There are many ways to reset the 1541 Floppy Drive without powering it off, but the most important I know of are:
- Reset via the Serial port
- Power/on Off "Simulation" (Internal reset)
Resetting via Serial port (pin 6 to ground) normally resets all the other devices connected to the serial bus. Some devices avoid being influenced by the line even if they can initiate the reset themself (I read some C64 PCBs do this via an ad hoc diode).
If for some reason, you want to reset the drive without turning it off and on and without impacting other devices on the serial bus (e.g. if you use some internal additional hardware as Megalodos or speeder) you have to "simulate" a power-off and on (as far as I understand practically you have to completely discharge the reset circuit capacitor for as long as 300ms).
So the "internal reset" can practically be achieved by attaching your "internal device" reset line in some specific point of the PCB: as simple as that. When I tried to do that on my 1541 I was anyway stuck because I had clear instructions - and correspondent PCB reset points - only for another specific PCB version. Looking for a solution I was really surprised about how many variants exist of the 1541 PCB. Each of them has a different "reset point" so I had to study a bit...
I came out with a list of different PCB/drive versions and correspondent reset points 
. I want to share this list with this community, hoping it will be helpful to some other noobs like me, and also to ask for help with corrections because Commodore did a mess with PCB/Schematic reference numbers when issuing the docs, so I'm not totally sure that I got them all and right.
You can find the list in the table at the bottom of this post (and the next one)
I have two questions that some of you (with more electronic/experience knowledge than me) can probably answer:
- what is the role of the 220-ohm resistor that is present on some of the PCBs, placed between LS7406 and the charge/discharge capacitor in the rest circuit?
- why in the hell is this resistor present in the pre-release documentation, then it's gone from the docs and from early PCBs, and then came back with new versions of the PCB and drive models.
Please take care: most of these "reset points" are deduced from the schema and PCB pictures 
(I tested them only on my 7400007 PCB), so please double-check not to attach the rest line to +5V. Not my responsibility if something goes wrong.
| Drive Model/version PCB # Schematic # Notes | Reset point on the PCB | Schematic (part of) | PCB (part of) |
| Vic 1540/41
Original (manual) Longboard ------ PCB Assy #1540008 ------- Schematic #1540001 ------- On the manual PCB and Assy exchanged? |
R59 or Pin 12 of UD1 | 1_schema.png | |
| Vic1540/41
Longboard ------ PCB Assy #1540007 #1540008 #1540038 ------ Schematic #1540008 (alternative) ---------- Here the 220 ohn resistor vanished, as on the real PCBs. Sometimes 7406 is substituted with compatible Mitsubishi’s M53206P | R43 connected to C56 the side facing the nearest border of the PCB or Pin 12 of UD1 | ||
| 1541 “Short” CR Board
---------- PCB Assy #1540048 #1540050 ---------- Schematic #1540049 --------- Schematic perhaps numbaered #251749 | R25 facing the large capacitor C46 or Pin 2 of UB1 | see full image for reset points | |
| 1541 “Short” Board A/A2
------------- PCB Assy #250442 #250446 ------------- Schematic #251748 | R57 facing the large capacitor C46 or Pin 2 of UB1 | 4_schema.png | |
| 1541B/C
Short
Board
------------- PCB #250448 ------------- Schematics #251854 -------------- The schematic number is also written on PCB | R12
or Pin 10 UA1 | 5_schema.png |
Some other drives in the next post due to image number limitation 
