Problem Toei cm-r20 Green issue?

[Ronnie Dent]

I think this might be the right sheet, I checked the tabs of Q8 Q16 and Q24 they were all 106v, will have a good look in that area for suspect tracks

 

[gunblade]

you need a signal on it

 

[Ronnie Dent]

you need a signal on it

Ah, that's an issue then! Need to see if I can setup a 60 in 1 to at least feed the screen, thanks again Grant, saves me chasing my tail!

Cheers Ronnie

 

[gunblade]

did adjustment of screen control make any difference?
if not then likely a voltage missing

 

[Ronnie Dent]

did adjustment of screen control make any difference?
if not then likely a voltage missing

The screen volts beside focus? Yes the brights and dims image R G and B makes no change, going to rig up a 60 in 1 to it shortly

Thanks Ronnie

 

[gunblade]

out of interest what do r149 and r152 read, thats if i have the right schematic

 

[Ronnie Dent]

R152 is 2.5 ohms in situ struggling to find R149

 

[gunblade]

looks like r149 is on pin 4 of flyback

 

[Ronnie Dent]

Doh right under my nose! So
It reads 0.2 ohms so close to zero

Thanks Ronnie

 

[gunblade]

specs on schem say 2.2 ohm but its likely reading almost short due to circuit, you could lift one side but i expect its ok

 

[Ronnie Dent]

specs on schem say 2.2 ohm but its likely reading almost short due to circuit, you could lift one side but i expect its ok

Grant it’s more like a link wire than a resistor has pink sleeving

 

[gunblade]

so someone has replaced the heater resistor with a short as the picture was dull, i wonder how much voltage the heater is getting - you will not be able to read the heater voltage without a high quality bench meter

 

[Ronnie Dent]

It looks factory tbh Grant even the solder looks undisturbed , so a fluke is no good for reading the heater volts?
Thanks Ronnie

 

[gunblade]

not unless its a 87v or similar spec, if its factory forget about it

 

[Ronnie Dent]

Cheers Grant at least a couple of things ruled out with your help. Will get a signal in it tomorrow and try and do those voltage checks it the flowchart
Thanks Ronnie

 

[Ronnie Dent]

Actually the image is not bad! Weird! Colours are maybe a bit off but seem to be there, can’t seem to get full vertical deflection and the scores are a bit squashed at the top?

 

[gunblade]

ignore it, the 60 in 1 do behave with a verticval lin issue, wait until you get a proper game board on the cab

 

[Ronnie Dent]

ignore it, the 60 in 1 do behave with a verticval lin issue, wait until you get a proper game board on the cab

Thanks Grant, been a bit of a red herring the green raster! After twiddling the R G B pots I have a decent image, thanks again for all your help with this

Cheers Ronnie

 

[Retroman839]

Why did green dominate ?

 

[Ronnie Dent]

Why did green dominate ?

No Idea! Grant said it needed a signal, with no signal the R G B pots did nothing but did with an input