Power Supply Repair

[D Finnigan]

The power supply in my Apple II Plus completely failed about 2 weeks ago.
This afternoon I drilled out the rivets and opened it up. This is what I
found:

http://macgui.com/upload/gallery/f_0/user_2/regular/upload_4601.jpg
http://macgui.com/upload/gallery/f_0/user_2/regular/upload_4600.jpg

The yellow capacitor marked 1. in the first picture has a bulge in the side.
The fuse marked 2. had failed. The capacitor is probably what failed a few
months ago and made the big stink.

The fuse is probably what failed 2 weeks ago. I removed the fuse and bridged
its place with something that was not a fuse. I applied power and the
component marked 3. in the first picture sparked and released some vintage
smoke.

I don't even know what that component is. I would like to send this power
supply to someone who knows about repairing them. Any takers?

--
]DF$
The Marina IP stack for Apple II--
http://marina.a2hq.com/

[6502en...@gmail.com]

Maybe this can help you:

http://www.applefritter.com/?q=content/apple-iie-power-supply

[D Finnigan]

6502enhanced wrote:
> Maybe this can help you:
>
> http://www.applefritter.com/?q=content/apple-iie-power-supply
>

Yeah, that's a pretty close to match to my problem. I sure hope the coil
hasn't been permanently damaged, but it probably has... :-(

[ultramagnus_tcv]

On 2017-04-23 21:59:39 +0000, D Finnigan said:

> Yeah, that's a pretty close to match to my problem. I sure hope the coil
> hasn't been permanently damaged, but it probably has... :-(

Is UM's PS replacement a possibility for you?

m

[D Finnigan]

I've looked into it, but not at that price. I figure I can get it repaired
or buy a replacement for less than $95.

[James Davis]

From another thread:

On Wednesday, April 19, 2017 at 12:33:31 PM UTC-7, D Finnigan wrote:
> ultramagnus_tcv wrote:
> > On 2017-04-19 15:05:12 +0000, D Finnigan said:
> >
> >> You'll find a lot of good information for new and returning Apple II
> >> users
> >> such as yourself in The New Apple II User's Guide, a softcover book
> >> published a few years ago, on sale for $25:
> >> http://macgui.com/newa2guide/
> >
> >
> > Worth the purchase. I have one and I'm _not_ the author. ;-)
> >
>
> Seconded. I have 2 copies, and I don't even _own_ any Apple II computers
> anymore (switched to emulators-only last week). ;-)

So, if you do not own any Apple II computers, how is it that you have one with a blown power supply? Did you steal it?

And, why are you hyping your own product as if it is someone elses product?

[6502en...@gmail.com]

No one needs your book!!!

There are a lot of people in the Apple II community who like to help other's because they like each other and what they do with the Apple II.

F.e. this page where you get all what you need:

http://www.appleii-box.de/index.htm

Or a forum like this or www.applefritter.com .

Really, no one needs your book - all information is here - for free - without stupid tries to sell products that no one needs! Try eBay where the other dubiously people offer their old stuff for month's or year's to reach moon-prices without success ...

[ultramagnus_tcv]

On 2017-04-24 03:13:36 +0000, D Finnigan said:

> ultramagnus_tcv wrote:
>> Is UM's PS replacement a possibility for you?
>
> I've looked into it, but not at that price. I figure I can get it repaired
> or buy a replacement for less than $95.

That's a good point. I hope you can repair it since that'll be fun.

At least, I imagine you can get a gently used replacement without the
particular problem and maybe cannibalize the parts. :-)

[D Finnigan]

I'm wondering what caused the fuse to blow. The question is: assuming that
the damage done yesterday was not fatal, if I replace the yellow line
capacitor at C1, will that be the fix to the whole problem?

[Michael J. Mahon]

The short in the line filter capacitor is certainly enough to blow the
fuse.

Bypassing the fuse is enough to fry the common mode filter coil, since the
line filter capacitor is still a short (which is why a blown fuse should be
replaced, but never bypassed).

