Subject: Re: semi-OT: Power Computing 100 power supply

From: chris <[email-masked]>
Date: Fri Apr 4 09:19:26 2003

>I've got a Power Computing 100, one of the earliest Mac clones  
>(equivalent to Mac 8100/100, though the logic board is physically  
>different). It seems that its power supply has died. It is a Seasonic  
>SSH-200G. I'm pretty ignorant about PSU standards, so am not sure what  
>I need to look for in a replacement -- a friend said "it looks like an  
>AT power supply, but that little 4-pin plug [which connects to the  
>logic board, I think] is non-standard, so a standard AT PSU won't work  
>as a replacement." It also has two large 6-pin plugs that plug into the  
>motherboard as well. The rest of the plugs are standard 4-pin.

If you find out any info, forward it on to me. I recently aquired one of 
those as well, and the power supply, along with every other cable in it, 
has had all the wires cut.

It looks like someone either was fired and pissed off, so they took their 
revenge on the machine, or more likely (since the hard drive is missing 
as well), the machine was officially "decommissioned" and rendered to an 
unusable state to take it off the books.

Before I go thru the effort of patching the leads together, if I can find 
a suitable, available replacement, I'll go that route for the purpose of 
testing it to see if the system has been damaged in other ways (then if 
it works, I'll go back and patch the power supply together, just because 
it will be fun).

I did ask a Power Computing list if the Power100 used a standard AT power 
supply, and was told that it does not. However, the person that gave me 
the response spent no effort discussing how it differs, but did spend 3 
paragraphs telling me not to waste my time with a Power100 and instead to 
buy a used PowerTower Pro. So that told me that they just didn't get it, 
and didn't understand the interest in reviving an old machine... which 
also makes me suspect the validity of their answer (not that failing to 
understand old computers equals a lack of knowledge of the power 
supply... just that it seemed more like an uninterested/uninformed wave 
off of the power supply question in the effort to push me to a newer 
faster machine).

-chris
<http://www.mythtech.net>

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From: Marion Bates <[email-masked]>
Date: Fri Apr 4 09:41:00 2003

Jim's post had a good link -- powerwatch.com. (Thanks!) I am on a 
cruddy connection right now, so haven't pored through it in depth yet, 
but take a look.

What I may do is look for an entire Power 100 machine on eBay (found 
one last week, but the seller pulled it unexpectedly before it was due 
to end). They're usually pretty cheap. If I end up going that route to 
get a PSU, I'd be happy sell you the rest of the parts for cost of 
shipping. (Probably ought to keep them for the next piece that fails in 
mine, but I don't have the space for that. Plus I will become obsessed 
with finding another PSU to make the second PC100 work, so I'll buy a 
third, etc.) Obviously if we did this, you would still need a power 
supply too, but might be a good way to share the cost of other parts.

FYI for when you either patch up the one you've got, or replace it. In 
the powerwatch bulletin boards, for Power 100s that don't boot, people 
said to check three things: The logic board battery (I remember that 
from other Macs -- and mine is testing a little low, so I'm gonna go to 
rat shack and try that first), the fuse in the PSU (mine's fine), and 
the lithium button battery in the PSU itself (! what? Anyway, mine 
tested fine. Why does PSU have its own battery? lol). One thing I 
wondered about -- I tried to test the power supply itself by plugging 
it into the wall, flipping the switch to "on", and probing the leads 
with a voltmeter. Nothing. But with this particular computer, you have 
to have that switch on AND push the soft power-on button, either on the 
front of the case or from the triangle key on the keyboard. So, is it 
possible that the PSU is not dead, but that I am not getting anything 
because the power-on signal's not being sent when it's not in the 
computer? Not, not, not, not?

Sorry for the ignorance. I want there to be a giant scorch mark and 
melted plastic if the power supply's really had it -- that'd be more 
convincing.  ;)

Thanks again,

-- MB

On Friday, April 4, 2003, at 10:15 AM, chris wrote:

> I recently aquired one of
> ...

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From: "Dr. Ido" <[email-masked]>
Date: Fri Apr 4 09:49:01 2003

>I tried to test the power supply itself by plugging 

Also, most switchmode power supplies will not power up without a load of
some sort.  For example, to test ATX power supplies outside of a computer I
connect an old HDD as a load and short the power-on line to GND.  Same
principal applies to Mac power supplies except you short the power on line
to +5V (from memory, it's been a while so check before you short anything).

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From: Jim <[email-masked]>
Date: Fri Apr 4 09:57:00 2003

<http://db.allmac.com/allmac/action.lasso?-Database=ItemSell&-Layout=WEB&-Response=TheDetails.lasso&OurItemNum=PWR-0200&-search>

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From: Marion Bates <[email-masked]>
Date: Fri Apr 4 10:04:00 2003

Ah, cool! Thank you for the advice. I am even more eager to try 
replacing that motherboard battery now.

Thanks again.

-- MB

(By the way -- is everyone getting two copies of my posts? If so, I 
apologize...recently unsubbed and resubbed because I changed email 
accounts, and maybe I did something stupid.)

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From: James Rice <[email-masked]>
Date: Fri Apr 4 12:04:01 2003

I have a fully functioning Power 100.  The power supply won't start if 
the pram battery is dead.  It's the standard 3.6v 950mAH lithium cell 
that 75% of all Mac's use.  Rat Shack has them for around $10 or Fry's 
has them for $6.00.  It's a Tadiran TL-5151.  Some Mac's you can crowbar 
into starting without the battery by rapidly pressing the power on 
button several times off and on, but the Power 100 isn't one of those.

I'm working on my Mac clones this weekend, so I can check voltages and 
pinouts.  I adapted an ATX supply to my Daystar Genesis MP800.  It has 
an uptime of over 5 months as of this week.  I've since picked up an 
original Daystar/Magnetrol supply, but sine the 550watt ATX is still 
cooking, I haven't installed it.

You are right about the lack of response on the lem PowerComputing 
list.  Nobody want's to talk about the NuBus machines.

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From: "TeoZ" <[email-masked]>
Date: Fri Apr 4 15:00:00 2003

There are people on ebay selling the pram batteries cheap, I purchased 2 and
had them delivered for less then you can get one ordered at radio shack.
LEM doesnt have much going on with nubus machines, everybody has the OSX bug
there anymore. And yes, macs do act wierd when the battery is low or dead..

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From: James Rice <[email-masked]>
Date: Fri Apr 4 15:59:00 2003

They do have the OS-X bug rather bad.  I have 10.2.4 running on one of 
my Daystar Genesis boxes with a Sonnet G4-800 card and a Tempo Trio 
ATA-100 card.  Runs Jaguar  very respectably.  Everything else is MacOS 
6.x-9.x.  Since I love NeXT cubes so much, I had to try Jaguar.