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Misbehaving VBXE


CharlesMouse
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Hello all,

I wonder if anyone might be able to suggest a fix for my seemingly unhappy VBXE. (Lotharek version installed in a non-Freddy 800XL, along with a U1MB, dual-POKEY, SIDE2, and Sio2SD). Yep, it's safe to say I've put a fair bit in to my 800XL but I'll freely admit being pretty new to Atari systems and I'm still learning my way.

All has been working well (within the limits of my understanding! I still haven't sussed how to work the various proggies needed to flash/upgrade these devices) but I knocked my machine while powered up and not for the first time the VBXE partially popped out of the motherboard socket. As before, with a sigh wondering if this is the day I bite the bullet and just solder the darn thing perminantly to the motherboard, I opened it up to reseat the VBXE (so the cable-ties didn't work!). As before my 800XL seemed to be working fine again once reassembled...

...then I loaded a VBXE-specific game to be greeted by a corrupted screen. Several tests later I variously got; screen corruption, hard lockup, the app claiming the VBXE isn't present, or I need to load the FX core, depending on what I tried to run. 'Normal' Atari software runs just fine.

Hmm, I tried the fc.xex app that manages the VBXE to see if the last 'accident' scrambled it's settings and if necessary reflash the core. (I have at least sussed how to work that app) Sadly it nolonger loads but leaves the machine locked up with a couple of scrambled lines of text in the middle of the screen.

 

.I'd more than happily post more info / screenshots if helpful. My hope is I've just scrambled the flashROM, and so pulling said ROM to reprogram it externally would sort the trouble as fc.xex just crashes at present. Does sound likely? Thoughts? Can anyone point me in the direction of a .bin file I can use to manually flash the ROM..? (As the fc.xex utility seems to flash cores in to selectable blocks I have no idea how to construct a .bin file from the available core files)

 

.My sincere thanks in advance.

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Knocking it while powered up to the point of it crashing the system, probably not the best idea.

 

When I installed mine, I made it easier for the VBXE to sit at least near to flat in my 800XL by reinstalling one of the nearby capacitors.

From memory it's the one up/left from the Antic socket and normal sits near upright.

By removing it and putting another same cap in, install so there's plenty of exposed lead on the component side which then allows you to lay it flat and create more valuable space.

 

Also note a hint provided elsewhere - with VBXE, U1Meg and a bunch of other upgrades in the machine you're suddenly putting much more demand on the power supply and it might not be up to it.

 

Hint 2 - from memory I put a piece of firm plastic under the VBXE to ensure nothing on the underside was able to inadvertantly provide shorts elsewhere.

Edited by Rybags
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It's wise not to throw the system around, yes, but despite the mechanical leverage force exerted by the cantilevered VBXE, it shouldn't really be falling out of the socket when the machine's moved around. The implication seems to be that the machine worked fine prior to the latest bump, and problems with the Antic socket or adapter are absolutely characterised by the symptoms described here. I've installed half a dozen of these boards in XLs and often found it helpful to go at the pins on the Antic adapter with some flux and solder wick. Too much solder at the base of the pins means the adapter will not sit level in the socket, and consequently make marginal and intermittent contact and spring out of the socket with the slightest encouragement.

 

Common problem area number two is the Antic socket itself: either not replacing it with the provided precision socket (instead sticking the adapter in the old tin socket), or fitting the precision socket and doing so badly, resulting in address line problems, intermittent video issues, etc, etc.

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Thanks for the thoughts chaps. Please find below some photos of my system, and it running. I guess most are self-explanatory, the screenshots are:

-Yoomp! (a normal game running, er normally)

-Mr Proper VBXE (crashed)

-fc.com (the VBXE programming app, crashed but seemingly doing something)

 

Just to clarify all was working well prior to the latest unfortunate jolt.

As you see the motherboard has been substantially recapped, also there's no components fowling the underside of the VBXE.

Yes, the wiring is still a bit ugly but I'll tidy all that some time or other...

 

So how do those pins look? I'd be very happy to hear I just need to wick some solder out of them to restore my VBXE and improve the connection...

