Ts18 verticle problem

[jr_tech]

Have you tried a different 6SL7? Possibly this one has grid emission.

Could there be a carbon path in the tube socket between pins 5 and 4 that is pulling the grid more positive than it should be?

You really need to get better voltage measurements... can you get another HV probe or fix the one you have?

jr

[timmy]

Originally Posted by jr_tech

Have you tried a different 6SL7? Possibly this one has grid emission.

Could there be a carbon path in the tube socket between pins 5 and 4 that is pulling the grid more positive than it should be?

You really need to get better voltage measurements... can you get another HV probe or fix the one you have?

jr

I tried several 6sl7 no change as for my hv probe tossed it last year could not fix it. Carbon path , well anything is possible but I need to find out how to know if there is a carbon path taking place befor I get into changing that socket. Do you have an idea how to determine if there is a carbon path. I don't here anything arcing nor do I smell any corona from hv. Pin 5 SAMs shows 320 Vdc and I find odd that the 6.8 meg at pin 5 gets warm but the other 6.8 don't.

[jr_tech]

I would unsolder all of the connections to either pin 4 or pin 5 and mesure resistance between the two pins... leakage as high as 10 meg or so could mess up the bias on the tube.
You really need to get another HV probe, as low HV could be te main source of the problem.

jr

[timmy]

Originally Posted by jr_tech

I would unsolder all of the connections to either pin 4 or pin 5 and mesure resistance between the two pins... leakage as high as 10 meg or so could mess up the bias on the tube.
You really need to get another HV probe, as low HV could be te main source of the problem.

jr

I thought maybe low hv but the crt is super bright and I tried adjusting the ring on the 1b3 and of course no change. Should the tube remain in the socket when I remove from one pin and test?

[jr_tech]

The tube shouldn't make any difference, unless it is the cause of leakage... try it both ways. You could also check the tube itself for any leakage between pins, but since you have tried several different tubes without changing the symptoms, it is unlikely that you will find any leakage unless they all have the same fault.

jr

[EdKozk2]

Timmy,
Did you ever try spraying any cleaner into the vertical hold and size control to see if it would stabilize the vertical roll? Did you try wiggling V9, V11, or V12 while the set is on to see if it helped? I come across worn and dirty contacts all the time in old equipment. The cause of all sorts of issues. Just because parts are swapped or tested doesn't always eliminate the root cause.
Do you understand how the vertical feedback loop works with this set? If you have a scope, check to see if you are getting the proper trigger signal to your vertical oscillator grid from the sync separator/ integrator network.
Ed

[timmy]

Originally Posted by EdKozk2

Timmy,
Did you ever try spraying any cleaner into the vertical hold and size control to see if it would stabilize the vertical roll? Did you try wiggling V9, V11, or V12 while the set is on to see if it helped? I come across worn and dirty contacts all the time in old equipment. The cause of all sorts of issues. Just because parts are swapped or tested doesn't always eliminate the root cause.
Do you understand how the vertical feedback loop works with this set? If you have a scope, check to see if you are getting the proper trigger signal to your vertical oscillator grid from the sync separator/ integrator network.
Ed

I did spray the verticle pots in the beginning thinking it would help but it didn't and yes I moved v9 ,11 , and 12 , nothing helped and I don't have a scope I'm an auto tech, lol so I wouldn't have that for a tv but I have 4 other of these sets I have done and never came across something like this I mean these sets are kind of simple but this problem is kicking my ass. I replaced every mica in the vert and horiz along with all the wax caps were done. After the wax caps fired up and the vert went down hill fast and since then I did the Micas one at a time to hoping to find the one culprit but after replacing all I'm still left with this problem. I checked to see if any carbon shorts in the 6sl7 socket and none showed up. And all the 6 kv caps new also. Just don't get what's going on I am out of areas to check. In the beginning it seemed like a resistor went up fast but I only found one 2.2 meg that went up to 22 meg so I changed it and the 2- 6.8 meg resistors at the 6sl7 measure around 7.5 meg not all that high since I think my other sets were around there to but they work . And thinking one was breaking down in circuit I subbed them and still make no difference. I also subbed the vert size and hold pots no change. And also moved v10 the oscillator no change.