Emac Step Down board recap

[coreAngel]

Hello everyone this is my first post (after my intro post) so forgive me if i'm a bit nervous asking questions, or making a long post i just like to explain myself as best as i can..well i have a Apple Emac from 2002-2004 i got it from my old highschool before 2009 (they were going to get rid of them...recycle them etc..) so i managed to get one and it sat in my closet for a while and got used sparingly just for web browsing etc, but a couple of months ago it was working fine until i noticed it started shutting off at random, and a odd noise was coming from the speakers, i've never opened it except to remove dust, after disassembling it completely i noticed the step down board, with capacitors with a brown/reddish covering so i thought they were chemicon's except the weren't...i thought they were i removed the board almost every single Sus'con capacitor was blown with the exception of one tiny one.the rest were spilling electrolyte everywhere..i thought the damage was confined to there, after removing the logic board every chemicon capacitor had blown, and nichicons as well, the only ones that didn't blow up were the black matsushita ones which had me confused....anyway i recapped the stepdown board however i am puzzled with some of the caps, i think i did a acceptable job replacing them these are what i used

Nichicon PW 35volts 1200uF 105c
united chemicon EKY 35volts 680uF
Nichicon PW 10volts 1200uF
panasonic m 1000uF 16V
panasonic fr 16VDC 1500uF

my question is are these good choices, does a step down board need low esr caps? only one cap is 85C else is 105C i attached pics to show what i did those suscon caps were huge as compared to these which are much much smaller...i left a suscon cap there till i got a replacement for it a rubycon light blue cap from radio shack i dont think its a bad cap but i could use some advice....the only other cap i had was a lelon cap which is crap...what are those light blue caps? fakes?( radioshack which is closing down so i got a lot of rubycons) thanks for any help you can provide

[Jooo]

Re: Emac Step Down board recap

The blue rubycons are probably really old. I think it has been atleast 20 years when theuäy had that color, if not even more. Otherwise they are probably legit.

[coreAngel]

Re: Emac Step Down board recap

The blue rubycons are probably really old. I think it has been atleast 20 years when theuäy had that color, if not even more. Otherwise they are probably legit.

Its only one tiny cap 100uf 35v , so if it old and its so tiny and it's 85C should it hold out? or should it be replaced? the only other choices i have in my stash are lelon,and other no name brand...

here are some pics of the recap i did..

[Jooo]

Re: Emac Step Down board recap

What series are the lelons? Many will probably disagree with me but personally I have never had or seen problems with the low esr series from lelon (RXK, RXW and RZW) I have personally used those series in some repairs.

[coreAngel]

Re: Emac Step Down board recap

What series are the lelons? Many will probably disagree with me but personally I have never had or seen problems with the low esr series from lelon (RXK, RXW and RZW) I have personally used those series in some repairs.

no they are some cheap radioshack lelons it was the lighter blue covering on the outside so i dont know if they are good, i replaced it with a rubycon as i mentioned even though i've heard it's old, thing is the board is in an area where it dosen't get too much ventilation with the exception of the thick aluminum,steel? cover that goes over everything then the outer plastic shell, i think the metal is a heatsink? so it's going to get warm but not too warm, what surprised me the most though was the cap from chemicon was a UCC(united chemicon cap) i thought they only made special capacitors like the much larger ones not tiny ones.

[coreAngel]

Re: Emac Step Down board recap

They are from the PSU of a Sony STRD611 stereo receiver?

no this is a stepdown board from an apple emac pc

[Agent24]

Re: Emac Step Down board recap

If it's a switching power supply you need to use Low ESR capacitors.

[japlytic]

Re: Emac Step Down board recap

I have also seen capacitors on the monitor/power supply board go bad (in this case, the section which goes to the CPU board and stepdown board) - the capacitors I also recommend changing on the monitor/power supply board are (all low-ESR):
C908 (1200uF 16V), C913 (2200uF 35V), C920 (2200uF 35V) (20V for stepdown board)
C910 (2200uF 16V), C924 (2200uF 16V), C925 (2200uF 16V) (CPU 12V)

[budm]

Re: Emac Step Down board recap

no this is a stepdown board from an apple emac pc

You mean it is buck converter which is switching power supply.

[LLLlllou]

Re: Emac Step Down board recap

I recapped the stepdown board however i am puzzled with some of the caps, i think i did a acceptable job replacing them these are what i used

Nichicon PW 35volts 1200uF 105c
united chemicon EKY 35volts 680uF
Nichicon PW 10volts 1200uF
panasonic m 1000uF 16V
panasonic fr 16VDC 1500uF

"united chemicon EKY 35volts 680uF" no such series as EKY, you probably mean KY.

