The "Indestructible iMac" v2.0 - Poly revision 2

[momaka]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

so i can use mobo-grade caps in a psu with using lower-capacity as well? cool!

Not really. The output caps of a PSUs are in series with a toroid or coil more often than not - basically they form a LRC circuit. Changing the capacitance and ESR can significantly change the operation of this circuit (i.e. resulting in more ripple), so generally polymer and motherboard-grade capacitors are not recommended for PSUs.

[Topcat]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Not really. The output caps of a PSUs are in series with a toroid or coil more often than not - basically they form a LRC circuit. Changing the capacitance and ESR can significantly change the operation of this circuit (i.e. resulting in more ripple), so generally polymer and motherboard-grade capacitors are not recommended for PSUs.

Agreed. You can get away with it sometimes, but its not recommended. I've never tried polymodding a psu, just because the ESR is so low, atleast on the motherboard-grade polies I have in stock.

[shovenose]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

ploys are in use in some more expensive psus. is there such thing as a psu-grade poly?

[yyonline]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

ploys are in use in some more expensive psus. is there such thing as a psu-grade poly?

I've seen Chemicon PSA in some Seasonic PSUs. So, that's the same polymer I see used on many motherboards. So...that points to no. I'd bet that the PSU was designed with polymers in mind. So my guess here is that the PSU design probably has more to do with it than the exact type of polymer caps used.

[seanc]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

I've seen Chemicon PSA in some Seasonic PSUs. So, that's the same polymer I see used on many motherboards. So...that points to no. I'd bet that the PSU was designed with polymers in mind. So my guess here is that the PSU design probably has more to do with it than the exact type of polymer caps used.

Aye, there's one in my Seasonic S12-II 500w PSU. It shares the same layout as the Antec EA-380 - which doesn't have any polymer. They must have adjusted other components accordingly.

[shovenose]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

is it true if you use a ploymer in a psu it willshort out and explode?

[seanc]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Considering mine has been working fine for 2 years and came from the factory this way...

[370forlife]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Usually those power supply's output filter are designed around solid caps. They are usually found after the coils where they can actually help reduce ripple a bit. They are used on the DC-DC VRM cards in power supplies that use them as they work out much better there.

I believe there was a AcBel psu made for Gigabyte that used all solid caps on the output. It had high ripple and poor transient response.

I still want to find out if those cheap psu's with no pi-filters would benefit from using ULESR caps.

[Logistics]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Ah, HAH! So I made a wise decision in ordering the LG's. I was a bit confused because in my Digi-Key catalog the Nichicon LG is not categorized as a polymer capacitor, nor does their catalog describe it as one, but the ACTUAL Nichicon datasheets say it is a polymer so I ordered them, anyway.

*sigh of relief*

[ratdude747]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

FWIW I still have the 17" I was sent to test... It sees almost no use though thanks to shoddy PPC software support. It still runs well.

[godonr]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Too bad progress made these obsolete. We've sent several hundred to the grinder. They still make a great first computer for kids! Glad you got to enjoy my castoffs for a while anyway.

[momaka]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

What a shame! Perfectly good hardware ruined by software "progress" (I call it software planned obsolescence).

I just poly-modded an old Pentium 4 HP DC5000 SFF computer today. Probably not worth the time and effort to anyone these days, but I think they still make decent office PCs. Coupled with old indestructible 80 GB HDDs from WD and Seagate, I think these will last quite a while. There's a big pile of them at work. I think I might fix them up.

[Topcat]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

I still have 3 working iMacs. I finally had to get my wife something a little faster....she got the garbage find EEE all-in-wonder C2D/4GB ....still cranking along like a champ!

[ratdude747]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Still have my Poly prototype... not in service though (nowhere to use it right now). But it runs 100% stable so I have no doubts about the cap blend.

[mockingbird]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

What a shame!

I agree... I've been meaning to set up a Hackintosh so I can run Sweet16 to emulate a IIgs.

Up till now I've been using Kegs on Windows but it's not that good at all. Maybe I need a faster CPU.

[Uranium-235]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

tc you need to have a part of your store dedicated to selling shit you fix.

[Topcat]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

tc you need to have a part of your store dedicated to selling shit you fix.

I should....I have a ton of crap here I need to sell.

[Logistics]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Both the 17" and the 20" I recapped run fine, but even with a fresh install of 10.4.11 they seem like they aren't all that fast. You know that fast feeling you got when you installed that new copy of windows on the best hardware available during that time... just don't get that with these iMacs.

[JuniperSprouts]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

I would HIGHLY recommend maxing out your RAM on those PPC models.

Also:
http://mintppc.org/
http://penguinppc.org/about-2/distributions/

-

Another idea:
Gut the G5 iMacs & install a Raspberry Pi or a U-ITX or a M-ATX board...anyone know if it would possible with a PC motherboard's VGA (or DVI or ?) & the iMac's controller & inverter & ??

[Logistics]

Re: The "Indestructible iMac" v2.0 - Poly revision 2

Yeah, the 1.8GHz 20" I recapped is for me, plus the wife got the 17" G4 she wanted. On the 20" I'll probably load Lubuntu or perhaps Mint since I want it for more utilitarian reasons like research. But I'll look into maxing the ram like you said.