Replacing the last power supply cap

[adamct]

The cap has one terminal on one end, and two terminals on the other end. Do that mean anything?

[adamct]

Well, I now know it is metalized polypropylene, and I know it is DC rated. I also know it is not a motor start cap. So the only open question is whether it matters that it has two terminals on one side...

[adamct]

Hmmmm...could it be an HVAC cap? If so, any reason not to use one?

[Paul Birkeland]

That could be a terminal, or just a mounting stud, but the datasheet you linked to isn't very specific.  It would seem reasonable that the bottom stud is not connected internally, especially since this is a motor run cap.

-PB

[adamct]

Thanks. Here is a picture. I think I'll buy a couple and try them out...

Just to confirm: it is OK to replace the 220uf electrolytics in the power supply with 200uf film caps, right? Would a 250uf cap be better?

Best,
Adam

[Paul Joppa]

The ebay listing says 420vDC but the data sheet says 420vAC. The data sheet says metalized but does not say what is metalized - polyester, polypropylene, dried snot, kleenex, who knows?! The maximum 5kHz frequency makes me suspect it might not be polypropylene - not clear why you "now know it is ..."?!

Sorry, I'm just a suspicious SOB. It's cheap, give it a try - the worst that can happen is a blown fuse, and a REAL Bottlehead buys them by the gross at Costco!  :^)

[2wo]

200uf should be close enough. The data sheet calls out a "Fixing stud"

fixing: Stud M 12 x 16 mm
Maximum torque (fixing) 10 Nm
Case Material :

[adamct]

I found this data sheet, which shows they are polypropylene. I agree it is odd that the data sheet doesn't mention the DC rating, but the label on the cap itself does show a DC rating (you can see it if you enlarge the picture in the eBay listing). The seller confirmed that they aren't motor start caps.

[adamct]

200uf should be close enough. The data sheet calls out a "Fixing stud"

fixing: Stud M 12 x 16 mm
Maximum torque (fixing) 10 Nm
Case Material :

Great. Thanks, John.

[adamct]

Well, I've now got four of them on the way to me. Worst comes to worst, I can add them to my growing collection of unsuitable 200uf caps. I recently received a call from a dealer in Miami, who said he had an eccentric client with a pair of mint, 200uf metalized Kleenex caps available for the right price. Apparently these are fairly unusual, since they still have pieces of vintage snot on them. I'm afraid I won't be able to resist that siren song. The second mortgage on my house should be approved any day now, and then those caps WILL be mine!

[Paul Birkeland]

The data sheet says metalized but does not say what is metalized - polyester, polypropylene, dried snot, kleenex, who knows?! The maximum 5kHz frequency makes me suspect it might not be polypropylene - not clear why you "now know it is ..."?!

Hey PJ,

If I roll you some copper foil/kleenex caps and pot them in mineral oil, can I put them in your BeePre?

[Doc B.]

200uf should be close enough. The data sheet calls out a "Fixing stud"

That's what we call PB when he's doing repairs for customers.

[galyons]

That's what we call PB when he's doing repairs for customers.

+1   

Cheers,
Geary

[2wo]

I still offer my, Earwax impregnated, Gum wrapper caps.

Available in copper or Spearmint...John 

[adamct]

So the 200uf Icar caps arrived today.

THEY.

ARE.

MASSIVE!!!

We will see how they perform, but they make me laugh just looking at them. Here is my question: the terminals are massive bolts with chunky nuts that screw onto them. I'm trying to envision myself soldering leads onto there, and I just don't see it happening. I've got to believe my soldering iron would just lie down and call "Uncle". Any advice? Should I try it anyway? Or do you think I can/should just wrap the stripped tip of the lead onto the terminal and cinch down the bolt? Is a physical connection enough here?

I'm cautious about attempting to solder leads on, as I don't want to get solder in the terminal threads and thereby render it impossible to screw a bolt on if I need to.

Pictures to follow when I get a chance...

Best,
Adam