Hello,

I am trying to repair a Movit2 programmable cartridge. The problem of this cartridge is that data is not written to static RAM. ROM program works ok but F3 (erase data) don´t clear all the movements and some new ones appear. F2 (Charge data) seems to write the movements to static RAM but all data is lost when RESET or Power off.

Does anybody has schematics of this cartridge? Or, images of the pcb? There is a cut pcb track with a wire connected to 74LS04 chip.

Thank you very much

Oscar

check the inside battery because SRAM required a power supply for save data

Hello,

Jipe, I don´t see any battery. There is a 0.047F 5.5 v electrolytic capacitor (flat and wide one)... just guessing, is this capacitor used for store a few minutes the info in the SRAM until plug-in in the robot (that has battery cells)?

The chip that stores data (I think) is a Sharp LH5101L3, there is another Sharp LH233107 (ROM) and 74LS123, 74LS32 and 74LS04... rest of components are resitances, diodes and other minor capacitors.

Greetings,

Oscar

the capacitor 0.047F 5.5V is a gold capa use in mega-sram and replace battery for save sram and store data for many day

for testing it insert the cartridge in a MSX few 1 minute

extract it and open

test the capa with a multimeter if you have 3,3v to 5v is ok else search and check a diode in the circuit

Hello,

I have tested the capacitor and I have 3,3 v. There is a diode connected near the capacitor. I have removed it from the board and it measures 630 aprox in one direction and infinite in other (tested with multimeter - diode checking).

Is strange the detail that when you erase (Discharge) the memory you don't get empty program. Some programming appear. I have tested with two computers and both show some programming moves when clear the memory, but the moves that appear are different in each computer, but always get the same movements (no random) for each computer.

I don't know if you can understand this, with my english

Greetings,

Oscar

Does it really writes to the SRAM ok? Write data, read it back and compare.
I have just checked that data retention voltage for this cip should be 2v, thus in your case neither capacitor nor diode is a problem.

try cleaning the cartridge connector

I also had been thinking about it, but in case of durty connector ROM would not work too. But anyway worth trying! To be honest I did not understand the situation.