MicroHacker Forum

Go4IT wrote: ↑21 Jul 2020, 22:37

oscarboiro wrote: ↑21 Jul 2020, 22:01 from instructions need ADV7181C, and i have 1x ADV7181B
is possible the problem comes from wront video ADC?

Definitively, they ARE DIFFERENT!
"C" is needed for MCA graphicsboard to work:
diff_adv7181c_and_adv7181b.png

oscarboiro wrote: ↑21 Jul 2020, 22:01 I look the graphic board of NX (DVD) and have ADV7181B

Oh boy, you should have better looked at my BOM instead... such a pitty.

Besides it's interesting to know that NX-Plus uses the B-Version, we know that the NX graphicsboard is different from MCA.

So, don't let this drag you down - Go fetch a C-Version, replace it and you are there!

Thanks!!! tomorrow i need boy another, but this time the correct part!!!

but im happy, i dont broken the graphic board!!! hahahaha

thanks!!!!!

Today i order the ADV7181C, in two days i think comes.

I remember when i made a video input selector with arduino, before use a max video switch, i use a transistors, and in the first test, i received a wrong video signal, very similar of video image in this MCA, i do´t remember, but i think it was the faulty transistor, now Is possible i have a bad component in the MCA graphis board.
Today i remove a capacitor of 100nF andwhen i read, have 118nF.
i don´t trust that all the components have the correct value, the oscillator they sent me was wrong, and possibly not the only one.
next time, i will read one by one, and check the value before welding.

i don´t know where the fault is, but i know it has to be a faulty or wrong component.

now my options are:

1- Replace ADV7181B to ADV7181C, if work, i made a party , else go to step 2

2-Try to find test points to verify and try to find a possible defective component (Test all).

3- Remove all components, clean the board, and start process, in this time testing all parts before weld.

4-Make a fire and send all to garbage!!! hahahah

I think 1) is sufficient. If 2) comes in place, we can share data. I give you some MPs and values and you check it.
Besides, don't be too picky with values. Most parts, especially caps ans resistors have huge tolerances of up to 20%, which is normal. If there where critical parts with less tolerance, i would put a note on it. Otherwise simply cope my BOM, try to be as lean as possible and it will work. It took me a long road to get there, and i looked after those params.