SE/30 buzzing sound every 10-12 seconds

[smrieck511]

A little confused here.

I thought tantalums were one kind of capacitor and polymers were another kind.

If when you refer to polymer tantalums, you mean the ones that come in tin cans similar to the electrolytics they replace, then these don’t need derating, i.e. you don’t need to substitute a 16v with a 25v.

This video explains the reasons why you might want to go with 25v polymer tantalums. I did and they have been perfect.

 

[croissantking]

This video explains the reasons why you might want to go with 25v polymer tantalums. I did and they have been perfect.

Thanks - I was confused as I thought polymer and tantalum were different things.

 

[s_pupp]

Thanks - I was confused as I thought polymer and tantalum were different things.

There are aluminum, aluminum polymer, tantalum, and tantalum polymer electrolytic capacitors. It has been my experience that when people talk of “polymer capacitors,” they are usually referring to aluminum polymer.

 

[jmacz]

This video explains the reasons why you might want to go with 25v polymer tantalums. I did and they have been perfect.

Disclaimer: I only scanned the video and didn't watch the whole thing as it's long. I've also used double rated tantalums (eg. 25V tantalums instead of 16V for applications involving 12V).

The quote above is suggesting using polymer tantalums over solid tantalums, and that it's explained in the video, but I didn't see that?

What I did see is JDW covering the fact that polymer tantalums have a 20% derating whereas solid tantalums have a 50% derating. And that what this means is that with polymer tantalums, you can still utilize a 16V part to replace the 16V electrolytic cap on 12V, but with solid tantalums you'd need to use a 25V part to replace the 16V electrolytic cap on 12V. He also mentioned he was having an issue finding a suitably sized 25V solid tantalums. But I didn't see something that specifically said to avoid solid tantalums. As long as you get the right voltage rating (due to derating) in a package that fits, is this really a concern?

Or maybe I'm reading into the quote too much and it was not making a claim of polymer specifically over solid tantalums.

 

[djc6]

FYI everyone in this thread who said the buzzing sound was the hard drive was right - here is a video, I was eventually able to "fix" the drive and image it with a BlueSCSI v2 in initiator mode: https://68kmla.org/bb/index.php?threads/how-to-fix-quantum-prodrive-40s-from-se-30.48844/

I recapped my machine with the following per JDW's video, ordered from Mouser.

TCJE476M025R0050 Qty 10 Tantalum Polymer Capacitors 25V 47uF
TCJB105M050R0300 Qty 1 Tantalum Polymer Capacitor 50V 1uF
MAL211890509E3 Qty 1 Axial Capacitor 470uF 25V
227TTA025M Qty 1 Axial Capacitor 220uF 25V

I like that the Tantalum capacitors are yellow - they blend in with the other yellow components on the board.

Per the datasheet, TCJE476M025R0050E and TCJB105M050R0300E (note the added "E" on the end) are black versions of the tantalum caps if you prefer.