F100 CPU#2 repair

[casey]

Ah, RS do stock the connector. I'll send you a DM tomorrow (later today actually.....).

 

[casey]

Door buzzer sounds if the key is in ign off position on both doors

I have managed to induce several different "buzzer/beep/chime" sounds today! Can you confirm if it is an "interrupted" buzzer sound on a door open condition, not continuous?

Some further testing today, so:

"....with ignition on, under what circumstances can chimes be induced?" - could this happen if the boot and/or hood are ajar? If not, what else might induce it?

 

[RandomVillager]

Beep beep when door is open. (Checked my video on my thread)

Nothing when the hatch is open unless mine isn't reporting it back as open or the hood but i don't see any sensor/switch to say if that's open

 

[casey]

Some serious work went into producing this F100 pinout function list today.

I have learned a lot about the F100 circuit functions by changing input conditions and probing with a multimeter and an oscilloscope. The only failure mechanism that would prevent a repair would be failure of the 4 bit microprocessor, which is custom mask-programmed at manufacture to Mazda's design and no spare parts are therefore available. All other components look to be replaceable.

It would also be possible to replace the whole module with a new design, using modern components and a programmable controller.

Although I claim "100%" confidence for the function of some of the pins in the attached, without actually checking on a real car (rather than my bench simulation), I can't really be 100%

I'd welcome anyone checking the described functions on, so I can be 100% on all the pins, enabling me to progress, with confidence, to designing/building a bench test box.

 

[RandomVillager]

Well done on the work so far.

I'll try and confirm whats on there with the car when I get chance maybe at the weekend.

 

[casey]

Beep beep when door is open. (Checked my video on my thread)

Nothing when the hatch is open unless mine isn't reporting it back as open or the hood but i don't see any sensor/switch to say if that's open

Thanks - that is EXACTLY the beep sequence I'm getting

Re the hatch/hood, the only way to know for sure would be to trace the F100 "1K" pin to wherever it goes. Something in the car should produce a battery condition on that pin (which could be a hatch light switch, when open) and, when the ignition is on, will create a chiming sound from the F100 module "sounder".

 

[RandomVillager]

Anything on the ewd I know there sketchy depending on what year they are aswell. I'll have a dig around in Saturday

 

[casey]

"ewd"? Electrical Wiring Diagram? If correct, on the JDM ewd, pin1K is shown in a dotted box and goes to the Auto Transmission PCB and the reversing switch. My friend has translated the function to "Inhibitor Switch". I think the 1K pin must have been repurposed on manual gearbox cars to another function. On most (USA centric) diagrams, pin 1K isn't used. My strongest guess is it's connected to the rear hatch light, which would be "on" with the hatch open and the necessary 12 volts would be what pin 1K requires to trigger a chiming sound.

Should be easy to check, turn on ignition and open rear hatch. Chime or no chime ?

If not that, then something else in the car is producing a 12 volt trigger to pin 1K when the ignition is on. Or, maybe the wire from pin 1K doesn't connect to anything in certain models, it's only there to connect to an auto gearbox, but why a chiming sound, that sounds like a classic door open or seatbelt off warning. Seatbelt monitoring is via pin 1F on the module I have.

 

[RandomVillager]

Have the rear hatch open most of the time ATM while working on the car.

Keys in or out there isn't any chime with it open only when either door is open and key is present in the ignition. Turning it to the on position turns off the beep beep beep then after a short period it constant tones for the low coolant only cause the ECU doesn't see the level sensor cause my harness doesn't have it provisioned yet. (Rywire tucked harness)

 

[casey]

I think I will have to record the chiming sound at some point and post it up. It might help to identify the conditions that trigger it

Had a spare couple of hour yesterday, so made a start with initial Arduino programming and associated breadboarded hardware to repeatedly loop through:

1. The door handle operation triggering the ignition barrel lamp and then the lamp cancelling when the ignition is turned on.
2. Seatbelt unattached, triggering the dash warning lamp and interrupted buzzer sound when the ignition is turned on, until the seatbelt is attached.

Where needed, using relays to ensure complete isolation from 5v Arduino inputs and outputs and possible 12v on F100 connectors.

Test sequence stages are displayed on a small OLED screen and also a couple of LEDs to simulate appropriate car lamps.

I hope the coding for the rest of the test turns out to be as easy as so far!

 

[casey]

Pretty much finished the prototype bench test box. I have made a few tweaks since I made the video though, to give more info on the screen. I also think the trigger line for the tacho rpm warning is used to trigger the F100 buzzer when the coolant is low too. That trigger wire comes from the main cluster CPU board, which connects to the coolant sensor.

Next step is to source a suitable connector for the F100 module (the one I'm using isn't fully populated with the pins I need) and build this prototype on a soldered breadboard and put it in a suitable enclosure box.

Once that's done, I'm happy to accept any F100's in for repair

 

[jandesousa]

This makes me very happy..... probably gonna make a lot of FD owners very happy

 

[Jester*]

Casey doing the FD lords work right here.

 

[Matt]

Real credit for the work and progress gone into this