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Atari 65XE computer that is very unstable


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3 hours ago, manterola said:

Sorry, but it looks to me that the first thing to do is dealing with the RAM. Most of the symptoms sound like RAM problems. Unfortunately, it is not fun to desolder those 8 chips, and even worst when it is a 65XE and that PCB....

Sure, and normally I would be saying this also, and it still might be the case, but the OP confirmed all Ram blocks (and os rom) are white in self test IIRC. (Ignore that image he posted as he was having pot issues causing intermittant colour issues/interference before - now all fixed.)

 

No ram chips were running hot when he felt them. I'd normally double check ram with Syscheck II, but given no red blocks and lack of overheating ram chips, and very specific behaviour to do with sio, IMHO Pokey is looking suspect at the very least.

 

In terms of fixing, without syscheckII, the OP would have to likely desolder all ram chips, socket them, then install new chips - which is a lot more work than replacing the pokey in the first instance, and desoldering so many chips increases liklihood of board damage - especially if not used to it.

 

Of course I could be wrong. :)

Edited by Beeblebrox
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If I get the test probes, you can give recommendations on what data lines and chips to test.

 

I know the essential three is clock, power and reset and if one has failed, the chip may not work properly.

 

The oscilloscope I have gotten is an analog one so no frequency measuring, capture or auto lock.

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@TGB1718

 

I have a solder sucker and removed lots of fluorescent transformers from circuit boards and had great success in removing them without damaging the circuit boards, never lifted a pad or ripped a trace, and then resoldering the transformers back onto the circuit boards.

 

The LCD panels got their backlights back and worked ever since.

 

And even if I damaged a trace, I am good at soldering bodge wires back to where the traces were.

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The seller of the £50 Atari 7800 hasn’t responded yet.

 

Really don’t want the seller to not reply as it has lots of value, potential and it has Ballblazer which has the POKEY 

 

https://en-gb.facebook.com/marketplace/item/1371988156744752/?ref=search&referral_code=null&referral_story_type=post

Edited by LaunderMan2008
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Just now, LaunderMan2008 said:

Seller still not responded despite new text, hasn’t even read any of the both :( 

 

Any other recommended listings for any POKEY containing devices, in case the seller doesn’t read the messages.

I'd give it time. For example ebay says 2 days. They might be away or busy. :)

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Unfortunately the seller still hasn’t read the messages :( 

 

But I will give the seller 5 days to read the message before I give up on it, I will also tell mum to message again on the third day of the 5 day “grace period”.

 

Once this 5 day “grace period” is over anyone can claim the listing and try to buy the Atari 7800, I will put the link up on the day after the “grace period” finishes :) 

 

Going on a bootfair on next week, most likely not going to have even a single retro game, not even a ruined Xbox 360 disc as it is one of those bootfairs inside a building that has clothes, old person junk, incomplete toys and boardgames, I rarely ever have luck with bootfairs inside buildings as they are very small and only donations are allowed, no own stalls, these inside building bootfairs are charity fundraisers for our community centers and care homes, the only one that is a building bootfair and is good is the YMCA one but is not open this time of year.

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Just buy the 7800 package, You can always put a fpga or other pokey in the 7800 cart later, using real pokey in the 8 bit

You spend too much time wringing your hands and you won't have anything.

 

I don't feel your problem is the Pokey just yet... but you could also luck out and swap the pokey between the cart and computer and end up with both a working 8 bit and cart. Pokey can fail with IO issues but still be fine for stereo or cart use (sound works fine)

 

I see a bad solder joint on the 74ls pin 1 above the inductor resistor cap row

Edited by _The Doctor__
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7 hours ago, _The Doctor__ said:

Just buy the 7800 package, You can always put a fpga or other pokey in the 7800 cart later, using real pokey in the 8 bit

You spend too much time wringing your hands and you won't have anything.


I have tried to text the seller if they can ship as it is too far away and they haven’t even tried to read my message for the past 4 days and I will only wait for 4 more days before I give up on trying to get the Atari 7800

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  • 3 weeks later...

