Apple III power supply capacitor replacement
schmidtd
get Google to give me deep results from this newsgroup... I get one
page for anything I try. So I'm sorry for the duplication...
Given the exploding capacitor problem in a /// power supply:
http://i421.photobucket.com/albums/pp293/groinkhi/IMG_0191.jpg
there were some recommendations on the size/capacity/rating/type that
would be appropriate here. What were they, again?
David Wilson
It is a mains filter capacitor. I have had the same parts fail in my
IIe and IIgs power supplies.
http://en.wikipedia.org/wiki/Filter_capacitor#Mains_filtering
I replaced mine with a 250V AC Mains - Metallised Polypropylene
Capacitors - X2. eg: http://www.jaycar.com.au/productView.asp?ID=RG5238&keywords=mains+capacitor&form=KEYWORD
John B. Matthews
<0f309bd3-a19e-4603...@j32g2000yqh.googlegroups.com>,
schmidtd <schm...@my-deja.com> wrote:
> I know that this was asked and answered recently, but I can't seem to
> get Google to give me deep results from this newsgroup... I get one
> page for anything I try. So I'm sorry for the duplication.
Is this the thread?
<http://groups.google.com/group/comp.sys.apple2/browse_frm/thread/
1e592d5cd327fbbd>
Lately, I've had better luck with an explicit search:
group:comp.sys.apple2.* "apple ///" capacitor power supply
> Given the exploding capacitor problem in a /// power supply:
> http://i421.photobucket.com/albums/pp293/groinkhi/IMG_0191.jpg
> there were some recommendations on the size/capacity/rating/type that
> would be appropriate here. What were they, again?
C24 appears to be a 0.22 µF capacitor on the schematic:
<http://www.1000bit.net/SUPPORT/SCHEMA/a3/050-0057-a.jpg>
Out of curiosity, is that the one?
--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>
schmidtd
> In article
> <0f309bd3-a19e-4603-a5ee-a4f5b0c62...@j32g2000yqh.googlegroups.com>,
>
> schmidtd <schmi...@my-deja.com> wrote:
> > I know that this was asked and answered recently, but I can't seem to
> > get Google to give me deep results from this newsgroup... I get one
> > page for anything I try. So I'm sorry for the duplication.
>
> Is this the thread?
>
> http://groups.google.com/group/comp.sys.apple2/browse_frm/thread/1e592d5cd327fbbd
Yes - that's the one! Now, why won't Gurgle bring it up with a search
on "Power Supply" in this group? The search results are only one page
long, and don't include that thread. This is new behavior lately. My
faith in Google has been shaken!
> Lately, I've had better luck with an explicit search:
>
> group:comp.sys.apple2.* "apple ///" capacitor power supply
Will try that next time, thanks.
> C24 appears to be a 0.22 µF capacitor on the schematic:
>
> http://www.1000bit.net/SUPPORT/SCHEMA/a3/050-0057-a.jpg
>
> Out of curiosity, is that the one?
Yes indeed. Thanks, John and David, for your help. Mouser seems to
have some suitable replacements.
PZ
4:00am at Kfest the first night. They make a good stink, thats for
sure. It was a 20 year old GS which hadn't been used for a period of 2
years, loaded with peripheral cards, so it shouldn't be a surprise. I
brought a backup motherboard but didn't think about bringing a backup
supply. I'll add it to the list for next year.
I ended up buying a LittlePower and borrowed an ATX supply from James
Little John. That took care of me for the rest of the week. When I
got home, I transplanted a 150w, mini ATX supply into the GS power
supply case, so I'm back in business now.
-Paul
Rich Jordan
> On Jul 30, 10:20 am, "John B. Matthews" <nos...@nospam.invalid> wrote:
>
> > In article
> > <0f309bd3-a19e-4603-a5ee-a4f5b0c62...@j32g2000yqh.googlegroups.com>,
>
> > schmidtd <schmi...@my-deja.com> wrote:
> > > I know that this was asked and answered recently, but I can't seem to
> > > get Google to give me deep results from this newsgroup... I get one
> > > page for anything I try. So I'm sorry for the duplication.
>
> > Is this the thread?
>
>
> Yes - that's the one! Now, why won't Gurgle bring it up with a search
> on "Power Supply" in this group? The search results are only one page
> long, and don't include that thread. This is new behavior lately. My
> faith in Google has been shaken!
>
> > Lately, I've had better luck with an explicit search:
>
> > group:comp.sys.apple2.* "apple ///" capacitor power supply
>
> Will try that next time, thanks.
>
Google groups search has been misbehaving for months; so far I haven't
received any response, or even an acknowledgment, to the complaints on
their support groups.
If you use advanced search and specify the groupname (similar to its
inclusion in the basic search example above) you may have better luck.
Patrick Schaefer
> Given the exploding capacitor problem in a /// power supply:
> http://i421.photobucket.com/albums/pp293/groinkhi/IMG_0191.jpg
> there were some recommendations on the size/capacity/rating/type that
> would be appropriate here. What were they, again?
220nF is written on the capacitor, 100nF should work as well. You can
also just remove the part and accept the higher EMI emission level --
this old machine doesn't fulfil the CE requirements anyway.
In any case the "X2" rating is important. This means suitable for direct
connection across the mains supply. You cannot use a regular 400 or 630V
MKP/MKT here.
Patrick
schmidtd
Thanks for that. I can't see "X2" anywhere on Mouser's lists, but the
data sheet on this guy:
http://mouser.com/Search/ProductDetail.aspx?qs=jSRw5K5ir6X7MRY8O2L9FA%3d%3d
does make reference to appropriateness for mains use (i.e. 250V is ok,
400V and 630V are not).
Michael J. Mahon
All true, but there is also a protective function of the capacitor. It
low-passes short spikes on the power line that could damage the bridge
rectifier, too.
Anything within a factor of two of the design value should be fine.
Using too large a value will subject the fuse to inrush current spikes,
possibly shortening its life, as well as increasing the capacitive
line current flow, which is mostly a power factor issue.
-michael
NadaNet 3.0 for Apple II parallel computing!
Home page: http://home.comcast.net/~mjmahon/
"The wastebasket is our most important design
tool--and it's seriously underused."