i think i tried another blanker tube with no change and there is no resistor on the hv rec socket. the crt plug off only comes up alittle bit.:smoke:

Well changing the resistors from 1.5 to 1.0 would not do much.... I figured if they
were off, like the one you said was 1.5 and the other 1.6 and the pot .5 meg, then
it may have changed the range of HV if it shifted the bias on the grid of HV Reg.

So, with no plug on end of crt, hv changes by how much...?

And no HV lead attached to tube HV goes to how much...?

Can you make both of those readings again with no other work done in between...?

And one more.... HV connected, Plug on tube.... Brightness at cutoff - Dark Screen..... What id HV.....?

Make each of these tests with the HV adjusted to MAX.....

And write out each reading, and condition for the reading....
Acceptable answers are not "same as before" and or "they are good".
We need the condition, and the value - please.


And the cap between the grid and cathode of HV reg, you replaced that one....?

Anyone got an objection to running the set without that cap for a test...?
Just in case it's not working at that high voltage....

As a matter of fact, you should make these tests on both your sets with the same
chassis, or allow someone with the same set chassis to do them and have an
ongoing comparison..... And for each of these tests, please also record
the B+ Boost..... I think it's 390V.....


.

hv without the crt is 19kv adjustable by the pot but 19 at max. hv with crt 22kv adjustable by pot at max. the cap you are talking about is the 033 i think and was changed a few times with new ones. at the cap that is the place for the jumper for the hv current and with that jumper section open with no meter in between the hv will not adjust by the pot and it goes over 30kv. brightness down dark screen the hv is between 22-23kv hv pot maxed brightness up the hv drops more so depending on whats on the screen. the b+ is in place it is good that was the first thing i ever did check and i find myself still checking it, lol,lol...

And what are the voltages at pin 1 and pin 5 of the 6BK4 Shunt when the HV adjust
is at min, and max....?

.

6bk4 reg tube pin 1 402 volts and pin 5 390 volts but i dont remember if the bright was down when i had checked it as i hope this helps.hv current dark screen hv pot low 1.64 pot high 0.93 bright up pot low 1.16 pot high 0.20

If you mean .93ma with a dark screen and HV set to max, that's your problem. Most of the Sams I've read for roundies specify .8ma with a dark screen, HV set to whatever the schematic calls for. If you're pulling any more than that, chances are you're getting close to melting the 6BK4 as you're likely exceeding it's dissipation. You see HV schematic information has more to to with the regulator tube than it does the chassis.

For example, the 6BK4B (which is what most will have in their chassis) is rated at 40 maximum plate watts. Taking into account a 20% tolerance, this tube can be expected to dissipate somewhere around 32 watts continuously. Typically it comes to around 25 watts though, RCA designed the shunt circuit conservatively to maximize the shunt tube's life.

So for your example with a dark screen and the HV pot at 'low' and drawing 1.64ma (assuming a 23kv anode), that comes to 37.7 watts- easily above what RCA would have designed it to do, and dangerously close to the tube's maximum dissipation. I strongly suspect that if you look at the tube's structure under those conditions with a darkened room, you'll see the plate glowing which can be seen reflected off the bottom part of its structure (the part containing the grid and cathode, it's usually shiny so you can see stuff in it).

For the other example: .93ma@23kv=21 watts which is much better but again, outside what I would consider normal for a shunt tube which should be closer to .8ma. Obviously whenever you have something on screen, shunt current should drop as the CRT beam current picks up where the regulator left off. You should check to make sure the shunt tube's cathode current drops as brightness increases, if not the regulator circuit is suspect. Also take a look at your B+boost voltages, as that's where your regulator is taking its reference voltage from. If B+boost is jacked, so will regulator cathode current as the grid receives it's marching orders from whatever B+boost is doing.

Yah, miniman hit it with what I was looking for, the bias in the tube is pretty high....
I was going to ask about those current readings, are they ma. and how accurate
do you think your meter is...?
Also that voltage I asked about B+ Boost, you did not post a number...?
You need to measure these things today, not look up your old posts, we need
to clarify exactly what is happening.... Your B+ Boost could be too high, this could
be why the voltages at the reg. are higher than the schematic says they should be...

.

dark screen brightness down hv pot set to min, ma is 1.64 hv pot max , 0.93 brightness up hv pot set to min 1.16 hv pot set to max 0.20 and the dvom i use i do trust it i did compare with another meter to be certain. the 6bk4 dont even get all that hot to the point of melting, no where near. i cannot get 23kv even to stay for a moment. i will have to check the exact b+ voltage under a load, where would the best place be to take this reading at this point ? and yes this is milli amps. the sams show the voltages and they are not far off it seems to me unless 5-10 volts would make a world of difference, i dont know.

