Strange STe link wire

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wub
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Strange STe link wire

Post by wub »

I have the CA4003290 motherboard in my STe, the version with 2 wires coming off the sound chip and going to the piggybacked chips below the simm slots. I also have a single link wire on the bottom side of the PCB that is coming from the shifter but has come off from wherever it was going and is now floating around freely. By the length and shape of it I would guess it was going to the blitter? I can't find any mention of this link online anywhere!

If I run the new STe version of Lotus Turbo Challenge I get a couple of problems. The chip music will drop out after a while and not come back, while the samples carry on playing correctly. By this point the graphics on screen are starting to corrupt, a flashing line under each car that gets 1 vertical row taller each level, and the background has horizontal rows of corrupt data that get worse each level too.

512kb games seem to run ok, although my drive light comes on after a while and disk access(I'm using a gotek) can cause a freeze for games that access the disk. I need to test more if this is actually the case and not just a game that isn't STe compatible, but I wondered if anyone had any ideas what might be wrong and where that link wire should be going?
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exxos
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Re: Strange STe link wire

Post by exxos »

Do you mean this ? viewtopic.php?p=87768#p87768
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: Strange STe link wire

Post by exxos »

https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
wub
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Re: Strange STe link wire

Post by wub »

Hi Exxos, yes, that's the version of motherboard I have.

Edit: Ah, maybe not. I definitely don't have the REV 5.1 board, the REV level is blank on mine. Will it do any harm to add the link if I don't specifically have the 5.1 revision board? Either way I feel stupid for not looking at all the different REVs before I posted!
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Re: Strange STe link wire

Post by exxos »

Those are just factory bodges. As for your game problems its hard to say. These machines suffer from all sorts of issues. I suggest you look in the software essentials section for YAART and start by testing your RAM, also run GB6 and see if things are stable and if corruption starts to appear after a while,
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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People should find solutions to problems, not find problems with solutions.
wub
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Re: Strange STe link wire

Post by wub »

Thanks for the advice, I'll do that!
wub
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Re: Strange STe link wire

Post by wub »

Well, do I feel stupid or what!

Firstly, my board is indeed a 5.1 rev model. The confusion was caused by the REV number being printed on the underside of the board in dark green and not on the top, where it explicitly says REV in big white letters. I assumed I had a REV 000 board and didn't examine the underside of the board closely enough.

I'm still not sure why any of the search engines I used failed to bring up the picture on the second link you posted, I searched for "STe link wire on PCB" and found nothing. I've checked my board this morning though and the link is coming from the same pin on the shifter so I'll go ahead and solder it back on.

I ran YAART for long enough to get to PASS 32 and then GB6 doing the full test on loop for 10 tests. I didn't let the STe cool down between tests as it usually takes less than half an hour for the problem to show up. Both test ran flawlessly with no problems, and things were getting nice and warm so I should have seen something. I reset and ran Lotus Turbo Ste immediately, and while the chip music was working ok, the screen graphics were immediately the worst I had ever seen them. I reset and loaded GB6 again and it ran the tests with no visible errors.

I'll add the link wire back now and see what happens when I repeat the above tests tonight. I've already recapped the PSU so I'll also order the caps to do the motherboard, just to be sure.

Thanks for your help so far, and apologies for my obvious incompetence! :)
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Re: Strange STe link wire

Post by exxos »

That is strange. Maybe post a video if it happening.

I did investigate some video faults on the STE a few weeks ago which could possibly be related to what you are seeing.

viewtopic.php?p=73580#p73580

viewtopic.php?p=78497#p78497
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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wub
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Re: Strange STe link wire

Post by wub »

Hi again, sorry it took me a while to get back to you. I wanted to have the STe on for a really long time to see what happens when it gets proper hot. It was on for 10 hours continuously on Sunday and about 8 yesterday. As long as I don't load up Lotus Turbo STe then everything looks good.

Thanks for those links regarding video problems. I'm glad to say that I haven't got anything going on like that, even with the link wire detached the display has always been really clear and stable with an RGB+audio to SCART lead. That's pretty much why I didn't recap the main board right away.

With the link wire attached again the video glitches in Lotus are better, they are the same as I described above but are now only showing on the screen every now and then. I'd say every 1 to 1.5 seconds a single frame will be corrupted and visible. That might suggest that memory is not actually being corrupted at all and the frame buffer is getting corrupted on the way to the video out. But I'm grasping at straws as I have no idea how the ST works yet for things like that.

In Frontier: Elite 2 I have to turn off sound FX as I get a continuous ringing noise, like the ping sound just repeating itself. It does that right away, before the STe has a chance to warm up. The music works fine though and I can save/load games after any amount of time with no problems.

If the major problems only show up running one particular game then I might just settle with it as is for now. There's clearly something funny going on somewhere but it may be a case of having to wait until it gets worse to diagnose properly?
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Re: Strange STe link wire

Post by exxos »

Problem is, these machines have multiple faults. This is why we have the mandatory fixes. But there are of course many faults which haven't yet being diagnosed.

You could try the HC CPU from the store to see if that changes anything. For the better or worse. If it does I then you likely have to start doing the fixes.

If you have a SR98 PSU, you could experiment with upping or lowering the voltage a bit. You might hit on something more stable, or not. But slugging out the fixes is the only way to cure all well known problems. Recapping the PSU should be done at the very least.
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https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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