What is this "processor"

[eduaqa]

I have a M&S SYSTEMS, and not working well. The display keep showing Realz ... meaning release, like if a had push the 2 talk button simultaneously, I already disconnect the processor board and still show the same. I put a 10K resistor on the connection that comes from the board, because otherwise it would be expected that behavior, but even with that still the same, it's like something on the board is not able to compare voltage as reference.
Seems to be a exclusive chip made to this, but I believe should be based in some other.
If was able to find some data sheet would at list to know which pin are used for compare
On the top of the cihip says M&S SYSTEMS 830100A 404328A20S
The chip has 64 PINs ... I tried to attache the picture, but not finding how. Maybe somebody on the forum can tell how to add pictures.
Thanks

[eduaqa]

Re: What is this "processor"

Let see if the pictures goes

[Per Hansson]

Re: What is this "processor"

Hello, please see this FAQ for how to insert photos in your posts:
https://www.badcaps.net/forum/showthread.php?t=1868

Have you checked the four discrete transistors Q1 > Q4 on the board to make sure they are ok?
And also that super capacitor C1 on the board, does it still hold a charge with the unit unpowered?
If not maybe it lost some important parameters like how the intercom wires are configured if that is possible to change?

It is also possible that the TC4093BP schmitt trigger has one or more failed gates.
It is probably used to get a clean trigger from the external wiring for the intercom system.

[eduaqa]

Re: What is this "processor"

The super capacitor I replaced and it can hold the charge (clock)
Q1 > Q4 at least without unsoldering seems OK
but the trigger has a strange behavior ... if I touch the pin 1,2 with the finger, of course after discharging static it reset the clock (turn off, and comes back as 12:00)
about wiring I'm testing the board isolated from the rest, I'm powering it with 5.1V from a regulated power supply and it's disconnected from the rest
I put a 10k resistor on the PINs that comes from the main board where the talk buttons are connect otherwise it will understand that I pushed both buttons (in this case release function) that why a put the resistor to not simulate release but still happening ... connected to the other board or not.

[eduaqa]

Re: What is this "processor"

Some adicional information for the main IC on the board
PIN 4 goes to the main power line
PIN 8,9 goes to the main ground line
PIN 11,12 has a 4mhz xtal
PIN 16 goes to the main ground line

[eduaqa]

Re: What is this "processor"

I draw the schematic for the Q1 to Q4 which are MPS2907A, but I don't understand
the collector goes to the PINS 5,7 of the main CI and has about +4.5v
The pin 6 of the CI comes from the board and has around 5v when no button pressed, 3.8v when talk external pressed, and 1.6 when talk to the room pressed, and 0.5v when both button pressed what means release
But for now stay in release independent of the voltage on the pin 6
So seems or other factor is making the main CI understand the release is been requested or is not able to do voltage compare

now the part that I don't understand ... MPS2907A is PNP, but according to the diagram I did from the board the emitter is connect to the 5v using a 511ohms resistor. I'm considering that it EBC 1 2 3 pins

and 2 of the MPS2907A has nothing connect to the collector

[eduaqa]

Re: What is this "processor"

Found the processor, it's a Hitach HD404328, still didn't help a lot, but checking the pins and where connected to the main unit board to try to track what is causing the processor understand the RELS (door release) is been requested