silvertone roundie - Page 7 - Videokarma.org TV - Video

timmy · #91 10-28-2012, 08:32 AM

ok the hv sweep set up did nothing so now i took voltaqes off the video output tube pin7 is to be 230 v but i only get 152 v pin 8 140 v but i get 133 v and pins 3-9 is supposed to be 5v but im getting -0v so i am really lost here and i did try another video out tube. i also check the 6fq7 horiz oscillator tube voltages, pin 1 is 20v right on, pin 2 -.1v i get -.238 v and pin 6 245v i get 248v.

ctc17 · #92 10-28-2012, 09:31 AM

What is pin one of the video out tube? Does adjusting the contrast change these numbers?
Are you using no signal?

The brightness and contrast control will move those voltage a bit.
Maybe C3 is shorted, leaky or in backwards?
Maybe theres something up with C40 and the blanking isnt working right? or the resistors in that area....

Im sure you replaced C3 (250uf) just because its new doesnt mean its good.

timmy · #93 10-28-2012, 05:44 PM

well i really think im just going to leave this set alone because im making myself crazy and others. everything i looked at did not seem all bad and the crt thankfully is ok unless there could be gas in it and not show with a glow of any kind. its amazing it has a great picture my only problem with it is that a white pic is not so white, white scenes has kind of a reddish tint to it and at the same time the white shows the hv drops. so if this is all that bothers me then maybe ill live with it. small white scenes are fine just the ones that take almost the whole screen has the reddish tint and no matter what i adjust it is what it will be because the hv cant keep up or there just is not enough for whatever reason. i tried again today 24kv at crt 6bk4 cap off then with cap off i pulled the crt plug off and i get what looks to me is 32kv. why the crt plug in it wont go over 24kv this is the question. i did change c3 and im sure if it were backwards it would have vented or other things may be worse off then they are. again if the crt bias is raised even alittle bit then the screen should not bloom the way it does. so this to me is a weird mystery that maybe ill solve one day.

ctc17 · #94 10-28-2012, 06:10 PM

Look at where that cap is in the circuit, it goes from the contrast wiper to ground. If it was shorted it would cause biasing issues with the video out.

Yea take a break, you can come back to it later and will be freshend up. If I spend too much time on one tv my eyes start to blur out then I know its time for a few days off.

timmy · #95 10-28-2012, 06:23 PM

Quote:

Originally Posted by ctc17

Look at where that cap is in the circuit, it goes from the contrast wiper to ground. If it was shorted it would cause biasing issues with the video out.

Yea take a break, you can come back to it later and will be freshend up. If I spend too much time on one tv my eyes start to blur out then I know its time for a few days off.

well if that cap were shorted then the contrast control would not work or work well? because it works very good.

ctc17 · #96 10-28-2012, 07:14 PM

Quote:

Originally Posted by timmy

well if that cap were shorted then the contrast control would not work or work well? because it works very good.

If it was shorted it would work very well but it would shift the dc bias on the tube. Why not just check it?

timmy · #97 10-28-2012, 07:23 PM

is this cap right at the contrast control? a disc? ok that cap is electrolytic and its under the chassis. sorry for the brain fart it must be the storm coming.....

timmy · #98 10-28-2012, 07:48 PM

im looking at the schematic and that cap was a problem c3d says 250uf @50v but the can said 50uf@50v and c3c says100uf but it was 20uf on the can so sams was mistaken as always there were alot of mistakes. so i put in what was on the cans.

ctc17 · #99 10-28-2012, 08:34 PM

I hope you got your **** in order, everyone in that area, I know bryan and you, maybe a few others. Yall were lucky enough to get warning and get what you need.
I have never had to deal with something like this where you have warning. We have earthquakes that for the most part hit without warning, and we are due.

Ok, forget all that, cnn is on and the propaganda is melting my brain.

The values of that really dont make a big deal. You said the plate voltage was low and that would indicate a bias issue.

timmy · #**100** 10-29-2012, 06:50 AM

well dan how about i do this, what if i take the wire off the wiper pin of the contrast contol and check the cap that way ? this way i wont have to remove the chassis.

Penthode · #**101** 10-31-2012, 10:56 PM

Hey, I have been following this thread and one thing seems to jump out at me. If the HV regulation is bad under load, what is the shape of the HV rectifier? Have you changed it? Is the filament lighting properly?

From what I have gathered on the thread, a big clue is the 32kv when the CRT is disconnected and the regulator cap removed. Putting on the regulator cap brings it down to 24kv with minimal loading by the regulator itself.

It is looking to me simply that the HV rectifier itself or associated circuitry (filament dropper resistor) is bad. But I think the key is the rectifier: if you have swapped it I'd try swapping again!

timmy · #**102** 11-01-2012, 06:44 AM

Quote:

Originally Posted by Penthode

Hey, I have been following this thread and one thing seems to jump out at me. If the HV regulation is bad under load, what is the shape of the HV rectifier? Have you changed it? Is the filament lighting properly?

From what I have gathered on the thread, a big clue is the 32kv when the CRT is disconnected and the regulator cap removed. Putting on the regulator cap brings it down to 24kv with minimal loading by the regulator itself.

It is looking to me simply that the HV rectifier itself or associated circuitry (filament dropper resistor) is bad. But I think the key is the rectifier: if you have swapped it I'd try swapping again!

i have tried several rectifier tubes including a solid state tube. the filiment does light so its no that and there is no filiment resistor.

ctc17 · #**103** 11-01-2012, 09:46 AM

Sense he's able to get 1.5ma at the shunt cathode that rules out a HV issue. Something is overloading it. Gassy crt or bias issue

Penthode · #**104** 11-01-2012, 10:32 AM

1.5ma?

If that is true, I agree it's a gassy crt or a bias issue.

timmy · #**105** 11-01-2012, 10:44 AM

how about the hot voltages which were 140v was right on but the other is -55.9V but the sams shows -50v so i really dont know if this could mean a bias issue. and with the set playing i get no color glows in the neck nor do i get anything with the crt tester in the cutoff mode as far as a blue glow, so im really lost and out there at this point.