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Wolfpacker
12-22-2000, 03:48 PM
This past August I purchased a used Powercurve 120 with no hard drive, no video mmemory, and no RAM. It made the start-up chime when I plugged it in, so I figured it was OK.

It wouldn't boot after I installed the new video memory (Kingston, from someone else) and the new 32 Mb DIMM from MacGurus. It wouldn't boot after I removed the new V & RAM memory. It would get both fans running and light the power LED. Now the fans won't come on--the power LED flickers on, the fan(s?) turn over once or twice and then nothing. It's as though I fried the relay switch (I assume it's a relay switch) trying to make the CPU come alive. It was being reluctant to work prior to giving up.

I wonder if I zapped it with an unnoticed static discharge (this shag carpet probably doesn't help) while I was trying to figure out if I had a Power 120 or a Powercurve 120 (the latter)--I had the case open a lot. I had started to remove the CPU daughtercard at one point; but I tightened everything, I thought.

I followed "Catplastic"'s New Motherboard Adventure (and others) and learned from there to replace my battery, although I can't figure out why a bad battery would prevent start-up. My old battery was putting out 2.5 volts DC.

When I checked the power supply with a DC voltmeter, I get about 1/2 a volt when the power switch is on or off. This really makes me think I have a bad switch. I'll remain optimistic about my processor card for the time being.

Thanks for the help.

Go Pack!

MadDog
12-22-2000, 04:46 PM
Bad switch or bad powersupply. Do you have another case/powersupply you can swap around ?

Mad DOg

Wolfpacker
12-22-2000, 05:25 PM
No, I don't have another power supply, except the one for my Performa 466, which I'm using for it. Could I bypass the switch or get one from Radio Shack?

Anything else?

Wolfpacker

magician
12-22-2000, 09:07 PM
how are you testing the output from your power supply?

Louie
12-22-2000, 09:18 PM
The PRAM battery should read 3.6v. The power connectors should read +5 and +12 on the red and yellow. The two center wires a ground. Read with power on.

Wolfpacker
12-23-2000, 12:38 AM
Regarding Magician's question of how I'm checking the power supply, I'm using a Micronta 22-211 multimeter with the supplied "stick" probes. I set the meter on 15 and then 3 DC volts. I inserted the probes into the unused outputs from the power supply and kept changing where I put the probes until I got a positive reading (this was before I read Louie's post). The contact was loose, but the readings were consistent.

My readings now are about 1/2 volt DC; it's like it's not coming on or something. I think I may have abused my power supply switch earlier--I wasn't releasing it when I pressed it or something.

My PRAM battery, which I installed this week, now reads 3.0 v across the terminals, as installed. Could this missing voltage be what I'm reading at the unused power supply outputs? Wait, let me check....no, I checked the readings without the AC plug; I detected no voltage drop. Does that mean the ~.5 v I read earlier is the standby power? (I think the very helpful Frank of Sleepy Hollow Computers [formerly the Lisa Shoppe] is the one who told me about standby power, on a Mac X/L---Lisa 2.)

It looks like I need a power supply or to get my power supply fixed.

By the way, thanks for helping me out on your day off. The BB system, with email notification, is groovy cool. I'll probably get back to this after I corral a few other cats.

Thanks again,

Wolfpacker

Louie
12-23-2000, 12:58 PM
I've seen PRAM batteries that read 3.6v that were too weak to start. $10 at Radio Shack.

It also sounds like you power supply is shot. Here's one place to get one http://www.dttservice.com/index.html .

Wolfpacker
12-23-2000, 02:28 PM
Thanks for the info Louie. The cost of the power supply at DT&T isn't bad, I guess--70% of what I paid for my 0/0 machine (sigh).

The really frustrating thing is the battery (assuming the CPU isn't shot)is that I just replaced it *this week* $9.99 + tax at Radio Shack. The Pelican State supplier included an identical battery w/ the computer. What could drain the battery--secondary currents on the power supply (since transformers work in both directions, or is that just w/ AC current)?

Where is the PRAM--on the logic board? My Powercurve has no memory installed currently. The PRAM keeps the settings, right? How could not having PRAM battery prevent start-up? That's really driving me crazy too.

Maybe St. Nick can find room for a power supply in his sack.

Later,

Wolfpacker

magician
12-24-2000, 01:03 AM
definitely sounds like a busted power supply.

http://macgurus.com/infopop/emoticons/icon_biggrin.gif

Chucko
12-26-2000, 05:57 PM
Power supplies for Power Computing machines are nothing more than cheap old ATX supplies. Any generic ATX P/S with the fan on the back side of the housing will do. If you must spend lots of money on one, get a Silencer from PC Power & Cooling. The 235 watt version is only $69, will power any Power machine short of a fully loaded tower, and they're mighty quiet!

