Fixing Switchmode Plugpaks.

M

Maurie Daly

Guest
Has anyone had any experiance with fixing these beasts.
Looks exactly like your normal plugpak that Dick Smith sells, but has
no weight and in my case has an oddball rating 5V @ 5A regulated.
Not easy to pull apart as its in a sealed plastic case which Im
getting ready to hacksaw apart.
The 240 V input is totaly open cct so Im hoping there is a fuse inside
which is blown.
A conventional plugpak with these ratings is hard to find .

Tnx
Mauried
 
Maurie Daly wrote:
Has anyone had any experiance with fixing these beasts.
The 240 V input is totaly open cct so Im hoping there is a fuse inside
which is blown.
Click to expand...
I fixed a 16V 3A supply from an IBM Thinkjet. Solder joints
on both the AC input connector and the main PS cap had failed,
and they just needed a touch with the iron to fix them. You
probably have the same problem with the connector.

As far as cracking open the case, avoid the hacksaw if you can.
The case will be molded with a lip inside on one half and a lip
outside on the other, and is probably glued shut. You want to
crack the glue joint. I did it by putting the case in a vise
with the top edge raised 1cm (not under pressure), then lightly
tapping on a broad-bladed screwdriver placed against the "inner"
half. Working along the edge and all around the joint, it cracked
the glue joint nicely, and the case glued shut again afterwards.

Clifford Heath.
 
On Mon, 30 Aug 2004 14:17:07 +1000, Clifford Heath
<cjh-nospam@nospaManagesoft.com> wrote:

Maurie Daly wrote:
Has anyone had any experiance with fixing these beasts.
The 240 V input is totaly open cct so Im hoping there is a fuse inside
which is blown.

I fixed a 16V 3A supply from an IBM Thinkjet. Solder joints
on both the AC input connector and the main PS cap had failed,
and they just needed a touch with the iron to fix them. You
probably have the same problem with the connector.

As far as cracking open the case, avoid the hacksaw if you can.
The case will be molded with a lip inside on one half and a lip
outside on the other, and is probably glued shut. You want to
crack the glue joint. I did it by putting the case in a vise
with the top edge raised 1cm (not under pressure), then lightly
tapping on a broad-bladed screwdriver placed against the "inner"
half. Working along the edge and all around the joint, it cracked
the glue joint nicely, and the case glued shut again afterwards.

Clifford Heath.
Click to expand...

Thanks Clifford.
Fixed, an open circuit 1 Megohm resistor.
Once I got the case open it was easy.
Your technique worked fine .
I wont throw these things away so fast in the future.

MD
 
As far as cracking open the case, avoid the hacksaw if you can.
The case will be molded with a lip inside on one half and a lip
outside on the other, and is probably glued shut. You want to
crack the glue joint. I did it by putting the case in a vise
with the top edge raised 1cm (not under pressure), then lightly
tapping on a broad-bladed screwdriver placed against the "inner"
half. Working along the edge and all around the joint, it cracked
the glue joint nicely, and the case glued shut again afterwards.

Clifford Heath.
Click to expand...
Top notch description of how to open those critters. The colder they are,
the easier to open. Yes, I have used the freezer!!

Took me about 3 or 4 before I stumbled on that method. The faults are either
meltdowns, or easy to fix. i.e. electrolytics, solder joints and some faults
caused by rough handling. Once its open about 10 minutes or less will tell
you whether to repair or replace. Hold the old ones as a parts reserve.
These things seem to come out of just a few factories.

Bill.
 
Clifford Heath wrote:

As far as cracking open the case, avoid the hacksaw if you can.
The case will be molded with a lip inside on one half and a lip
outside on the other, and is probably glued shut. You want to
crack the glue joint. I did it by putting the case in a vise
with the top edge raised 1cm (not under pressure), then lightly
tapping on a broad-bladed screwdriver placed against the "inner"
half. Working along the edge and all around the joint, it cracked
the glue joint nicely, and the case glued shut again afterwards.
Click to expand...
Excellent tip Clifford! I've nastily mauled many a sealed unit trying to get
the sucker open. Hopefully future attempts will come through less mangled...

Russ.
 
Maurie Daly wrote:

On Mon, 30 Aug 2004 14:17:07 +1000, Clifford Heath
cjh-nospam@nospaManagesoft.com> wrote:


Maurie Daly wrote:

Has anyone had any experiance with fixing these beasts.
The 240 V input is totaly open cct so Im hoping there is a fuse inside
which is blown.

I fixed a 16V 3A supply from an IBM Thinkjet. Solder joints
on both the AC input connector and the main PS cap had failed,
and they just needed a touch with the iron to fix them. You
probably have the same problem with the connector.

As far as cracking open the case, avoid the hacksaw if you can.
The case will be molded with a lip inside on one half and a lip
outside on the other, and is probably glued shut. You want to
crack the glue joint. I did it by putting the case in a vise
with the top edge raised 1cm (not under pressure), then lightly
tapping on a broad-bladed screwdriver placed against the "inner"
half. Working along the edge and all around the joint, it cracked
the glue joint nicely, and the case glued shut again afterwards.

Clifford Heath.



Thanks Clifford.
Fixed, an open circuit 1 Megohm resistor.
Once I got the case open it was easy.
Your technique worked fine .
I wont throw these things away so fast in the future.

MD

Hello
Click to expand...

That's interresting.
I've fixed a couple over the last few years with the same fault.
The 1 Meg R supplies startup power; no R = no start.

We should point out that these things have some lethal voltages in them
and they should be treated with the same respect as full sized off-line
switchmode power supplies.

Paul Bealing
www.pmb.co.nz
 
Bill Bailley wrote:
Top notch description of how to open those critters.
Click to expand...
:) I take a special joy in fixing "non user servicable" items,
particularly when there was deliberate "life expectancy engineering"
involved. Subvert our chuck-away culture!
 
"Clifford Heath" <cjh-nospam@nospaManagesoft.com> wrote in message
news:1093911899.238980@excalibur.osa.com.au...
Bill Bailley wrote:
Top notch description of how to open those critters.

:) I take a special joy in fixing "non user servicable" items,
particularly when there was deliberate "life expectancy engineering"
involved. Subvert our chuck-away culture!
Click to expand...
It gives me a buzz to resurrect some items. Next project is to fit ball
bearings to a Simson drier motor. The darned bushes they use last just a bit
longer than the clockwork timer. It makes me cross to see these companies
earn future profits by selling crap today. A pox on their houses.

I retrofitted ball bearings to a Mistral ceiling fan motor instead of the
sintered bushes. It worked perfectly and quietly from the word go, and has
continued to do so for 15 years!! Four dollars well spent.

Bill.
 
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