I have a TAC20-03 where the 24V LED's and the 5V LED are all flickering. I have 23.6VDC coming in from the power supply to the IOA and no measurable AC ripple. I have swapped Power supplies with another car and same issue. I installed new IOA board and 186 board from TKE and still the same issue. I have disconnected all the 24VDC outputs from the IOA board and still the PS lights are flickering and the 5VDC LED is flickering rapidly. Not sure what to check next. Also the WD LED is out on the 186 board but I think that is because the 5VDC is not working properly. looking for suggestions. Thanks
Still having power issue with this job. Removed all connectors for IOA except CON28 and also removed 186 board from IOA and still the 24V LED's and the 5V LED flicker. The IOA board is dead...no WD LED. Second IOA board, Second 186 Board and second 24V Power Supply...all still doing the same thing. Could the Transformer be bad? Or do I have a bad ground? I can't connect using IMS because the 186 isn't working. Can I try to connect with Hyperterminal to try and load SW? Looking for ideas and suggestions. Thanks
I wouldn’t worry about connecting a computer until you have a solid P5. When you’re taking your 24v readings what are you referencing for ground? Use the G24 test point on the IOA. If you see a flicker when reading P24 with the black lead there but not when reading from controller ground there is probably is a bad G24 connection. You may already be reading from the test point though. Pulling FB3 and FB4 fuses would isolate the P24 that makes P5 a little bit more. What do you actually read on P5 from G24? You can read get P5 on Con35 pins 27-30. I would want to install a new IOA with just Con28 plugged in and no CPU. Is it possible you replaced the IOA first with the old CPU so that a bad CPU could’ve taken out the new IOA? That’s all I can think of except putting a scope on P24 to see if there’s something you aren’t seeing with a meter. Or using a different 24v power supply plugged into the outlet in the machine room to rule power out.
