Electronics > Repair
[QUESTION] Defective Factory CH341A, which changes to do?
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md5001996:
Anybody know which components to replace?

I see that Quartz crystal oscillator is 13Mhz (it says TXC 13.CUS37) must be 12Mhz, and C5 must be replaced with a 15~30pf capacitor (because that 0 ohm is a resistance acting as bridge). Although i do not know the size of C6 capacitor (must be 20pf)

Also, i dont know if C4 has the correct capacitor, because is small and must be 4.72nf.

Can someone validate me if it will work as I have it? and if not, what components to change besides the ones I named?

Maybe I'm wrong, that's why I ask here to know what to do really and not to lose my CH341a that I can not return to Amazon, since it arrived to me after 2 months.

Things I understand I should do after changing the wrong components:

* Do the mod from 5.5 to 3.3v by installing a switch that connects the VCC leg of the CH341A and switch between 5v (C2) and 3.3v (C1).

* The WP /HOLD mod (which I am not clear on what it fixes, but I would like to make the mod to ensure more compatibility). Although it seems that my ch341a has different tracks than other users, so i will need a new image to do correctly the mod in my ch341a. Besides that, I don't know which resistor value would be the ideal size for the mod ( 472, 271 or any libreboot recommended between 1k to 10k ohms ?)

Swich mod and wp /hold mod photos are not mine (it's todo photos). Any help will be appreciated!

m k:
https://pdf1.alldatasheet.com/datasheet-pdf/view/1132609/ETC2/CH341A.html
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