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Display has problems on startup
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Mar 2, 2002, 11:40 PM
 
Hello,

My brother recently has started having more and more issues with his 17" Sony Monitor and Power Computing Power Tower Pro 250. On start-up (from powered off), the monitor does not properly "sync" up and display the screen. It requires a single reset after a power on, and then the monitor goes green and displays a signal. This happens now at every single boot-up. Any ideas what is causing this problem? Mayebe a dead PRAM battery, but the clock is correct...

Any suggestions are appreciated,
-Ben
     
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Mar 3, 2002, 11:06 AM
 
Originally posted by bserebin:
<STRONG>Hello,

My brother recently has started having more and more issues with his 17" Sony Monitor and Power Computing Power Tower Pro 250. On start-up (from powered off), the monitor does not properly "sync" up and display the screen. It requires a single reset after a power on, and then the monitor goes green and displays a signal. This happens now at every single boot-up. Any ideas what is causing this problem? Mayebe a dead PRAM battery, but the clock is correct...

Any suggestions are appreciated,
-Ben</STRONG>
     
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Mar 4, 2002, 10:11 AM
 
Try (on startup) to zapp your PRAM 5 times to reset the video-settings.

(Press and hold Control+Alt+P+R at startup untill you hear the
startup "BANG"-sound 5 times; the screen will also flash every time as it reboots; this should reset it)

Also : download and re-install any driver-software for this monitor !

cheers,
Carolus
* iBook 600 *
and loads of oldie Macs ;-)
     
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Mar 4, 2002, 04:28 PM
 
I zapped the PRAM and Bang! No more display. :-(

After zapping the PRAM as mentioned, 5 times, upon reboot, the monitor will not come on anymore. Rebooted numerous times, nothing. I even zapped it twice to try to get it back to normal. Nothing.... no display and no Mac.

Not a happy camper,
-Ben
     
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Mar 5, 2002, 02:46 AM
 
Pull the PRAM battery and check it's voltage... or just replace it. I recently had very nearly the same problem you described with a couple other ageing computers. Twas the battery alright.

You will have to (or should) reset PRAM once you install a new battery. If you still have problems, try removing the PRAM battery and unplugging the CPU, leave it this way for at least five minutes, reinstall the battery, plug it back in to power, turn it on, and zap the PRAM.
     
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Mar 6, 2002, 01:47 AM
 
Thanks Rainy Day for your suggestion, but it did not help. Could the motherboard be toast?

I brought my brother's PTP 250 to my house and connected my monitor (Sony 15sf) to it and I was now able to see a flashing question mark. Better than seeing nothing on his Sony 200sf. So, I tried to boot from a Apple OS 9.1 CD, no such luck. Apple 8 CD, nope. Holding 'C' down did nothing. I was able to boot from a Network Disk (that's a 1.44MB floppy disk), and upon running Disk First Aid, no HDs were visible. Upon running Disk Setup, one HD was not mountable, and the other 2 were ready to be initialized (not visible). Something, I don't want to do. So, I continued to troubleshoot.

I pulled out my PRAM battery (from my work-horse 8600/300) and put it in his Mac. I zapped the PRAM (twice) and then tried tried starting up. Flashing disk. PRAM zap 5 times, flashing disk only.

I pulled out one of his HDs, and connected it to my 8600 via the external SCSI bus on SCSI ID 1 and was able to see it (all his files and folders) and ran Disk First Aid v.8.6 (comes with 9.1), Norton Disk Doctor 6.0, all without any errors. I made sure the System Folder was blessed, and set the HD to SCSI 0, and tried to bootup. Nothing (flashing disk) only. I disconnected all the SCSI devices except for this single HD, still, flashing disk. I connected the single HD to the external SCSI bus, nope, flashing disk.

I then pulled the PRAM battery, unplugged the computer, and waited 10 minutes, and zapped the PRAM and a flashing disk only. So...

I have no other ideas... any suggestions or comments... is this a sign for my brother to "go buy a new dual processor G4 Mac".

Thanks,
-Ben
     
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Mar 6, 2002, 08:29 PM
 
Some good troubleshooting there Ben. You pretty much covered all the bases. I'd say the SCSI controller is toast. Clearly the HD is good. If there's some kind of expansion slot, you might be able to buy a plug-in SCSI card. Don't know if the on-board SCSI controller IC is socketed or not (probably not). Might be possible to replace it if it is. Also, might be possible to swap out logic boards if someplace like Shreve Systems has it for a decent price (usually not, but sometimes). It may indeed be time for your brother to invest in the next generation hardware. Sometimes it just isn't worth the cost of fixing old equipment.
     
