• Please review our updated Terms and Rules here

5150 not booting. Please help?

F

Fire-Flare

Experienced Member
Joined
Dec 17, 2009
Messages
273
Location
Washington State
I tried to start it up this morning, and it threw a fit of long beeps.

I've removed the drives and all the cards except for video. And now it's not beeping at all. It just repeats the video card's start-up screen.

The hardware looks and smells fine, switches are as follows for 0 disk drives, 256k onboard memory, and VGA video card:

Block 1: On-off-off-off-on-on-on-on

Block 2: On-off-off-on-on-off-off-off
 
Last edited:
You mean it was working fine before and then the very next time you tried to fire it up, it did what you just described?
 
The VGA card is a possible problem. Do you have any other card that you could use instead?

If not, try the following. It will help us to determine the state of the motherboard.

Remove the VGA card, and leave the all switch settings as they are. so all there should be connected to the motherboard is the power supply and the speaker.

Power up. After about 45 to 50 seconds, there should be a single beep. That beep indicates that the POST has successfully finished. Do you hear the beep?

If so, that gives us confidence that the motherboard is good. It doesn't prove that the motherboard is good though (the POST is a crude test only).

If you didn't hear the beep, we can be very confident that something is wrong with the motherboard or PSU. Why the PSU? Some of the clone power supplies send a fake POWER GOOD signal to the motherboard (e.g. they generate POWER GOOD even if the 5 volt line is sitting at 4 volts). If your 5150 has the original IBM power supply, that would tend to lay fault at the motherboard.
 
Fire-Flare said:
It was stored in another room for about half a year.
Click to expand...

Relocating a computer sometimes causes expansion cards to unseat a lil bit, causing a computer to seemingly fail without reason. My guess was also the PSU btw, but frankly my knowledge of old IBM's is quite limited. I do understand basic hardware troubleshooting though, I've troubleshooted a couple hundred computers in my life so I consider myself savvy in that respect.
I hope you get her working again :)
 
modem7 said:
The VGA card is a possible problem. Do you have any other card that you could use instead?

If not, try the following. It will help us to determine the state of the motherboard.

Remove the VGA card, and leave the all switch settings as they are. so all there should be connected to the motherboard is the power supply and the speaker.

Power up. After about 45 to 50 seconds, there should be a single beep. That beep indicates that the POST has successfully finished. Do you hear the beep?

If so, that gives us confidence that the motherboard is good. It doesn't prove that the motherboard is good though (the POST is a crude test only).

If you didn't hear the beep, we can be very confident that something is wrong with the motherboard or PSU. Why the PSU? Some of the clone power supplies send a fake POWER GOOD signal to the motherboard (e.g. they generate POWER GOOD even if the 5 volt line is sitting at 4 volts). If your 5150 has the original IBM power supply, that would tend to lay fault at the motherboard.
Click to expand...

Removing the video card didn't help, neither did reseating the power supply connectors.

The PSU from an AT clone, it's made by Enhance. Are those known to give problems? (or known at all?)
 
Flip the first switch in the switch bank once, then back to re-seat the switch, so-to-speak. I found that the DIP switches can become wonky if the machine is moved about (mine was transported and the floppy switches got weird). It sounds like yours is in POST-loop, which is controlled by the first switch (if it's the same as the 5160, and I assume that is).
 
I switched all of them back and forth, no change but it seems to be looping. The screen was resetting and I can hear a faint click at about the same interval.

What else would cause this?
 
Got a meter? I'd start troubleshooting by checking the voltages at the motherboard--in particular, see if things change when the board resets itself..
 
Perhaps a bad RAM chip somewhere is causing the system to restart when it's tested. Try setting the DIP switches to 16K RAM (SW2 1-5 on, 6-8 off), so that the minimum amount of RAM will be recognized and tested. The PC should now almost instantaneously beep and boot up to Cassette BASIC (if you have it set to 0 floppy drives) when turned on.

Raven said:
Flip the first switch in the switch bank once, then back to re-seat the switch, so-to-speak. I found that the DIP switches can become wonky if the machine is moved about (mine was transported and the floppy switches got weird). It sounds like yours is in POST-loop, which is controlled by the first switch (if it's the same as the 5160, and I assume that is).
Click to expand...

On the 5150 PC, the first DIP switch controls whether it will boot directly to Cassette BASIC (on) or will try to boot from the floppy drive first (off).

On the XT, the first DIP switch was changed so that (off) is "normal operation," since it is assumed that an XT will always have at least one floppy drive installed, and (on) now puts the self-test into an endless loop.

Source: http://www.rci.rutgers.edu/~preid/pcxtsw.htm
 
TNC said:
Didn't the AT- class machines have another pinout for the power connector?
Click to expand...

No, it's the same, but in particular, pay attention to the Power Good signal--if it's not stable, the system will keep rebooting. This just sounds so much like a power supply issue.

The 5150 BIOS (IIRC) tests enough memory to get the BIOS and display setup, and then resume testing the rest. If that first block doesn't pass the test, the system just halts with no indication.
 
vwestlife said:
Perhaps a bad RAM chip somewhere is causing the system to restart when it's tested. Try setting the DIP switches to 16K RAM (SW2 1-5 on, 6-8 off), so that the minimum amount of RAM will be recognized and tested. The PC should now almost instantaneously beep and boot up to Cassette BASIC (if you have it set to 0 floppy drives) when turned on.



On the 5150 PC, the first DIP switch controls whether it will boot directly to Cassette BASIC (on) or will try to boot from the floppy drive first (off).

On the XT, the first DIP switch was changed so that (off) is "normal operation," since it is assumed that an XT will always have at least one floppy drive installed, and (on) now puts the self-test into an endless loop.

Source: http://www.rci.rutgers.edu/~preid/pcxtsw.htm
Click to expand...



Ah, forgive my lack of knowledge about the 5150 then.
 
I'll second the PS as the first place to look. It really helps if you can get another PS to try. I rebuilt a PC PS with the innards of a mini AT PS. It's a quick cheap solution if thats found to be the problem.

framer
 
I've seen these things at my local hardware store, as well as a couple of big-box stores. The last one cost me $2.99:

90899.gif
 
You must log in or register to reply here.
Back
Top