8k cart. for a 16k cart.

Modding and Technical Issues

Moderator: Moderators

Post Reply
vic user
VicGyver
Posts: 1401
Joined: Thu Mar 25, 2004 9:40 am

8k cart. for a 16k cart.

Post by vic user »

Hi;

I would like to trade a 16k cart. I have, for an 8k cart.

If anyone would like to do this, then let's mail each other the goods!

chris
Leeeeee
soldering master
Posts: 396
Joined: Fri Apr 23, 2004 8:14 am

Post by Leeeeee »

Why would you want to do that? If it's a C= 16K cart it can quite easily be made 8K by cutting a trace.

Lee.
Boray
Musical Smurf
Posts: 4064
Joined: Mon May 03, 2004 10:47 am

Post by Boray »

If it's a Commodore, then you can cut in two places and then solder in a switch that has 8 switches on it, cut a hole in the front plate and then you will get a cart with two 8k blocks you can select freely.

/Anders
PRG Starter - a VICE helper / Vic Software (Boray Gammon, SD2IEC music player, Vic Disk Menu, Tribbles, Mega Omega, How Many 8K etc.)
vic user
VicGyver
Posts: 1401
Joined: Thu Mar 25, 2004 9:40 am

Post by vic user »

The reason why I wanted to trade, was so I could have 8k in banks 3 and 5.

I didn't know you could fiddle with the 16k cart.'s

Time to open one up then :)

Chris
Leeeeee
soldering master
Posts: 396
Joined: Fri Apr 23, 2004 8:14 am

Post by Leeeeee »

Depending on your skill level you can do more or less anything. Go see ..

http://www.themotionstore.com/leeedavis ... index.html

While this is a bit extreme you can see the pads that select the blocks.

The C= 8K cart is just a 16K cart with half the chips missing, which is what the above was before I started on it.

Lee.
Boray
Musical Smurf
Posts: 4064
Joined: Mon May 03, 2004 10:47 am

Post by Boray »

The thing to look for inside is 8 points where you can solder and cut things to select blocks. The first 4 is for the first 8k block. The second 4 is for the second 8k block.

It should look like this:

Image

Now if you want a cart that always is block 3 and 5, then you can just cut at 1 and 5 (or unsolder if they are soldered), then solder at 7 and 3 instead. But switches are of course nicer. Then go to an electronics component shop and bring the cart and ask for an 8-switches switch that fits on the other soldering points (the 16 dots above). Then just cut at 1 and 5, solder on the switching component and make a hole for it in the cart's metal cover. But with the switches like that, you won't be able to change the switches with the cart plugged in... For that you need to do something else... But this is probably the easiest way to make your cart switchable.

/Anders
PRG Starter - a VICE helper / Vic Software (Boray Gammon, SD2IEC music player, Vic Disk Menu, Tribbles, Mega Omega, How Many 8K etc.)
User avatar
ral-clan
plays wooden flutes
Posts: 3702
Joined: Thu Jan 26, 2006 2:01 pm
Location: Canada

Post by ral-clan »

Okay, I just found out about being able to run cartridge ROM images by loading them off disk or tape into the proper memory segments.

I have two switchable ROM packs, but not documentation. Is there some sort of standard for the DIP switch settings so I can know which areas the RAM is being allocated to? Or is this detectable via some sort of POKE, so I can experiment to find out where the RAM is?

One of my cartridges is the famous "SPECIAL CARTRIDGE" by Audio Computers. I believe it has a set of 4 dip switches (can give a total of 24K RAM I think).
carlsson
Class of '6502
Posts: 5516
Joined: Wed Mar 10, 2004 1:41 am

Post by carlsson »

I'd use POKE and PEEK, perhaps with a couple of different values and positions to ensure it is not flakey.

BLK1: POKE a value into 8192-16383 and read it back with PEEK
BLK2: Ditto for 16384-24575
BLK3: Ditto for 24576-32767
BLK5: Ditto for 40960-49151

If you get a consistant read-out, there is functional RAM. If you get a different value than you poked and it changes for every PEEK, it is bus noise due to the memory area is unconnected.
Anders Carlsson

Image Image Image Image Image
User avatar
eslapion
ultimate expander
Posts: 5458
Joined: Fri Jun 23, 2006 7:50 pm
Location: Canada
Occupation: 8bit addict

Post by eslapion »

way back then people used to add switches to flip the first bank between blk1 and blk3 and the second between blk2 and blk5. Flipping this second switch to blk5 would also make your ram expansion read only.

This was quite useful as it allowed you to load up any cartridge image in either blk1 and 2 or 2 and 3 then flip blk2 into 5, press the reset switch or type SYS64802 et voilà! you have a running game cartridge!
Post Reply