Rodime 20MB Macintosh Plus External Hard Drive Capacitor Replacement

[_nec6678]

I've had this external Rodime external 20MB hard drive with my Mac Plus for as long as I've had my Mac Plus. I was using it once a couple of years ago, when some sickly-sweet smelling smoke came out the back. Conveniently, there is a fan on the back of the unit that allowed for the quick spreading of the smoke, and conveniently I was using this drive in a small room. I open it up, and I see that one of the electrolytic capacitors has vented, along with some seemingly okay, albeit sketchy, Rifa capacitors. Fast forward a couple of years to now, when I finally decide it's time to order replacement parts for the unit. Listing the values of the electrolytic capacitors was easy, except for one that was in a sleeve I had to cut off in a tight space. However, I've never dealt with Rifa capacitors before, so i know very little on what to replace them with. There are the translucent brown ones, labeled "4700pF" along with "Y", so I am assuming these are 4700pF Y-type safety capacitors. Then, there are some white ones, labeled "220n K 100- RIFA 353 FW2". From what I've read, these are not part of the main power circuit. Finally, there are some similarly-shaped solid yellow Phillips rectangular prisms. They are labeled "0 01/250V~ X2 W1 330 44 MKT-P 40/085/21 6PF. I have attached some pictures, although you will have to excuse the relatively poor image quality, since I took them with my Sony Mavica floppy disk camera. I'm not quite sure what all these letters and numbers mean, and I don't want to mess anything up, so any help on identifying what replacement parts I need to order would be greatly appreciated.

 

[JDW]

Sony Mavica floppy disk camera photos! Love it!

The translucent brown 4700 pF is a Type Y (line-to-earth) safety capacitor. Not sure if it's Y1 or Y2, but it's probably 250VAC rated, which means that either Y1 or Y2 can be used. That's because Y1 offers an 8,000V impulse rating, while Y2 is a 5,000V rating, and Y1 typically works with wall socket voltages of 250VAC and higher, while Y1 is often 250VAC and lower. But you'll need to measure the lead spacing to choose the right part, and once you have that info, you can select one from Mouser here:

https://www.mouser.com/c/passive-components/capacitors/safety-capacitors/?capacitance=4700%20pF&product=Safety%20Film%20Capacitors&product%20type=Safety%20Capacitors&safety%20rating=Y1~~Y2&termination%20style=Radial&instock=y&active=y&rp=passive-components%2Fcapacitors%2Fsafety-capacitors%7C~Safety%20Rating

The solid yellow 220 nF (0.22 µF) is a Type X2 (line-to-neutral) safety capacitor. Again, lead spacing will determine your pick, which you can see on Mouser here:

https://www.mouser.com/c/passive-components/capacitors/safety-capacitors/?capacitance=0.22%20uF&product=Safety%20Film%20Capacitors&product%20type=Safety%20Capacitors&safety%20rating=X2&termination%20style=Radial&voltage%20rating%20ac=275%20VAC&instock=y&active=y

The solid yellow 10 nF (0.01 µF) is also a Type X2 (line-to-neutral) safety capacitor. Again, lead spacing will largely determine your pick, which you can see on Mouser here:

https://www.mouser.com/c/passive-components/capacitors/safety-capacitors/?capacitance=0.01%20uF&number%20of%20pins=2%20Pin&safety%20rating=X2&termination%20style=Radial&tolerance=10%20%25&instock=y&active=y

Note that a Polypropylene (PP) Dielectric is superior to "paper".

Max. Operating Temp. of 105°C or higher is just fine.

Please be sure to let us know how the recapping job goes. And if your ears ever need a rest from all that spinning platter noise, a BlueSCSI or similar SD card drive solution offers not only silent operation, but very low power and little to no heat too.

 

[_nec6678]

Thank you very much! I was able to find the same parts on DigiKey, and put them into this list. The white and translucent ones have 10mm lead spacing, and the yellow ones have 15mm lead spacing. Judging by the condition of the translucent Rifa capacitors, I am replacing them at just the right time, since they look and feel cracked!