Question Old Packard Bell 640 Motherboard - blank display from onboard video and external cards.

[kikipcs]

Hi,

I've got an old Packard Bell Multimedia PC I've been trying to get working again for old time's sake. After replacing all of the capacitors for fresh ones, sourcing some parts and thoroughly cleaning the board and connectors, I was just about to fire this thing up.

However, on a first boot, I noticed that the onboard speaker emitted a short beep, yet there was no display at all. The CRT's power on LED kept flashing, as if it was in a standby mode.

I brought another, 100% flatscreen LCD - and it didn't work either. It went into the standby mode and stayed there.

So, I bought some video cards, namely an ATi Mach64 VT and a Matrox Mystique - both tested, working, and in perfect shape, hoping that would solve the problem. The result was the same.

How can it be that neither the onboard video nor external video works? I should add that the motherboard seems to be working quite flawlessly; an external fan spins when plugged in, without ram it buzzes about indicating there's no RAM detected, and when I plug in a floppy drive with a DOS boot disk, the PC begins reading from the disk. Yet there's no video signal at all, and I'm stopped dead in my tracks with restoring this Packard Bell back to its former glory. Needless to say, I'm desperate to get over this issue.

Has anyone here had a similar problem, or has any advice I should try? That'd be much, much appreciated.

 

[BFG-9000]

If it's an actual PB640 motherboard, there is a BIOS flashing jumper J9C1 which if set to 2-3, will result in one beep and no video but tries to find a BIOS file on a floppy disk.

The jumper has to be on 1-2 for the system to boot normally.

 

[kikipcs]

It is a 640 - has only 1MB of VRAM.

While J9C1 was on the "NORM" setting, disconnecting the jumper uncovered a broken pin! I will try to short those pins with a screwdriver and post the results ASAP.

And that might actually answer why the floppy drive was acting how it was. I should have clarified it more; without floppy, after the POST seek test it keeps moving the motors, while when with a boot floppy inserted, it reads something, but stops after a short while. Nevertheless I'll poke into it right now and reply as quick as I can.

 

[kikipcs]

Edit: pin 3 was indeed cracked diagonally. Shorting the pins with a screwdriver and powering on the PC resulted in signs of life from the PC - as in, there's something on the display. There's a whole load of messages on POST, though - I'll try to figure out something better than a screwdriver to bridge them and report to you.

 

[BFG-9000]

That's great! Given how Intel designed these boards, I wouldn't be surprised if there was no connection to one pin at all and it's just a jumper holder.

I suppose after only 24 years there aren't going to be any more new BIOSes, so you could just solder them. But for a factory appearance, replacing the pin would look better.

 

[kikipcs]

That's great! Given how Intel designed these boards, I wouldn't be surprised if there was no connection to one pin at all and it's just a jumper holder.

I suppose after only 24 years there aren't going to be any more new BIOSes, so you could just solder them. But for a factory appearance, replacing the pin would look better.

Well, I've tinkered with it a bit, and I'm pretty much 100% sure that that is the problem at hand. While I could go about and solder a new 3-pin jumper connector, what I think I'm going to do is just solder those two pins together. Won't make that much of a difference; it's a tiny thing and should anyone notice it, I'll give them the rundown on it.

I'll still let you know if that has fixed the problem completely, but given how it almost magically came back to life, the only thing I can say right now is: thank you. After over a week spent trying to figure out what's wrong, browsing through forums, old archived sites, making posts on my own, it was you who gave the smallest yet most important bit of advice. Seriously, I would've never thought of it, let alone guessed it - there's nearly no documentation about these boards, and I guess only experience akin to yours would know of the PC's behavior when in recovery mode. Thus again, thank you - you're a saving grace. I'll send you a PM or reply to this post once I solder it and test it thoroughly.

 

[kikipcs]

Alright, back again with a little report.

So far, i've tried bridging the pins with solder - the result was a blank screen, no beeps.

Then, I bridged the pins from the underside of the board - figured since one pin was broken it would be broken pretty much all the way, so bridging them from the bottom would make a more solid connection. Tested it with a multimeter, the connection was proper. Upon boot-up, the result was the same as above - blank screen, no beeps.

Right now I'm going to solder off the whole pin thingy and jump the two vias with a wire - but before that, I brought it all back to the original configuration without bridging and as expected, there was that beep and an attempt to read the floppy. To be 100% sure, removing the RAM yielded the low buzz - so the board is definitely alive and well. I'm running a skeleton configuration and if the bridging still results in a blank, beep-less screen, I think I have another issue on hand that's preventing the board from POSTing.

 

[BFG-9000]

There weren't too many layers in those old boards, so if a pin is indeed cracked between layers then sticking a wire all the way through should sort that. You did say it's pin 3 that was cracked though, which is the one that's not supposed to be jumpered to 2. What happens if you completely remove just that pin?

I suppose there could be layers connected by that pin too, so may have to replace that one as well, even if a u-shaped wire goes through the other two.

