bill, are you powering the tech2 from the vehicle via the cigarette plug?

 

No, from the obd connection.
Thanks for the reply

 

i would try to power the tech2 via some other method (batteries, line power adapter, etc) just to make sure it's not car related.

 

It is annoying to deal with the reboots, but really the ODB port is the best way to power your Tech2. Removes any ground loop issues that can cause data loss. Especially if you are doing programming, probably OK if you are just reading values and such

 

External power won't help. It will still reboot.

 

Normal behaviour with standard clone unit I'm afraid.

There are some modifications that can be made - for example chnaging the voltage regulator in the VCI along with converting from RJ45/RS232 to USB.

These require some electronics skills and the ability to interpret russian forums.

http://diy-tech2.blogspot.nl/2014/07/upgrade-you-gm-tech-2-clone.html?view=sidebar

 

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...

 

An original Tech2 under normal battery conditions does not reboot during engine start. This is related to the voltage regulator on board and the margin it needs to maintain 5V output to the Tech2 board. The original voltage regulator can keep this voltage with a dropped battery voltage down to 7V or even lower.
This is not related to the VCI hardware.

 

Thanks guys, I think I'll persevere for now lest I screw everything up.
Thanks again everyone.
Bill

 

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.

 

and trimmed to 5V before
Works very fine.

What exactly did you do to accomplish this?

 

I'm a little bit ham handed to tackle the mod, it looks like a pretty simple operation though.
Danka
Bill

 

Looks good. Parts ordered to fix mine up.

 

trim 5V

I struggled also a bit with that. I had to turn the brass screw on the trim poti maybe 10-20 times counterclockwise to bring the poti to a working range. At start just screwing half turn left or right changed nothing.
Good luck!

 

Did you use an external power supply?

 

Yes, I used an external power supply, and checked the output voltage with a multimeter. But you could also use the power supply provided with the Tech2.

 

I thought I had a stack of 4.7 OHM resistors to get this mod done this weekend, only to find out I didn't. 47, 4.7K, but no 4.7.

I have had a couple GM vehicles that didn't cause my clone to reboot when started.

 

I thought I had a stack of 4.7 OHM resistors to get this mod done this weekend, only to find out I didn't. 47, 4.7K, but no 4.7.

Good that you replied. I meant 4.7 kOhm and 1 kOhm, but I am quite sure that both 1kOhm will also work.

 

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...?

 

There are a couple of pictures just up a few posts.

I am down in Pueblo. Now that I see I need to use 4.7K Ohm resistor, I'll be doing mine tonight. If all works out, and you want to, you can send me yours and I'll install one in your Tech 2. I bought five of the boards.

 

Pretty easy. Took me about an hour and a half after forgetting my power supply at work. Odd power supply connector for the Tech 2, but I finally found a universal one and the Tech 2 powered up. Will find out tomorrow if it fixed the reboot issue.

 

Weird. It rebooted the first time I started the vehicle. I immediately shut the key off and tried it four more times without a reboot.

 

Worked on a Cadillac today and probably started the car a dozen times with the scanner attached and not a single reboot. I am very pleased with this mod. ;ol;

 

Thanks for update and good to hear that it also works for you.

 

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?

 

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?

It's allways good to be careful

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!

 

Thanks for a superfast reply!
I have BC547B/547C and BC548/548B/548C at home. From this link:
http://bme.yeditepe.edu.tr/Labs/datasheets/BC547.pdf
It seems the difference between 547/B/C is min and max "DC current gain"
Could I use any of those I have instead of BC547?

 

I'm quite confident, that any of them will work!

 

Great, thanks! I have just ordered the regulator board, I'll get back with the result in a few weeks.

 

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!

 

I also can confirm that it is very tricky to remove the regulator. Finally I worked with a friend and two soldering guns to heat all the pins simultaneously and lift the regulator bit by bit...

Thanks for confirmation.

 

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.

 

$10 to anyone in the USA, shipped to your door. Tired of it sitting on my desk going unused. Ready to be installed.

 

$10 to anyone in the USA, shipped to your door. Tired of it sitting on my desk going unused. Ready to be installed.

I'll buy it so i don't have to wait weeks for my parts to come in. Send me a pm with your email address and i will send you paypal if that is ok.