Wednesday, November 30, 2016

Another A500+ Motherboard - Part 1

So on the Amiga Facebook pages, a rather nice chap (hi Russell!) let me have an A500+ motherboard for pennies. This board, as per the majority of A500+ boards, has battery leak damage.

Green edge connector

This does not look good

Curse you Varta!

So, anyway. A quick power up and all I get is, rather unsurprisingly, a black screen. This would normally mean a CPU failure but given the extent of the battery damage, this is a bit meaningless.

First things first, I removed all the removable chips to check for damage to the sockets. Again, as is fairly typical with these things, the Gary socket was toast. A connector in the socket had already disintegrated due to the corrosion from the battery leak and Gary himself was looking a little worse for wear.

Alas, poor socket...
This will need replacing. The picture doesn't really show how green the contacts are across the whole socket.

On to Paula. Oh, dear. The bottom half of her socket is almost as bad as Gary but the top looks OK. This will still need replacing though.,.

Even Agnus did not escape unscathed. There were telltale signs of green on her 84 pins too which did not surprise me (no picture I'm afraid) so, as I precaution, I will replace her socket as well.

The other chips faired rather better. The two CIAs, Denise, the ROM and CPU were all unscathed so no socket replacements needed for these. It looks like I will need to replace at least one, possibly more of the logic chips that are in the are of the acursed battery. The chip U12, which is a 74LS244, took the brunt of the leakage. Fortunately, I have one of these in my box of bits. I don't have any others though, so I'm hoping everything else can get away with a bloody good clean.

First task, remove the Gary socket. Normally, I would just cut the old socket off and then de-solder the pins but, for some reason, I decided to be a bit more careful and I'm glad I did. Once I had the socket off I could check for any further damage (there was a little bit) and try to clean any other corrosion up.

Gary socket gone - some cleanup works carried out.
It was at this point I realised I had no sockets of the same size as Gary's (or Paula's). I did have some smaller sockets with the same style of pins so I hatched a cunning plan. I would clean up the plastic frame from the original socket and remove the pins from the small socket and place them in the big socket. This was a lot less fun than it sounded.

Half Completed Gary
Once I had replaced all of the pins I realised that I would have to do the same again for Paula. But that's for next time...

Friday, November 25, 2016

Sadstick 2 - El Cheapo

The second of my 'additional' joysticks is the cheapest of the cheap. Cheapo McCheap of Cheapland could not have made this any cheaper if he tried (even on a particularly cheap sort of day).

Did I mention it's cheap?

It worked when I plugged it in to my Amiga but the down direction was a bit sluggish and intermittent. After I unscrewed the one screw in the base it became obvious why and I thought it would be an easy fix.

Either a super ingenious enclosure or it's cheap.

The switches in this stick are formed from a piece of spring metal with four lugs cut out and bent upwards. As the joystick is pushed, the base of the shaft pushes a strip of metal against the lug, making a contact. The 'down' contact just needed to be bent a little bit closer to the metal strip. And then it fell off in my hand. Bugger.

Spring Metal Switches - Cheap

What I ended up doing was using a long bolt and some nuts to make a riser from the base. By drilling a hole for the bolt and then inserting the bolt through the hole, a contact was made to the metal. I added a piece of copper from an old piece of Amiga A500 edge connector I had and screwed that onto the top, bending it slightly so the it was roughly the same location as the lug had been previously.

Just call me MacGyver
My heath-robinson switch

I did have to remove part of the base retainer to make my mod fit.

The handle has no components other than two plastic switches that push down a plastic 'stick'. This presses down onto another piece of (cheap) plastic that then activates the fire button switch. Incidentally, the handle spins round on this joystick but as far as I can tell, there is nothing stopping it nor was there ever anything to stop this. Perhaps they were relying on the friction of the springy rubber block in the base to stop rotation but it doesn't work.

So there you go. My mod fits after a bit of butchery with a craft knife and, yes,it does actually work. If only it weren't so CHEAP.

Saturday, November 19, 2016

Joystick Sadness (Sadstick?)

