Anyone Put A 10-Turn On A Megawatt.
A ten turn potentiometer? With poor eyesight and a crippled hand I sure could use some disassembly and reassemble tips. Such as what needs to be done to gain access under the board to solder leads ...
Forum Discussion
I have done the cheapowatt, and the Meanwell, but not a Megawatt. The pics somebody posted of the Mega's internals did not make it look significantly different than the cheapowatt. The components looked burlier but the circuit board did not appear to have more traces or more tightly packed traces. The cheapowatt appeared to be a copy of the megawatt, just using the least expensive components they could.
My Meanwell is a double sided circuit board and more closely clustered traces.
The Cheapowatt thread has some good pics in it of the Megawatt provided by Mena661:
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27939135/srt/pa/pging/1/page/9.cfm
BOth cheapowatt and meanwell used 1K ohm potentiometers. I know you said you bought 500 Ohm 10 turn pots. I'm not sure these will have the voltage range you desire. IIRC the 0 ohms was maximum voltage and 100 ohms minimum voltage, so a 500 ohm unit will likely increase the minimum voltage well outside of float range, if that is a factor.
That is of course if it has a 1K ohm pot.
I know the Pot on my Meanwell when removed read 973 ohms, and before I swapped it out minimum voltage was 13.23v. The 10 turn 1k Ohm pot I got maxed out at 1017 ohms, and when installed then minimum voltage fell to 13.12v when unloaded, I've seen 13.06v under a light load.
Max voltage with either Pot was 19.23v unloaded. I never loaded it at max voltage.
The Meanwell was more difficult to disassemble, and significantly harder to desolder and resolder some wires to it, but I've gotten a heck of a lot better at soldering since I did the Meanwell last October.
The Thermal pads between transistors/ and heatsink might tear on removal.
The thermal grease applied in the factory is nasty stuff, seemingly impossible to clean once it gets on fingers or other surfaces.
Actually accessing the circuit board is quite simple, just removing the phillips screws from the casing's lid, pulling the connector for the cheesy sleeve bearing fan, and then those Phillips screws which go through the bars which hold the transistors tight to the casing or heatsinks on the sides.
If you have the Megawatts with you next time you are on this side of the border, I'd gladly do it for you. I am about 40miles north of Chula Juana. I can give you some of those 18650 cells I just harvested from my older laptop battery pack. Not sure of their remaining capacity yet, but I really only need about 6 to 8 of them in my rotation, and I now have close to 18 of them left. But the panasonic ncr18650B's are not in the equation. I paid ~12$ a piece for those and their greater capacity is easily noticed in my uses.
My Meanwell is a double sided circuit board and more closely clustered traces.
The Cheapowatt thread has some good pics in it of the Megawatt provided by Mena661:
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27939135/srt/pa/pging/1/page/9.cfm
BOth cheapowatt and meanwell used 1K ohm potentiometers. I know you said you bought 500 Ohm 10 turn pots. I'm not sure these will have the voltage range you desire. IIRC the 0 ohms was maximum voltage and 100 ohms minimum voltage, so a 500 ohm unit will likely increase the minimum voltage well outside of float range, if that is a factor.
That is of course if it has a 1K ohm pot.
I know the Pot on my Meanwell when removed read 973 ohms, and before I swapped it out minimum voltage was 13.23v. The 10 turn 1k Ohm pot I got maxed out at 1017 ohms, and when installed then minimum voltage fell to 13.12v when unloaded, I've seen 13.06v under a light load.
Max voltage with either Pot was 19.23v unloaded. I never loaded it at max voltage.
The Meanwell was more difficult to disassemble, and significantly harder to desolder and resolder some wires to it, but I've gotten a heck of a lot better at soldering since I did the Meanwell last October.
The Thermal pads between transistors/ and heatsink might tear on removal.
The thermal grease applied in the factory is nasty stuff, seemingly impossible to clean once it gets on fingers or other surfaces.
Actually accessing the circuit board is quite simple, just removing the phillips screws from the casing's lid, pulling the connector for the cheesy sleeve bearing fan, and then those Phillips screws which go through the bars which hold the transistors tight to the casing or heatsinks on the sides.
If you have the Megawatts with you next time you are on this side of the border, I'd gladly do it for you. I am about 40miles north of Chula Juana. I can give you some of those 18650 cells I just harvested from my older laptop battery pack. Not sure of their remaining capacity yet, but I really only need about 6 to 8 of them in my rotation, and I now have close to 18 of them left. But the panasonic ncr18650B's are not in the equation. I paid ~12$ a piece for those and their greater capacity is easily noticed in my uses.
