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Yet another restoring a 800XL thread...


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Hi folks,

        just me cataloguing my attempts to resurrect my old 800XL, owned by me since I was about 13. Last time it worked, it was showing a bunch of dead RAM in the self test, and then died completely. I have finally got the parts to replace at least the RAM and the CPU (this gets hot when turned on). My first attempt at repairing one of these, so comments/criticism are welcome... Checked the computer out with a Salt cartridge (would that even be of any use?), and it came up with an error code 99. 

 

Cosmetically, it's a disgrace, my father was it's custodian when I went to university, and he was quite the smoker as you guys can probably tell... The white stickers on the keys were for my reference regarding control combinations. I was annoyed my 65XE let you know what buttons to press, but the 800XL didn't.

 

Plenty of MT RAM in here, so that's first to go, whilst I wait for some 40 pin sockets... Will be socketing and dropping new RAM in tomorrow.

 

Regards

 

Si

 

 

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@Simon Carter Whilst you wait for the 16pin ram sockets (dual wipe?) - it's worth running a multimeter continuity test over the RAM traces and vias whilst you have access. Just in case the removal has caused any imperceptable damage to the vias and traces. I had this once where the damage was virtually invisible and it took me ages to realise. Could have saved myself days of chasing other causes.

 

Also using wicking to clean up the excess solder/particles on both side of the vias is definitely recommended whilst you have access.

 

Sounds like the CPU has died for sure if it get's hot as soon as it powers on.  

 

I picked up a NOS CPU the other day on Ebay UK for £13

 

 

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Those Micron DRAMs are prone to dying with age, especially if you look at them sideways on a day ending in “y” but SALLY’s aren’t the usual first suspect. And they do tend to run warm, though not “hot” per se. If the machine was booting into the Self-Test or running your SALT cart, SALLY was basically not dead yet.

 

So check your power supply to be sure it’s putting out a steady 5V DC. Once get replacement sockets and memory, give everything a good cleaning and go from there. 

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15 minutes ago, DrVenkman said:

Those Micron DRAMs are prone to dying with age, especially if you look at them sideways on a day ending in “y” but SALLY’s aren’t the usual first suspect. And they do tend to run warm, though not “hot” per se. If the machine was booting into the Self-Test or running your SALT cart, SALLY was basically not dead yet.

 

So check your power supply to be sure it’s putting out a steady 5V DC. Once get replacement sockets and memory, give everything a good cleaning and go from there. 

@DrVenkman I think the machine was booting to Self test initially, enough to show bad ram - then it stopped booting altogether and died. It's not 100% clear when the SALT cart test was done. My thinking was that the ram gave up the ghost completly, and/or so did the CPU vefy shortly afterwards. 

 

Yup the CPUs do warm up slowly a little, but as you say not hot.  It sounds like here the CPU gets hot almost as soon as the machine powers up.

 

Of the several 800XLs I've bought and fixed over the last 12 months, alongside other issues I found the CPU was DOA on around maybe 30% of the cases. Bad RAM was by far the most main consistant cause of most failures, and then a mixture of other failures from the likes of the PIA or ROM ICs. (I am surprised just how many PIA and ROM chips I've binned). I always test the ICs in a know working (fully socketed) machine. I also always triple check before I bin and revisit ICs after other fixes are made, as sometimes you'll get a ROM IC reporting as bad on Sys Check II, and it turns out it is the bad ram skewing the results.

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Sounds like a short in there if the CPU is blowing hot instantly... 

 

Can't add anything to what you have been told...Good luck Simon...

 

If all goes well I think you are a big candidate for retrobrighting :) (well not you personally :) )

 

PS: I concur with our Typhoon engineer, that caps leg on U9 look like its cut?

 

There's a couple of pads on U14 that look destroyed (could be the light)

 

On the back of the board the pads need a cleanup as on the 3rd and 5th empty socket there looks to be joined pads. The old board needs a good scrub, all sorts of gunk mixed around resistor legs etc.

Edited by Mclaneinc
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13 hours ago, Simon Carter said:

The white stickers on the keys were for my reference regarding control combinations. I was annoyed my 65XE let you know what buttons to press, but the 800XL didn't.

I used watercolors to paint both the graphics characters and the interntional characters on the front of the various keys myself... after seeing my cousin-in-law's 130XE back then. The heart and the diamond were the only ones for which I used red color instead of white. ;)

 

I'll maybe start a similar topic myself next week (or later) when I finally have some time to finish cleaning the insides of the 8-bits and start connecting them for test prurposes...

 

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My Mojo is slowly rising but still not playing much..At the mo we are literally surrounded by mental health issues, the special needs kids above us are way out of control, we don't get on with them otherwise I'd offer help as an ex special needs teacher. My sister in law is having huge meltdowns and is very close to a sectioning order. All of it hitting my own depression quite strongly, but I'm made of stern stuff..

 

It just makes the notion of playing not so fun but we are ok...

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13 minutes ago, Mclaneinc said:

My Mojo is slowly rising but still not playing much..At the mo we are literally surrounded by mental health issues, the special needs kids above us are way out of control, we don't get on with them otherwise I'd offer help as an ex special needs teacher. My sister in law is having huge meltdowns and is very close to a sectioning order. All of it hitting my own depression quite strongly, but I'm made of stern stuff..

 

It just makes the notion of playing not so fun but we are ok...

@Mclaneinc of course... totally get it. Sorry to hear that. Been a tough few years for me also. Ah ya know what...  gaming in front of a computer sometimes is the last thing ya need when in that zone/frame of mind. I find getting out of the city and into the countryside helps a hell of a lot. I am lucky - I live on the edge of the countryside...(although can get to the city (Brighton, E.Sussex), very quickly). Main thing is to not bottle it up and share stuff with ya mates.

This sunny weather we are having is really making a difference.

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