zd-20u
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ole00
New board revision?
Hi, I really want to attempt this mod, but the big issue is my board revision is quite different from yours (mine is ZD-20U-4, while yours is ZD-20U-8).
Attached are the pics of the PCB front and back.
What modifications do I need to do to my board?
The pictures unfortunately do not show how the traces look underneath the big black capacitor, what's underneath the C1 capacitor (there seems to be trace in the middle of the C1 footprint ?) and also what's underneath the D (diode on the left also has a trace in between the footprint obscuring the point where it is connected to). If you are willing /able to desolder D, C1 and gently lift the big capacitor (if you break it, the replacement is cheap) to reveal the traces I think I might be able to help (or "help" in the unfortunate case). It is a risk, I might make a mistake and damage your soldering iron beyond repair...
No rush. Also if you could investigate where the red wire is exactly connected (on the right side, next to C1). It looks to me the red wire is a ground patch (probably design flaw fixed in later revisions), but it looks the spot close the C1 (the bottom pad) is quite crowded, there seems to be a little via there. I'm not sure whether the via and the bottom of C1 are joined or not.
Whelp, I forgot to mention that red patch wire is something I soldered there to keep it permanently turned on when connected to a power supply. It wasn't there by default. The original metal lug wire was connected on that barely soldered pad on the upper left of the zener diode
Thanks for the pictures of the revision 9, it's interesting how "innovative" these guys are :). I can't spot the difference between revision 8 (only the solder point of the brown thick wires are square and possibly machine soldered rather than manually) and revision 9. Am I missing something? Anything unusual on the bottom side of the PCB? The left part of the PCB on my instructional pictures show the D1 and the silver "shake" tube and the yellow wire already de-soldered, as the mod requires them to be removed.