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Help - Screen lines after U1MB Install on 800XL


Xebec
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Hey folks, so I finally decided to be brave and solder in a U1MB on my 800XL. My soldering skills are total shit but whatever.. I'm sick of having a U1MB and no way to use it since the 800XL that I had Lotharek install it on died :).

 

Now that it's installed and working, I'm getting faint (but very annoying) lines down the screen. When the screen is totally black inbetween booting it looks like the lines are reddish. Any suggestions on how to resolve?

 

3 images showing the lines and my crappy soldering job. I can confirm that the red wire on the left is touching the pin I think it's supposed to be.. the resistor I soldered onto for the green cable (PHI2) register 777 ohm.

 

Blue = R/W, Black = Reset, Red = Halt.

 

pics:

 

http://imgur.com/gallery/PprsC

 

 

post-34887-0-45879000-1500856740_thumb.jpg

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Try tidying up and re-routing those wires: they appear to be traversing traces coming off the ANTIC chip and criss-crossing all over the video circuit. You're probably seeing clocking noise on the screen.

 

I don't think I'll be able to successfully re-solder at different angles - would a thin strip of aluminum (+ electric tape underneath to prevent shorts) work as a sort of barrier to filter out the noise?

 

And the video circuitry is the stuff underneath the MMU (the chips)? or a different area? (I know the bottom row is GTIA - ANTIC - SALLY - PIA)

 

Thanks!

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Video circuit is up at the top-left. Not sure if shielding would work. The solder joints themselves look a little worrying, almost as if the solder mask is the only thing preventing shorts to adjacent tracks.

 

As always - you the Atari man. The wires near/over the video circuitry is causing noise. thank you!

 

One other question if I may - I'd like to put a stereo pokey on this system but it has the giant green (capacitors?) sticking up near POKEY preventing me from plugging in the board. I can't bend them down enough - what's the alternative arrangement? Just replace with smaller/ modern caps?

 

My POKEY is socketed so even with the socket + riser it's not tall enough.

Edited by Xebec
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I'd like to put a stereo pokey on this system but it has the giant green (capacitors?) sticking up near POKEY preventing me from plugging in the board.

Yeah, that's a common which issue I've encountered before too. I usually heat the legs of the capacitor with the iron on the back side of the board so I can lift the cap sufficiently that it will safely bend over on its side. If the legs aren't long enough, just remove and replace with the same part, but leaving enough leg length that it can be mounted flat (sideways) on the board. Sometimes a 45 degree tilt is quite sufficient, though.

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