A few weeks ago I spotted a job lot of three joysticks on eBay for a very reasonable price. I was only really interested in one of them, and at the price I paid, the other two were a bargain.

Or so I thought.

The first of the additional sticks was a Cheetah Annihilator. If you are interested in retro gaming in any form then you will probably already know that this particular joystick could be described as the worst joystick in the history of mankind. If this was the last joystick in existence and I had to choose between the eternal fires of Hades or playing Sensible Soccer for an hour with this joystick then I'd be reaching for the suntan oil.

Imagine my (non)surprise when I realised it was broken. The handle didn't centre properly, the fire buttons on the top of the handle didn't do anything and the handle itself wasn't screwed together properly. Once I undid the screws in the handle it became apparent why. The previous owner had deliberately screwed it together in such a way as to grip the shaft of the joystick (no sniggering at the back) thereby semi-concealing the fact it's buggered.

The second joystick is very much an el-cheapo generic joystick from the cheap end of cheapo land. This one at least seemed to make no pretence at being anything other than cheap. Did I mention it's cheap?

I tested both of them on my Amiga and, sure enough, the fire buttons didn't work on the handle of the Annihilator but the base fire button did. The directions all worked but nothing could hide the sagginess of it. El Cheapo worked but the shaft twisted rather unnervingly but that's for another post.

So, do I bother doing anything with the Annihilator? Of course. 

Opening the handle revealed two wires connected to two random pieces of metal. Also inside was a 'z' shaped piece of black plastic and another chunk of the interior. After puzzling over the bits for a while it suddenly became obvious what I needed to do. Bin it...just kidding.

Comprehensively Broken

The two pieces of metal formed the 'switch' for the fire buttons and the 'z' piece held them in place. The only snag was that one side of the area that holds the 'z' piece had snapped off. To solve this I used a tactic normally reserved for large, heavy parts of Warhammer models. PIN IT! Basically, drill a hole from the exterior of the handle through to the inside. I actually did two holes. Then, superglue the broken piece back where it should be and let it set. Once set, I got the drill out again and extended the two holes into the superglued part. Finally, two pieces of stiff wire (a paperclip) were cut to length and superglued into the holes and left to dry. Job done.

Two tiny holes betray the pins

Re-instating the switch was straightforward after that. The only tricky bit was ensuring that the pieces were the right way around. The way the switch works is this. If the top button is pressed the button pushes the spring metal down onto the other piece completing the circuit. If the trigger is pressed the the button presses the metal where it makes contact with the other piece, completing the circuit. Cheap and nasty.

Next up, in the base, the switches used for the directions are of the 'dome switch' type. These are the same as used in the original QuickShot and QuickShot II joysticks. In this case they were covered in a huge sticky sheet of clear tape that was also covered in what looked like sawdust. I had to remove the tape (yuk) and carefully take the domes of the sticky side. I cleaned them with isopropyl alcohol and re-attached with a few small pieces of sellotape. Easy. (Apologies there are no photos of this - phone camera let me down.)

The next problem was that the handle just rotated around the shaft because the plastic lugs inside the handle which normally slot into the joystick shaft had snapped off. This was solved relatively easily with a couple of bolts. I drilled a hole on each side of the handle and inserted bolts long enough to slot into the shaft. 

New anti-rotating bolt fitted

Finally, how to make it a bit less sloppy. This was more difficult but I had an idea of using a spring of some sort under the shaft. As luck would have it, I had a few single battery boxes used in small projects. The spring contact from one end of one of these boxes was just the right size and strength to fit under the main shaft. The result was more than acceptable and a darn site better than it was originally. Again, apologies for the lack of photos on this bit - I did it at the same time as the dome switches and, for some reason, no photos came out..

So for this joystick, the only signs of anything being 'different' are a couple of tiny holes on the handle near the fire buttons, and what looks like a couple of screw heads at the bottom. A small price to pay to make it work.

All repairs done - re-assembly in progress

Re-assembly complete and all tested

It's still a steaming pile of crap though...