Modified Op-com V1.59 OPCOM MCU to PIC18F458

I have bought several Opcom clone interface with firmware V1.39, V1.45 and V1.59 from different online stores. I have tried to update one 1.49 to 1.59, but the modified one failed to work on my Corsa C. But OP-COM 1.45 did work OK. One opcom V5 (software 2010.08V) hardware works without issues, another one works not so good.

This is what I found:

First of all, let’s compare my opcom 1.59 interfaces. The one from Aliexpress has Chinese MCU marked OP-COM and the other one from obd2diy.fr has a PIC mcu, model PIC18F458-I/PT.

opcom-v1.45-pcb-1
Bad clone opcom v1.59 with OP-COM MCU

opcom-v1.45-pcb-2

Good clone with PIC18F458-I/PT mcu

opcom-v1.45-pcb-3

I decide to modify the bad clone to have PIC mcu. I found this picture which shows what changes are needed:
(NOTE: Not sure if the method works on yours. You are on your own risk)

opcom-v1.45-pcb-4

And then I started doing my own thing. Hot air soldering is the key. I managed to remove the MCU using 350 degrees on a square output flow head. The extra capacitor and diode also went away. See my procedure below:

opcom-v1.45-pcb-6

opcom-v1.45-pcb-7

opcom-v1.45-pcb-8

opcom-v1.45-pcb-9

opcom-v1.45-pcb-10

opcom-v1.45-pcb-11

opcom-v1.45-pcb-12

opcom-v1.45-pcb-13

opcom-v1.45-pcb-14

opcom-v1.45-pcb-15

opcom-v1.45-pcb-16

opcom-v1.45-pcb-17

opcom-v1.45-pcb-18

 

What next, I have the PIC kit 3 programmer ordered (missed the post today) and few PIC chips, hope to get it this week. As software, I found an archive with opcom fw 1.39 and bootloader hex file. I will try it and let all know if it worked.

Job done, chips came today. I used soldering pasta, a bit more than needed. I shooted fw 1.39 + bootloader in the PIC and all went ok. So, don’t through away your dead opcom, maybe they have a chance to be fixed.

opcom-v1.45-pcb-19

opcom-v1.45-pcb-20

opcom-v1.45-pcb-21

opcom-v1.45-pcb-22

opcom-v1.45-pcb-23

opcom-v1.45-pcb-24

Job’s done. I am happy.

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