Macintosh 12” RGB Display (M1299 / M1296) with Vertical Linearity issue?

[Retrotechie]

First does the chip have power, +12v on. Pin 13?

You must be getting horizontal so is there any 50hz sawtooth type signal on pins 11 or 10? I imagine the output you posted is pin 7 maybe? Have you checked that the deflection yoke isn’t open? If it’s ok, I would trace out the circuit and draw the schematic between the vertical yoke and the chip.

 

[felangga]

First does the chip have power, +12v on. Pin 13? You must be getting horizontal so is there any 50hz sawtooth type signal on pins 11 or 10? I imagine the output you posted is pin 7 maybe? Have you checked that the deflection yoke isn’t open? If it’s ok, I would trace out the circuit and draw the schematic between the vertical yoke and the chip.

First does the chip have power, +12v on. Pin 13?

You must be getting horizontal so is there any 50hz sawtooth type signal on pins 11 or 10? I imagine the output you posted is pin 7 maybe? Have you checked that the deflection yoke isn’t open? If it’s ok, I would trace out the circuit and draw the schematic between the vertical yoke and the chip.

Finally I fixed it!!

The issue was on the vertical height line.
It has a tantalum (1uf/35v) which is dead.
Since I don't have any tantalums, I replaced with electrolytes type

 

[Retrotechie]

Nice! I imagine that is in the vertical yoke circuit which is resonant. Great job!

 

[felangga]

Thank you.
But now I found some other problem, if it running for some time (around 15m). It will shutting down and producing some noise.
I need to pull the power out from the main, and wait for several second before I turn it on again.

Is there any thermal protection for the monitor?