My 1541ii didn’t come with a power supply. I initially tested the drive with some pins on power leads from my variable power supplies. That worked to test that it was functioning. It certainly wasn’t the best way to use the drive long term. I had a MeanWell dual output 5Volt and 12Volt supply I picked up for another project and had ordered in a 4pin Din connector. The next time I used the 1541ii drive, I had wired it up with that drive. Well right as I started using it the drive failed on me (see prior post). It turned out the SRAM failed for some reason. I don’t know if it had anything to do with the MeanWell supply or not. That supply requires a minimum load on both outputs for it to work properly. I don’t know if it wasn’t getting that load and was sending the wrong voltages to the unit.
After that I went back to using my regulated variable supply for the 12Volts and a 5Volt fixed bench supply I have to test the drive from there on. The MeanWell is intended for another project, but it my not be used for that project either as I don’t think I will be providing the “minimum load” on it.
I decided to order in a used dual voltage power adapter from Ebay to become the new supply for this drive. The one I picked up is 5Volt 1.5Amp and 12Volt 1.5Amp. So it is more than sufficient for the job, provided the quality and condition of the unit is good.
All I really needed to do was cut off the existing 4Pin Mini Din connector and replace it with a properly wired 4Pin Din connector. While I could have purchased a cheap new supply and done the same thing with it, I felt this “old” supply was probably going to be better quality than the cheap replacements. It did come in looking a bit dirty like the picture above, but it cleaned up well and tested fine.
Here is an image of an original supply. Notice the Pinout there. Only 3 of the pins are used on the 1541ii Supply. It is said that the ratings on these original supplies were rather low, potentially causing them to overheat and be unreliable. That sounds a bit like the original Commodore 64 supplies now that I think of it..
Here is the supply with the connector changed out.
While I don’t normally wire the “ring” of the Din Connector up to anything, I did wire the second ground to it as it was a convenient way to keep it out of the way, and I don’t know if that 4th pin goes to anything inside the 1541ii. I probably should have taken pictures of the connector before closing it up.
After soldering on the wires to the pins in the Din connector I insulated all the pins and wires with Liquid Electrical tape. It has a bit of hold to the wires, but mostly is to help prevent shorting in the connector in case a wire pulls loose. There isn’t much room in there to get normal heat shrink on the pins, as it is best to keep the casing to wrap the clamp part of the connector to. I did the same thing with the Commodore 64 power connector, and my new video/monitor cable.
I did put a piece of heat shrink on the cable under the strain relief cover of the Din plug. That piece of heat shrink builds up the end of the cable just a little and makes the strain relief bit grip well. Without it, that relief tends to pull back easily and will likely tear prematurely. I have done the same thing on my Commodore 64 Power Supply’s Din plug. I wish I had done it with my new video cable I made. My old original video cable could have really used it as well, but I don’t want to take apart the connectors and redo all of the soldering on them. There is a bit of risk in damaging the Din plugs as they melt easily when the heat is applied to solder and desolder the wires.
The supply seems to work fine with my 1541ii. The Din Plug quality is rather lacking though, I think it will hold up ok, but the fit isn’t the nicest.
Muldrf's Hobbytronic 