Amiga 500+ leaking battery and other issues/questions

[M]

Hi, my Amiga 500 Plus spent many years stored away, I recently got it out and it still worked so I sold it on eBay.  The guy I sold it to couldn't get it to power on, so I refunded him and paid for him to return it, and sure enough I couldn't get it to power on either.

I took it apart and discovered the battery had leaked so I removed it.  Potentially repairing the board is way beyond my technical knowledge so before getting rid I ordered an A300 power supply... and the Amiga now works.  However I realised I didn't have the A501 RAM expansion attached, so I attached it with the memory modules facing up (if you're looking down at the Amiga keyboard) and it wouldn't turn on, I then unwisely tried it the other way round and the Amiga turned on but wouldn't output video/the floppy drive didn't work.  It stayed this way for a few boot attempts and I thought I'd f**ked my Amiga, but after leaving it for about 10 mins it's now working again.

tl;dr questions:
- Which way does the A501 expansion board go?  I'm 99% sure the memory modules were facing up originally (again if you're looking down at the keyboard etc.)
- would the A300 PSU have anything to do with it not powering on with the expansion board?  My old power supply was one of the more powerful 312503 units
- is the Amiga fine with no battery and should I clean up the battery acid with vinegar?  I used isopropyl alcohol but I don't want to do any further damage, a lot of youtube videos seem a bit aggressive in their clean-up methods (the Amiga seems to be functioning fine).

[M]

Me again =) It turns out I don't have a A501 board, its a Marpet MP500A with four SIMMS on.  Does that mean the computer had 2MB RAM total?

[guest7146]

Hello.

ORIENTATION:
The A501 is usually fiitted inside a screened can so you wouldn't be able to see the components at all.  But if you were to remove the can then you would find that it fits with the component-side facing up.  This means you would only see the bottom side of the board from the trapdoor.
I've never come across a Marpet MP500A but I would imagine it's the same deal.  The A501 has its connector offset from centre to dissuade you from fitting it the wrong way around.  Is there not something similar with the Marpet MP500A?

A300 PSU
I think a PSU from an A600 machine, provided it is in good working order, should be able to power your A500.

BATTERY
The AMIGA is fine with no battery, it just means you will have to set the clock manually each time you power on.  If all you're doing is gaming then of course the clock won't really matter at all.

VINEGAR
Be a bit careful with leaked NiCAD batteries.  Some explanation:
NiCAD batteries use potassium hydroxide as an electrolyte.  When this leaks from the battery it reacts with the carbon dioxide in the air and forms potassium carbonate.  I believe this is the white powder-like material you see hugging around the battery itself.  I would be interested to learn more about this from someone more knowledgable than me.
But, importantly, there are probably also cadmium salts in the mix here and these are quite toxic.  So take some care.

You may also see some green material on the leads of components and ICs.  I'm not certain but I think this is Green nickel hydroxide.

I'm not sure about neutralising with vinegar.  I've heard this as well but I'd like to further understand the science before I apply vinegar to any of my own AMIGAs.  Are there any chemists on these forums?

[M]

The A501 has its connector offset from centre to dissuade you from fitting it the wrong way around.  Is there not something similar with the Marpet MP500A?

There isn't.  I just tried the board again, the Amiga was doing lots of odd stuff, and then I got a 'not enough memory' error whilst on the Amiga loading screen

I think a PSU from an A600 machine, provided it is in good working order, should be able to power your A500.

It was apparently purchased as a spare and never used, it at least looks brand new, not the usual yellow

I'm not sure about neutralising with vinegar.  I've heard this as well but I'd like to further understand the science before I apply vinegar to any of my own AMIGAs.  Are there any chemists on these forums?

This confirms my feelings.  I saw another video saying you should clean it with isopropyl so I'll probably leave it as it is.

Now I've just got to work out what to do with this Amiga, as many happy memories as it holds I have too much in the way of old computer bits/consoles etc..  The only issue is when the guy returned it to me he didn't package it properly so it sustained a bit of cosmetic damage to the keys/case.  I know there's a crowdfunding thing to reproduce them but I doubt I could buy some then get my money back. However a Gotek floppy drive emulator does look interesting...

P.S. Just realsied I posted this in the software section?  Sorry I meant to post it under hardware issues.

