replacing capacitor in PSU
 

I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

orange wrote:
I cannot find anywhere replacement capacitor (680 uF, 200V).

Look harder. Try Googling.

http://www.alltronics.com/capacito.htm

On 1 Aug 2005 14:13:32 -0700, "orange" put finger
to keyboard and composed:

I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

If you are running on 240VAC you could use a single 330uF 400V cap.


- Franc Zabkar
--
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Franc Zabkar wrote:

If you are running on 240VAC you could use a single 330uF 400V cap.


According to the header he's posting from Russia. Does anyone know
what the line voltage is there?

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Link to my "Computers for disabled Veterans" project website deleted
after threats were telephoned to my church.

Michael A. Terrell
Central Florida

I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

If you are running on 240VAC you could use a single 330uF 400V cap.


- Franc Zabkar

bad idea.

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On 2 Aug 2005 00:16:03 -0500, me put finger to keyboard
and composed:


I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

If you are running on 240VAC you could use a single 330uF 400V cap.


- Franc Zabkar

bad idea.

why?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

OK, thanks all, I'll try ordering it from that site (unfortunately it
might get 'lost' in the customs )
BTW, I'm from Serbia and Montenegro and voltage here is 220V.

I've ordered them from 'Debco Electronics Inc', very very cheap 2$ per
piece (other places want more than 4$), hope it will not be of bad
quality, and that it will arrive in a year or two, heh

Any capacitor of same value (or slightly higher) with a higher voltage
rating will do fine. As this is a switch mode supply remember to use 105
degree parts or you'll be replacing that part pretty soon.

Dave
"orange" wrote in message
oups.com...
I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

me writes:

I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

If you are running on 240VAC you could use a single 330uF 400V cap.


- Franc Zabkar

bad idea.

No necessarily. If running a dual voltage (120/240 VAC) power supply
on 240 VAC, the input circuit forms a bridge rectifier with its output
across the two main filter caps (in series). The quesiton is what happens
with the centertap. If it's not used for anything else, then this approach
can work, but you'd have to trace the input circuit completely to be
sure it won't simply release smoke. :)

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me wrote:
I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.
If you are running on 240VAC you could use a single 330uF 400V cap.
bad idea.

In most switched mode power supplies, in 220V operation, the primary
capacitors are placed in series, so in that case the idea is actually
very usefull. You have to disable the voltage switch, of course.

---
Met vriendelijke groet,

Maarten Bakker.

On 02 Aug 2005 08:59:36 -0400, Sam Goldwasser
put finger to keyboard and composed:

me writes:

I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.

If you are running on 240VAC you could use a single 330uF 400V cap.


- Franc Zabkar

bad idea.

No necessarily. If running a dual voltage (120/240 VAC) power supply
on 240 VAC, the input circuit forms a bridge rectifier with its output
across the two main filter caps (in series). The quesiton is what happens
with the centertap. If it's not used for anything else, then this approach
can work, but you'd have to trace the input circuit completely to be
sure it won't simply release smoke. :)

In most PSUs that I've seen one could simply replace one of the two
caps with a single 400V type, link out the remaining one, and then
remove the two redundant wires going to the 240/120 selector switch.
Some designs may have MOVs in parallel with the caps, in which case
these should be removed.

By coincidence, yesterday I dismantled a Sony TV set which had a PSU
which was configurable for single or dual capacitors. The Australian
version of this set had a single 560uF 400V cap, and the other cap was
linked out. The PCB real estate allotted to the 400V cap was slightly
larger than for the 200V one.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

On Tue, 02 Aug 2005 15:05:26 +0200, put
finger to keyboard and composed:

me wrote:
I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.
If you are running on 240VAC you could use a single 330uF 400V cap.
bad idea.

In most switched mode power supplies, in 220V operation, the primary
capacitors are placed in series, so in that case the idea is actually
very usefull. You have to disable the voltage switch, of course.

The switch is open in 240VAC operation so it doesn't need to be
disabled, but removing the two wires is a good precaution. I do it as
a matter of course whenever I open a PC PSU.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

, so in that case the idea is actually
very usefull. You have to disable the voltage switch, of course.

an important note...

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On 3 Aug 2005 17:37:54 -0500, me put finger to keyboard
and composed:

, so in that case the idea is actually
very usefull. You have to disable the voltage switch, of course.

an important note...

Not really. In a 240V system the voltage switch is open. I'd still
remove it, though, but for reasons of redundancy and added security,
not necessity.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

"orange" wrote in message
oups.com...
I cannot find anywhere replacement capacitor (680 uF, 200V). Can I use
any other value for capacitance? I need two of them replaced
(identical), they are inside switching power supply, the biggest ones.


You can use one of same or higher voltage and similar uF rating, doesn't
have to be exact.