Fixed HP1741A in a big shape but... I bet in a focus problem, and you?

[SAUL BRITTO]

[Alex Eisenhut]

You are in storage mode, you might have some trapped charge. Turn down the beam intensity to 0 and press erase a few times. If that doesn't work, there is a deep erase button on the back, follow the procedure in the manual.

[SAUL BRITTO]

Thank you Alex Eisenhut. Actually this scope is still coming to me, this is a picture that the seller sent me.
I hope you are right.

[edpalmer42]

I have the 1744A - an enhanced version of the 1741A.  I didn't look it up, but I think the writing speed on mine is much faster.  I normally run with the Brightness control fully CCW, the intensity much lower than shown in the picture, and the focus at about 12:00.  With the Brightness control turned up, blooming like in the picture is guaranteed to happen.  You have to balance the Persistence, Brightness, and Intensity.  They all have to change as you change the Horizontal speed.  But when you get them right, it's glorious! 

[SAUL BRITTO]

I have the 1744A - an enhanced version of the 1741A.  I didn't look it up, but I think the writing speed on mine is much faster.  I normally run with the Brightness control fully CCW, the intensity much lower than shown in the picture, and the focus at about 12:00.  With the Brightness control turned up, blooming like in the picture is guaranteed to happen.  You have to balance the Persistence, Brightness, and Intensity.  They all have to change as you change the Horizontal speed.  But when you get them right, it's glorious! 

What  really does that deep erase? Of course I suppose, but I would like a  clarification if possible.

[SAUL BRITTO]

Deep erase on the manual looks like a dangerous process!!!

[coppice]

I have the 1744A - an enhanced version of the 1741A.

In what way was the 1744A enhanced? I remember it as cost reduced model with a limited display area.

[edpalmer42]

Deep erase on the manual looks like a dangerous process!!!

I don't know.  The 1744A doesn't have 'Deep Erase'.  The manual only talks about B-scan for erasing deeply stored images, but I've never used it.

Ed

[edpalmer42]

I have the 1744A - an enhanced version of the 1741A.

In what way was the 1744A enhanced? I remember it as cost reduced model with a limited display area.

Oh, so now you're going to force me to look it up!  Fine!  Be like that!           Just kidding!   

They're both 100 MHz, but the 1741A has a storage writing speed of > 100 cm/us.  The 1744A has a storage writing speed of > 1800 cm/us.

[SAUL BRITTO]

Look at this:

[SAUL BRITTO]

But,guys:  can't be a focus defect, anyway?

[edpalmer42]

But,guys: this can't be a focus deffect, anyway?

Yes, it could be defective.  Until you get it on your bench you won't know for sure.

[SAUL BRITTO]

But,guys: this can't be a focus deffect, anyway?

Yes, it could be defective.  Until you get it on your bench you won't know for sure.

I think will measure this voltage very well, I do have a high V RCA probe that measures 58kv,maybe this focus V is around 2kv?

[edpalmer42]

But,guys: this can't be a focus deffect, anyway?

Yes, it could be defective.  Until you get it on your bench you won't know for sure.

I think will measure this voltage very well, I do have a high V RCA probe that measures 58kv,maybe this focus V is around 2kv?

Okay Saul, I'm onto you now!  You're just looking for an excuse to take it apart and poke at it.  Haven't you learned yet?  We don't need an excuse!  We do it 'cause we want to!   

Just follow the procedure in the manual to measure the HV.  It tells you where, how, and what you should measure.

[SAUL BRITTO]

But,guys: this can't be a focus deffect, anyway?

Yes, it could be defective.  Until you get it on your bench you won't know for sure.

I think will measure this voltage very well, I do have a high V RCA probe that measures 58kv,maybe this focus V is around 2kv?

Okay Saul, I'm onto you now!  You're just looking for an excuse to take it apart and poke at it.  Haven't you learned yet?  We don't need an excuse!  We do it 'cause we want to!   

Just follow the procedure in the manual to measure the HV.  It tells you where, how, and what you should measure.

No I do not have it in my hands right now. I'm just trying to get an idea of what I purchased blindly. I have two HP1740A and already have a little experience with these scopes not so much with the hp1741a, for its storage resource

[oldway]

In my opinion, this scope has no fault, only wrong settings.
The guy who sell this scope does not know how to operate this scope.
See on brighter picture:
What's wrong ?
Delay time base selected instead of main time base.
Main time base not triggered because no input signal and automatic trigger is not selected.
Focus almost anticlockwise.

[SAUL BRITTO]

oldway> I do not know if the seller is a technician or has any knowledge in this area

[oldway]

oldway> I do not know if the seller is a technician or have any knowledge in this area

Looking at the picture, he has not for sure 

[SAUL BRITTO]

oldway> I do not know if the seller is a technician or have any knowledge in this area

Looking at the picture, he has not for sure 

Good laughs  here!

[Alex Eisenhut]

I agree with oldway, I remember seeing that kind of bloom when the settings are wrong. I think leaving a bloom like that in the CRT while it's OFF is not a good idea.
But if it survives shipping, it means at least everything is working.
Deep erase can be dangerous, it's only a last resort.
I no longer have the 1741, I gave it away years ago. But I remember it had a burned-in image from the lab it came from, it took a lot of erasing and fiddling to get the image to disappear.

If you press erase a few times and it doesn't go away, run it in auto erase with no input signal, put it in auto mode with no beam intensity and it will store nothing and erase the screen continuously.

This is also in the manual IIRC.

[SAUL BRITTO]

I agree with oldway, I remember seeing that kind of bloom when the settings are wrong. I think leaving a bloom like that in the CRT while it's OFF is not a good idea.
But if it survives shipping, it means at least everything is working.
Deep erase can be dangerous, it's only a last resort.
I no longer have the 1741, I gave it away years ago. But I remember it had a burned-in image from the lab it came from, it took a lot of erasing and fiddling to get the image to disappear.

If you press erase a few times and it doesn't go away, run it in auto erase with no input signal, put it in auto mode with no beam intensity and it will store nothing and erase the screen continuously.

This is also in the manual IIRC.

Thank you Alex.I believe now will look this scope with a bit more care

[SAUL BRITTO]

Guys please, be pacient with my "english" because I speak portuguese and to me it's beeing hard.

[SAUL BRITTO]

I already have some experience with this  HP scopes because, I have a few more 1740A that was defective and repaired myself and I think they are excellent.

[SAUL BRITTO]

It cost me about $ 40 with shipping fee. It was a good price?

[SAUL BRITTO]

Hi friends. When I worked with tube tv, seen many triplers causing a similar defect. As the anode lost the ability to attract the electron beam causing, this type of screen. Tomorrow the courier will deliver the scope in my home.