A500 Upgrades

[GadgetUK]

Would WD40 be good as a contact cleaner? Stupid question I know...

Yes!  That's fine for joystick microswitches.  What make is it?

Personally I would do the 1Mb chipram mod, thats easy.  Then add a 4 or 8 Mb board from kipper2k.  If you are going to get a HDD (which can be hard to find for a 500) then definitely get the 8Mb board, if you are just going to stick with floppies then 4Mb is all you need, and infact is probably an overkill - that said price difference is hardly anything so I would stick 8Mb in.

If you do get a HDD, then and only then, consider getting 3.1 ROM and a ROM switcher, and if you want to be able to press a key to quit in whdload (software that runs games from HDD) you might want that 68010, I wouldnt bother tbh as you wont be running at stock speed.

You can make that 1Mb chip RAM toggleable with a switch btw, if you dont permenantly want 1Mb chip ram.

ECS denise isnt really needed unless you want to play ECS games, which I think need kickstart 2+ (eg 3.1), so not much point in doing that chip unless you get HDD and 3.1 kickstart etc.

External floppy is a good idea, try to get a cumana - those thing run forever.  If you need a new joystick, look for a good cruiser or zipstick.  I prefer the cruiser myself as its easier to hold but zipstick tend to be more robust.

I would add more RAM to those empty sockets youve got then you would have 1.5Mb chip ram, but it would require soldering many pins.  If you explore that idea make sure to get sockets and solder the sockets in place and not chips - stick the chips in the sockets.  Getting those RAM chips could be tricky - try EBAY or aminet.  I saw a cut off board section just last week that had those RAM chips on it, but they needed desoldering first.

I would be interested to know the model of the RAM on your board, the older revs like mine have 41256, or 51258, 81256 etc.  And there are normally 16 of them, I think yours has 8 and 8 empty spaces?

[GadgetUK]

Oh oh oh!!!! Before I forget!!! THE upgrade you MUST get in my mind is a HxC Floppy Emulator from Lotharek (google that name). It replaces your FDD with an SD slot, stick a 2gb SD card in for £4 with hundreds of games and you are away. For a 500 its easier than the HDD route imo. They cost around £60 ish but well worth it. There are different models, some with LCD and buttons etc. To get the best result you need to be handy with DIY but you can avoid fitting an LCD etc, its up to you how you mount the thing.
 
Heres the drive in my ST:-
 
See this thread for how I did this, and earlier up the thread is a pic of an amiga with an external unit:-
http://atariage.com/forums/topic/208925-hxc-floppy-emulator-where-to-mount-the-lcd/
 

[GadgetUK]

Wow, thanks for everyone's fast responses!
 
 
 
I will try not spend too much at once Mike!!
 
I do already have an external floppy, so I'm on the way! Lots there I don't understand yet, so will start researching right away. I've got a Rev 6A board, and GadgetUK told me it already has a better Agnus than earlier ones. I'm a total novice when it comes to anything electronic, but enjoying learning about my Amiga!!
 
What I've got to do now is somehow find out why my comp pro joystick has stopped turning left! I have taken it apart and tried to test the switches for continuity, but not quite sure if that is what I should be doing? Need to find at least one more in any case.
 
Thanks again, if it's ok to ask a question or two anytime, I'll be very grateful!

To test continuity its easy:-
 
On each microswitch (take the joystick to bits so you can get at the switches), you will see 2 contacts on each switch with a wire going to each contact. Put your black wire on one contact and the red wire on the other, and put meter on continuity test or ohms. Press the switch and it should be a short circuit, or very low <= 10 ohms. Test the good switches first so you can see it going on and off correctly on your meter, then test the dodgy switch.
 
Some times those microswitches fail, you can salvage them from other joysticks, and I believe there are suppliers of new microswitches still depending on the size and type etc but they are pretty standard.
 