The current seems high as miniman explained. And since the reg is working off b+boost
we will have to figure it out... We're trying with the clues we have.... I got one
of the rca schematics off the internet, it says 390v and 376v to grid of 6bk4, you
have 402, and 390V grid I believe.... So lets look at your B+ voltages.....
Check them right off the caps in the PS.... 405V-c125 160mfd.,
386V - c120A 80mfd, and I think the last was 276V c-120b 50mfd.

Does your schematic have a total current for the HV output...?
as in picture tube plus HV reg....? and an acceptable way to
determine total....? As per sams.... to be accurate...



.

Sure would be easier to follow this thread if there were some daggone punctuation... :smoke:


From what I gather, the regulator seems to be working as it should. You said you put a new fly in it? You probably wired it wrong, there's no reason for HV to be drooping like this.

omg this set

:smoke: yes it is a new flyback and this set always had a hv issue but i thought i had found the problem when i changed the fly i discovered the 1v2 was wired wrong and since correcting that the focus voltage and the overall focus had much improved. i found the mistake and corrected it and checked other areas for other mistakes and having the sams i was able to check areas and fix the wiring mistake. i also double checked all the work i had done by the sams and found none.

Yes, he said new fly, and he rewired the focus circuit because something was wrong...
I thought something may be wired wrong too, that is why I asked the questions
about Horiz. Centering, and focus the other day... I figure if they work, and have
some reasonable range, then maybe there is no mistake...... In one of the
earlier threads I also asked about the new fly, and if all the contact points
were correct, or if there were mods on any install note sheet....

It would be cool if someone with recent experience on this chassis takes the point....

That reg. circuit is too simple to be causing all this trouble....

.

well there were no mods or special notes in this set. the hv reg does look simple but i have this set for 2 years plus and was never able to find whats going on with it . so i might just as well try the crt from my other set because of the mark on the inside of the glass on the crt thats in the set now was not there when i first got it but over a small amount of time this set has on it since i have the mark appeared so maybe the interior dag somehow is damaged and causing all of this i dont know but ill have to rule it out once and for all.

Can you post a picture.....? I'm gunna say I don't think you have any inside tube
coating problem.... You would have arcing, or some other problems.... Just not sure....

.

my computer that has the pic of the mark on the inside of the crt i cant use it at this moment but it is here on karma under 21fbp22 crt there is a good pic of it. let me know if you cant find it.

the pic of the crt is on page 6 under gassy 21fbp22

I remember it now..... I'm not concerned about it.... Don't think it's a problem...

.

well i dont know at this point, but i do really appreciate the help from all the members here and i do try but at the same time i was never a tv tech and i really im sorry for driving everyone here crazy with this nutty silvertone.

Well, since you got this set with HV problems, and found some wiring mistakes in the
focus area, you should take a few steps to ensure that no problems were introduced
be work done by someone else..... I think you should get, or borrow a good camera,
take pictures of the flyback, the wiring, and under the chassis, post good clear picts, and
some the focus wiring you found and repaired.... There are people here who have
recently worked on and own several of them.....

You might also find that if both of your sets are identical, as far as the chassis goes,
that visual comparison might be a very good idea.... I'm confident the problem can
be found, there are lots of people here who know this chassis inside out....

By the way, which Silvertone is this one.... 63, or 65...? And are they the same.....


.

I am curious about a few things.
1. where and how are you measuring the regulator current?
2 what is the actual B+Boost voltage? Should be ~1000 - 1200volts if I recall correctly.
3. Have you checked the screen grid resistors in the Horizontal output tube. I think there is a 47 ohm and 13K ohm that if they drift high at voltage cause low High voltage.
One thing that bothers me is that all the controls seem to have to be at one end of their range. This indicates a voltage problem in the B+ or Boost voltage. Possibly not enough drive from the horizontal output stage.
4. Have you checked for leaky caps in the horizontal yoke windings?
The 1.5 meg resistors in the regulator circuit are a matched pair. I would not change them to different values. Since they are 20% they are not out of spec. The key is they should be the same value. Yours are about 7% high, but they are very close to the same value.

Enter ye the 10th circle of hell,

Timmy CTC-12 clone HV regulation.

Sams can have mistakes, bounce the schematic against an RCA one?

the silvertone is the pic you see on this page its a 1963. the other ones i have are 65 silvertone and it has a different focus circuit. and besides i have went over this set with the sams hoping to find a mistake by another tech but have yet to find anything other then the focus circuit. and the other is 65 maggie which has a problem as well and that one has the 2v2 circuit. the only thing i can say is when i got the set i changed the focus coil because it had a burn mark so i assumed it was bad and after putting the new one in befor finding the focus miswire the focus was not good at all. so i took it out only to find that one part of the coil had opened so now i couldnt use it anymore and moyers sold me the last one. i then checked the ohms of the old coil and to my surprise up against the sams and it was good but i dont know what the history was to have burned the coil the way that it did but it was still good so i put it back in with a new resistor i think it was 100k because the old one was burned clear apart and its been in there since. even though the ohms check good im not sure if this may be a cause for the hv problem. one other thing i remember is in first getting the set going the horiz hold was all the way to one end so what i had done to correct that was tweeked the coil on the vert board and that fixed that and now it has range left and right to adjust if need be as befor it didnt. sorry for the edits but i did have arcing at the neck somewhere under the yoke when i first got it going but this may hjave been when i took off the reg tube cap to check hv at the time but never did arc again since.

