nsivw
29th March, 2017, 02:41 AM
I am new to the Tacho Pro World and i just bought a cheaper unit that I thought was going to be a good item. Well it is not a good item...But My question is I notice that The OLDER Tacho Universal CPU Boards have a Crystal osilator and a PIC12F629 located next to the Intel CPU.....The newer made Boards do not have these items on it any more, however the solder pads are still there......I am asking if anyone knows what these components did??? I have almost mapped out the entire DB25 Connector plug on top of the unit and I know that pins 7 and 8 are used to Communicate with the Special Adapters like the NEC and 9s12 type...They are also used on the Chrysler_OBD2 cable board and the CHRYSLER_CCD bus and SCI cable....From testing this communication network seems to be a (SPI) Serial Peripheral Interface.....This set up uses a Data wire (pin 8) and a clock output makes the data match the processor clock in order to read the bits correctly. On my programmer I can test pins 7 and 8 and I seem to get some Data looking wave forms on pin 8 but pin 7 does not show a proper Clocking waveform....I traced Pin 7 and it follows the main board down to a 2.2K resistor then into the CPU board...And this connection goes directly to a CPU pin that is next to the Crystal and PIC (if they were there) I also notice that some repair kits come with these items.....My programmer will not connect to any adapter other than the EEPROM boards....The NEC and 9s12 do not even get reconized by the programmer as seen on youtube...It seems many people say the same thing about the units they have,,,others say everything works fine, However who Knows what Board design they have....I am thinking the removal of these parts has caused the Tacho Pro to lose the Adapter Communications need to work at all....If anyone knows about this (Change or Redesign) and the reason it was done, I would love more input....I believe the original function of those parts was to match the Clock Speed of an adapter so the CPU can translate the Data Messages sent over Pin 8....Without those items on the board the CPU cannot see or talk to the Adapters and that is why many people say the tacho pro does not do OBD.....If anyone has info on this please share...I am thinking of getting a Reapair kit that has the Crystal and PIC included and installing them and see what happens....Cant be any worse off...Leason to learn....WHEN BUYING CHINESE CLONES, SPEND THE SAME AMOUNT YOU WOULD IF YOU BOUGHT THE REAL ITEM.....THEN THINK ABOUT IT AND BUY THE REAL ITEM....I could count 10 things wrong or missing from my package and I am still trying to get it to work....