT going through a resistor on the farther side of the 190v line, all others have current limiter/ voltage drop resistors that should be warming up with power pushed through them.

This again can be related to V6 cathode or even the socket, as it is the only tube that has a direct connection to 190v w/o going through resistors.

The whole point of putting in the new larger watt R215, is so it will heat up less, and hopefully make the problematic heat more and easier to find, it's bad anyway at 18k.

Yes I already changed the 15k and it to gets warm and c61 I took one leg off and tried it still pulling down and the cap tests good unless the problem is somewhere else and it’s affecting v6 red plating. V6 out still have the draw down.

More then likely this is the whole problem this set has with the oscillator and video and sound it seems maybe the problem started out small and finally shorted out to whatever or wherever it is I can’t check resistors anymore because they are all good so it don’t leave much else but possibly a disc cap.

You still have no HV, and therefore no boost, so it's a bit odd for it to be red-plating, as there should be no bias on pin 8.

Try voltage check on each pin of V6, with tube in and out, monitoring voltage as the set is turned on.

Ok there was a resistor pin 7 of 6cg7 to pin 1 of v6 which is the 190v source the resistor is a 560k it checked.800k so I changed it and I felt it and was warm so I disconnected one leg and the hv came back and it’s stable at -45 so if I put the resistor back the voltage pulls down so there maybe a problem at v10.I’m thinking the 56pf cap may be shorted since it’s tied directly to ground and the 56k resistor is 61k.

R93? OK , getting someplace, power has to be going somewhere, leaking out C66 or C65 , or even R94? C66 prob.

if bad, it must be replaced with another N750 class or better type.
https://www.tedss.com/LearnMore/Ceramic-Disc-Capacitors

or else it wont be stable.

R93 is the 560k after I changed r94 is a 56k it measures 61k so what’s left but the 56pf cap. .022 is new I double checked that one.

Well if you have a NPO one, that would be even better then N750 class.

More trouble I clipped one end of the 56pf and pulled one side of the .022 still shorts with the resistor connected but good with it off. This is nuts I thought the cap was it.

there is only 2 places for the power to be going then, R94 (internally bad ) or V10 has a short grid to cathode. this will be evident by the wrong voltage on pin 7.

Ok I’ll look into that r94 that’s a 56k that measured 61k v10 I tried a new one befor ever removing that resistor and it made no difference. Would the vertical hold pot being disconnected have any impact on this.

So actually the 190 is feeding the 560k resistor to v10 where it’s being pulled from that point when it’s attached to v10.

yes, R93 R94 is supply power to the grid of V10 A pin 7

How far is the voltage dropping?

jr

From 190v to 40v

Since it is unlikely that the small current through the 560k resistor, even if it was shorted to ground (only 0.34 ma for 190 volts), would load down the 190 volt supply, the real load appears to be that V10 gets turned on hard when the 560k resistor is connected, and it’s increased plate current is loading down the weak 190 volt supply. :scratch2:

jr

I’ll clip that resistor and check it again but it can’t be a short grid to cathode since the short is still there with the tube out.

When v10 is out short still there.

None of this makes any sense here, given on the info provided.

You are saying this.
If R93 is disconnected, 190v is no longer loaded, and you get HV, but it's not C66 or V10 cause you tried it w/o them in the line.

Odd.

Things to try.
Disconnect R93 from the 190v line and hook a 620k 1w resistor from the 190v line to gnd ( aprox R93 +R94).
If it's able to keep 190v up and get hv, then the resistors in the set may be bad, even if the meter says good.

Or C65 is leaking, the 190v line does not have the power for the plate on pin 8 of the 6hs8 if C65 is leaking and trying to power it.

Also this could be a combo of things.
What is the voltage in/out and across R215.


Here are all points 190v feeds.

1- V6 cathode p1 C61
2- V6 g3 p9 R90,R89
3- V10 g1 p7 R93,R94
4- V12 g2 p3 R124
5- V21 plate p1 / cathode p7 R168
6- pullup R160
7- V21 g1 p2 r169 r170
8- pullup r149