afweismann - 2024-04-29 12:18 PM
7.78 v on the second battery. It holds an ok charge, though definitely showing its age.
No luck on the JTAG schematics or image. The fuse had continuity and I also used a wire to circumvent it. Still nothing.
IMO that is inadequate... the .08 volts is within component variation if we assume 7.7 +/- %5 is equal to a "dead/discharged" battery.
It appears you have an under-voltage for boot, can you get a battery in the vicinity of 8 volts, or apply 8 volts DC to the MP900 battery prongs?
(See my photos above, watch polarity, notched side is positive terminal
)?
Charging circuit may be faulty but should still boot off a fully charged battery...which IMO, you obviously lack.
Suggesting just rule out this possibility... the old "close but no cigar" scenario... maybe close but not enough to boot.
best regards and hoping for your success!
Edited by joval 2024-04-30 9:51 PM