HP 54111D dim display

Forget all about rejuvinating. That CRT is not likely to respond like a TV CRT.

I couldn't get a real print on it but most of these things have a DC filame nt supply which is rectified off the flyback. Note that they are turned and the fast sweep is vertical and the slow sweep is horizontal. Just imagine the two deflection circuits swapped.

As such, off the flyback (VERTICAL OUTPUT) there should be a winding for th e filament supply. There may be a filter going dry.

If the supply is alright, there is the place you put a tertiary coil in ser ies with the winding to boost the voltage.

As far as what the voltages actually are, if the geometry is correct, the v oltages are probably correct.

Rejuvination is a last resort on something like this. Even if you can get a CRT for it, the alignment is hairy and scary.

I couldn't get a real print on it but most of these things have a DC filament supply which is rectified off the flyback. Note that they are turned and the fast sweep is vertical and the slow sweep is horizontal. Just imagine the two deflection circuits swapped.

As such, off the flyback (VERTICAL OUTPUT) there should be a winding for the filament supply. There may be a filter going dry.

If the supply is alright, there is the place you put a tertiary coil in series with the winding to boost the voltage.

As far as what the voltages actually are, if the geometry is correct, the voltages are probably correct.

Rejuvination is a last resort on something like this. Even if you can get a CRT for it, the alignment is hairy and scary.

It is a color raster scanned display. OP should read up on the color display adjustments and go through the procedure. If that does not work, a new tube would be the next thing. There might even be a LCD upgrade available for less than a new tube.

We still do not know what the power supply is doing.

I bet a simple adjustment of the screens on the CRT would get some more years out of it.

How could you read my post and not realize that I know that ?

adjustments and go through the procedure."

Why ? To f*ck it up ? When you have a fault the LAST thing you do is adjust . He should CHECK the geometry. In a raster scanned display the geometry is dependent on proper voltage supplies. If the geometry is right, the voltag es are right, no matter what the print says.

would be the next thing."

Sure, Keysight has them on the shelf right between the hen's teeth and the philosopher's stones.

less than a new tube. "

What planet are you from ? Are you saying that they would engineer a Tcon b oard and backlight assembly for an old obsolete piece of equipment they no longer support ? You'll get that right after world peace.

If the geometry is right, it is doing what it has to do.

years out of it. "

Know much about CRTs ? Sure turning up the G2, which will be common to all three guns is likely to get a more usable brightness level. However, this t ype of video drive might start (or accelerate) the cathode stripping proces s.

The best bet is to increase the filament supply. Usually 10 - 20 % will do it, and it usually will last. Rejuvination might cause a G1-K short.

It can be run that way but with the likely bandwidth the circuit will have to be modified to overpeak the video output. I have done this a few times. First the G1 is tied to the K through a resistor, high enough not to cause damage due to the filament voltage but low enough that it is coupled to the cathode which stabilizes the frequency response. Then a proper location in the circuit for a peaking cap must be chosen, and of course its value. For this I would need a real print, not one of those enhanced block diagrams w hich seems to be the only thing I can get.

With a real print I can give more details on what to do. I am very experien ced at extending the life of color CRTs, did it for decades. But this overp eaking stuff only applies if there is a short in the CRT. Most of the time it just works.

HAHA, an LCD refit for a color CRT. Thanks for the laugh.

The emgineering cost would exceed the value of the whole unit. That is befo re one such modification is produced. What's more, if it is a Trinitron it is a bit easier because it has a cylindrical curvature on the screen. A cur ved LCD screen is expensive, even if it is only curved on one axis.

Yup, be sure to let us know when you got that space/time continuum thing be at. I think ole' Bert Einstein was holding out on us.

Top posting just so you don't need to read through all the BS again.

There is so much wrong with what you posted that it would take forever just to tell you.

Here, check out this supplier of LCD displays that replace CRT tubes in raster scanned displays used in HP and Tek instruments.

I just replaced the CRT in a HP70004A MMU unit - cost $400 .

Stop being such an asshole.

How could you read my post and not realize that I know that ?

adjustments and go through the procedure."

Why ? To f*ck it up ? When you have a fault the LAST thing you do is adjust. He should CHECK the geometry. In a raster scanned display the geometry is dependent on proper voltage supplies. If the geometry is right, the voltages are right, no matter what the print says.

would be the next thing."

Sure, Keysight has them on the shelf right between the hen's teeth and the philosopher's stones.

less than a new tube. "

What planet are you from ? Are you saying that they would engineer a Tcon board and backlight assembly for an old obsolete piece of equipment they no longer support ? You'll get that right after world peace.

If the geometry is right, it is doing what it has to do.

years out of it. "

Know much about CRTs ? Sure turning up the G2, which will be common to all three guns is likely to get a more usable brightness level. However, this type of video drive might start (or accelerate) the cathode stripping process.

The best bet is to increase the filament supply. Usually 10 - 20 % will do it, and it usually will last. Rejuvination might cause a G1-K short.

It can be run that way but with the likely bandwidth the circuit will have to be modified to overpeak the video output. I have done this a few times. First the G1 is tied to the K through a resistor, high enough not to cause damage due to the filament voltage but low enough that it is coupled to the cathode which stabilizes the frequency response. Then a proper location in the circuit for a peaking cap must be chosen, and of course its value. For this I would need a real print, not one of those enhanced block diagrams which seems to be the only thing I can get.

With a real print I can give more details on what to do. I am very experienced at extending the life of color CRTs, did it for decades. But this overpeaking stuff only applies if there is a short in the CRT. Most of the time it just works.

HAHA, an LCD refit for a color CRT. Thanks for the laugh.

The emgineering cost would exceed the value of the whole unit. That is before one such modification is produced. What's more, if it is a Trinitron it is a bit easier because it has a cylindrical curvature on the screen. A curved LCD screen is expensive, even if it is only curved on one axis.

Yup, be sure to let us know when you got that space/time continuum thing beat. I think ole' Bert Einstein was holding out on us.

Jurb6006

Like the fable about the fox and the scorpion. "It is my nature."

I killed my dim 12" CRT with a B&K Model 440

I hear so many people killed their tubes. I wonder why, boosting heater voltage never caused me to lose one. And I pushed it all the way to 66% on occasion, and 33% routinely. I mean permanent boost.

NT

Failure to RTFM. Rather that boost the filament voltage I hit the G1-K button. It boosted it a bit so I hit a couple more times. The third time killed it.

raster scanned displays used in HP and Tek instruments. "

I'll stand corrected on that. I never thought anyone would put the money into such a unit. However what I said about the CRTs stands.

I am surprised the cost is so low. And congrats on getting that job done. Sounds like loads of fun.

to tell you. "

I did everything I said I did.

Born that way but sometimes it comes out that way. Though your knowledge of CRTs might not be top echelon, I did not mean to demean your skills. And CRTs are obsolete.

So, this asshole has useless knowledge.

My point is why are you doing that in the first place? Why use a method that either kills or damages the tube and only has short term benefit anyway?

NT

Did you not read what I said?

I didn't know any better. Never done one before.