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Hi everyone.. I happened to see a gm clone MDI on aliexpress with wifi for just under $128 and decided to roll the dice.. I have a few clones already and my genuine MDI bit the dust after many years, it gets old fast remembering to bring it home, then bring it to work,etc so I gambled on this one..

Anyways.. it has a problem.. Pin 2 vpw fails.. It can read or sniff messages, or if you use the Data Bus Diagnostic Tool you can look at the voltages like an oscilloscope and it does see voltages and can see modules on the bus.. Problem is whenever it tries to send it fails.. With nothing on the bus you can see a little tiny rise in voltage, 0.00 volts to 0.010 volts, maybe.. Such a minimal change it damn near looks like noise except it only shows up as jitters when I try to send a command, I'll try to remember to get a pic if anyone wants to see it.. This makes me think it's making an attempt but the circuit that raises the voltage is messed up.

In any case my question is has anyone repaired one of these? specifically for the vpw write circuit? I'm assuming it uses some sort of transistor to raise the 'talk' voltage and that would either be missing or broken or the resistors/diodes/fuses,etc are also absent or broken.. Hopefully it's just a bad solder joint, these aren't exactly excellent examples of soldering and assembly, lol..

I do have another clone to take apart and compare, that will be my first task, maybe tonight or maybe sometime this weekend but I thought I'd throw this out to you guys and see if anyone's been there already..

I feel your pain lol
I bought a tech 2 clone from aliexpress that wouldn't communicate on vpw.
i just bought another vci module from a different aliexpress seller .
I also bought a mdi 2 with wifi from aliexpress
It turned out to be a mdi inside a mdi2 case

If it is going to take you longer then an hour and half to fix it
just return it and get another

mattyjf01 wrote:I feel your pain lol
I bought a tech 2 clone from aliexpress that wouldn't communicate on vpw.
i just bought another vci module from a different aliexpress seller .
I also bought a mdi 2 with wifi from aliexpress
It turned out to be a mdi inside a mdi2 case

If it is going to take you longer then an hour and half to fix it
just return it and get another

lol, thanks.. Yeah on the MDI2's being fake mdi 1's, I broke down and bought a real one..

I found a little time and compared the boards to another clone I had, said screw it and swapped boards out, It was the lower board causing the problem. Still didn't see anything wrong with it, sent out a message to the seller.. Never tried returning anything with aliexpress, I'll see what happens..

ironduke wrote:

mattyjf01 wrote:I feel your pain lol
I bought a tech 2 clone from aliexpress that wouldn't communicate on vpw.
i just bought another vci module from a different aliexpress seller .
I also bought a mdi 2 with wifi from aliexpress
It turned out to be a mdi inside a mdi2 case

If it is going to take you longer then an hour and half to fix it
just return it and get another

lol, thanks.. Yeah on the MDI2's being fake mdi 1's, I broke down and bought a real one..

I found a little time and compared the boards to another clone I had, said screw it and swapped boards out, It was the lower board causing the problem. Still didn't see anything wrong with it, sent out a message to the seller.. Never tried returning anything with aliexpress, I'll see what happens..

The key to winning a dispute on aliexpress is to clearly document the problem. Take Pictures (I doubt they'd do much good in this specific case) and Video and use simple language so the translator doesnt mess it up. Also make sure to buy items that have 'free returns' which actually means the seller won't ask for the defective item back. It might not be too expensive to ship something back depending on your proximity to China.

Well, Aliexpress did message me back asking for video proof which I simply took video of the MDI I purchased and my plow truck and it failing to communicate and then another video with my mdi2 and it communicating just fine.. Included information including that I had access to another MDI2 and 3 other MDI's I could video as well if needed.. They came back and offered me half my $$ to keep it or full refund if I shipped it back..

I took the half money back offer.. It seems to work ok with pin 1 and pins 6&14 and 12&13 at least.. Don't need VPW pin 2 that much, I'll label this one as what's wrong with it and probably keep it at the house. I have 2 other broken ones so I might be able to swap some parts.. Not sure on swapping parts from the genuine MDI but the other broken clone is fair game to swap out I would assume..

Thanks for suggestions, I kind of want to take some time this winter with a scope and another clone MDI to see if I can fix this one.. Boards looked identical between them when I looked earlier, no missing components..

Half is better then a stick in the eye!

get yourself a genuine cable and it should work with the clone. size of the connector is slightly different but its easy to fix