"Panasonic m 1000uF 16V" no such series, M is the Logo for matshushita, the parent company of Panasonic.

my question is are these good choices, does a step down board need low esr caps? only one cap is 85C else is 105C i attached pics to show what i did those suscon caps were huge as compared to these which are much much smaller...i left a suscon cap there till i got a replacement for it a rubycon light blue cap from radio shack i dont think its a bad cap but i could use some advice....the only other cap i had was a lelon cap which is crap...what are those light blue caps? fakes?( radioshack which is closing down so i got a lot of rubycons) thanks for any help you can provide

In order to tell if they are acceptable replacements, we will need to know manufacturer, series, voltage, capacitance, and physical size in mm, of each original capacitor. Replacements must have same or higher ripple current rating, and same or lower ESR.

Any cap you get from Rat Shack is going to be general purpose crap. They should work, but they won't last long.

[coreAngel]

Re: Emac Step Down board recap

"united chemicon EKY 35volts 680uF" no such series as EKY, you probably mean KY.

"Panasonic m 1000uF 16V" no such series, M is the Logo for matshushita, the parent company of Panasonic.




In order to tell if they are acceptable replacements, we will need to know manufacturer, series, voltage, capacitance, and physical size in mm, of each original capacitor. Replacements must have same or higher ripple current rating, and same or lower ESR.

Any cap you get from Rat Shack is going to be general purpose crap. They should work, but they won't last long.

let me clarify some of the things i mentioned in the post

the United chemicon cap is KY series (pun intended)


the panasonic m series does exist is as its listed on mouser

http://www.mouser.com/Search/Product...667-ECA-1CM102

plus info from panasonic




all of the previous capacitors were sus'cons

here are what were on the board

1500uf 16v x 2
1200uf 35v x 2
680uf 35v x 1
3300uf 10v x 1
1200uf 10v x 3
1000uf 16v x 1
2200uf 16v x 1

and one small 16 v 100uf

all of the sus'cons have no series just sc105 degrees c 0442(v) is v the series?

all were replaced with

Nichicon PW 35volts 1200uF
UCC KY 35volts 680uF
Nichicon PW 10volts 1200uF
panasonic m series 1000uF 16V
Rubycon cew 100uf 16v
panasonic fr 16VDC 1500uF

(more info )


the rubycon was purchased from radioshack and its a rubycon ce w 16v 100uf - yes i think it's an audio cap i dont have big plans for this pc as it's not going to be too stressed though

of course the capacitors i have now are much skinnier than the previous one's but they are same voltage and capacitance does this help, any advice you can give will be very appreciated

[Agent24]

Re: Emac Step Down board recap

the panasonic m series does exist is as its listed on mouser

http://www.mouser.com/Search/Product...667-ECA-1CM102

plus info from panasonic

Well that's just great! Way to cause confusion, Panasonic

In any case... it's clear from the datasheet that your "Series M" is just a general purpose series. So it will not be suitable for a switching PSU here. Panasonic Series FM, FC, FJ or similar would be better.

all of the previous capacitors were sus'cons

here are what were on the board

1500uf 16v x 2
1200uf 35v x 2
680uf 35v x 1
3300uf 10v x 1
1200uf 10v x 3
1000uf 16v x 1
2200uf 16v x 1

and one small 16 v 100uf

all of the sus'cons have no series just sc105 degrees c 0442(v) is v the series?

No, the series is SC. It's an old series and does not show on the website anymore. You can get the datasheets here:
https://www.badcaps.net/forum/showpo...22&postcount=5

all were replaced with

Nichicon PW 35volts 1200uF
UCC KY 35volts 680uF
Nichicon PW 10volts 1200uF
panasonic m series 1000uF 16V
Rubycon cew 100uf 16v
panasonic fr 16VDC 1500uF

(more info )

the rubycon was purchased from radioshack and its a rubycon ce w 16v 100uf - yes i think it's an audio cap i dont have big plans for this pc as it's not going to be too stressed though

What you do with it is irrelevant. It's what function the capacitor performs in the circuit that depends on how much it will be stressed.

Your Panasonic FR, Nichicon PW and UCC KY are good. The Panasonic M is not.

