A3020 with components dropping off...

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Paul
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A3020 with components dropping off...

Post by Paul » Thu Sep 17, 2015 11:36 pm

Hi all.

I've just got an A3020 off eBay. Doing the usual battery replacement, I've come across another problem and wondered if anyone else had the same. With literally no other battery damage , two surface mount caps fell off (on the sound circuitry).

Why did this happen? Do they leak and rot?

Cheers, Paul.

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paulv
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Re: A3020 with components dropping off...

Post by paulv » Fri Sep 18, 2015 12:23 am

I've had an SMT cap leak and damage the PCB on an A5000, and of course Amigas are well known for needing their caps changing due to leakage and failure so it wouldn't surprise me if other machines of the same era had the same issue.

Paul

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danielj
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Re: A3020 with components dropping off...

Post by danielj » Fri Sep 18, 2015 5:43 am

Does the cap-gunk damage the PCB? If so I wonder if it's worth re-capping A30x0s pre-emptively...

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Re: A3020 with components dropping off...

Post by daveejhitchins » Fri Sep 18, 2015 6:58 am

danielj wrote:Does the cap-gunk damage the PCB? If so I wonder if it's worth re-capping A30x0s pre-emptively...
Probably . . . Is there a parts list anywhere?

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Re: A3020 with components dropping off...

Post by paulv » Fri Sep 18, 2015 7:59 am

danielj wrote:Does the cap-gunk damage the PCB? If so I wonder if it's worth re-capping A30x0s pre-emptively...
Just like a battery....

http://www.retro-kit.co.uk/page.cfm/con ... e-repairs/

Paul

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Re: A3020 with components dropping off...

Post by Paul » Fri Sep 18, 2015 8:29 am

Thanks for the replies and suggestions!

I tried to attach photos yesterday but couldn't as they were too big. I've now since downloaded a resizer =D> and so here they are.

On the schematics it's all on the sound side SndVSS and SndVDD. C63 and another one (after the photo was taken) fell off. I don't trust c80 and c90 now either. Does anyone know of a parts list so I can replace them? The printed info on C63 said 16v u3.

I wonder if there is a fault with the surface mount caps that makes them go leaky? In which case I'm going to have to check my other machines too :| All good fun though.

Cheers!

Paul.
Attachments
A3020SndCapsFallOff.jpg
Caps dropped off! Underneath corroded.
A3020BatteryRepair.jpg
A3020 Battery Repair
A3020Battery.jpg
A3020 Battery just starting to leak.

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Re: A3020 with components dropping off...

Post by Paul » Fri Sep 18, 2015 8:31 am

Oops, that should read C62... not C63.

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danielj
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Re: A3020 with components dropping off...

Post by danielj » Fri Sep 18, 2015 8:52 am

Parts list:

https://ia801707.us.archive.org/7/items ... puters.pdf

That's horrible, the pages are all out of order. I've just rejigged it into something that's actually readable. Attached.


d.
Attachments
A3010_A3020_A4000 TRM.zip
(3.56 MiB) Downloaded 27 times

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Re: A3020 with components dropping off...

Post by Paul » Fri Sep 18, 2015 10:10 am

Thanks for doing that Daniel.

I feel a Farnell order coming up later today!

Cheers.

Paul.

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Re: A3020 with components dropping off...

Post by danielj » Fri Sep 18, 2015 11:09 am

Thanks Paul - if you could pop up a consolidated SM cap list when you've done it, that'd be awesome?

d.

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Re: A3020 with components dropping off...

Post by Paul » Fri Sep 18, 2015 5:55 pm

Yeah, will do. I'm going to replace all the surface mounts so will do a list and photos. I'm thinking this could be a can of worms like the battery issue..

I had one fall off a spare A7000 mobo a few years back too, but I think that was due to a physical clash with a cdrom / backplane mounting tray... still worth looking into though.

All in all its worse than the beeb scenario if my fears are right as it's going to start killing Arcs...

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Re: A3020 with components dropping off...

Post by 1024MAK » Fri Sep 18, 2015 7:26 pm

danielj wrote:Does the cap-gunk damage the PCB? If so I wonder if it's worth re-capping A30x0s pre-emptively...
Yep, and maybe...