[scuzzb494]

I've removed dozens and dozens of batteries from all kinds of machines and always use vinegar. It basically cleans up the board and removes all the battery flakes and goo. I then neutralise with Andrews or baking soda. I do dilute the vinegar a little. I dry off with cotton buds and maybe apply a mild heat if I'm in a rush. Never had a problem and all my computers still work no problem

http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0901.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0902.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0904.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0905.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0906.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_0907.htm
http://www.scuzzscink.com/amiga/scuzzblog_november17/scuzzblogdnovember17_1001.htm
http://www.scuzzscink.com/amiga/scuzzblog_september17/scuzzblogdseptember17_1602.htm
http://www.scuzzscink.com/amiga/scuzzblog_september17/scuzzblogdseptember17_0905.htm

[M]

Hmm ok.  I've got a couple of pics from before I cleaned up the board:



Battery removed but still not cleaned up:


Just watched a vid' where the guy was pulling chips to clean the sockets.  I don't think I'm brave enough to do that

P.S. what type of vinegar do you use?

[M]

Me again, I'm bumping this rather than starting a new topic and explaining it all again (hopefully that's ok?).

So the Amiga stayed disassembled in a box, I recently decided to repair the damage to case (glue bits back on), and it came out alright, and upon reassembling the Amiga I powered it on and...
- no video output apart from a black screen
- power/drive lights faintly illuminated
- no clicking sound from the floppy drive

I then dissembled the Amiga again to bench test it which's how I had it running before, but with the same result as above. Any ideas?

I'm fairly close to flogging this thing as spares/repairs.

[blindguy]

Really need to test trace and other things with a Multimeter to verify where the data is flowing.
Let me know if decided to scrap it. I have a few pieces laying around and enjoy desoldering. 
You will probaly have to desolder the chips and pull them to test.  I would pull and throw in a working Amiga to make sure the big stuff like the CIA and Paula and stuff are all still good.
As I said, let me know, please don't trash it, I'm always looking for a project.

[paul1981]

I'd suggest pulling the socketed chips which appear to be affected with the green corrosion and cleaning the chip pins and socket. If you had green on the pins then there will be green in the socket contact, hence it is not working. I'd say that's the likely reason from looking at your photos.
Socketed chips can require reseating anyway over time, even without corrosion. Same with wire looms/plugs and such.

[Brian Hoskins]

Nowhere near the worst battery leakage I've seen on an A500+, but even so it's pretty nasty and you're going to want to make sure the the PCB has been fully cleaned.  Please consider the following:

• Post new photos showing the cleaned PCB so we can advise further
• Make sure the pins on the expansion connector have been cleaned.  A fibre pen is your friend here.
• Gary was infected.  Get him out of the socket, make sure the pins are fully cleaned, and - crucially - make sure the socket is not contaminated.  If the socket is contaminated it can sometimes be better to replace than repair.
• There are some PCB traces that go off to Gary in this area.  I can't tell from the photo if any are broken but there are some which look suspect.  You may need to buzz these out.

[Brian Hoskins]

• There are some PCB traces that go off to Gary in this area.  I can't tell from the photo if any are broken but there are some which look suspect.  You may need to buzz these out.

https://www.amigapcb.org/ is your friend here.

[M]

Hi thanks for the responses, here's a picture of the board now:



I had a look at pulling the chips before, I need a puller for that don't I?

I'm running it without the expansion board that I likely blew 

[M]

This would be ok? https://www.amazon.co.uk/Velleman-VTIC-Low-Cost-Extraction-Multi-Colour/dp/B003U8DXNA/ref=sr_1_1?keywords=ic+extractor&qid=1572445541&sr=8-1

[Brian Hoskins]

OK, good job so far but the PCB and components require more work.

The area around U12 requires further cleaning.  I would definitely replace C12.  I would consider replacing U12 also but you have to be careful because the battery leakage has probably compromised the PCB pads and if so it will be easier to damage them.  If you do decide to replace U12 I would recommend carefully cutting it out and then desolder the remaining pins separately - this will allow you to reduce the stress on the individual joints.

Some of the PCB tracks look compromised and you need to buzz them out to check.  In fact I would do this first because if you do have broken tracks, and this is beyond your ability to repair, it might not be worth you doing anything else.

Gary requires attention.  You need to get that IC out of there and thoroughly clean.  Also inspect/replace the socket.
I like that you are considering a proper tool for this.  Careful use of a flat-blade screwdriver will do but it's very easy to cause damage this way.  The tool you suggest looks alright to me.  Even so you will want to be careful - that IC probably won't come out super-easily and if you yank it you'll end up bending pins.  Just go slowly, carefully, with patience and it'll be fine.

[blindguy]

This would be ok? https://www.amazon.co.uk/Velleman-VTIC-Low-Cost-Extraction-Multi-Colour/dp/B003U8DXNA/ref=sr_1_1?keywords=ic+extractor&qid=1572445541&sr=8-1

That one should work but I prefer one with a screw to tighten the clamp.  Just seems a bit nicer to me.

https://www.amazon.com/ENGINEER-Extractor-SS-08-Extracting-Brand/dp/B000TGLSVK/ref=sr_1_3?keywords=IC+Extraction+Too&qid=1572463492&sr=8-3-spell