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Tech 2 reboots when engine is started

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38K views 113 replies 21 participants last post by  pierrox  
C
#1 ·
Is it possible to start the car andnot lose connectivity to the tech 2?
It seems that some of the functions require "start engine".
Thanks
Bill
 
#16 ·
So you're saying a bonafide Tech2 won't reboot during start up (ie: will stay on running whatever mode you started with) while attached to the obdII port?

The rebooting issue with a clone Tech2 is because of NQR (not quite right) parts in the VCI?

Otherwise my clone works fine--seems a bit risky to mess with it--especially while I'm still under warranty...
 
E
#9 · (Edited)
LM2596S based voltage converter

Hi there,
I replaced the voltage regulator with a LM2596S-based regulator you find tons of at ebay. These regulators have some advantages:
- very low margin needed, so the regulator works down to 6,xx Volts and Tech2 survives engine start on my car.
- the LM2596 has an On/Off-pin, to get the same behavior as the original tech2 to power on and off with the power button. Unfortunately the high/low-logic is inverse, so that I had to add a transistor (BC547) and two resistors (4.7k and 1 kOhm) to integrate it correctly. The pin 5 of the regulator had to be lifted from the board to solder a wire to it.

Enclosed find some pictures. The regulator is sticked to the board with some very adhesive double sided adhesive tape... and trimmed to 5V before
Works very fine.
 

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#20 ·
So if cranking voltage stayed high enough, even a clone would not experience enough voltage drop to go into a re-boot mode?

I'm smart enough to fix helicopters, but not near smart enough to trust myself reading and interpolating Russian language or schematics.

Is the necessary mod documented anywhere in English...?
 
P
#26 ·
Wiring details & VCI fail on tech2

Hi!
Thanks for sharing your Tech2 voltage fix!
I replaced the original voltage regulator in my clone with the MORNSUN DIP VRB1205LD-15W (from Aliexpress) recommended on the Russian blog. Unfortunately it did not make any difference, It still restarts when cranking the engine. Do you have any idea why it did not help? Also read another forum post with the same problem when installing the Morsun regulator.
I am planning to test your modification instead, is seems this is the regulator you used?
http://www.ebay.com/itm/LM2596S-Ste...e-Regulator-Buck-Converter-/381435199537?hash=item58cf4f4031:g:dCYAAOSwsB9WClvd
Also, I’m not very good at electronics, so I’d like to double check that I interpreted your pictures correctly:
Picture 2:
The yellow wire and the 1kOhm resistor on the red wire is attached to the BC547 collector, the 4,7kOhm resistor on the blue connects to the base and the black wire connects to the emitter?
Picture 1:
Is pin five on the regulator attached only to the yellow wire (not to the added PCB)?
The two black wires goes to the (-)IN and the two red ones to the (+) IN on the added PCB?

I’m also getting error messages from the VCI when running the tech2 selftest; failing on DLC1, Gnd FET, VCI I/06, Loopback. I have checked the wiring in the loopback adapter and it seems the correct pins are connected. Also I get different errors running without the loopback so it is probably the VCI. However the Tech2 seems to work alright despite this. Any ideas about this?
 
E
#27 ·
per740 said:
  1. I am planning to test your modification instead, is seems this is the regulator you used? http://www.ebay.com/itm/LM2596S-Step-Down-Power-Supply-Module-DC-To-DC-Voltage-Regulator-Buck-Converter-/381435199537?hash=item58cf4f4031:g:dCYAAOSwsB9WClvd
  2. Also, I’m not very good at electronics, so I’d like to double check that I interpreted your pictures correctly: Picture 2:The yellow wire and the 1kOhm resistor on the red wire is attached to the BC547 collector, the 4,7kOhm resistor on the blue connects to the base and the black wire connects to the emitter?
  3. Picture 1:Is pin five on the regulator attached only to the yellow wire (not to the added PCB)?
  4. The two black wires goes to the (-)IN and the two red ones to the (+) IN on the added PCB?
Click to expand...
It's allways good to be careful :confused:

ad 1: yes, I used one of these...
ad 2: yes
ad 3: yes, lifted from the PCB without contact to it, and only connected to the yellow wire
ad 4: yes.

Good luck!
 
P
#32 ·
Hello again! I have now installed the modification and can confirm it works perfectly, no more restarts when starting the engine! It was a bit tricky to remove the Morsun regulator since it is attached at 5 pins and the solder fills the hole in the PCB. I used a de-soldering braid rolled tightly around the pins and heated using a lager soldering iron repeatedly. The suction pump did not work at all. Thanks again for sharing the solution!
 
4
#34 ·
I stuck a plastic spoon handle under the end with the two pins. While slightly prying with the plastic handle, I went back and forth heating the two pins. They would slowly pull out with each touch of the soldering iron. After they were out, switched to the three pin side and did the same. Once the old regulator was pulled from the 5 pins, I used a nail clipper to pull the pins from the main board while heating them one by one.
 
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