A5000 - diving in at the deep end!

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rubber_jonnie
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

Badwolf wrote: Thu May 26, 2022 10:51 pm
stephen_usher wrote: Thu May 26, 2022 9:03 pm How big are real gobstoppers? I'm sure they'll grip if they get a bit sticky. ;-)
Buy a really big one and keep sucking till it fits!

BW
That's the ticket!!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

Despite all the good stuff happening yesterday, I've got a horrible feeling that this is going to be a repeat of my Mega 4 thread. In other words, it's a long time before I get to the end!!

I started to look at the problems with the floppy last night and pulled the board so I could buzz things out. Sure enough I found a problem with one of the lines and ran a bodge wire to fix it. Just one bodge wire.

There was a temp battery in place, so I expected that CMOS would hold, put everything back in place powered on and.... back to FDD LED post codes.

What the...

So I disconnected one end of the bodge wire. No change. Hold down delete on boot to clear CMOS. Nope. I sometimes get a signal to the display, but nothing on screen.

I then noticed a small patch of corrosion on one of the SMD ICs, clean that up, nope. I now get this:

Screenshot 2022-05-27 at 10.22.39.png
Screenshot 2022-05-27 at 10.22.39.png (181.91 KiB) Viewed 1125 times

So I'm back to CMOS issues again. Dammit GRRRRRR.

Well, at least I am getting post codes, though after everything was running great yesterday bar the floppy, I'm kinda miffed.

I guess there is more to come on this one.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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alexh
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Re: A5000 - diving in at the deep end!

Post by alexh »

That's what I'm afraid of for mine.

Have you tested IDE yet?

I can see corrosion under my IDE connector socket, I don't want to but I think removing, cleaning, checking continuity and replacing the IDE socket might be necessary for me.
Principal ASIC Engineer - SystemVerilog, VHDL
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

alexh wrote: Fri May 27, 2022 10:56 am That's what I'm afraid of for mine.

Have you tested IDE yet?

I can see corrosion under my IDE connector socket, I don't want to but I think removing, cleaning, checking continuity and replacing the IDE socket might be necessary for me.
I was trying to repair the FDD socket so I could run the formatting software for the HDD. FDD was working to the extent that I could read disks, but got an error 23 when formatting or running hform from the floppy disk.

I have similar concerns re the IDE socket, but I can only work on one thing at a time, and now that means getting the board to boot again. I'm concerned that something much more serious has failed, in particular something major, though why after installing one bodge wire I'm unsure.

Of course it could be more connections have failed mechanically when I handled the board as it is old and areas near the battery may still be fragile.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Badwolf
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Re: A5000 - diving in at the deep end!

Post by Badwolf »

rubber_jonnie wrote: Fri May 27, 2022 10:26 am There was a temp battery in place, so I expected that CMOS would hold, put everything back in place powered on and.... back to FDD LED post codes.
What's your battery voltage? Is it's possible it's discharged (often through the motherboard if diodes aren't quite in the right spot) taking you back to square one?

BW
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

Badwolf wrote: Fri May 27, 2022 12:04 pm
rubber_jonnie wrote: Fri May 27, 2022 10:26 am There was a temp battery in place, so I expected that CMOS would hold, put everything back in place powered on and.... back to FDD LED post codes.
What's your battery voltage? Is it's possible it's discharged (often through the motherboard if diodes aren't quite in the right spot) taking you back to square one?

BW
Voltage is just under 3.3v, so well within the operating voltages of the RTC/CMOS IC. Even if the battery is dead, pressing delete on boot should set defaults, it's not even doing that anymore, so something new has failed, I'm sure of it.

Also, I'm looking at some other areas of the board and I think some of the caps have leaked, so I need to look at replacing those and checking for trace failures.

I love a good project....
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by Badwolf »

rubber_jonnie wrote: Fri May 27, 2022 1:17 pm I love a good project....
I'm dreading getting my A3000 out again. I bet I didn't get everything first time around...

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

Badwolf wrote: Fri May 27, 2022 1:23 pm
rubber_jonnie wrote: Fri May 27, 2022 1:17 pm I love a good project....
I'm dreading getting my A3000 out again. I bet I didn't get everything first time around...

BW
I'd do it sooner rather than later...
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by rubber_jonnie »

Well, it's been a good afternoon with the A5000, especially after it died on me after the initial repair à-la Mega STE!!

I had been advised that caps are not usually a problem, but there are 5 around the RAM/ROM area that are the little aluminium dustbin type:

PXL_20220529_154909869.jpg
PXL_20220529_154909869.jpg (441.02 KiB) Viewed 1066 times

I hate those little buggers, just one nearly destroyed my Amstrad Alt-386, and the ones in my A1200 were caught, but barely in time!!

Looking closer there was a distinct area around each one that was showing signs of leakage, with nearby components grimy and black, a good indicator that cap goo is flowing.

PXL_20220529_154823558.jpg
PXL_20220529_154823558.jpg (373.58 KiB) Viewed 1066 times

So I removed them, and sure enough, once I got desoldering there was a distinct fishy odour, so my suspicions were correct.

Out of the 5 caps, 4 came off cleanly, but one came away complete with one of the pads, another sign that leaky capacitors were using their goo to eat away crucial parts of the board.

Once removed I gave everywhere a good cleanup.

I used my previous technique of a flattened piece of tinned wire to a nearby via to complete the repair:

PXL_20220529_163511077.jpg
PXL_20220529_163511077.jpg (343.5 KiB) Viewed 1066 times

Whilst it isn't a nice rectangular shape, it is at least a workable solution.

With repairs done, and a default set of the CMOS, it's running again :)

PXL_20220529_173243007.jpg
PXL_20220529_173243007.jpg (210.32 KiB) Viewed 1066 times

Which is a bit of a relief.

So back where I started around Wednesday, but I'll take the win for now. Next up it's fixing the FDD as it's still giving me a 23 error (I have the recommended parts on the way) and I'll need the FDD to work in order to run the IDE formatting tool, though at the moment due to it dying on me, I haven't even buzzed out the IDE lines!!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: A5000 - diving in at the deep end!

Post by alexh »

Lucky that fixed it. (Or experience?) Anyhow nice read. Good to see you're going again
Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STf,STfm,STe,MegaST,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
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