i measured the hv current at the jumper location at the 033 cap and i used a fluke dvom and i do trust it works fine. i checked any and all resistors at the base of the hot and they are fine. the sams says the b+ voltages the highest is 400 and 390 volts and other lower ones right off the caps in the PS. the b+ is up because i would not be able to get the voltages at the crt that i get and they would be low but at around 700 volts at the crt seems the b+ is ok. the only thing i did not do is check or change caps in the yoke but i did write it down as something to check. i also had double checked my work with any resistors or caps that i had done which i had changed caps under the chassis only because of this problem and also unsoldered the caps and check them the simple way with a meter and they looked fine thinking maybe i got a bad one or 2. i have a new meter that checks, NF,MFD in caps and also frequency but dont know yet if it goes as high as 15,730.

Hey, Had a black-out for a few hours this morning... Someone took their pickup a few
quarts of alcohol and went out to get some wood........ Now we got 2 phone poles
on this street cut in half and hangin in the air....

Bill is right about the H-output tube screen voltages, I'm not sure but I think we went over it
before on another thread.... But you better check, the 47ohm, and 13K resistor off pin
4-8 of 6dq5 also suppose to be around 145V there....
My schematic don't have the number, but off the cathode of the damper tube somewhere
should be a test point for B+ Boost, and it should be around 1KV like bill said... Check your
Sams it may have a test point and a number.... 1Kv ~ 1200V ??

Also, since you said you are not a tech, I want to be sure you are aware B+, and B+ Boost
are two different things.... B+ Boost does not come off the power supply section of the tv, it
is part of the voltage from the horiz. output section of the tv..... Generated off the Damper
tube.... They may have a point where they show a test spot, and a Voltage number, so use their
test point....

Did you check or replace the caps on the yoke... C 105 ?? Good one to look at....

.

ok, the 2 resistors of the 6dq5 have been double checked and are ok. the b+ voltages and the boost voltages i know are from different places and i hope the sams shows a test point for the boost voltage. straight b+ i know comes first from the transformer to the diodes then to the caps. i do have alot of tv experence with the new garbage, smd and so on. i know this chassis dont have a boost diode so ill hope to find a test point at the damper for this boost voltage. i was looking at the rca schematic and c105 is one that is there and ill check that. i also know what the doubler caps do ,lol,lol so i do understand...:yes: and the screen voltage at the hot pins 4-8 142 volts and pins 1-5 -56

those 2 resistors are 100 ohm and a 47 ohm at the hot , i think i replaced the 100 ohm after getting the set and recapping as i went over this and found that resistor drifted very little and probably didnt even have to change it. just checked the sams it shows pin 2-7 385 volts pin 9 is the one with the hv and it says do not measure. im showing only a 720 v boost source but that dont tell it all.

This pic shows B+ Boost, where it's made, but not necessarily where
to measure it.....

And the screen grid resistors.

.

ok yes i have the same here but this sams is alittle different by the numbers your 3 is my 9 but same location. ok the 13k 7 watt i probably checked that one already but i will again. so now ill have to find out where to test this boost voltage because i believe i hit that spot already by accident and burned another fluke dvom out so i dont want to do that again.

NO - be careful, there are very high voltage spikes there ! !

.

my mistake there is no c105 in the yoke the sams i have dont show it nor does the rca schematic but shows it in the color board as a disc cap. the yoke appears to have c 123 caps

horz pos pot wired right, not open?

horiz pot new and wired, came with the fly.

I don't know for sure on your set, but on CTC-15 clones I have the boost supplies the high voltage side of the CRT screen/G2 potentiometers, and IIRC the vertical linearity control pot.

On my Silvertone CTC-15 clone there was an SS boost diode that was bad when I repaired my set. Your set may be the same or different so take this with a grain of salt.

i think my other silvertone has that diode but not this old 63 , boy for a freebie this set has been truly a thorn in my side for sure,lol..:tears:

does the focus voltage vary from about 4k to 5k, I use a simpson 260 to check.

Its easy to miss wire a focus coil.

in focus, the voltage is just befor 5kv and yes it will vary and i looked at the sams for the position of the taps to make sure i had it right. wired wrong may give all this headache.

it should very about 1kv
you have to becareful about those focus coils, often they are generic replacements with extra lugs or lugs that are in different orders. Generally you use the included instructions when replacing. they are variable transformers that vary both phase and amplitude adding or subtracting from the voltage going to the focus tube.

what was the problem with the orig FLY?

there was no problem with the old fly i had a new one and decided to change it thinking the fly was the problem with the hv, but it made no difference.