...my assumption that all is electrically well but I'd scrambled the ROM was based on the observation that non-VBXE software still works fine and video output via the VBXE is unaffected.

...I'm very tempted to permanently solder the darn thing in (once confirmed working) but I don't like installing mods/upgrades I can't easily reverse.

 

 

Thank you all again.

 

 

PS

Silly me - the VBXE doesn't have a socketed flashROM (I was thinking of my U1MB) so the brute-force approach isn't going to work if a scrambled ROM indeed is the problem. Originally programmed via JTAG..?

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Edited by CharlesMouse
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Thanks for the photos. If it's any consolation, Mr Proper crashes on my machines as well most of the time. :)

 

It's hard to tell from the angle, but I'd say those pins are well awash with solder. The socket is almost a push-fit in the adapter board anyway (I've made several and had to use a desk vice to force the socket into the PCB, although these were Candle-made PCBs on which the holes were actually a little smaller than intended), and only the lightest amount of solder is required. I can almost guarantee that the thing will fit more snugly when cleaned up.

 

Antic socket looks OK from the top - not that it's very revealing - but tireless continuity and short testing won't go amiss. Legacy software can often work just fine until the VBXE's MEMAC window is opened up, then all goes to hell. I've repaired several VBXEs which appeared to work fine until the control registers at $D6xx/D7xx were accessed, at which point everything went completely to pot. Fixing shorts/open circuit invariably resulted in a perfectly functioning system.

Edited by flashjazzcat
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Antic shares many pin connections with the CPU, so it's fairly easy to test the socket installation between the two.

Most of the remaining pins are connected or common with GTIA, so not too much work to verify the entire thing.

 

Though of course practically none of the pin coincidences will be the same pin on each chip, you'd want to have pin diagrams of each handy while testing continuity.

Edited by Rybags
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Thanks again...

 

Well that's really frustrating!

I wicked out a good deal of solder from the VBXE pins and indeed it seats much better in ANTIC's socket, but still no joy.

I can be pretty sure I have one or more cracked traces, or bad joints: If I boot the machine with the VBXE in place while applying some pressure to ANTIC it won't boot, and still won't boot without pressure... It will boot again if I give the VBXE board a little wiggle, but same issue with VBXE aware software.

(Interestingly if I try to load to load the VBXE falcon image it says it can't find the VBXE on D640, so I guess flashjazzcat is bang on the money. If it's of any relevance the little red led on my VBXE board lights up solid on boot and stays that way unless any VBXE-aware software runs, in which case it blinks a good deal then returns to solid red when said software fails)

Because it was easy I reflowed all the ANTIC socket pins - no joy - so I continuity tested all 40 pins, and they were all fine to both Sally and GTIA, where applicable. Also no shorts that I could find. I therefore assume I've got an intermittant connection somewhere (a b*gger to trace) or the bad connection(s) is on the VBXE board itself. Typically I gave a friend my spare 800XL so I can't swap the board across to get a better idea where the issue is.

 

.Further thoughts most welcome.

Edited by CharlesMouse
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Pin 20 of Antic is A15 - Antic has the full address bus and self-decodes and won't function properly without it. I doubt the machine would work at all if that pin wasn't present.

 

http://www.atarimax.com/jindroush.atari.org/achantic.html

 

Probably the only pins that you could live without would be 4 (light pen) and /RNMI (system reset switch not used XL & later).

Pin 1 Vss is GND and Pin 21 Vcc is +5V power - it's possible VBXE could source these elsewhere.

 

Maybe your next test should be test continuity between the Antic mounted on VBXE and appropriate points on the 6502 and GTIA, doing so while jiggling the board to see if any are intermittent.

The site linked above has the pinouts you need - just cross reference like functions using the charts for 6502, Antic, GTIA.

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Hmm, some of these issues are appearing on my machine as well.

 

The power supply currently is 1.5A. I have a 2A coming *just to rule that out* My secret hope is that I plug it in and everything works perfectly.

 

Here is my problem and this has been happening consistently: Whenever I exit out of a VBXE enabled program (SC, LW), it crashes. Hard. I am pretty sure this would not be caused by the signal doubler I have attached, but software wise.

 

Here is a video.

