"Brightening" a dim tube

[SirPeale]

I've got a 25" K7000 with a very dim picture.  After capping it didn't help, I swapped chassis with a known good one and found the same result.

I'm all up for adding another winding to the flyback and connecting it to the neckboard, but here's my question: do I have to isolate it altogether, like you would with a short, or can I leave it as-is and add the winding with a piece of wire around the core of the flyback?

[Ken Layton]

Put it on a rejuvenator.

[grantspain]

when i was a trainee there was a monitor chap who used to do something with a resistor on the neck card,i guess it was on heater voltage circuit-never tried it myself but i remember it working

[SirPeale]

Put it on a rejuvenator.

Ken: although I do have a rejuvenator, I am not sure of it's operational status and I do not have a CR23 adapter for it.  It's the one that the chap from the Canadian Op forum was giving away.  When I received it it was bouncing around in a box with no packing material around it.  Though I can easily make a CR23 adapter for it, I'm loathe to hook up a tube that might fry easily.

And the nearest person to me that I know has a rejuvenator lives two hours away.

[SirPeale]

when i was a trainee there was a monitor chap who used to do something with a resistor on the neck card,i guess it was on heater voltage circuit-never tried it myself but i remember it working

Aha, that's an interesting idea...temporarily short out the resistor so the heater voltage is on full.

[grantspain]

when i was a trainee there was a monitor chap who used to do something with a resistor on the neck card,i guess it was on heater voltage circuit-never tried it myself but i remember it working

Aha, that's an interesting idea...temporarily short out the resistor so the heater voltage is on full.

the chap was pretty crazy,he used to talk to the monitors when he fixed them but he was the best monitor tech i have ever seen-and i remember this trick he used,he said it was an old trick they used in 70's on tv's in peoples houses
he was very crazy though

[SirPeale]

Sometimes the craziest people make the best techs. 

That's the only thing I can think of that he could have done with the heater, shorting the resistor so it heats up for a moment.

[ChadTower]

That's nuts.

I say test the rejuvinator on an old TV.  I had to recap mine when I got it - the big cap that it discharges into the tube was dried up.  I might be even more than two hours away but you're welcome to use mine if you want.

[SirPeale]

I don't have an old TV that I'd use it on, and if I did I'd want to use the tube for a swap.

[Rickn]

Yes shorting out the heater resistor will narrow it down to the tube being week and needing to be rejuvenated. The rejuvenating process hits the cathodes with a high votage RF. It 'cleans the cathodes" so to speak.

Shorting the heater resistor long term is a bad idea, expect the tube to go completely with in a reasonably short time period, may be as a long as 9~12 months. I guess if you are willing to have a better picture for that time frame, go nuts.

Good luck

Rick

[Kevin Mullins]

I've rejuved many a K7000 tubes of a few different brands. Always made a big difference.
Even doing a simple short test on the color guns that don't show as being shorted, "remove the short" anyways...... wow, what a difference.

[SirPeale]

I have a replacement tube from a TV I just found on the curb, so that's always a candidate.  I've had this TV for over a year for a client and I want it gone.  I know the tube is going south, and since this is going in a shooter the screen needs to be bright.

[ChadTower]

I don't have an old TV that I'd use it on, and if I did I'd want to use the tube for a swap.

Are you actually saying you don't know how to find an old unwanted TV?   

[SirPeale]

I don't have an old TV that I'd use it on, and if I did I'd want to use the tube for a swap.

Are you actually saying you don't know how to find an old unwanted TV?   

Lately they've been as rare as hens teeth, and like I said, if I found a TV I would not sacrifice the tube in it!

So I hooked the monitor up, and shorted the resistor...and nothing.  It didn't get any brighter.  Curious, I metered the heater voltage.  IIRC it should be somewhere around 6.3VDC, correct?  I was reading just over a volt.   Bad flyback?

[SirPeale]

Oh, my original question hasn't been answered: can I wire it up as-is, or so I have to cut the traces anyway?

[Ummon]

the chap was pretty crazy,he used to talk to the monitors when he fixed them...

I've always talked to, or at, my stuff. Conversely, I never address things as or consider them by some genderal identity. They are things.

[ChadTower]

Lately they've been as rare as hens teeth, and like I said, if I found a TV I would not sacrifice the tube in it!

That's just weird.  Around here you see 5 a week on Freecycle of all sizes, working.  You see them on the side of the road.  Every recycling depot is overrun with them.  CL free ads for TVs are everywhere.  Everybody is looking for a way around the $10 recycling fee.

[SirPeale]

They don't let you take them from the recycling depots anymore. 

[ChadTower]

They don't let you take them from the recycling depots anymore. 

Maybe find a smaller one?  Ours is run by one cranky old fart who sits in a shed by the gate.  If he likes you you can take stuff as long as you don't make a mess.  If he doesn't like you good luck even dropping leaves off on the compost pile.