hameg hm203-6 x axis not working

[quentin]

I am trying to repair a hameg 203-6 oscilloscope and i have cheched almost all chips and found no broken components and the only way to make it half work is to take the time knob an move it between specific channels. And even like that i have only manage to make the y axis work.

Does anybody have a idea to what is causing this problem?

also i tried cleaning the time knob but it made no changes and when i probe the adjustment channel it shows me the right voltage


i appologise if my english is bad
thanks

[akimpowerscr]

First of all, welcome to the forum....

If I understood correctly, the time base of your HM203-6 does not seem to be working.

Could you apply a signal to both channels at the same time (preferably low frequency sinusoidal) and tell me what you see on the screen when you press the xy button?

[shakalnokturn]

As akimpowerscr said.
Also does the X-Pos. control work?
My first scope (that I still have since '98) is a HM203-6, it's going the same way as yours, the timebase is intermittent, I know it's a contact problem because I can stop/start the problem pushing down on the Trig./ Timebase PCB.
If ever you need a second HM203-6 to repair yours I have a working one to sell 

[IRmska]

I have a working HM203-7, (its a close model, I guess it shares most of the internals), I can check some lines or specific parts, whatever you might need to check on a working one, just let me know!

[quentin]

Excuse me for my absence, i was bored about the scope and totally forgot that i posted this

-using the calibration pins on the oscilloscope (square signal of 2v) i can make the vacuum tube display the voltage but not the time (sorry, i couldn't use sin wave sadly my frequency generator is broken too)
-using both channels with the x-y button makes a sideways line with the square signal of 2v (see in the picture)
-since the timebase is not working and it could be the contact fault on the time base knob, what can i use to clean it ?
-the trig does not light up so it may be due to the poor contact or an other problem

checking directly on an other oscilloscope is not necessary, just responding to my questions is enough, you are already wasting too much time for me 


Thanks to all of you for responding to my questions, i greatly appreciate it