Oscilloscope Hameg Analog trying to repair

Hi,

This is my first post and hope you can guide me I own this old one osciloscope and want to make back to life, if this worth. I powered and no image get, i move and get sometimes a image line and sometime is i move i get some image. Can be some cold solder? When the stuff start works fine like 1 min and goes black and need to tap and image back a little and disappear. I add photos and video, thx.

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http://youtu.be/glGKZEoNAos

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The fact that taping is effective could indicate a defective CRT.

Your scope begins a sweep intermittently. That is to say, the sweep trigger circuitry is unreliable and does not always begin a sweep. Does the trace always begin and disappear at the same positions? If so then the beam is reliable to that degree.

The sweep trigger must be very sensitive. It must decide whether to respond to an incoming signal, or to its own internal 'idling' circuit. Can you locate a potentiometer that adjusts the auto 'idle' sweep in some way?

Have you tried all combinations of sweep setting: ... auto sweep trigger, signal level trigger, upward going signal, downward going, mains AC trigger, etc.?

Did you spray cleaner into all potentiometers that affect the sweep trigger?

Once a sweep begins, can you slow it down, and then act quickly to change something and watch if it affects the beam?

Hello norbac,
You need to have the scope running and using the handle of a small screwdriver and tap gently around the CRT PCB to see if you get any changes. Same goes with any of the other PCB's.
You need to try and isolate the section that is sensitive to vibration. But since the scope is fairly old as shown by the components used, you're best off blanket soldering all the PCB's.
If you have access to a digital capacitance meter, I would suggest you check all the electrolytic's in the power supply and CRT PCB.
I can see in some of the solder joints that they are showing signs of crystallizing due to age.
As BradtheRad has suggested, try spraying the pots and switches with CRC 2-26 contact cleaner or something similar.
Regards,
Relayer