Same goes for the microswitches soldered onto Mice boards for left and right click, they tend to be standard and can be replaced pretty easily.

[GadgetUK]

Joystick is a comp pro, also have a quickshot that down doesn't work on. Sounds like it is also micro switched.
I'll give them a go with the WD40.
 
I'm ok with the few games that I have for now, they all worked fine before, but I may try to find some that I don't have anymore. But probably they would be fine with stock Amiga, with the trapdoor expansion. It would dbe great fun to add more RAM to the board though!!
 
The RAM is D424256C, does that sound right? There are 4 chips and 4 spaces on this board.
 
Here they are:
 
[ATTACH]2854[/ATTACH]
 
Would it be hard to find the chips and sockets?

Ah yes, I see now.  You've got 4 but they are 4 x higher capacity than the 41256.
 
Just search for 424256, needs to be DIP package:-
 
http://www.ebay.co.uk/itm/D424256C-80-NEC-DIP-20-IC-/290458263493?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item43a0a95fc5#ht_63wt_1161
 
£5 each isnt too bad, but means £20 for the chips you need.
 
Then sockets:-
 
http://www.ebay.co.uk/itm/DIL-DIP-IC-Socket-6-8-14-16-18-20-Pin-Sockets-UK-1st-Class-Postage-/290767443526?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item43b3171646#ht_1897wt_1161
 
You need 20 pin DIP sockets, which that seller has.
 
Simply solder the sockets in place, stick your chips in and I think you are away.  There might be a jumper or something, I will check in a min.

[GadgetUK]

Get confusing readings from the joystick. I've got the multimeter set to 200 ohms, lowest setting. But when testing the good switches, don't get a constant reading when pressing the switch, might begin with 142.7 down to 0.14. But constantly changing. Strange.
 
Even the bad switch still give the same kind of changing readings.
 
Tested the fire buttons just in case. Right fire gives the same changing values, but left is completely dead, even though it's not a micro switch, just two metal contacts pushing together. They do make contact, just made sure!

You aren't making firm enough contacts on the pins, that's all. Press hard and get someone else to move the buttons / directions etc and it will be more constant.
 
EDIT: If its metal contacts and they are definitely making contact then it could be the main wire. Sometimes the wire can work if you bend it certain directions, its worth trying that on the Amiga, plug it in, and hold the button or direction that's not working and bend the main wire at different points to see if it makes any difference at all.
 
Oh, i've just remembered - you swapped your CIA's around, if one was faulty (giving you flashing LED etc) then you could have put the duff one in the position that handles joystick input... If you dont get anywhere with the stick try swapping the stick into the mouse port and see if you can find a game that will use the mouse port and see if that's working with the stick (I suspect it will if your mouse is working), that will prove its the CIA, or you could just swap the CIA's around again and see what happens.  If the stick has been working intermittantly it won't be the CIA it will be the stick btw.  Ideally test another joystick in the port to rule it out but most likely problem is the buttons or the wire.

[GadgetUK]

I reckon I could just about handle doing that. Well I'd give it a go...the resistors shouldn't be too hard to find?

Will be easy to find resistors, the really hard thing to find are the RAM chips at reasonable price.  £5 is cheap really, I looked at the old 41256's for my model and they were £3 each and 16 are required for my version =O   Luckily because I used to be in the industry I found 80+ of them in my IC collection =)

[GadgetUK]

Sorry, that is definitely not correct. You are not going to get more than 1 MB chip ram without upgrading to a 2 MB Agnus. And that is not simply finding a 2 MB Agnus an replacing the old 1 MB Agnus...

Yes, you are correct, I had forgotten he has a 1Mb Agnus. Still worth doing to have 1Mb on board and 512Kb of fast(slow) RAM.
 
In addition to the chips you should probably put some decoupling caps on the there - 0.33uF (I've got some if you do decide to do it, just pay for postage you can have the caps - I got a bulk lot of 50 and i've only used 2 so far.)