I will help you CrowHater...
Before it stopped working at all it sometimes fired up....after couple of tries. Thought that it could be some heating problem.
My first test was to put some heat on the circuitboard. Tried on several places and whenever it was hot enough it fired up. as soon it was cold it did not work. thought it was the processor first....did a resoldering job...did not work. Tried to resolder the memory...no success. Tried then to heat each component separately. took some time. Managed to narrow down the area a lot. Ended with one component. Hidden under the other circuitboard (card reader).
Tried to put the soldering iron directly on the component and every time it was done it booted correctly. YEAAAA.....bingo...
had a spare part of that step down converter. This converter decreases the voltage from 12V to 1.2V, which powers the processor...
Removed the old one and put in the new one. And Voila...it reboots now every time.
Same problem with both units....
See attached picture, have marked the location. The chip is U4 and model is. LSP5503
https://pdf-datasheet-datasheet.netd...iconductor.pdf
Hope it helped CrowHater.
Thanks...it did ... ;-)
TIP: each converter has a coil attached on the switching pin(output). Just test on the coils the voltage on each coil. Should be 10V, 5, 3,3 1,8 and 1.2 V.
There are 6 coils on the circuitboard. If all the outputs are working...then it is something else than the powersupply.....in my case it was the powersupply of 1.2V that did not work all the time, only when warm it started to work....