I believe MIDI IN is causing this.

Unplug MIDI IN coming from the keyboard, and the games should work smoothly (only use MIDI OUT coming out of the Sound BlasteR).

I connected the cable that says "IN" where in the keyboard says "IN" and the one with "OUT" printed on where in the keyboard says "OUT", is it correct ?

So I have to only leave the "OUT" cable in the "OUT" slot like that ?

But that way how's the data going to be delivered to the keyboard if that's its output ("data going towards the gameport") slot ?

The keyboard is a Yamaha PSR-160, by the way.

EDIT: Just tried like that with only "OUT" in the keyboard, it still freezes the PC.

I just tried the opposite I left only the "IN" one in the keyboard and it isn't crashing anymore 😁
But now it's glitching: every time I complete a level, for example, the last note of the previous music keeps playing over the subsequent music, making an ear rape after a while, the same after I exit the game: the last note keeps playing until I restart the keyboard, that's some annoying thing 😢

Out on a plug goes into in on a port if that makes sense 😀

It comes OUT of the sound card and IN to the MIDI module.

The Sound Blaster will cause issues in games if it receives MIDI IN. Disconnect it, just have MIDI OUT on the Sound Blaster go to MIDI IN on your MIDI module.

I take it the MIDI IN on your keyboard acts like a MIDI module, it plays music?

EDIT: Your photo doesn't help a lot 🤣 Got a wide shot of everything connected?

OH MY GOD, the (486) PC just went nuts !!!
It began to show random pixels on Doom while the MIDI was working, then it froze, now when I power it on it does 4 beeps like that: BEEEEEEEP, BEEP BEEP BEEP and the screen looks like an ASCII canvas with the "checkerboard" ASCII symbol and the DOS cursor randomly moving around while it does the boot stuff... creepy.

Ok, sorry for the off topic (even though it's not so off topic because it has NEVER done that before playing around with MIDI), here are the pictures of how I cabled the keyboard:

right into the gameport !!!

And this is how the PC now boots and looks like after I got the MIDI to work in-game:

Fun fact: the PC isn't actually dead: it actually boots and works, I just can't see a damn thing of what I'm doing... and it has only ISA x16 slots, I have no idea what kind of graphics card I can find for it, now 😒

Here, I just ran Doom:

At least the MIDI is playing perfectly 😁 😁 😁

Unplug the MIDI cables and see if you still experience the same problem.
If not, then it's possible that, with all the plug and unplug of your MIDI cables, you accidentally loosened the monitor cable.
Try, on both ends, to unplug and plug in again the monitor cable. If your graphics card is not onboard, then you can also try to reseat it again.

It's onboard (integrated), I'm now trying to power it on without the MIDI cable... nope, still 4 beeps...

I also tried to remove and reseat the video memory stick (I was surprised, I thought I'd find some sort of 30-pin SIMM and instead it looks like a PCI thing without the rest of the card, just a memory stick with PCI-shaped pins) but still nothing...

What the hell happened, I have absolutely no idea, how to fix it, I have no idea neither 😕
Why would MIDI interfere with the onboard graphics card ?

I read on Google that 4 beeps made of 1 longer and 3 shorter means bad video memory contact and says that the solution is to reseat/change the graphics card... but mine is onboard !!!

Look, I just made a video: https://youtu.be/i9jujiibZew?t=47

> PCI thing without the rest of the card
Sure this is video memory, not cache? Photo of mainboard!

Either a video RAM chip is dead, or a soldering joint is open, or the video chip has damage. Try to push the chips on the mainboard while the game is running and check if it has an effect.

h-a-l-9000 wrote:

> PCI thing without the rest of the card
Sure this is video memory, not cache? Photo of mainboard!

Either a video RAM chip is dead, or a soldering joint is open, or the video chip has damage. Try to push the chips on the mainboard while the game is running and check if it has an effect.

It's this memory here, look:

How could a video RAM chip die or a soldering get off by doing absolutely nothing and just playing with the MIDI ?

Are you sure this is video memory? It looks more like a cache module. Look near the VGA out connector and on the motherbord there should be a video chip and close to it, video memory chips. Usually they are soldered or in brown sockets. But it depends on the motherboard.