Since the common mode filter coil seems to still have continuity in both
windings, it seems you've lucked out, and the supply is now operational.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com

[D Finnigan]

Michael J. Mahon wrote:
>>>
>>
>> I'm wondering what caused the fuse to blow. The question is: assuming
>> that
>> the damage done yesterday was not fatal, if I replace the yellow line
>> capacitor at C1, will that be the fix to the whole problem?
>>
>>
>
> The short in the line filter capacitor is certainly enough to blow the
> fuse.

OK. What happened is that while I was installing the single-wire shift key
mod, I inverted the machine several times during disassembly. I had the
machine disassembled and tested the shift key mod. Worked OK. When I
reassembled the machine with the case back on, suddenly the machine was
dead.

So I reasoned that with all the movement, something must have dislodged, and
that must have been the last blow against the capacitor that failed several
months prior.

>
> Bypassing the fuse is enough to fry the common mode filter coil, since the
> line filter capacitor is still a short (which is why a blown fuse should
> be
> replaced, but never bypassed).
>
> Since the common mode filter coil seems to still have continuity in both
> windings, it seems you've lucked out, and the supply is now operational.
>

I still need to replace the line filter capacitor.

[Michael J. Mahon]

D Finnigan <dog...@macgui.com> wrote:
> Michael J. Mahon wrote:
>>>>
>>>
>>> I'm wondering what caused the fuse to blow. The question is: assuming
>>> that
>>> the damage done yesterday was not fatal, if I replace the yellow line
>>> capacitor at C1, will that be the fix to the whole problem?
>>>
>>>
>>
>> The short in the line filter capacitor is certainly enough to blow the
>> fuse.
>
> OK. What happened is that while I was installing the single-wire shift key
> mod, I inverted the machine several times during disassembly. I had the
> machine disassembled and tested the shift key mod. Worked OK. When I
> reassembled the machine with the case back on, suddenly the machine was
> dead.
>
> So I reasoned that with all the movement, something must have dislodged, and
> that must have been the last blow against the capacitor that failed several
> months prior.

So I'm guessing that after the capacitor popped and smelled, it cleared its
momentary short and you left it installed.

If this is the case (and it's actually how X1/X2 capacitors are supposed to
work, but with smaller, non-case-rupturing shorts), then the capacitor had
a second, longer lasting short episode which took out the fuse before the
common mode filter coil could overheat.

When the fuse was bypassed, the capacitor short didn't clear, and the high
line current overheated the coil, but not to destruction.

>>
>> Bypassing the fuse is enough to fry the common mode filter coil, since the
>> line filter capacitor is still a short (which is why a blown fuse should
>> be
>> replaced, but never bypassed).
>>
>> Since the common mode filter coil seems to still have continuity in both
>> windings, it seems you've lucked out, and the supply is now operational.
>>
>
> I still need to replace the line filter capacitor.
>

Yes, that's a good idea. Fortunately they are inexpensive and readily
available. Pay attention to the voltage rating, but don't be too concerned
about matching the capacitance value--anything from half to twice the value
is fine. (Often on-sale items are close but not exact.)

[D Finnigan]

Michael J. Mahon wrote:
> D Finnigan <dog...@macgui.com> wrote:
>> Michael J. Mahon wrote:
>>>>>
>>>>
>>>> I'm wondering what caused the fuse to blow. The question is: assuming
>>>> that
>>>> the damage done yesterday was not fatal, if I replace the yellow line
>>>> capacitor at C1, will that be the fix to the whole problem?
>>>>
>>>>
>>>
>>> The short in the line filter capacitor is certainly enough to blow the
>>> fuse.
>>
>> OK. What happened is that while I was installing the single-wire shift
>> key
>> mod, I inverted the machine several times during disassembly. I had the
>> machine disassembled and tested the shift key mod. Worked OK. When I
>> reassembled the machine with the case back on, suddenly the machine was
>> dead.
>>
>> So I reasoned that with all the movement, something must have dislodged,
>> and
>> that must have been the last blow against the capacitor that failed
>> several
>> months prior.
>
> So I'm guessing that after the capacitor popped and smelled, it cleared
> its
> momentary short and you left it installed.