@TGB1718 @Beeblebrox


The bootfair was terrible (no video games at all and it was overpriced clothes and candy stalls from influencers that I don’t give a care about, it was basically a market not a bootfair) and I haven’t found neither a Ballblazer or a computer to steal POKEYS from and I am always looking and searching to the point of searching listings for each computer model separately, my maximum is £25 now not £20.

 

I have my mind set on acquiring a N64 console and some 30 American games and my mind is set on that task currently, I still set some time aside to search for POKEY donors.

 

Dad also ordered a composite cable so hopefully my CRT will like that signal a bit more :) 

 

 

 

 

Edited by LaunderMan2008
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31 minutes ago, LaunderMan2008 said:

@TGB1718 @Beeblebrox


The bootfair was terrible and I haven’t found neither a Ballblazer or a computer to steal POKEYS from and I am always looking and searching to the point of searching listings for each computer model separately, my maximum is £25 now not £20.

 

I have my mind set on acquiring a N64 console and some 30 American games and my mind is set on that task currently, I still set some time aside to search for POKEY donors.

 

 

In the UK i've never come across and Atari 8 bit or games console ever at bootfairs or in charity shops I'm afraid. Ebay is the best bet as an abundance of them by contrast. More and more people are seeing people list them, recalling they have an A8 or 7800 games console in the attic, and listing it. Unfortunately they tend to list them at fairly high prices.

 

As such you won't get either for your budget. Even if listed at a reasonable price you'd struggle.

 

So as mentioned above in various replies it could also be ram. Ram or pokey issues. 

 

Maybe focus on the N64 for now and maybe revisit the 65XE at some stage. 

 

When you do I think keeping an eye out for a donor non working/for parts A8 machine is a good bet. You might get one for £50 to £60 if you are lucky. Or just bite the bullet and save up to buy a known working 800XL, 65XE, or better still 130XE. (Or an A8 with a ram upgrade).

 

I just think at this stage it's proving difficult with your budget and sourcing a Pokey, if it is the pokey causing the issues, is not easy.

Edited by Beeblebrox
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I did see several retro gaming vendors and I saw 2 had an Atari 2600/7800 tub filled with games for £2 a piece and that was in 2023 very cheap deals to be had there, bee swarm every bootfair at them vendors, all other cartridge based games were selling for that price except games in a glass case and all Nintendo carts which was £5 for big carts (NES) £4 for medium sized carts (SNES N64) and £3.50 for small sized carts (Gameboy and Gameboy Advance).

 

I will focus on the N64 and complete that project/task for now.

Edited by LaunderMan2008
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  • 2 weeks later...

@TGB1718 @Beeblebrox

 

The n64 plan failed, someone bought the games before me, since the computer is stable enough to load tapes, I could try fixing the tape deck by replacing belts on it and try loading a real tape, tapping on the pokey seems to fix it for a little while when it bugs out, might try reflowing if that is the case.

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  • 1 month later...

@TGB1718 @Beeblebrox

 

Update: I have read plenty of documentation for the SDrive Max and figured out how to make the floppy drive functionality work and also the unstable problem was with a crack in one of the POKEY’s solder joints which I fixed quite quickly and was able to access lots of games and demos.

 

Here is the Axel F remix demo to show my computer is now working and I have received my composite cable so my CRT TV is now happy with the computer, the last thing to do is to put it back together and order some extra case screws and belts for the cassette drive to try loading off a real tape. :)


IMG_7276.thumb.png.8cace7b04552c542b7bf2d86252cf3eb.png

 

 

 

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7 minutes ago, LaunderMan2008 said:

@TGB1718 @Beeblebrox

 

Update: I have read plenty of documentation for the SDrive Max and figured out how to make the floppy drive functionality work and also the unstable problem was with a crack in one of the POKEY’s solder joints which I fixed quite quickly and was able to access lots of games and demos.

 

Here is the Axel F remix demo to show my computer is now working and I have received my composite cable so my CRT TV is now happy with the computer, the last thing to do is to put it back together and order some extra case screws and belts for the cassette drive to try loading off a real tape. :)


IMG_7276.thumb.png.8cace7b04552c542b7bf2d86252cf3eb.png

IMG_7275.mov 210.16 MB · 0 downloads  

 

 

Well done. :) 

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  • 1 month later...

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