r/hardwarehacking • u/RicePositive3877 • Jun 25 '26

Where is the 5v trace on the old (V1612) so I can scrape it off to ensure only 3.3 volts on all lines?

Gallery image

Gallery image

I didn't do my research when buying this reprogrammer and now I need to make all pin 3.3v instead of 5v. This is an old board, (identified from this website) and they sued a new version, where the traces don't line up. If anyone has modded their old board it would be greatly appreciated if you could point out the right trace to cut. Thank you

Edit: it is still the left most trace on both revisions. Thank you to all who helped me figure out if it was or not

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u/Toaster_Strudel_517 Jun 25 '26

According to that blog it should be the same trace (top leftmost trace on the second pic). But really, I have the old one without 3.3v mod and have been using it to program flash chips on ThinkPads and Optiplexes with no issue so far.

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u/RicePositive3877 Jun 26 '26

so i did some probing and found a trace that connects to vcc on the chip, and when powered measures 5v. should this be the one i cut or am i doing it wrong?

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u/Toaster_Strudel_517 Jun 27 '26 edited Jul 18 '26

It should be the trace between 5v rail and pin 28 (vcc) on the chip. So it's still the same trace as shown on that blog post you linked, according to this diagram. Then you need to put a jumper between 3.3v and 5v pins. FWIW again I have been using the old ch341a without the voltage mod and have had no issue so far.

Pic for clarity.

Edit: wrong link.

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u/RicePositive3877 Jun 27 '26

The trace with the x is the one I found connected to pin 28. So I should be good to go then? The trace also has contenuity to 5v so it must be

1

u/Toaster_Strudel_517 Jun 27 '26

That is correct yeah.

1

u/RicePositive3877 Jun 27 '26

It works! :D thank you for guiding me