Polar 115 xt+ "checksums verefi error"

There are no obvious electrical problems.
Corrosion, oxides, poor soldering are not visible.
The problem began to appear in April, at first rarely then more and more often.
The CP7(6) board on the other machine starts without problems. The rest of the boards were not checked (cutting model M, they were afraid to spoil it)
The battery is new, the previous battery was replaced with a residual voltage of 3.62v
BIOS 2.0.0 ver.CPX7 X/XT+/XT++
Already broke their heads, where to think?

 

The CP7(6) board has two rows of microswitches at the bottom.
Is there any information what they are responsible for and how they should be included?

 

Hi sir;

1) Perform a visual inspection : look for loose and broken wires, improperly seated connectors, loose or
broken wires
misset switch, missing jumpers. and so on.
Chech for obviously damaged component(components burned or discolore due to overheating);
Dust + dirt + tear +wear

2) Reseating Boards and components:
Edge connectors are a common souorce of problems. Power down the system and remove the PC
boards. Examine the edge connector
for contamination and clean with contacts cleaner contacts. Reseat any loose components such as
scoketed ICs) . Reseat the
boards and power up.

3) Power supply checks:
Check the power supply for missing voltages and voltages out of spec. A digital multimieter DMM can
be necessary, as
voltage specifications are quite tight: logic supplies for example: must be within + 5% percent of
5Vdc. All the
multiple supplies and all must be checked.

4) Board swapping:
Board swapping involves the substitutiono of a known godd board for a suspect one.

5) Clock for CPU:
Check the frecuency with frequency counter or a DMM included frecuency counter( like Fluke DMM)

6)Reset CPU:
reset cpu see the attached schematic, has Small Black button.

7) Components ; Rusting+Dry+Colder joint solders, Reheating the Back panel.
8)Cables; Corroded+Broken

Good luck

 

Another session of electronic magic happened. Polar loads stably and works like clockwork.
Unfortunately, I have nothing to tell you about the repair of this problem

Now a new question: Which of the forum members changed the 21.5" touchscreen panel to 115 XT+ Polar?

 

Good job.!

However in electronic, No magic does exist, only hidden problem.
You must yes, as I did indicate, x loose wires, connecty, edge connectors+ dry+ colder joints solder.

Blessings
@ing_dr