Williams CPU Rev. D Coil replacements

Kaworu5

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I am doing some repair on a Rev D CPU board, and the induction coils look like they are starting to unravel. I am scouring Digikey for replacement, and this is the closest I can find:


The schematic calls for a 2 uH .5 amp coil, this one is 2 uH at 2.5 amps. It "looks" the part, but I am concerned that the larger current capacity is asking for trouble.

Any thoughts?

- Jon

p.s. I tried searching the forums and came up with nothing, so if this has been answered, I am happy to be pointed there as well.
 
I am doing some repair on a Rev D CPU board, and the induction coils look like they are starting to unravel. I am scouring Digikey for replacement, and this is the closest I can find:


The schematic calls for a 2 uH .5 amp coil, this one is 2 uH at 2.5 amps. It "looks" the part, but I am concerned that the larger current capacity is asking for trouble.

Any thoughts?

- Jon

p.s. I tried searching the forums and came up with nothing, so if this has been answered, I am happy to be pointed there as well.
I defer to braedel
 
I had sourced some from a surplus. They do require some bending of the leads. (I bought all they had...) Send me an message and I will send you a set (3), just cover postage.

~Brad

Before:
1746157715277.png

After:
1746157754051.png
 
Originals were 100uf x 25v. I like them to be physically the same size, so went with a 150uf @ 35v Nichicon. The 330uf would normally be great for a filter cap, especially with similar ESR, but since the 'supervisory circuit' that monitors voltages to control CPU Reset depends on timing, that extra capacitance can have an undetermined effect (especially with switching supply). I would probably have swapped them out for something closer to original

~Brad
 
I am happy that @braedel has a surplus of coils, but I realize the original question has not been answered. Can a 2 amp 2 uH coil safely replace a .5 amp 2 uH coil in this application? I am thinking about the spare boards in the collection, plus the boards in Joust and Sinistar that will likely need some refreshing soon.

- Jon
 
I am happy that @braedel has a surplus of coils, but I realize the original question has not been answered. Can a 2 amp 2 uH coil safely replace a .5 amp 2 uH coil in this application? I am thinking about the spare boards in the collection, plus the boards in Joust and Sinistar that will likely need some refreshing soon.

- Jon
Yes.
 
I am happy that @braedel has a surplus of coils, but I realize the original question has not been answered. Can a 2 amp 2 uH coil safely replace a .5 amp 2 uH coil in this application? I am thinking about the spare boards in the collection, plus the boards in Joust and Sinistar that will likely need some refreshing soon.

- Jon
I would agree it can replace from an electrical/filtering perspective, but doubt it could mount on the board(packaging issue). The ferrite core looks like it would extent into a filter capacitor.

I bought a bunch of them (all same value) before I found one that fit and looked like it was from the 'era'.

~Brad
 
I am happy that @braedel has a surplus of coils, but I realize the original question has not been answered. Can a 2 amp 2 uH coil safely replace a .5 amp 2 uH coil in this application? I am thinking about the spare boards in the collection, plus the boards in Joust and Sinistar that will likely need some refreshing soon.

- Jon
Also, only the early Rev D boards used the vertical inductors (they only added them to comply with new FCC regulations). The later Rev D MPU's went with a horizontal inductor and that was also used on the Bubbles MPU (which is unique to Bubbles)

~Brad
 
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