Marantz 4400 - Scope turned on at first time after 8 years

[havols]

Hi Guys
I have a marantz 4400, and the scope never worked.
The fuse always blew when 4400 turned on.
After some help from AK members, I found the problem, a carbon track on a black power supply plug (pictured). I removed the carbon track, and reinstal the plug.
Now, i install a new the fuse and like magic, the scope turned on for the first time (photo). Fantastic.
But now, i just have the scope as shown in the picture. Not more.
There is something wrong wit SCOPE?
Is there any adjustment to be done?
Thank you all.

 

[havols]

*Photos

 

[havols]

When i turned off, one green light point goes down from the top, and stays in the center of the scope until it goes out.
What can be wrong?

 

[catrafter]

With everything operating normally, and the Oscillosope button ON, Audio button ON and Monitor on Tape1 (with nothing connected to Tape 1), see if you can adjust the rear panel Vertical and Horizontal controls to center the dot (you may have to turn up the rear panel intensity, don't get it too high or you may 'burn' the phosphor on the scope face. The rear panel focus should make the dot sharp.

If you cannot get the dot close to center or there is no visible dot, they may be problems with the scope deflection and/or power supply circuits. if you can get it the dot on screen, make a note as to whether you can move it with either the Horizontal or Vertical adjustments on the rear panel
The good news is since you see a 'dot' as it dies out on power off, the scope tube it's self is probably OK.

Please remember that there is enough voltage to be possible FATAL in the scope circuits. Be careful!
Report back and maybe we can check some voltage levels if you have a meter that is good to about 1000 volts DC.

Tom

 

[havols]

ThanksTom
done.

With everything operating normally, and the Oscillosope button ON, Audio button ON and Monitor on Tape1 (with nothing connected to Tape 1)

The horizontal adjust works normally.
When the horizontal pot on minimum, the oscilloscope runs out of green light (light go to one side). When the horizontal pot is in the center, normal green light on scope. When the horizontal pot adjust at maximum, scope without green light (light go to other side).
Vertical adjustment: pot at Minimum, mid or maximum: always has green light. Sometimes, depending on the focus pot position, when Vertical pot adjust at minimum or maximum, I can see a green dot that appears quickly at the top (as if stepping)
Should I take some voltage? I have a multimeter that I use on my tube amplifiers.
greetings

 

[rBuckner]

It's quite likely that one or more electrolytic caps have gone bad.

 

[havols]

It's quite likely that one or more electrolytic caps have gone bad.

in power supply?

 

[rBuckner]

Yessir. The ones like 10/22uF and 200 plus volts. But replace all of them while you're at it.

 

[havols]

Thank you rBuckner
I replaced two 10uf and two 22uf high voltage capacitors.
Now, I can see the best focus after adjustment of the pots for focus, vertical and horizontal adjustment(as in this photo).
Also try adjust the P900's vertical pots.
Again, when i turn off the receiver, a green light (a green dot) goes down the top of the scope and stays in the center until it disappears.
I will appreciate if you can continue to help me.
greetings

 

[havols]

Today, i played music with osciloscope ON.
I can see the green light by osciloscope (likephoto) shinin according music...
indicating that the oscilloscope was working, and varying by song, but out of focus or something like this
Regards.

 

[havols]

I measured some voltages on the scope board
J917 = 575V (580v in the scheme)
J915 = 534V (520V in the scheme)
J905 = 122V (100v in the scheme)
J906 = 89V (100V in the scheme)
Is there a problem with the power supply?

 

[rBuckner]

I don't think so.

 

[havols]

Thank's for your help.
Tomorrow I will travel to spend Christmas with family.
I'll be back in January, and will create a new thread to try fix the scope problem, and FM issue, which has a constant squeak without tuning anything.
Greetings, and merry Christmas.

 

[havols]

Hello everyone
I'm coming back ... in another effort to fix or SCOPE by my Marantz 4400 receiver
A summary from above thread.
The power supply was completely reccaped
Some voltages on the scope board
- J917 = 575V (580v in the scheme)
- J915 = 534V (520V in the scheme)
- J905 = 122V (100v in the scheme)
- J906 = 89V (100V in the scheme)
The Scope shines OK, but without focus, and as if it were directed upwards from the scope tube, not to the front..
But when i turn off the receiver, a green light (a green dot) goes down from the top of the scope and stays in the center until it disappears. This is the only situation that I can see a point in my scope.
I did a quick teste on 2sk30 and 2sc1507, with a multimeter in diode mode, and all seems OK.
Someone here can help me, to try to fix this big beast?
greetings from Brazil

 

[rBuckner]

Welcome back! Hope you had a nice Christmas time. Five months is a nice long vacation!

I have to ask... did you try adjusting the two centering knobs on the back?

 

[havols]

kkk. Yes rBuckner.
In fact ... it was a fantastic holiday month.
Then I came back, and I had a lot of work ... but I wasting time with a new a fisher tube amp and a Luxman r-1040 receiver ... these stuffs from the 60s and 70s are a vicious to me. Love them

Now it's the time of 4400 .... I still dream of this scope working.

did you try adjusting the two centering knobs on the back

Yes
This scope appears to be aimed over the tube, not reaching the front, except when I turn off the receiver with Scope ON.
When I adjust the horizontal pot, I can see the light moving sideways ... but not a point of light, but something like a patch of light.
When I adjust the vertical, I can't see any difference
Thanks

 

[havols]

What would be a next step?
Replace C1507 or 2sk30 transistors in scope board?

 

[fredmarantz]

Again, when i turn off the receiver, a green light (a green dot) goes down the top of the scope and stays in the center until it disappears.

That's normal for all Marantz scopes. At receiver turn off, the scope/dot will loose energy and make a slow strange travel across ( or up/down) the screen and disappear. Don't worry 'bout that.

best regards
Freddy

 

[havols]

Hi Freddy
The scope by my Marantz 4400 is not working fine.
It has a problem, described in posts above.
regards

 

[fredmarantz]

You asked: "When i turned off, one green light point goes down from the top, and stays in the center of the scope until it goes out.
What can be wrong?"

I was only answering the quoted question, that you put a couple of times without anyone answering. I answered it - but only that question.

But you probably also have some problems with the scope circuit.

You asked earlier: Are there any adjustments to be done? - My answer is "yes - there are at least 8 adjustments to be done". ( 4 outside on the back of the receiver and 4 inside. ) I wouldn't do the inside ones by myself. The ones at the back are centering (Horizontal + Vertical) - the 2 others are "intensity" + "Focus" - are you familar with these adjustments?

Do you have a servicemanual for the 4400? - do you have a user manual for the 4400?

If you're having trouble with the vertical adjustment - there could very well be a defect transistor in the vertical amplifier. Which one I can't tell you.