Mark
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Re: A3020 with components dropping off...

Post by 1024MAK » Fri Sep 18, 2015 7:31 pm

Paul wrote:Yeah, will do. I'm going to replace all the surface mounts so will do a list and photos. I'm thinking this could be a can of worms like the battery issue..

I had one fall off a spare A7000 mobo a few years back too, but I think that was due to a physical clash with a cdrom / backplane mounting tray... still worth looking into though.

All in all its worse than the beeb scenario if my fears are right as it's going to start killing Arcs...
Some laptops by well know brands have been affected by SMD capacitor failure. The boards can be repaired, but are often classed as write-offs I believe...

The problem is, this type of capacitor failure affects some types much more than others, as it depends on the electrolyte used in the capacitor. A well known search engine should find you lots on this...

Mark
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Re: A3020 with components dropping off...

Post by 1024MAK » Fri Sep 18, 2015 7:45 pm

For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki‬ - for answers to many questions...

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Re: A3020 with components dropping off...

Post by Zarchos » Sat Sep 19, 2015 6:21 am

Great link, Mark, very helpful thanks for posting.

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Re: A3020 with components dropping off...

Post by Paul » Mon Sep 21, 2015 1:28 pm

Ok, I've now got a list of replacement SMD Caps for the A3020, ordered my hot air station, and will keep you updated with progress (and parts list). Might even be a few photos or video of the repair work.

Thanks to everyone that's helped so far. Hopefully this will be useful for preserving Arcs. It's a bit of a concern that a complete set of hardware from a specific era could simply rot off the face of the earth..!

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Re: A3020 with components dropping off...

Post by danielj » Sat May 14, 2016 6:47 pm

Paul - did you ever get around to doing this? The parts list would be really handy if you've still got it knocking about.

d.

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Re: A3020 with components dropping off...

Post by Paul » Sun Jul 03, 2016 6:34 am

I had to put it on hold for a little bit... annoyingly after I had got the components and tools.

But I will be going ahead with the repair and will do a parts list and possibly also a video in the next two months or so...

Cheers,

Paul.

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Re: A3020 with components dropping off...

Post by Paul » Sat Jul 16, 2016 7:03 pm

OK... finally had a chance to take a look at the A3020. I'm obviously keen to get it working, with built in IDE and all!

I started by practicing with my hot air rework station on some spare circuit boards with surface mount components. Having removed 80% of the boards components, I felt is worked out the right amount of time, quantity of air and temperature to do it safely and without exploding those tiny caps [-X

After practicing putting components back on, and finding a good set of settings for that, I finally decided to approach my A3020.

Two caps had come off, so with spares in hand, I started to prepare the board. Sadly, even with gentle cleaning, two further suface mount capactors came off the board. On closer inspection, it appears that the pads on the board have degraded or come away slightly. Sadly, I think this means my surface repair cannot go ahead. I've traced out the tracks and will use my new AWG30 wire and perhaps some through hole components to repair the board.

It's an odd situation as I hadn't seen any battery leak issues anywhere near the area, so I'm assuming component leak / damage.

I'll now need to order the components, so it's all back on hold again. (Sorry!).

Here are some photos of the failed components and the A3020's motherboard.
20160716_192739.jpg
20160716_193459.jpg
20160716_192732.jpg
As usual, any advice or thoughts welcome!

Paul.

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danielj
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Re: A3020 with components dropping off...

Post by danielj » Sat Jul 16, 2016 7:17 pm

It will just be the capacitor goo causing the pads to lift :( - kynar and tying things to vias where possible...
d.

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Re: A3020 with components dropping off...

Post by danielj » Sat Jul 16, 2016 7:18 pm

What size are they all btw? (I haven't got the lid off mine, but I'd like to order in the bits before I take it to bits :D)

d.

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Re: A3020 with components dropping off...

Post by 1024MAK » Sat Jul 16, 2016 7:22 pm

That looks like it is the capacitors that are leaking, hence why it is only them that are coming off.

It is hard to tell how much PCB pad is left. I suggest you clean these sections of the board with IPA (Isopropyl alcohol) and a small brush (a cheap new toothbrush).

Mark
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