 

[kikipcs]

Just finished soldering a whole new pin thingy. I should've double checked - the pin that was split was the one that should be connected to pin 2 in normal mode - that is, it was pin 1. I was just looking from the opposite side of the board, sorry. 🙄
However, now that I soldered it in, triple checked with a multimeter to make sure the connection is good from the motherboard side and that the pins short 100% when a jumper is set, I cobbled it back together and gave it a boot.
Now, it displays no video, and no beep. When the jumper is set to recovery, the behaviour is back as it was - no video, one beep, attempting to read from floppy. I guess now it's transformed to that classic "no POST, no video, no beep" kind of situation. Have you got any idea as to what might be the most likely cause of this?

 

[BFG-9000]

The only time that should normally happen is if the CMOS Clear jumper J4K2 is set on 2-3 (not sure about the Password Clear). I don't know what happens when the battery is low either as all my Packard Bells had Dallas Realtime Clocks but one (a PB600 with VLSI chipset, which was obviously not made by Intel. It had an odd combination of AMD K6-III and PIO mode only, instead of Multiword DMA Mode2 like yours).

However I'm wondering if some trace inside the board is cracked, as it worked when you were prodding around with a screwdriver. Perhaps try poking with something plastic or your fingers?

 

[kikipcs]

Will double-check that jumper - 'I remember tinkering with password/CMOS jumpers when troubleshooting at the beginning. Also will poke a bit on it, and try to re-seat the memory - these old EDO ram sticks always give a feeling that you're damaging them whenever you insert them... As soon as I come back from work I'll get to it and report here.

 

[kikipcs]

Checked the jumpers - CMOS Clear was on 1-2, but the password jumper was set on "enable". Switched it back to clear/disable. Not sure that would change anything - this archived page says the BIOS doesn't support password protection.

I focused on the memory sticks - I removed one to check the chips online, see what capacity was one stick. When I came back and switched it on, I forgot to stick the second one in - in response, on recovery mode, I received low-tone buzzes. Thinking it was the memory that was at fault, I re-checked every configuration - one/two sticks, in various banks. All with the same result. However, after removing the graphics card from the riser, the buzzes disappeared! On recovery mode it's back to normal operation, and in normal mode it's blank screen again.

I'm starting to think the onboard video controller might be faulty.

 

[BFG-9000]

I have three Intel Advanced/MN-A LPX boards that are very similar to yours, most of which have some video problem, so perhaps it was common--however each works with PCI video. One board has a bad video chip and another has a bad VRAM socket so is stuck at 1MB even if RAM chips are installed, so all three have had PCI video cards in them for 20 years.

You can see the Intel documentation is a bit better than Packard Bell's. Page 38 suggests it may have copied something off your floppy into the flash chip, perhaps thinking it is the flash utility? It's too bad you didn't get to read all of the POST error messages.

 

[kikipcs]

It might indeed be faulty, because I don't see any reason as to why shouldn't I receive any video from a PCI card if the onboard video is switched off automatically. The card works perfect - tested it in a Slot 1 motherboard.
The floppy in question was a typical Win95 floppy - I chose that thinking it'd let me into DOS straight away, I could test the keyboard, all that... you know the drill. The floppy drive made, well, how should I put it... normal floppy noises? While the manual you provided explains why there's no video in recovery mode (which would've been a huge aid, considering it may really have tried to load something), what I think I'm going to try is source a 640 flash update from some FTP site (hope I can find one, haha) and well, try it out. I'm kind of hanging on a string - can't really think of what else might be wrong with it.

Come to think of it, while this may be a bit far-fetched, maybe the BIOS really was in some way damaged? This would explain the weird behavior with the RAM - sometimes it buzzes 3 times exclaiming there's no RAM, sometimes it doesn't - regardless of the RAM configuration. I'll try to find an update and let you know what's up next.

 

[kikipcs]

Alright - found an update for the 640, copied it onto a floppy, and proceeded with the instructions described in that manual. It did read, copied some files for a while, then the LED shut off - it finished its job. Swapping the jumper and powering the PC, there's still no signal - but at least now I have the most recent BIOS.

 

[kikipcs]

Case closed - computer has successfully booted up. Somehow. I don't really know how - I was ready to pack this thing up and shove it into my basement. I tried booting it in its case - the last time it did a POST was when it was in the case. Booted up - nothing. Booted up in the recovery mode - beeps, asks for a floppy. I inserted the floppy - it started loading, but then it beeped. Then, it beeped twice. Then the LED went out. It didn't act like that before. So I restarted the PC in normal mode, and still nothing. I was reaching for the power switch when I heard a faint beep. Dumbfounded, I looked at the display and it was still blank. I moved the display cable onto the video card and we have a POST screen!

Here's an Imgur album - proof that it finally booted:

https://imgur.com/a/7pEiaH7

View: https://imgur.com/a/7pEiaH7


Sure, there are some errors, but I can handle them without too much hassle. Looks like it works, then. Thank you SO MUCH - I would've never done it without your experience.