Plus with Horizontal Sweep Lines?

[snake88usa]

Well I decided to fire up my Plus today to test a hard drive that I had. This plus was working about a week ago and from what I remember I thought the CRT was under adjusted to where there was a pretty good size black border (i think). When I turned it on the screen was very bright and had some slanted horizontal lines. Up at the very top is a bright white line and the picture fills the whole screen (again, i didnt think it use to but I could be wrong). Is the repair steps similar to the SE/30? cause I found a website on it.

 

[uniserver]

maybe try to adjust some of the pots and turn down the brightness, maybe you can get  a picture back?

otherwise does it boot? chime?

 

[snake88usa]

Chimes loud. I turned down the brightness while it was on but that didnt change anything so ill try the brightness cut off and see if that does anything.

 

[Elfen]

I have see this one many times that I could almost recite from memory but I'll verify it with DMS. It is either R5 (470KΩ at 1/4 watt), or U12 SN74LS38; both on the  analog board. Pages 52 to 54 on DMS.

 

[snake88usa]

Well i turned the cutoff the slighest amount to negative. Like barely a turn at all, turned it on and it chimes... no picture.

 

[techknight]

Your cathode is definitely stuck on. So its either the logic IC on the analog board, or possibly the transistor that drives the cathode is shorted. Or logic board. 

 

[snake88usa]

Will turning the pot bring the lines back to the way it was? Can I do this while its on? Second, is it possible to test anything like the transistor without removing the analog board or discharging the crt?

 

[uniserver]

bang the AB with the butt end of your screwdriver while its on.

white wire J4 and maybe some others on j2 need to be re-soldered...

 

[uniserver]

i always adjust those with it on.

 

[Elfen]

Will turning the pot bring the lines back to the way it was? Can I do this while its on? Second, is it possible to test anything like the transistor without removing the analog board or discharging the crt?

i always adjust those with it on.

You can do this with the monitor on but you need to use some plastic "TV Adjusting Tools" or you can take some chinese food chop sticks and with a razor knife cut the end into a chisel point that would fit the parts that needs adjusting. And when you're adjusting, do it slowly ad carefully. If the part gets stuck in a position, do not force it. Turn it off and then inspect it closer. It could be that you've reach the end of its turning or what paint seal used to freeze it in place is in the way and you need to scrape it off. This paint seal is usually in Red. 

 

[gkmaia]

I have see this one many times that I could almost recite from memory but I'll verify it with DMS. It is either R5 (470KΩ at 1/4 watt), or U12 SN74LS38; both on the  analog board. Pages 52 to 54 on DMS.

Hi, I got the same issue on my Plus. 

Would you be able to let me know what is the DMS you are looking at? Or where I could download it?

Cheers!

 

[Elfen]

I have the actual DMS from the mid 90s.