Wolfpacker
12-26-2000, 06:39 PM
Thanks for the info Chucko; thanks again Louie, Magician, and Mad Dog.

Go 'Pack!

Wolfpacker

Wolfpacker
12-26-2000, 06:42 PM
Uh, Chucko, what's an ATX power supply?

Wolfpacker

Dogstarman
12-26-2000, 07:36 PM
Well, I ain't Chucko. But here's the low-down on an ATX power supply. It's a PC thing. You see, Windows folks have some good ideas. They really do. One of them was standardizing power supplies. There is an AT power supply format, then the ATX. It (mostly) corresponds to the motherboard form factor. Also used to describe the type of power connectors on the power supply or motherboard. Hope that satiates your curiousity for a spell.

Chucko
12-26-2000, 08:18 PM
Dogstarman's got it right. You can find cheap generic ATX supplies at any PC parts store. There's really nothing special about the Power Computing units.

Wolfpacker
12-27-2000, 02:00 AM
I got it. Standardization, aka a good design concept. Thanks Dogstarman.

Wolfpacker

professor
12-27-2000, 02:16 AM
If you're going to load the machine down with extra drives and a processor upgrade, it would be a good idea to go ahead and get a 250 or 300 watt power supply. That way you don't starve anything.

Dogstarman
12-27-2000, 04:44 PM
It's all about the standardized parts in PC-land. That's why there are so many vendors. I sometimes wonder if it'd be better or worse to have 200 companies making cards for Apple products...and 350 word-processors. Nah. It wouldn't. But I would second the Prof and get a big supply (well, they are actually quite small). I mean the 300 watt or better.

professor
12-27-2000, 10:50 PM
One thing I do like about having so many pc vendors is that it drives down prices, but you also can easily end up compromising the speed and reliability you may want and need.

Wolfpacker
01-01-2001, 07:05 PM
There's one thing I don't understand. Why does a dead battery prevent a (PCI PPC) computer from booting? I thought the battery just kept the PRAM going, and the PRAM just holds certain user settings. The battery died in my Performa 466, and it still booted.

Wolfpacker

Dogstarman
01-01-2001, 11:47 PM
It depends on the Mac. My Performa (RIP) would boot with a dead battery...just bad Date/Time & AppleTalk settings on every cold startup. My 9600...well, I haven't tried. My 7200 booted fine when I had a dead battery. I will check my 7600 someday, if the damn thing ever dies (still the original battery). Would it do the same thing to remove the battery and try a cold start?

Louie
01-02-2001, 01:30 AM
He's right. Some models do, some don't.

Wolfpacker
09-01-2001, 02:10 AM
Well, at long last I "screwed courage to the sticking place" and pried open my wallet. I went to a local PC shop and bought an ATX power supply (250 watts, I think, though the label said 140 watts). I also bought a used Apple monitor for $10, and went to Radio Shack and bought a new battery for $12.

I disconnected the old power supply (without removing it, just opened the case) and plugged in the new power supply and the monitor. I don't know if the el cheapo video RAM and the Acme 32M DRAM were installed at this point or not. I started the computer. I got a chime, a flicker on the monitor, and the monitor went back to its pre-startup green light blinking.

I tried several variations of video RAM and main memory in and out, together and
apart. I tried reseating the RAM. I plugged in a keyboard. Nothing helped. I eventually checked the multimeter that I had used to condemn the batteries and the power supply and found out it wouldn't read a good battery or even a wall socket.

I finally took the machine back to the PC dealer (without the memory--it would have saved a trip to town, which I made later.) The nice PC dealer took the ATX power supply back for two used power cords and cash.

More weird and unreliable results followed; mostly similar to the former, although I would sometimes press the button and get nothing--no ding. It got the point where it would take 5 presses of the power button to get one ding.

I finally got the machine to an Apple service provider in town. Their diagnosis, based on removing the CPU card and reseating it (which will make the machine ding) is that it's probably the logic board or the CPU card, but they don't have the parts to verify this by swapping the CPU card. No charge, at least.

So what happened? Improper storage? (Static from the carpet, cat hair, other?) Bad VRAM? Bad main RAM? A still undiagnosed problem (loose connection somewhere, etc.)?

Any suggestions?

Thanks again,

Wolfpacker

lasvegas
09-01-2001, 06:58 PM
I would say since removing and reinserting the processor board reliably produces a chime, the clock circuit on your processor board is likely bad. This could produce your original results of the chime and initial activation of the video before the clock crapped out and shut the system down. That clock controls everything!

