Caps! -- LC TDK Power Supply FIX For (Pizza Box Mac's)

[uniserver]

Per James1095's suggestion i just replaced just the (Lite Brown Caps) The Brand name of these pieces of crap is (ELNA) Long-Life

These Certain caps are the only ones that are leaking.





The rest of the caps are "nichicon" brand and they look like brand new.

SO that makes 4 caps total:

2 - 25v270uf

1 - 10v270uf

1 - 25v56uf

Ok so i didn't have any of the proper values in stock

here is a cross reference of what i used instead:

2 - 25v270uf I used: 25v 220uf

1 - 10v270uf I used: 25v 220uf

1 - 25v56uf I used: 50v 22uf

been going for a couple of hours now, this psu was completely dead before.

I think its possible because its just a PSU, the values (might not) be AS critical?





1 down, 3 more to go!



Will post Mouser Links:

http://www.mouser.com/ProductDetail/Nichicon/UPJ1E560MED1TD/?qs=sGAEpiMZZMsh%252b1woXyUXj6oVn37n4HpUQFNOlPXotnU%3d

UPJ1E560MED1TD

Nichicon Aluminum Electrolytic Capacitors - Leaded 56UF 25V 105c Data Sheet 3,615

In Stock

1: $0.20

http://www.mouser.com/ProductDetail/Nichicon/UPM1A271MED1TD/?qs=sGAEpiMZZMsh%252b1woXyUXj48hmzjy2eyCpwVeMTQca2M%3d

UPM1A271MED1TD

Nichicon Aluminum Electrolytic Capacitors - Leaded 270uF 10V 105c 8x15 Data Sheet 3,449

In Stock

1: $0.24

http://www.mouser.com/ProductDetail/Panasonic-Electronic-Components/EEU-FC1E271/?qs=sGAEpiMZZMsh%252b1woXyUXj0hftmTZXYuf23sYLmGRTj0%3d

EEU-FC1E271

Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded 270UF 25V ELECT FC RADIAL Data Sheet 1,173

In Stock

1: $0.24

here are the links for the caps i used:

B41828A5227M8

http://www.mouser.com/ProductDetail/EPCOS/B41828A5227M8/?qs=sGAEpiMZZMsh%252b1woXyUXj1SPYG7TfWbYyJLnEP7%2f9fA%3d

EPCOS Aluminum Electrolytic Capacitors - Leaded 220 UF 25V 8x11,5 SE 9,606

In Stock

1: $0.10

http://www.mouser.com/ProductDetail/Lelon/REAR22M1HBK-0511P/?qs=sGAEpiMZZMsh%252b1woXyUXjz8pyGOK%2fuWw47bPD%2f4N2Ag%3d

REAR22M1HBK-0511P

Lelon Aluminum Electrolytic Capacitors - Leaded 50V 0.22uF 20% 5x11mm Page 902

Data Sheet 8,976

In Stock

1: $0.06

Thread linked: Capacitor Replacement Thread . . .

 

[mcdermd]

Very nice. LC power supplies are notoriously flakey these days.

 

[uniserver]

Silly trick if your in a pinch,

2 out of the 4 BAD LC' PSU's I have, would start up if you sat them in-front of a heater for a while,

however if you turned it off after a while, it wouldn't come back on.

 

[James1095]

All of the caps in several of mine were Nichicon, and the same ones were still bad. Even those that weren't leaking tested bad with the ESR meter. Nichicon is a quality part, the fault lies in the conditions in the power supply. Switching PSUs are notoriously hard on output capacitors, and these are extremely compact units that place the caps in close proximity to other parts that get hot.

For whatever reason, ESR tends to drop as you heat up an electrolytic capacitor, so that's why the heater trick works. It's also why a classic symptom of failing capacitors is equipment that's cranky when cold but smooths out a bit as it warms up. Of course heating the capacitors also accelerates their demise, but at this point they're already shot anyway.

 

[CC_333]

Hi,

You know, I have an eMac that does this.

There must be some bad capacitors in there somewhere.

When I had it in a superheated shed this summer (it must've been at least 110ºF in there!), it actually worked on the first try. The rest of the time, I have to let it "warm up" before it'll do anything.

c

 

[uniserver]

james, i'm glad you motivated me to fix these things.

These LC PSU's are quite handy!

 

[James1095]

A hair dryer and a can of freeze spray can be very helpful lacking an ESR meter. If you can't find freeze spray, hold a can of air duster upside down and you will get pretty much the same thing, just be careful not to let much of the liquid drip on your skin or you can get frostbite.

Heat up areas of the board with the hair dryer, don't go nuts, just get it a bit toasty and fire it up. If it works, hit the caps one at a time with freeze spray until something happens. Any noticeable change in performance means it's a bad cap. Works sometimes on semiconductors too, I finally used this technique to locate a faulty FET that was causing intermittent scratchy noises in an old stereo receiver.

 

[uniserver]

i have all 4 fixed, tested them all for 2 hours + /under full load for 30 min. (in a LC II)

The very last PSU i did, i was really scrounging for caps, i found some but these are not anything like what is on there, but it seems to work fine.

( last fixed psu got these values )

2 - 25v270uf ----> 16v 470uf

1 - 10v270uf ----> 16v 470uf

1 - 25v56uf ----> 25v 47uf

I am sure there was a method to their madness with the values they chose, but the caps I had laying around seem to work good.

 

[uniserver]

Contact me if you need a power supply for a LCI LCII LCIII LC475 Q605 Performa Variant.

I literally have a stack of these power supplies, I bought 12 Pack of dead power supplies from a nice guy in GUAM,

I bought a pile of caps, and sat down one sunday and re-capped them all.

or if you want to do it your self, I highly recommend doing it. there is only 4 caps that fail miserably! (with the the TDK kind)

The other brands have similar issues but different values and in different spots.