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IBM 5150 Post Beeps, but that's it, help me!

integrale

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Joined
Feb 27, 2010
Messages
13
Hi and help!
my 5150 post beeps just fine but the 5151 monitor appears to be dead and i'm assuming that it has no OS, also the bios may not be too happy either.
So is there any way i can connect to a VGA monitor?
Lots of questions, but i'd be really happy with any answers.
Mr Peanut, Dave.
 
If it's not the card, installing a fitting ISA VGA card would be your best bet.
 
It depends on the BIOS revision of the 5150. If it's the earliest, it doesn't understand BIOS extensions; if it's later, you can use an 8-bit VGA card. But no, without spending money, you can't use a VGA monitor on an MDA card. Double-check your motherboard switches for the correct display type setting, however. Sometimes you can find a compatible monochrome monitor from something like an old Brother word processor in a thrift shop that will work in place of your 5151.

But first make sure that your 5151 is indeed dead. Generally, these are pretty robust things.
 
Please describe the machine. Just the model number can't tell much by it's own.

The machine beeps, in that case, is it one short beep, or one short folowed by long beeps?

You say that the problem may be the 5151 monitor. Are you sure the videocard you are using does monochrome, and that the motherboard is set to use monochrome? In addition, can you see the raster lines when you turn the brigthness all the way up? I assume you have plugged the connector into the graphics card and not into a serial card, but please check to be 100% sure.

What other devices/cards do you got in it? is it a 2-floppy system, or has a harddrive been added sometime durning the lifecycle of the machine?
 
When diagnosing an old PC, I always take the step-by-step approach. First, take out all the expansion cards, and set the DIP switches for the minimum configuration: no floppy drives, no video, and just the base RAM (either 64K or 256K, depending on the revision of your motherboard). Power it on, and after the memory check, you should just hear a single short beep from the speaker, indicating that it has booted up directly into Cassette BASIC.

Then, add in the display adapter, set the video DIP switches accordingly, plug in the monitor, and power it on. Now you should be able to see what's going on. If not, there's a problem with either the display adapter or the monitor. (Also, make sure you are using the 5151 with an MDA card -- it will plug into a CGA card, but won't display anything, and the wrong video signal type may even damage the monitor!)

If you don't have another monochrome monitor or MDA card to try, you can swap in a VGA card and use a standard VGA monitor -- as long as your PC is the later BIOS version, usually found on the 64/256K version of the motherboard (which is the most common). Most 16-bit ISA video cards will work fine in an 8-bit slot. Set the PC's DIP switches to "No video", which is the setting used for VGA or EGA.
 
One more addition--the PC is unaware if a monitor is connected or not. If you get a beep and then the floppy drive isn't selected, you're dying pretty early in the boot process.

I'd respectfully amend vwestlife's statement and say "some 16-bit VGA cards can be used in an 8-bit slot" as I have a pile of them that can't.
 
I'd respectfully amend vwestlife's statement and say "some 16-bit VGA cards can be used in an 8-bit slot" as I have a pile of them that can't.
Well, I wouldn't expect some of the later, really fancy accelerated ones to work, like Diamond or Tseng, but almost all of the more basic, earlier 16-bit VGA cards I've tried (Trident, Oak, Western Digital, etc.) do work. Some also have a jumper to select either 8-bit or 16-bit mode.
 
Hi ,
the post beep is just the short single beep to say "i'm o.k." so maybe the card is o.k. and it is the monitor?
I'm having trouble finding another monochrome monitor but i have located a 8 bit CGA card
so at least i may see if anything is going on at all.
The mother board is a 64KB-256KB it has a single 5.25 floppy drive, the main HDD has the "click of death" so it has a HDD expansion card fitted.
The 5151 monitor remains silent when turned on and shows nothing at all on the screen regardless of the contrast and brightness settings turned fully clockwise as instructed in the manual.
 
update!!
i set up the switches for a monochrome display so now when i turn off the computer i briefly get a green "squiggle"? a bit like a heart monitor showing a heart beat.
Is this a good sign?
 
update!!
i set up the switches for a monochrome display so now when i turn off the computer i briefly get a green "squiggle"? a bit like a heart monitor showing a heart beat.
Is this a good sign?

Then we can for sure say that the monitor does get sync. input.

Do you have any posibility to take pictures of the internals of the PC and post them here?

The beep means that it passed POST, so it's nothing wrong with the computer. Therefore, it must either be your graphics card, monitor, or a conflict. Try to set the brigthnes fully on now after you set the switches... Can you see curved lines on a green background?
 
I've turned the brightness fully up but no lines or anything else at all.
Here are some pictures of the internals as requested to maybe make things a little clearer.
 

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I've not seen both a hardcard and a normal harddrive in the same system before... That one card is clearly a real IBM MDA and should work perfectly with a 5151... A last thing you could try is to attempt to boot after having removed all other cards than the floppy-controller and MDA.

It really sounds like something is wrong with your monitor. It seems to get sync signals, but the brigthnes-signals doesn't seem to reach all the way to the picture tube. If you know how to fix monitors, and the safety-procedures involved, I suggest you should check the signal amplifier.
 
I've turned the brightness fully up but no lines or anything else at all.
Here are some pictures of the internals as requested to maybe make things a little clearer.

Why do you have two monochrome display cards installed?

attachment.php
 
Are you certain there are no conflicts with the MDA?

Yes, the multifunc card only contains extra RAM, problably a real-time clock, a serial port (clone of the Async card), a parallel port (clone of the parallel card, so it's not using the same address as the MDA parallel port), and perhaps it got a header for a joystic-port.

However, if it has a certain hardware failure, it may conflict, but that's very unlikely.
 
Okay--it's just not usual to see a serial port on a PC with a DE9F connector (DE9M was the rule). Which leads me to another bit of speculation--that someone plugged the 5151 into the serial port. +/-12 could potentially do a fair amount of damage, eh?
 
Okay--it's just not usual to see a serial port on a PC with a DE9F connector (DE9M was the rule). Which leads me to another bit of speculation--that someone plugged the 5151 into the serial port. +/-12 could potentially do a fair amount of damage, eh?
Not very clear, but it looks like a -9M to me, as it should.
But I'd echo the advice to temporarily pull all the cards except the MGP; pretty busy, and lots of places for a bad cap or whatever to bring the system to its knees.
And I don't think the brief flash guarantees that the sync & drive are OK; a collapsing voltage somewhere could just be briefly activating the horizontal oscillator.
 
Not very clear, but it looks like a -9M to me, as it should.
But I'd echo the advice to temporarily pull all the cards except the MGP; pretty busy, and lots of places for a bad cap or whatever to bring the system to its knees.
And I don't think the brief flash guarantees that the sync & drive are OK; a collapsing voltage somewhere could just be briefly activating the horizontal oscillator.

You're right--on close inspection, it's a 9M. Ah well, time to get new glasses. A logic probe or an oscilloscope could verify the presence of a pulse train on the sync outputs; they're plain TTL-compatible outputs.
 
I've removed all cards apart from MDA, i've then booted up and still nothing visible or flashing on the screen ,
although with the screen completely turned off you can see very faint horizontal and vertical lines?
 
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