Console diagnostics?

[+Vorticon]

Hey guys, what would possibly cause an F18A equipped console not connected to the PEB to refuse to boot and just go to the F18A green title screen?

[+arcadeshopper]

Hey guys, what would possibly cause an F18A equipped console not connected to the PEB to refuse to boot and just go to the F18A green title screen?

Is there a nanopeb? If so make sure it's on

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[Tursi]

That's pretty much it - anything that prevents the console from booting will give you that. The F18A screen is always loaded at powerup - if you see it, it's because the computer never wrote any other commands to the VDP.

 

[+Vorticon]

Welp, nothing is connected to the console... What would be the most likely culprit?

[+arcadeshopper]

Welp, nothing is connected to the console... What would be the most likely culprit?

CPU clock sound

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[+FarmerPotato]

On 9/30/2019 at 7:11 AM, Vorticon said:

Hey guys, what would possibly cause an F18A equipped console not connected to the PEB to refuse to boot and just go to the F18A green title screen?

I’m sorry your F18A 4A is stuck .. mine does this sometimes.  I power cycle on and off real slow and eventually it goes back to normal and stays good. I don’t have a clue why. 

[GDMike]

Sounds like a memory issue on the F18A, if you swap back to reg f18 as temp. Does it boot? 

I know it's not a NANOPEB, but one of my NANOPEB does the same thing. Boots to a blue screen. I'm suspecting memory or the memory controller.

Seems there's no protection circuit for filtering power on it. Maybe your prob is similar. Boo! I hate that, I don't have an F18A but I'm learning about these new products and their lack of circuit protection for memory as a possibility..not certain, but I'm wondering why it would just do that? Hitting the power on/off any which way should never be a reason to kill a card, especially with great caps these days and switching ps circuits.

Edited October 1, 2019 by GDMike

[Tursi]

The fact that the F18A green screen appears means that the F18A and the F18A memory is working fine (the bitstream loads the image into VDP RAM and it's displayed until it's overwritten by the host computer). It's possible, but very unlikely, that there's a CPU interface issue, but there are far more likely causes of the system not booting. As long as there are no broken pins and it's well seated in the socket I wouldn't be inclined to suspect that.

 

Vorticon, does the sound chip reset? That would give indication as to whether the CPU is functioning.

 

As for your Nanopeb lockups, GDMike - you're thinking too hard. Most Nanopebs have connection issues to the side port - I have to be quite careful when attaching mine not to cross over two pins (as the port isn't sized correctly). When I get it right, it's very stable, but every boot issue I've had have either been connecting it wrong or not providing power.

 

FamerPotato - you might just have a dirty power switch. Either that, or it's wearing out. Try getting some contact cleaner in there as a quick and dirty fix.

 

[matthew180]

Something to keep in mind, the 99/4A is 30+ years old, and things will fail.

 

The FPGA on the F18A does a checksum when it loads the bit stream, and if there is a problem the board will not come up.  There is an LED on the F18A that looks like a power LED, but it is actually a "done loading configuration" LED.  If that LED is on, then the FPGA loaded its bit stream correctly.  If you get the older "green screen" (which means you are running an old firmware on the F18A and should update it), or the newer F18A power-on screen, then you know the FPGA loaded correctly.

 

23 minutes ago, GDMike said:

Sounds like a memory issue on the F18A

Uh?  Can you elaborate what this means?  The F18A uses a single FPGA which contains Block RAM that is used to implement the VRAM.  If the FPGA has a problem, see my comment above, i.e. it would fail to load the bit stream, the done LED would remain off, and the screen would never show anything.

 

34 minutes ago, GDMike said:

I don't have an F18A but I'm learning about these new products and their lack of circuit protection for memory as a possibility

What is it you are learning about these new products and their lack of protection?  The F18A has buffers for I/O to and from the host system.  And yes, if your power supply spikes, you can certainly blow up the F18A's buffer and / or power regulators.  It has happened, and I have a repair service for the F18A when it does.

 

17 hours ago, FarmerPotato said:

I’m sorry your F18A is stuck .. mine does this sometimes.  I power cycle on and off real slow and eventually it goes back to normal and stays good. I don’t have a clue why.

The main problem the F18A has in some systems is that the host's Power-On Reset (PoR) circuit brings the computer out of reset before the F18A's FPGA is done loading its bit stream.  When this happens, the F18A misses some of the initial commands the host computer tried to send to the VDP.  On the 99/4A that means you might not see the Mater Title Screen, but typically just pushing any key will continue as normal.  The 99/4A is known to generally have a slower PoR than most computers, so the F18A is usually ready in time.  If the system does not come up, and pushing a key does not move to the normal selection screen, then something else happened during the power-on.

 

Again, with a 30+ year old computer, you should expect problems like this.  Something like a dirty or worn out power switch can be as guilty as anything.

[GDMike]

I wouldn't know about the F18A circuit as its a question. I was referring to the NANO and it's bad ram possibly by power somehow and Wonder if it's a related type issue. But it's good to know that a repair option is there for his problem, AND the flag light's which is really cool for diags. As im learning like others regarding the cool stuff.

[GDMike]

Oh i forgot to mention, on my NANOPEB, I've got two good ones now, but two others I had died only after connection to speech synth as I narrowed it down to that, but no further because the speech synth works with the ti and doesn't smoke lol, I had made the dumb mistake of connecting my newly replaced NANO to the speech and it smoked. I've been using the other NANOPEBs with the same ps as previously used but no speech, as I was pretty sure that the speech card was the culprit. And I'm a happy camper. I've pulled the SD card board section off of the bad peb and it works fine slaved on the other PEBs. But the other section gives the same results, blue screen. There were no cases involved during my initial NANO-speech setup. But I learned the hard way just don't try THIS speech card and it ain't worth trying to add ANY. Hey, I apologize Matt if you thought I was trying to pinpoint the issue with the F18A, it was just a coincidence were talking blue/green lockups etc.. again, I wouldn't know the F18A, but glad you cleared that misconception up for us. Cool beans