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Mar 8, 2002, 01:44 AM
 
Hello,

Firstly, Rainy Day your on the money. And no, I'm not about to solder the SCSI sockets on the logic board. :-)

Thanks for your suggestions. Also, for future reference, the PRAM battery is Radio Shack Part # 23-026 (a Lithium Battery, 3.6 volts, 850mAh, Size 1/2 "AA") priced at $10.99.

I also posted my problem on Apple's forum, and the only new suggestion was to actually replace the battery, so I did.

What I Did:
So, I unplugged and pulled the battery out and pushed the on button every so off to clear any power left in the capacitors. Then it sat for almost 24 hours. Popped the new battery in, and then plugged it in. Display came on, but the flashing disk was there to. So, I booted off my trusty floppy disk (Mac OS 8.1TD) and no HDs were visible. So, I shutdown and put a clean HD (didn't care about formatting it) in and started it back up. I launched Disk Setup and the only option I had, was to initialize the disk. So, I did it. Upon formatting the disk, the partition appeared on the desktop. I then copied over the System Folder from the floppy disk and rebooted. Flashing Disk. I disconnected all the other HDs and CD-ROM and verifed that the terminator settings were correct. Then, I tried to bootup with only that drive connected. Nope. Then, I tried to connect the SCSI cable to the SCSI Bus 1 on the logic board. Nope. Then, I put it in a SCSI case, and connected it via the external SCSI connector. It worked!

So, the internal SCSI connectors are toast. I took a look for Power Computing logic boards, but found nothing. I guess an interal SCSI card is a possibilty and cheaper. But I'll let my brother decide, a new SCSI card and more hours of my support, or a new Mac. Hmmmm... I know what my girlfriend would prefer. :-)

Thanks again,
-Ben
     
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Mar 11, 2002, 02:02 PM
 
Interesting. I'm surprised that you were able to format the HD. That tells me that the SCSI controller is at least partially functional. The way SCSI drive formatting works is the host controller (i.e. the CPU) sends a "format" command to the drive. The drive then handles the mechanics of the format independently of the host (unlike some other systems where the host is actively involved in the process). This means that the CPU was at least able to send a "format" command out to the drive via the SCSI controller. What it doesn't seem to be able to do is receive data back from the drive.

Now i'm wondering if the SCSI controller is bad, or just the cable? It sounds like, from what you've said, that this machine has two separate on-board SCSI busses (and hence, two separate SCSI controllers?) I don't know what the connectors look like inside the box, but generally they are IDC-50 (50-pin connectors, two rows of 25 pins, side-by-side). If you have one of these on both SCSI buses, you're in luck as you can swap things around inside the box to determine if it's the controller or the cable which is bad. If not, you might be able to jury-rig some kind of external SCSI connector to internal SCSI cable (you may already have something like this inside an external enclosure).

Alternatively, if you have another internal SCSI cable (which you should have hanging off the CD), you might try connecting the drive to the internal SCSI with the other cable (ensuring proper drive termination, of course).

Actually, here's another possible source of the problem: Which is connected to the logic board: The HD or the CD? If it's the CD, remove it from the bus and connect the HD directly to the logic board. If that doesn't work, swap cables. Be careful to ensure proper termination (but you know that, i'm sure).

The goal is to reduce the number of independent variables which could be causing the problem, and thus isolate it. You don't know if the problem is the on-board SCSI controller, or one of the cables up to the terminator. Could also be a connector on a drive along the way. Several variables. It's all a matter of deduction and elimination.

In the end, however, your girlfriend might be right.
     
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Mar 12, 2002, 01:01 AM
 
Hello Rainy Day and all,

Just wanted to let you know how it ended... yes, it has finally come to a conclusion. But before I wrap it up, more troubleshooting...

I tried swapping the SCSI cable with a known working one, flashing disk. Also, during my previous testing, I had removed all SCSI devices except for a single HD and terminated it, flashing disk.

Also, there are 2 SCSI 50 pin connectors on the logic board right next to each other. One says Internal (I think) and External (I know this is right). I had previously attempted to use the external connector, and it made no difference (flashing disk).

So, I bought a SCSI card, an Adaptec PowerDomain AHA-2930U. This is the lowest end Adaptec that is bootable and has a single interal 50 pin connector and an external mini-50 pin connector. I popped the SCSI PCI Card in and connected the SCSI chain to the PCI card, Bang! It all worked again. No software or drivers to install, BIOS on card did it all. So, in the end, I think the two SCSI controllers were fried. Weird, because the external case connector worked, but none of the internals. Maybe that has it's own controller... but no more thinking about this issue. On to other things, like my 802.11b interests...

Good night and thanks everyone especially Rainy Day,
-Ben
     
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Mar 12, 2002, 07:24 PM
 
That's a head scratcher: Why it worked externally but not internally. But that sort of thing can really make your brain hurt, so...

Glad to hear you got it resolved, and from the sounds of it, for not too much money. Bet your girlfriend will be happy too.
     
   
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