Get yourself a new or used processor card. A great, inexpensive solution is one of the XLR8 options here on the GURUS site starting at only $200. Your PowerCurve should support just about any 604 board you might find though.

[This message has been edited by lasvegas (edited 01 September 2001).]

Wolfpacker
09-01-2001, 10:11 PM
Thanks!

Wolfpacker

Wolfpacker
09-02-2001, 01:08 AM
lasvegas:

Is the clock integral to the processor itself or a processor board sub-assembly? Ie., could some soldering iron hot shot (not me!) replace the processor clock, or is the board just too dense w/ surface mounted hardware, etc.?

My machine is still at the shop, but I seem to recall that it was covered with a heat sink, which blocked my view of the board itself.

When people speak of "re-clocking" a computer, are they speaking of a separate clock or a re-design? It seems like in the old days (when I just read and didn't stick my hands inside a computer), that a clock was a separate card. Did that pass away between the TRS-80 and the Appple IIgs?

Thanks in advance for reducing my ignorance.

Wolfpacker

lasvegas
09-02-2001, 05:16 PM
Things have changed a bit since the Trash80 and IIgs. Nowadays, most circuits are built out of Surface Mounted Components. The clock is built onto the processor board under the heatsink. The design varies from board to board to the point that a board is usually built to accomidate various forms of clock circuits (using only one). Clocking a processor card is possible and many of the processor upgrade cards use a series of switches to allow tweeking of the clock. It would require a lot of studying of your particular board to determine what tweeking could be done, but the cost just wouldn't be practical.

Your processor board (if original) is a PPC 601 built onto a 604-like board. It wouldn't be financially feasible to attempt to repair that board. You would be much better off purchasing an XLR8 board. Your motherboard is the same board used in PowerComputing's PowerCenter computer. It should work with virtually any old Apple 604 processor card as well. If you can find one to borrow, this would at least confirm that the XLR8 purchase wouldn't be a waste.

[This message has been edited by lasvegas (edited 02 September 2001).]

Wolfpacker
09-13-2001, 02:40 PM
lasvegas:

Thanks again for your help. I took my machine to MicroComputer Support Services (http://mcss-nc.com) in Greenville, NC. They essentially agreed with your diagnosis of a bad processor card; they did get it up and running System (8?) though they said every time the machine was powered down they had to pull the processor card and re-insert it which would let the machine boot. (I wish I had tried thatalong with hoooking up my external hard drive.)
Personnel at MCSS also stated that the CPU card slotwas cleaned. Theymost helpful. MCSS also waived the $40 bench fee.

So, the video & main memory modules are OK. I should have been morepersistant in diagnosing the problem. The batteries I bought from Radio Shack were fine; the power supply is OK. I can get a 604 card from MacResq (http://www.macresq.com/) for $50 or a G3 card from MacGurus for $200 or I can livewith the problem while I do other stuff like figure out why MacTCP doesn't want to work on my PCI machine. (Which is why I'm back onmyPerforma wiyththewornoutkeyboard.)

Thanks again,

Wolfpacker
("40 rounds!")

lasvegas
09-15-2001, 12:46 AM
¨÷I do other stuff like figure out why MacTCP doesn't want to work on my PCI machine.

I wouldn't even consider using MacTCP on a PCI machine! Open Transport is so much more reliable¨÷

MadDog
09-15-2001, 02:44 PM
MacTCP only works in 7.5.5 or earlier, right ? Either switch to Open Transport, or upgrade to 7.6.1 or later.

Mad Dog


http://www.macgurus.com/ubb/jollyroger.gif

Wolfpacker
09-16-2001, 10:24 PM
Thanks again lasvegas, and thanks Mad Dog.

When I said "MacTCP", I should have said "TCP/IP", which is part of Open Transport 1.1.1.

The reason I couldn't connect properly is that I didn't have OT properly installed--I just had the PPC components without the emulation compatible components. I read the documentation listing what was suppose to be installed and got that fixed Friday before heading out of town.

I'm new at this PPC stuff, though I had read enough in Mac magazines and elsewhere that there is the emulation aspect to consider (to allow for non-native software, right?). Of course, I'm not exactly state of the art, or rather I'm state of the art, circa 1996; but I do have a clock speed 4x faster than my ex-demo model Performa. I can quit grinding my teeth when I read on some neat software (like SETI search) "PPC required". (Yeah, I know--'and starting grinding my teeth when I read System X required.')

Thanks for once more reducing my ignorance.

Wolfpacker