oblitum

My guess would be a cracked battery voltage sense resistor, in the area indicated below or perhaps under that white block. Either the resistor body is cracked, or the metallised ends have detached from the resistor body, or the solder joint has cracked. I assume that the white block is some sort of rubbery substance to somewhat support the middle of the main board.

that something so small can cause too much catastrophe. If you ever come to Spain, I have a duty to invite you to a big lunch. very grateful for your generosity

Thank you very much for answering, I was looking at a post of yours from some time ago where you schematized that chain of resistors in a similar problem. I have done readings and the 1004 resistors give readings of 1 megaomnh except for the one under that rubbery block, I am going to replace the resistor now and try, I will give you answers in a while.
thank you very much for leading the way