silver_evo

Hey guys, been a while, i've been out to sea since christmas. Just got back and wound up seperating from my wife, Bah... Suck. Anyways, my Tactrix cable has a pretty weird fault in it. I can use Evoscan no problem. So i know the K-line tx/rx is working fine. Now when it comes time to use ECUFlash i get no connection. It loops thru all 4-init codes and fails. Boo. Ran it for 30 minutes to get battery voltage up. Tried again. Nope. Now here is the fun part. I ran a jumper from the positive terminal of the battery to the #26-pin of the white connector (reflash connector) this puts the car in program mode right right. Start a read rom and bam connects and reads the whole rom. Ok. So i checked the voltage on the output of the Tactrix cable and i get like ~5 volts (which is the USB host power coming thru). Once you initiate a rom read/write. The software Bit-bangs CBus0 and applies DLC Pin #16 to a 555 Timer ckt. This output is the +14.4 battery voltage which goes thru a diode-looking-deal and into the "BOOT" wire (reflash jumper). So My possible solutions are :

#1 - No power is available at pin #16 on the DLC connector, lemme go check right quick... Looks good, 12.7Vdc between pin 16 (+) and pin 4/5 (-)(GND)

#2 The 555 ckt is toast or something else around that area... Buy a new cable i guess... I hold the ~5V from the usb host power, but it never strobes to +12.5 from the battery... Hmmm...

#3 Software/Drivers is never Bit-enabling CBus0 or somehow the FT232 is damage/corrupt. I doubt it because evoscan works fine, and i used MProg3.02 to read/parse the FT232 and it works fine, CBus0-3 are set for I/O and CBus4 is set to #Sleep so i guess thats right (looks right). Also i CAN NOT re-program the FT232 so any changes to that data can not happen. I tried all my different versions of ECUFlash, my old 1.29, my 1.35 hack and my 1.38 hack, and 1.41. I've used the software enough to know which drivers work and which ones dont. Also it failed on two seperate computers, both of which worked before i left for sea on ecu flash.

#4 The re-flash connector was plugged in the entire time i was gone (2 1/2 months). Looking at the schematic, i dont see how that could have any effect on the ckt.

All the dummy-checks (continuity/voltage/etc...) are checked end-to-end , im pretty sure the fault is in the Cable ckt.

Well what do you think guys? Wire up a manual +12v switch that i flip to flash my rom (REAL RISKY if the switch gets flipped during a write... BRICKED! ). Try to rip the cable apart and search for failed parts and replace? Buy a new cable? Get a Kia?...

silver_evo

Im also talking with Tactrix now about a replacement or repairs to the cable. Ill keep you posted!

Update : The cable is 3 years old and they dont even make the 1.3U anymore so im on my own here.

acamus

Check Voltage at R9 (BOOT) end, if you want to flash it shall have 16V

silver_evo

Right it doesnt have +16v. I rigged up a test bench using an old ATX power supply and a fluke and my laptop to initiate ecuflash request. As expected, CBus0 switches high when you start a rom read. The Voltage Gets to the LM555 Reset pin. LM555 Triger, discharge, and Threshold all jump up to +12v due to the reset action. +Vcc on the LM555 is the 12v from the ATX power supply. Unfortunally pin 3 Output on the LM555 is 0Vdc. Never moves... I checked all the Resistors and caps around the LM555, they all appear to be ok. So that leaves the LM555 busted... Anyone have any ideas? Im pondering bypassing the LM555 and using something else... A new LM555CM SOIC is like $0.29. I dont want to wait for shipping though...

silver_evo

I've de-soldered the LM555 from the board. The resistance from output to GND was 10ohms indicating that the output stage transistors is shorted from collector to emmiter. Ill be headed to the shack a little later to get a replacement 555 timer.

silver_evo

Well i guess i didn't even need to make a thread. Its a good read i guess though. So i got a new LM555 from radio shack. It was a DIP size, not SOIC.... So.... I took a Network cable (thin conductors) Soldered the wires onto the pads inside the tactrix cable. Ran them outside the box. Soldered the new LM555 on the wires. Shrink wrapped all of them. Nice. Electrical tape on the outside to secure the case back together and hold the new LM555 in place. Did another bench test. BAM +14v on the "boot" wire. Hooked up in the car. BAM, read the rom. Awesome! So 3-years of tuning and i burned out a 1.69 IC. Good deal, glad i got it fixed. Hopefully the rain stops here so i can get out on SCCA this weekend with a new tune

WRC-LVR

iTrader: (1)

Nice writeup and great find on the schematic. I made my own cable for reading Nissans several years ago. That device also used a 555 soldered on the board.

This sounds a little different from the types of problems Tactirx cables have suffered in the past. But glad you posted up about it.

Milburn