Is there a missing memory chip on that stick?

edit: maybe not. I don't see solder pads where the chip would be. Have you tried removing the module and cleaning the contacts? Maybe it's just a coincidence that the issue started while you were experimenting with the MIDI.

Uhm, maybe it's an IRQ conflict ?
The MPU401 sometimes uses IRQ9 (or IRQ2). And VGA also uses sometimes IRQ9 (or IRQ2)..

(Note: IRQ2 and IRQ9 are cascaded on +286 PCs.
Which means in simple words: IRQ2 is used to access the second programmable interrupt controller (PIC, i8259).
Whenever something wants to talk to IRQ2 it is redirected to IRQ9. That's why they're sometimes called IRQ2/9.
This is quite confusing whenever you use old devices made for PC/XT bus (8bit ISA), because they are unaware of IRQ9.
And because IRQ2 is free on 8088 PCs. So having a VGA/EGA card on IRQ2 and a MPU401 on IRQ9 is quite troublesome.)

More about this stuff can be read here (see "IRQ2/IRQ9 Redirection") and here .

IRQ 9 - FREE (VGA vertical sync interrupt if enabled)

Note: IRQ 9 is used on some video cards for the "vertical retrace"
interrupt. This interrupt would have been handy for things like
video games, as it occurs exactly once per screen refresh, but
unfortunately IBM cancelled this feature starting with the original
VGA and thus many VGA/SVGA cards do not support it. For this
reason, no modern software uses this interrupt and it can almost
always be safely disabled, if your video card supports it at all.

If your card for some reason CANNOT disable this IRQ (usually there
is a jumper), one solution would be to clip the printed circuit
contact on the board: it's the fourth contact from the left on the
back side. I take no responsibility if you try this.

- Avery's favourite: IRQ2 (actually IRQ9). Watch that VGA, though.
Source: http://apenwarr.ca/arcnet/howto/cards.html

By default, the MPU-401 uses IRQ #9, although modern versions have jumpers for setting IRQ).
Whenever the MPU receives an incoming MIDI byte, it will interrupt the computer.
In your interrupt handler, you should keep reading bytes from DATA port while DSR is low.
Source: http://www.piclist.com/techref/io/serial/midi/mpu.html

Another problem is the ACPI's System Control Interrupt (SCI). It is also using IRQ9. 🙁

In DOS the VGA card doesn't use interrupts - except for one or two demoscene products. The corruption on the screen is not IRQ related.

> How could a video RAM chip die or a soldering get off by doing absolutely nothing and just playing with the MIDI ?
Getting warm, cold, warm, cold can eventually make production flaws surface. And you were working on it - the force from inserting the cards may have given the damaged part the rest. Or it was just coincidence.

Please make a picture of the whole board. Then we see what belongs to the video controller.

Ok, here are some pictures.

This is the "graphics card", I believe it's it because it says "Cirrus Logic" on the chip.

This is the 14-pin VGA connector

And this is pretty much the whole area of the motherboard with the chips and jumpers, there is a blue jumper near the GPU, as I have highlighted it

Maybe I'll now change the title of the thread because it's becoming something else than just the MIDI issue 🤣

You didn't "hot plug" the MIDI connector did you? (Plug or unplug it while the system is on.) That thing carries a nontrivial voltage - it's vaguely possible that a power spike could have done some damage, but 99.9% of the time this would be to some component on the sound card or keyboard. Actually I'm hard-pressed to imagine that could take out a Vram chip, but you never know.

No, I've never unplugged the MIDI cable from the sound card at all.
The sound card is even still working fine, I can still hear both MIDI music and game sounds… it's just unpleasant to the eyes !!! D:
Will a VLB graphics card fix it ?

Looks like defective Memory/DAC.

Today somehow I got it to show something better at boot… and then returned like that… hmmmm

Why not take the system apart, clean it (remove all the dust that is seen in the photos), clean all contacts (RAM, expansion cards, CPU) with 90% alcohol, basically give it a good detail, then put it all back together and see if it's any better. You've got nothing to lose by trying. While it's all apart, it will be easier to photograph and examine for any other clues.

I'll try, after all a good cleaning would be nice