Sprucing up my A500

[kedawa]

I recently pulled my A500 (NTSC, KS1.3, 1MB), which I picked up a few years ago, out of the closet to play around with it and do some much needed maintenance.

The first thing I did was to remove the battery from my A501.  It was covered in nasty white crystals and there was some damage to the board.  Fortunately the damage is isolated to an area with no traces or components, and the removal was easy.
However, when I powered up the Amiga, all I got was some noise from the floppy drive.  No LEDs lit up and there was no video output.  After removing and re-installing the A501 a few times the machine began working normally, but I'm still concerned because I could not figure out what was causing the problem.  All of the pins were lined up properly to start with.

My next job is to replace the left mouse button, as it is becoming less responsive, but I'm wondering what the best option is for a replacement component.  Is there a 'softer' switch that has the same dimensions?  I find the original buttons a little too stiff and loud for my liking, so if I'm going to replace them, I may as well address this as well.

After that, I may consider some internal upgrades, but I need to figure out which revision I have.  I know that it is a later revision than my childhood A500 (NTSC, KS1.2, 1MB) since it has two Amiga keys and a Commodore case badge, whereas my old computer had one Commodore key and an Amiga case badge.
I also noticed that this machine uses the A501 as chip RAM, while my old machine used it as fast RAM.
I'm not sure if that's enough information to figure out which motherboard revision it has, but I'd rather not disassemble the machine at this time unless absolutely necessary.

That's about it for now.  Any insight is appreciated.

[zipper]

>> I also noticed that this machine uses the A501 as chip RAM, while my old machine used it as fast RAM.

So it has been modified (if not rev8 mobo I think). But still can be rev 6 or earlier. You have to look at it to see the rev.

[freqmax]

@zipper, How does the different revisions handle the A501 extension?

[zipper]

Similarly - if you have at least 1 MB Agnus but the mobo needs to be modified to change "fast" ram into chip ram.

[efrenmgp]

I'd rather not disassemble the machine at this time unless absolutely necessary.

I think it will be necessary to know the motherboard revision... also, it could be dusty and/or some capacitors may be leaking. It's better if you take a look.

Regards,
Efren

[Tenacious]

After removing and re-installing the A501 a few times the machine began working normally, but I'm still concerned because I could not figure out what was causing the problem.

It doesn't take much moisture in the air to make an electrical connection unreliable, especially after a few years of storage.  A "light" application of contact cleaner may help some.  Don't use much.

My next job is to replace the left mouse button, as it is becoming less responsive, but I'm wondering what the best option is for a replacement component.

The original mouse is still working?  Wow!  If it is flakey at all, I'd replace the whole thing.  It's hard to replace the button switches with an good fit unless you can find that exact micro switch (I never found them).  

I also noticed that this machine uses the A501 as chip RAM, while my old machine used it as fast RAM.

Your old 500 had "false fast ram" (it didn't run as fast as the cpu).  It is preferred to map this as "chip ram", as your new 500 has been modified.

What do you want to do with this A500?  If you're after retro games, you're there already.  If you have a more robust vision, there are lots ppl here who have gone beyond 'stock".

[kedawa]

I'm mostly just interested in games, so I think I'm fine as far as RAM and KS go, but I'm interested in possibly using a VGA monitor in the event that my 1084s dies.

Converting the machine to PAL would also be nice.

I may also install a USB-to-serial adapter within the Amiga itself so that I can connect it to my PC, which has no serial port.  It just seems more practical to have the adapter on the Amiga side.

I picked up some microswitches from the electronic shop yesterday, so I'll see if they fit in the mouse.

[Zac67]

Converting the machine to PAL would also be nice.

If there's a 1 Meg Agnus inside, chances are good that you just need to isolate Agnus' pin 41: insert a thin strip of plastic between the pin and the socket or bend the socket contact.

I've soldered a cable to Agnus and added a switch to ground - closed NTSC, open PAL. Possibly later revs even feature a jumper / solder pad you need to open.

[kedawa]

Does the fact that I have 1MB of chip RAM mean that I have the 1MB Agnus?

[arttu80]

How did you determined that you have 1Mb of chipram? If it's really the case, you absolutely have 1Mb Agnus. Run SysInfo program to find out.

http://aminet.net/util/moni/SysInfo.lha

[kedawa]

Unfortunately, I have no way of getting software on to my Amiga.
I'm just going by what the program on my Extras disk tells me.

[freqmax]

Not even a serial link?

[Tenacious]

Unfortunately, I have no way of getting software on to my Amiga.
I'm just going by what the program on my Extras disk tells me.

That's why I asked about you your expansion plans.  The following is from another thread a few months ago.

Quote:
Originally Posted by michel3105 View Post
This is half an hardware issue and half a software question.

Here it is:

Let's say I've got a bare, unexpanded A500.
I want to run a demo (or whatever) on it, which is freely available for downloading, in the usual .mdf or .lha form.

So, I can download it on my pc hard drive, and...?

How can I create a floppy, possibly bootable, to feed to the Amiga 500?

Is WinUAE of any help?


thanks in advance



This comes up quite a bit and I realize the poster has since opted for an A1200. Not a bad path for a serious Amigan.

Here's another option, expand your unexpanded A500, at least moderately. As has already been said, add the 512K trap door ram expansion. Now you have the standard A500 for which most software was written.

Next step, add some FAST ram (like a Supra 500RX, it can take up to 8 Megs). With just 2 additional Megs of fast ram, the character and abilities of a lowly A500 changes dramatically. You can unLHA software to the Ram Disk and run it from there to try it out, without ever having to write to precious and rare 880K floppies. Serial cables and the required software to connect to your internet equipped PC are far more usable now. You will no longer need to use floppies as intermediate storage. A RAD: is now possible.

Take it to 4 Megs or more of Fast Ram and a RAD: becomes even more desirable. You could boot with 2 or more disks worth of all your favorite utils (unLHA, Amiga Explorer, Dopus, etc) and move it all to RAD. Now everything executes almost instantly and will survive a soft reset. Your Amiga can start to have a life separate from an internet connection!

Add a hard drive (even a small one, Amiga software is tight) in a side car, and your Amiga world opens even wider. Usually, these have some fast ram, too.

If you want to play an occasional game that doesn't like expansion, flip the disable switch.


In this day, with so much cheap hardware on eBay and elsewhere, there should not be that many unexpanded Amigas.

My 2 cents.

[freqmax]

Use a floppy emulator and circumvent the whole floppy issue

[arttu80]

Yes, it can be frustrating to have all Amiga software downloadable from Internet, but only on PC.
When I had only A500 at my disposal, I used serial cable between PC and Amiga. I was lucky I had my old Amiga disks, so I had JRComm ( If I remember correctly) program to use Amiga side serial connection. But it was slow transferring bigger files. The bottom line is that you must obtain some hardware/or software for Amiga side in order to transfer software to Amiga.

For Amiga 1200 / A600 it's a lot easier because you can use CompactFlash card reader in Amigas PCMCIA port. That is how I'm dealing with transferring issues, and it's fast.