I was asked to look at an Atari Lynx 1 console that had developed a graphics fault. Testing with my Zaku cartridge we see the fault straight away.
Looking at the schematics you can see a number of lines to the LCD come from the MIKEY custom.
On checking the signal at Pin 1 of the 74HC04 @ location U7 with the scope, I had no signal at all.
To get to MIKEY (and SUZY) you need to remove the RF shield. This is soldered on by the way of metal tabs. Heating these up with a soldering iron allowed easy removal of this.
The signal I was looking for comes from Pin 13 of MIKEY and looking at it under a microscope revealed some corrosion.
No idea how that happened but its a very likely candidate for the fault. I cleaned up the corrosion.
The break is not easy to see. Without removing the cartridge slot, this is quite a difficult area to get at but I persevered and got it patched and applied solder mask to the area.
Retested the Lynx and all appears to be working.
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