400 K Floppy Drive Repair Components

lundpk

New Tinkerer
Dec 16, 2023
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New Ulm, MN
blc.edu
My retro rebuilding club at my college is starting to work on some projects - one is a Sony 400K floppy drive. I started looking up components on Mouser's website, however I am now seeing issues with the availablity. The message "Mouser does not presently sell this product in your region." is coming up on the website for basic component. JDW did a nice job of putting together a component list.

Macintosh 400k SONY Floppy Drive Electrolytic Capacitors

Big PCB:

6pcs of 47uF 16V, D=6.5mm, H=8mm, Lead Spacing=2.5mm (Mouser: UTT1C470MDD1TP)

4pcs of 22uF 16V, D=5.1mm, H=8mm, Lead Spacing=2.5mm (Mouser: UPW1C220MDD6)

Small PCB:

4pcs of 10uf 16v, D=4.2mm, H=7mm, Lead Spacing=2mm (Mouser: UTT1C100MDD1TP)

6pcs of 10uf 35v, D=5.15mm, H=6.2mm, Lead Spacing=2mm (Mouser: UMV1V100MFD1TP)

2pcs of 0.47uF 50V (could be 16V), D=4.2mm, H=6.2mm, Lead Spacing=2mm (Mouser: USV1HR47MFD)

2pcs of 0.22uF 50V (could be 16V), D=4.2mm, H=5.8mm, Lead Spacing=2mm (Mouser: UMV1HR22MFD)

2pcs of 1uF 50V, D=4.2mm, H=7.5mm, Lead Spacing=2mm (Mouser: UTT1H010MDD)

=================

Are there other sources of components at this time?

Thanks,

Perry
 

JDW

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Professor Lund,

Great to see you posting here on TinkerDifferent!

I was trying to swap out capacitors in my two Carts after reading your post, but suddenly the entire website shutdown...

1759406835194.png


I guess I will need to wait until tomorrow.

Tariffs have wreaked havoc across all my Mouser Carts, I must say. It's very frustrating.
 

JDW

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The site is working today, but even though I have the site set to the Japan region (where I live), I am getting the same message...

1759441099896.png


That indicates it may not be sold anywhere, which is very odd.

Swapping out the caps is going to take time because the ones in my cart originally were the best caps available at the time. Now I am finding inferior ones. They will work, but have higher ESR. For example, consider the specs of one of the 22uF caps in my 400K Drive OA-D34V-22 Cart, with ESR of 270m-Ohms and 350mA Ripple Current:


An in-stock 22uF cap with the same physical size and lead spacing and capacitance has higher ESR, as evidenced by the tiny 50mA Ripple Current:


Sometimes choosing a higher voltage cap will reduce the ESR, but there is an upward limit to that because there will come a point when you won't be able to find a cap in the physical size you need, and if the cap is too big, it won't fit. That's why it takes time to find good replacements. You need caps that fit into the space on the PCB, have the right lead spacing, and also have good specifications (105°C, low ESR where possible, etc.).

Because I need to get read to go to work now, I will need to examine this later.