The Rubycon CEW will probably be OK since those small value capacitors usually have easy jobs in PSUs anyway. BUT! As already mentioned, CEW is old, general purpose, and not rated for high temperature so it's still not really that suitable.

of course the capacitors i have now are much skinnier than the previous one's but they are same voltage and capacitance does this help, any advice you can give will be very appreciated

Being quite an old PSU with discontinued capacitor series already, the replacements are likely to be smaller anyway due to advancements in capacitor manufacturing ability.

However, you should get rid of those Panasonic M series and replace with a Low ESR series as they are general purpose and will not last very long in a switching PSU due to the high ripple. They may also make the PSU run incorrectly due to their higher ESR.

Look at the datasheets for Su'scon SC Series capacitors. Look up the sizes\values\voltage of the capacitors you pulled. Find the ESR and RCR (ripple current rating) for the ones you pulled and make sure your replacements have the same or lower ESR, and same or higher RCR.

If the replacements are spec'd significantly lower they will not last very long.

[coreAngel]

Re: Emac Step Down board recap

Well that's just great! Way to cause confusion, Panasonic

In any case... it's clear from the datasheet that your "Series M" is just a general purpose series. So it will not be suitable for a switching PSU here. Panasonic Series FM, FC, FJ or similar would be better.



No, the series is SC. It's an old series and does not show on the website anymore. You can get the datasheets here:
https://www.badcaps.net/forum/showpo...22&postcount=5


What you do with it is irrelevant. It's what function the capacitor performs in the circuit that depends on how much it will be stressed.

Your Panasonic FR, Nichicon PW and UCC KY are good. The Panasonic M is not.

The Rubycon CEW will probably be OK since those small value capacitors usually have easy jobs in PSUs anyway. BUT! As already mentioned, CEW is old, general purpose, and not rated for high temperature so it's still not really that suitable.



Being quite an old PSU with discontinued capacitor series already, the replacements are likely to be smaller anyway due to advancements in capacitor manufacturing ability.

However, you should get rid of those Panasonic M series and replace with a Low ESR series as they are general purpose and will not last very long in a switching PSU due to the high ripple. They may also make the PSU run incorrectly due to their higher ESR.

Look at the datasheets for Su'scon SC Series capacitors. Look up the sizes\values\voltage of the capacitors you pulled. Find the ESR and RCR (ripple current rating) for the ones you pulled and make sure your replacements have the same or lower ESR, and same or higher RCR.

If the replacements are spec'd significantly lower they will not last very long.

thanks for clearing everything up, i went on mouser and repurchased with panny FR caps LOWESR types... including the rubycon one just to be on the safe side i dont want to turn on the pc and

[coreAngel]

Re: Emac Step Down board recap

I did order some Panny caps from Mouser the FR series with low ESR , and boy were they a bit expensive about 1 dollar a piece, what i was curious about was since it's a powersupply couldn't i use general purpose capacitors instead? Since a motherboard needs good low esr caps can i just get away with using some general purpose caps, and the rest low esr? just a question

[Agent24]

Re: Emac Step Down board recap

In a linear power supply you can use general purpose capacitors just fine, but in a switching power supply they need to be low ESR types.

In switching power supplies there is a lot of high frequency ripple generated which can only be filtered properly by low ESR capacitors. A general purpose capacitor does not have ESR low enough typically. They are also usually less tolerant of high temperatures, and switching PSUs are often quite hot.

The motherboard also needs low ESR capacitors because it will typically have several switching power supplies built into it. There is the main supply for the CPU Vcore, the supplies for the northbridge\chipset, and another supply for the RAM. There may be others. Most or all of them are switching types (typically buck converters), as space on a motherboard is at a premium and high efficiency switching converters take up far less room than anything else.

It is not enough to say that if the motherboard has low ESR capacitors then the PSU doesn't need them. Each set of capacitors is there for its own purpose and independent of the other circuitry.

[budm]

Re: Emac Step Down board recap

I did order some Panny caps from Mouser the FR series with low ESR , and boy were they a bit expensive about 1 dollar a piece, what i was curious about was since it's a powersupply couldn't i use general purpose capacitors instead? Since a motherboard needs good low esr caps can i just get away with using some general purpose caps, and the rest low esr? just a question

When power goes wrong it can take out the mother board with so you can take that chance and find out and use it as a lesson in electronics. I am sure the mother board will cause more then $1 capacitor when it fails.
Your power supply is switch mode power supply running at high frequency instead of 100Hz or 120Hz.