| Electronics > Repair |
| Aston Martin DB9 rear light LED driver repair.......... FIXED!!! |
| << < (3/6) > >> |
| jh15:
Check that all commons, grounds, earth is fully intact. very important. Many check for power supply voltage, ripple, probe on some ground, but the pcb may have corrosion/opens. |
| cpposteve:
Hi all. Thanks for all the help. I scoped the inputs to the mosfets last night to see if I could see switching on briefly then shutting down. Possibly to an error. As I was right. I did a single capture of it and could see it kicking in with a pwm signal but then shuts down. Was measuring 10.8khz but the period it was on for varied. Found it hard to measure as my memory depth on my crappy owon usb scoop is just rubbish. More poking and probing needed tonight. As for the grounding points, this was next on my list. Even though I have check many things multiple times. I’ve not gone and checked all ground points yet. If I could understand how the 2813d-3 works better I think it would help me fault find. Cheers all |
| fzabkar:
ISTM that it would be worth the time to trace the circuit around one of the four outputs. |
| cpposteve:
well after 6 hours on it tonight i can finally say we have success. luckily there are 4 2803d-3's in there, so checking voltages on each pins is what helped me here to compare. Pin 1 was getting a 2 higher voltage at its pin. tracing it back it is fed from the out put of the quad op-amp. the two inputs are fed from else where, but passing via a resistor, of which one of them was open circuit causing the op-amp to go higher then it should, fitted a new 0805 resistor and hey presto its fixed. i have spent almost 30 hours on this, and did not want to give up untill i found the issue, and im so glad i didnt stop until i did. would just like to say many thanks to all that have helped and given advice. cheers steve |
| BillyD:
It might be a fair bit of your time, but I bet it's still way cheaper than having to buy a new unit! Well done, was following this one with interest and no doubt someone will google it in future and find it useful. |
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