I just ordered some parts and will update you as soon as they arrive. The NJM2369 is actually pretty hard to buy and the delivery time is about 14 days.
The waffle plate measured out fine. Also after removing the plate the current draw stayed exactly the same, so I do not think that the plate...
I have to thank you for your time and patience!
I think I desoldered all external components and tested them one by one at this time, including IC702 and I renewed the solder joints of T302. I also desoldered C841 and measured 150uF across all frequencies.
For further reference, desoldering...
That is the output pin, when it is running:
And thats the output directly after shorting pin 1 and 2 with a resistor:
When it is running it is definitely switching the FET.
C843 and C844 are now both new but the problem is still the same.
Feedback when it is running:
CS is at 1V but got some noise on it, I tried to capture it with AC coupling:
I get 0.016 Ohms between pin 1 and 3 (4 wire measurement) and I think I even traced it out a few days ago, they are both connected to GND. So I can only connect the resistor between pin 2 and GND and it starts after removing the resistor.
I also just replaced C844 with a new one from a good...
The 4.7k resistor works but something like 10k seems to be to high. So the 4.7k resistor is the highest value this reliably is working. When I short pin 1 and 2 absolutely nothing happens, the board starts working after removing the resistor and stays in this state.
At the time the board was...
Thank you so much for your effort and great details about IC702! I will try out your suggestions today and add further information to this post.
One thing that is strange is that shorting pin 1 and pin 2 with a 4.7k resistor actually makes IC702 switching again. Something has to go wrong when...
@coulomb
TR310 is fine. I desoldered the MOSFET and tested it in a test circuit and it is switching normally.
@kiev
I just double checked the voltage divider and my measurements and solder joints are okay. I resoldered the 220k resistor and removed the 330k one. Even after removing the 330k...
I just meaured all pins with the oscilloscope and pin 7 is switching (picture) to some degree. I also desoldered all parts seen in the picture and checked them, all resistors are fine and I added the measurement values of the caps to the picture.
After quite some time I finally have time to take a last approach in repairing the OBC. I desoldered TR310 and the K3484 is working within its specs. Before desoldering the passive components one by one and checking them, is there something else I should try?
I took some high quality pictures...
I tried everything, from cold spray to hot air but I could not replicate the functioning state it was in before. I normally detect defective caps by using cold spray, but I could not find any defective cap, it is a complete mystery to me.
I also tried to find shortet caps using my multimeter...