MS9 29A turn off... Again

[nikolash]

Hi everyone,
I have issue on my main and last chassis MS9 29A... When i turn it on i have static but no picture and 2 seconds later i have a "click " and it turn off.
When i unplug remote board, i have a normal vertical collapse but screen doesn't turn off.
It's the third MS9 29A who let me down on 2 months
Please help me!
Thanks

[Svovl]

My friend's Astro City, which is currently sitting in my basement, has the exact same problem.
The chassis has recently been recapped, we have replaced the power supply, and the b+ voltage correctly measures 75.5 volts.
This weekend we will try to reflow solderings on the chassis and neck board - perhaps also replace the vertical deflection IC.

If none of this will work we are also looking for good ideas on how to troubleshoot this problem

[grantspain]

normally caps and deflection ic,there are a few other things that cause it

[nikolash]

How can i check my b+? On the middle leg of the bu and the ground?

[grantspain]

do not do that

check the b+ across the ground and pin 2 of the flyback or + of 100uf cap at c515

should be about 74-76v

[nikolash]

Ok thanks!
And when i unplug remote, screen doesn't turn off, it's a clue of the issue?

[grantspain]

sounds like vertical deflection ic to me

[nikolash]

My B+ is now 75.5V (73V before), i check the vertical deflection IC on pin 1 / Ground and i have 11.1 volt and between pin 8 and 13/ ground 22 volt.I order an LA7837 , but it seems ok? what can i check now?

[Svovl]

We so far got the faulty Astro here to work by reheating a couple of dodgy looking solderings on the neck board and chassis.
We'll see how long time it keeps working

[nikolash]

Well done! Do you change the vertical deflection ic ?

[Svovl]

Well done! Do you change the vertical deflection ic ?

Nope, wasn't needed

[rugdoctor]

Check the remote board and its header. My ms9 also wasn't displaying a pic when the plug and header of the remote board was plugged in crooked. Even mimicked a vertical collapse

[nikolash]

Remote board and pins are ok.

[Svovl]

Well done! Do you change the vertical deflection ic ?

I just tried to start the machine after it had been sitting in a relatively cool room (around 18C), and the picture was all messed up, it folded over it self and was close to vertical collapse.
After 10 minutes the picture looked normal, but wobbly, after 15 minutes it had perfect picture.

I suspect that the vertical deflection IC is indeed sick as, as far as I know, it is quite temperature sensitive. So we are probably going to replace it soon.