Pentranic chassis screen jumps

[Retroman839]

Nichicons going in 👍

 

[Retroman839]

Also C907 4.7 uf 100v missing from my bag from saccarrus cap kits usa

 

[Retroman839]

Re capped
Still have shimmering on edge of pixles ..
Will try ferrite core to block emi on the rgb s

 

[Retroman839]

Spent some time with this monitor this evening …

Found a couple of things
1 …. One heat sync is sparking if I touch it with a ground wire
Short on pentranic ch 288 heat sync

And the second is
The interfearance I have narrowed it down to the brightness circuit ..
Pentranic ch288 cga interfearance on the brightness

So I guess in regards to the heat sync I have a short somewhere.

Not sure if video of the interfearance which only appears now when I turn brightness pot up helps narrow down a possible reason for it?

 

[gunblade]

is there a transistor on that heatsink? does it have an insulation sheet?

 

[Retroman839]

is there a transistor on that heatsink? does it have an insulation sheet?

Transistor yes ..
I will have a look at the insulation sheet ..

Funny thing is …
The pin and Cush effect when I add ground to the heat sink I cannot correct it ?
Which has left me scratching my head because screen has nice geomatry as is..

 

[gunblade]

why are you adding a ground to the heatsink?

 

[Retroman839]

why are you adding a ground to the heatsink?

I’m trying to find out why I have interfearance

I have added A ground to main heat sink ..

Added a ground to monitor frame ( for dag wire ) kneck pcb .

Each ground added improves the interference.

Só I was looking to see if I could find another place that when grounded improved the interfearance further .
not to add a permanent ground but more to try to track down where the interfearance is coming from?

 

[gunblade]

i still think its completely wrong type of tube for the chassis

 

[Retroman839]

i still think its completely wrong type of tube for the chassis

I think your right.

I have always thought that.

I’m really happy with the picture though it’s great apart from the interfearance .

I can dial the interfearance away. I’m just trying to see if It could be removed?

I’m thinking I have a short in the brightness circuit ..
As this heat sink obviously has a short then all ground planes around it must have voltage on them also ?
I have image nice ..
Now and can omit the interfearance lowering sub bright & brightness , and flyback .. but it nags me that it’s still something possibly that could be ironed out .

I have no idea if it’s in the brightness circuit , but when brightness pot on Controll pcb is turned up Thats when the interfearance reveals its self.. like a sparkling aroumd edges of anything colour against the
Black back ground.

Or if this is something causes simply from a wrong value yoke and chassis Combo.