F100 CPU#2 repair

[casey]

Following on from my cluster repair work (see here) , I'm now investigating how to repair F100 modules (and closely related F110's).

Related old thread from 2018 here

Many thanks to Efini-dan for the loan of his F100 to develop a test box. I have already dismantled the module for a quick look:

The F100 performs similar functions to it's predecessor, the CPU box in the RX-7 1st gen (FB).

Some years ago, this was my first "RX" test box project, a tester for that CPU - amazingly, the main connector on both modules is exactly the same, so I can use re-use my test harness without the need to make a new one!

FB test box:

The same connector fits the F100!

Watch this space for developments.....

 

[RandomVillager]

i love this kind of stuff.

Keep it up Casey

 

[jack.am]

Will you marry me?

 

[casey]

46 years too late, already taken mate

 

[jandesousa]

Just been reading your post regarding the speedo cluster and came across this post as well. This is amazing work man. You are going to make a lot of rotary owners very happy I've got the dreader "belts" light flashing which I believe is the F100 failing issue. I desperately want to get this sorted so please do let me know if you are able to help with this. Top man

 

[casey]

Sadly, I'm not immediately able to offer a repair service for F100's, as I need to do some "reverse engineering" of the PCB to determine the circuitry and components, then work out how to test for faults. The good news is, the majority of the components look to be readily available, so repairs ought to be possible.

I'll keep this thread updated with my progress and announce when I'm happy to accept modules for repair.

Currently I'm busy working out how to test & fix increasingly unreliable RX-8 OMP's (or MOP's if your prefer) which are an eye-watering £800 for a new unit from Mazda, with used ones becoming scarce too. I hope/think I'm close to a solution there!

....and then there's the completion of my development work on FD Cluster speedo repair, using an all new PCB "daughterboard". Loving the challenges though

 

[casey]

I'm making some progress in "reverse engineering" the F100 circuitry. However, I have hit a snag with finding connector/connection info.

All the wiring diagrams (USA based I'm guessing) refer to the CPU#2 having a 20 way (J4-01)and an 8 way connector (J4-02), as in this diagram:

I found this picture of "CPU#2's" online which showed an FD01 and F110 (later variant of F100). Same size and shape casing, but much newer PCB design inside. Crucially, the FD01 has the 20 and 8 pin connectors, as per all the wiring diagrams I have found.

PCB inside FD01:

A much newer, double-sided PCB board, same shape as F100 PCB, but totally different!

So, there are 3 different CPU#2's!! Does anyone know anything about these "variants" and why they exist?

I need a wiring diagram that relates to the F100/F110 that is, seemingly, the most common module in (I'm guessing) JDM and European spec cars? Can anyone assist? Worst case I'll take a Japanese diagram, if that is the only one available, as I have a friend who is a Japanese translator.

I'm going to struggle without knowing how the F100 connects to the car!

 

[jack.am]

Huh, weird. I have a 1993 JDM car and I have the later PCB. Wonder if it's not the original (and it's still broken).