Tech Edge WBO2 Forum

[jmlay]

I must not this was a functional unit since the build in 2003. At some point pin 6 of the of the O2 sensor failed a connection, requiring repair. Post this repair I was able to calibrate the O2 sensor, note I had the connector disassembled & the wires plugged into the sensor with no crossed connections.

Feeling good about my repairs & the ability to calibrate I reinstalled th unit in my auto preeminently. Unfortunately I failed to power down the unit & when running my cable I either shorted a wire to ground or shorted 2 or more wires together, where was my head... Found the 3 amp fuse blown, replaced. Since this time the unit will not function, I get a power light only when the O2 is connected, power & heater when o2 is disconnected (both solid).

I performed some testing with the results below. I do not know if I have blown the st202 & the atmel or both. Seeking any advice available!!!

=======================

With O2 disconnected:

-Power & Heater lightning on solid

With o2 connected Power on solid

Power & ground test:

- section 2.x power tests are within specification

loopback test, section 1.5 with pin 2 & 3 jumperd:

- Terminal would echo 1 charater but no the charter pressed.
- Changing baud rate of terminal to 4800 echoed a single charater a pressed, not 2 charaters as described

loopback test, section 1.5 with pin 2 & 3 od U1 jumperd:

- Terminal echoed a single charater a pressed, not 2 charaters as described
- Changing baud rate of terminal to 4800 echoed a single charater a pressed, not 2 charaters as described

[Thomas]

Hi!
Hm. Doesnt sound very promising :-/
1st of all you should check if there is Power on the unit. As far as I know it should get its current directly from the LM7805 (or whatever) voltage regulator.
So if you say you get Power LED "on" only when sensor is plugged I assume that the unit gets some current "backwards" via the heater-wire. Probably some shorts in the connector plug? Please double check to prevent it from further damage.
If the Wideband is unplugged, the leds should work. If they don't - check if there are 5V at the microcontroller. If they are, check if you can communicate via serial cable to the unit (from your PC by using wbutil.exe). If you can't and the Atmega gets current, try do re-flash the unit (Firmware upgrade). If you don't succeed, set the rescue reflash jumper and try again. If this won't work there is a high chance that your atmega is dead (because loopback worked if I got it right?).
Thomas

EDIT: Sorry, if Term echoes a single character it probably is NOT working. Just unplug the RS232 cable and see what happens: If you get single echo with cable plugged and no echo at all with cable unplugged: All is ok.
If behaviour with plugged and unplugged cable is the same there is something wrong.

[jmlay]

Thomas,

Thanks for responding. Was a very SAD day indeed, I should have been more cautious...

All power is correct at all IC's & processor. Microcontroller has 5 volts. O2, cable & plug all test good, no shorts or crossed wires.

Honestly I am not 100% positive the RS232 tests were successful. The test procedures indicated for every charter I pressed I would see 2 of that charter in HT, I received a single charter but only after flipping the baud to 4800. AS you described this could be the Atmel as the ST202 will not be the deciding factor in baud rate. Communication via hyperterm certainly seems to be an issues so am not real confident WButility will be a success. I have not tried the WButility since the initial failure, will execute this this evening along will the other options you describe.

I will see about picking up another st202 & another Atmel today. I "assume", if all other components are working properly I should be able to flash the Atmel.

Thanks,
Mike

[Thomas]

Hi.
Try the following: Shorten Rx and Tx at your serial cable and see if you get douple echo if you press any key. Then, you'll see a working loopback. The Baud rate should be irrelevant.
If you see every character once or twice depends on if you have local echo enabled or not in hyperterminal.
It is important that you can NOT replace the Atmega with any other atmega.
You need an genuine preprogrammed TE µcontroller, because only this one has the bootloader inside.
Btw: If your HIN202 git fried replace it with a MAX202, to my experience they work much more reliable.
And check if there is still some shorts on ouer sensor cable!

Thomas

[jmlay]

I replaced the st202 with a max232, rs232 results are the same with either. WBUtil times out trying to connect to the com port, port5 in my case thru a USB adapter. If I jumper 2 & 3 I get a single echo back to HT, indicating the serial connection to the end of my cable is good. I will be checking thru to the Atmel next but I believe the RS232 driver is working fine & the problem is at the Atmel side. I may go ahead and order an new Atmel from TE if possible.

I did re-pin the cable due to issues we discussed in another thread in regards to the incorrect connectors. I am 100% confident in the cable build for my 7075 O2 sensor. It tones out as it should with no shorting between the pins or ground. I am wondering if there is a blown logic driver that is pulling down when the O2 sensor is attached. I was working in a not as well lit area last night & I could see the heater LED was on but very dim with the O2 sensor plugged in, previously I thought it was not lit. A refresher on the LED's, when O2 is not connected the heater & power LED are on & when the O2 is connected heater is very dim & power is on..

[Masi_K]

Or a blown or cracked solder ?

[jmlay]

Nope, all looks good. I have kept the smoke in the traces where it belongs.

Mike

[jmlay]

All,

Just wanted to update this thread. I ordered a new Atmel quite a while back & finally had the opportunity to install it last night. Seems to be working 100% after replacement. Will test in the next week or 2 in the vehicle but I expect no issues.

word to the wise NEVER for get to remove power from the controller when the wires are exposed!!!!

Mike