 

 

Sorry, it is sideways. I'll work on that . . .

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This probably won't be a helpful bit of info, but I get similar crazy looking graphics characters and colors when I load Last Word. But it only lasts a short bit and then when the prog is loaded all is well. I don't think of that as a problem at all, but I bring it up in case it clues into why yours does it forever after crash.

 

I should add, I'm using Altirra emulation.

Edited by fujidude
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Hi,

 

(Interestingly if I try to load to load the VBXE falcon image it says it can't find the VBXE on D640, so I guess flashjazzcat is bang on the money. If it's of any relevance the little red led on my VBXE board lights up solid on boot and stays that way unless any VBXE-aware software runs, in which case it blinks a good deal then returns to solid red when said software fails)


.Further thoughts most welcome.

 

Maybe it´s a good idea to use the LS138 directly. This behavior might be a problem accessing VBXE´s control registers at $D6xx. I think you´ve connected the desired pin from the 8-pin VBXE connector with your U1MB. So try to connect it directly with pin 9 of the 74LS138 (placed bottom of the MMU). In the VBXE manual (Lotharek version) there´s until today an error and the usage of pin 8 written - but that´s wrong, pin 8 is ground.

 

Good luck, Jurgen

 

 

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Hmm, some of these issues are appearing on my machine as well.

 

The power supply currently is 1.5A. I have a 2A coming *just to rule that out* My secret hope is that I plug it in and everything works perfectly.

 

Here is my problem and this has been happening consistently: Whenever I exit out of a VBXE enabled program (SC, LW), it crashes. Hard. I am pretty sure this would not be caused by the signal doubler I have attached, but software wise.

 

Here is a video.

 

 

Sorry, it is sideways. I'll work on that . . .

The free media player VLC can rotate and re-save video for you.

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Note that TLW is not using the VBXE driver in your video, and is therefore not accessing the VBXE hardware at all. It's just running as a standard Atari application.

Wow, I di dnot know that. So, the 80 columns is done with the program by itself? I thought that version of TLW was VBXE enabled? How do I make it access the VBXE?

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Download the test version with the VBXE driver:

 

http://atari8.co.uk/the-last-word/

 

That project has been in stasis for some years now, but if you try it and find problems, I might be motivated to finish it. :)

 

Challenge . . . accepted!

 

Okay, so I was *pretty* sure that was the version I was using, but I re-downloaded Download The Last Word 3.3 Test 7 just to make sure. Copied it over to the SiDE2 and . . . well, I will let the pictures tell the tale.

 

Ultimate Setup is pretty self-explanatory

 

Minimal CFG file is just the minimal VBXE file (VBXE.SYS). (I have a version that does not have FAT.SYS loaded and it makes no difference in any scenario I could test)

Dir of LW, shows what is in the LW dir.

My autoexec.bat is as follows:

PROMPT $L$P\>

TD ON

PATH CAR:;E:>UTILS>;E:>LW>

SET MANPATH=E:>SDTK>MAN_CMD>;E:>SDTK>MAN_DRIV>

SET LWPATH=D5:>LW>;

 

Contents of LW.SYS is what is in the LW.SYS file.

"Fullboat Config.sys" pic is what is in the Config.sys file I usually default to.

 

Finally, here is the YouTube:

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  • 2 weeks later...

Bah!

Still can't get the pesky thing to work right. What I believe I know so far:

-It was working absolutely fine

-It had a habit of popping out of it's socket (fixed, thank you for the advice!)

-It stopped working after the last time it popped out...

...I assumed it had corrupted it's flash in the process, but happily much appreciated advice suggested what I really had was a bad connection or short somewhere. (not seeing the VBXE 'window' it seems)

-Having endlessly tested everything I'd swear there are no shorts or bad connections...

...but I wonder how true that is - I suspect one or more cracked tracks giving an intermittent connection that I can't locate with the equipment I posses.

 

So:

If I still had my other 800XL (given to a friend) I'd swap the VBXE across to test if the 'fault' is really the motherboard, or the VBXE...

...but short of buying another 800 just for testing I can't do that.

 

 

Further thoughts / suggestions would be much appreciated.

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