Correct.

>
> If this is the case (and it's actually how X1/X2 capacitors are supposed
> to
> work, but with smaller, non-case-rupturing shorts), then the capacitor had
> a second, longer lasting short episode which took out the fuse before the
> common mode filter coil could overheat.

And this probably happened because I turned over the power supply a few
times too many.

>
> When the fuse was bypassed, the capacitor short didn't clear, and the high
> line current overheated the coil, but not to destruction.

Well I don't know if the coil is still OK. Can they spark and make smoke but
still be OK?

>>
>> I still need to replace the line filter capacitor.
>>
>
> Yes, that's a good idea. Fortunately they are inexpensive and readily
> available. Pay attention to the voltage rating, but don't be too concerned
> about matching the capacitance value--anything from half to twice the
> value
> is fine. (Often on-sale items are close but not exact.)
>

Thanks. As of right now, the power supply is inoperable due to the missing
fuse and the damaged capacitor (and possibly the coil too).

[Michael J. Mahon]

Actually, unless there's loose metal in the supply, it's unlikely that
changing its orientation had any effect--just a coincidence.

>> When the fuse was bypassed, the capacitor short didn't clear, and the high
>> line current overheated the coil, but not to destruction.
>
> Well I don't know if the coil is still OK. Can they spark and make smoke but
> still be OK?

Maybe. You'll find out when you try it. (The sparking concerns me, but give
it a try. The worst that can happen is that its windings are shorted
together and the fuse will blow again. If either coil is open, the supply
simply won't turn on.)

>>> I still need to replace the line filter capacitor.
>>>
>>
>> Yes, that's a good idea. Fortunately they are inexpensive and readily
>> available. Pay attention to the voltage rating, but don't be too concerned
>> about matching the capacitance value--anything from half to twice the
>> value
>> is fine. (Often on-sale items are close but not exact.)
>>
>
> Thanks. As of right now, the power supply is inoperable due to the missing
> fuse and the damaged capacitor (and possibly the coil too).
>



--

[Nick Westgate]

On Monday, 24 April 2017 09:38:46 UTC+12, D Finnigan wrote:
> I don't even know what that component is. I would like to send this power
> supply to someone who knows about repairing them. Any takers?

If you want someone who refurbishes any Apple II system, and has had glowing praise of their work posted on FB, John Keoni Morris:
https://www.facebook.com/john.k.morris.16

He's very helpful, gives out free info. I don't have his email sorry.

Cheers,
Nick.

[D Finnigan]

This was very helpful:
ftp://bitsavers.informatik.uni-stuttgart.de/pdf/apple/power_supply/Astec_Power_Supplies_Aug82.pdf

It has schematics and a complete parts listing. Combining this info with the
photos I took allows me to order the correct replacement parts. I see that I
have an Astec 11040B model.

I will give it a shot myself.

--
]DF$
Apple II 40th Anniversary User's Guide:
http://macgui.com/newa2guide/

[D Finnigan]

Anyone know how to easily remove the PCB from my power supply after I've
taken out the 6 screws? I'm hesitant to pull or cut anything in case I do
the wrong thing.

Reference pictures:
http://macgui.com/upload/gallery/f_0/user_2/regular/upload_4601.jpg
http://macgui.com/upload/gallery/f_0/user_2/regular/upload_4600.jpg

[Polymorph]

Looks the very similar to the //e PSU's I've repaired.

To remove the PCB, I would do the following:
1) Using needle nose pliers, crimp the back of the black plug leading out of the PSU so that it can fit through the hole in the metal case
2) Unscrew the ground (green) wire from the case near the mains socket
3) Using needle nose pliers, remove the 2 black and 1 red wires from the PSU PCB by carefully pulling up (the leads slide onto poles on the PCB)
4) Pull the 2 spade connectors from the PSU switch
5) Remove the screws holding the PCB to the case
6) Gently lift the PCB from the end away from the mains socket and slide out

Hope that helps.

Cheers,
Mike