snow bros problem, Floppy, A500

[Toni Wilen]

Originally Posted by trydowave

Does anyone think that the CIA chip is definately at fault now? I want to make sure before i buy.

Swap CIA chips over (ODD with EVEN and vice versa). At least one CIA chip is damaged if behavior changes. For example stops booting completely, problem seems to disappear, floppy drive stops working and so on..

[trydowave]

john i'm using a parallel cable made especially for adf transfer. this stays in while the amiga is powered on. i hope this hasnt killed the CIA chip.

toni: are the chips exactly the same then if they can be switched. why would they be called odd and even?. how do know which one to replace?

also have you heard of this cable?
http://eab.abime.net/showthread.php?t=65213

do you think this could of caused it, or is it more likely that the cia was damaged prior. (probarbly impossible to tell)

[DDNI]

I damaged a few a500 CIA chips by connecting and disconnecting parallel port devices whilst the power was on...

[trydowave]

Are CIA's from C64 compatible with Amiga 500s CIAs?

ive got a dead c64 here and i think it has those chips. not sure if there soldrered though

still got another c64 alive and kicking

[john1979]

Just out of curiosity, how usable is your 500 with the (presumably) damaged CIA chip.

Do most games work? Can you still do the parallel/serial transfers?

[trydowave]

so far i've had the following issues:

Snow bros: Running too fast with gfx flickering
Apidya: Intro running 50% slower with gfx flickering
Ruff and Tumble not loading (changed adf until it did)
Supercars 2 not loading, green wiggly lines? (changed adf, fixed)
fightin' spirit 2 button support acting weird
bubble and squeak 2 button support not working correctly
shadow of the beast music seems slightly slower but i might be remembering wrong.

ADF transfer over the parallel cable is now working again. before it was only ever copying snow bros even when i selected another adf???
So i got rid of the program and downloaded another. That fixed it. Can transfer adfs again.

I can still do all serial transfers

All other games, about 50 of them, work with no problems, so far.
But. i only got the parallel cable recently, i did all the other transfters using the serial. Ill recheck the other games and see if new problems occur.

[trydowave]

heres a link to the apidya intro. is has slow sound and speeded up graphics. actually watching it like this made me chuckle abit as it looks and sounds ridiculous
[ Show youtube player ]

game runs normally afterwards

[emufan]

Originally Posted by trydowave

Are CIA's from C64 compatible with Amiga 500s CIAs?

ive got a dead c64 here and i think it has those chips. not sure if there soldrered though

still got another c64 alive and kicking

i never thought about this, but it is possible, at least what i red here and here.
_BUT_ you must ensure , you only use CIa chips with label 8520 with the amiga.
i only repeat what i was reading over there.
can someone confirm?

EVEN vs. ODD cia: on some boards it is printed near the chips, older boards do not have this information. look at some motherboards of a500 revisions here (scroll down that page for the photo links).

off topic: while others bulding or buying expensive accelerator boards, you got a speedy machine due to killed CIAs.
indeed a very strange behavior

[trydowave]

Odd and even. are they the exact same chip then? i imagine they are as they can be switched. why do they have different numbers on them then?

cheers
tony

[emufan]

yes 100% the same chips. but again, only 8520 types with the amiga .
here is another posting about this question.

By the way. I've always wondered. Are CIA's from Amiga 500 compatible with C64's CIAs? It's a 8520 after all? And are 6526 and 8520 interchangeable? I've got a C64C board that has one of each so I guess so.

answer:

The timers are different- the 8520 uses a binary counter instead of BCD. Any program that utilizes the timers would be affected. To what extent this will affect different programs, it's hard to predict.

next to label 8520 - different value: not sure, different manufactor or another date of making them, cannot say exactly.
CSG or MOS labeled on the chips.

btw: if you pull them out of the socket, do it step by step, on right side of socket, then left side, until you can take them out easily. their legs can bend easily. and do not make scratches on the motherboard, while using a flat screwdriver to pull them off - things happen, i know that myself

[trydowave]

Originally Posted by emufan

do not make scratches on the motherboard, while using a flat screwdriver to pull them off - things happen, i know that myself

yes i know. i think this is how i killed my a600 when reseating the rom

[emufan]

yep, this suxx. touching metal shield before playing with the chips is also a good idea

btw. do you have C64 machines with 8520 on it?

and read what Toni Wilen said:

Originally Posted by Toni Wilen

Swap CIA chips over (ODD with EVEN and vice versa). At least one CIA chip is damaged if behavior changes. For example stops booting completely, problem seems to disappear, floppy drive stops working and so on..

if he says you can swap them, then you can do it.

[john1979]

Originally Posted by trydowave

yes i know. i think this is how i killed my a600 when reseating the rom

For this reason I use a flat bladed screwdriver that is wrapped in sellotape at the end, if you jab into your mainboard by accident it won't hurt as much.

[emufan]

yep, good idea.

[Toni Wilen]

Yeah, both CIA chips are identical. Back in the day CIA swapping was one of the easiest and most common troubleshooting method. CIAs were (and still are) the most fragile chips in Amiga (Directly connected to parallel, floppy and joystick ports).

[trydowave]

Hello. I've just swapped over the CIA chips as instructed. Very carefully too

and i think i've solved the problem. i dont think the cia chips are at fault at all now.

In the back of the amiga every port is connected to something. Theres an RGB scart connector, Parallel cable for adf transfer, Serial for transfering, floppy cable with 3 other drives connected as well as the audio connections and the mouse and joypad.

After swapping the CIAs and getting the same issues I thought id try removing the parallel cable. The problems we're still there. I then reomved the serial cable and apidyas intro starts to run normally?

I'm going to try snow bros and see if thats working too but all this time the serial cable, connected to my laptop and the amiga was the problem. I have no idea why this is though so if someone more knowledgable than me could let me know i'd be very interested.

I'm just glad i don't have to fork out for some new CIA chips now

UPDATE: Snow Bros now running at correct speed. But 2 button option not working. It is on turrican 3 but not on snow bros? Currently using an original Master System pad.
Fightin' Spirit still has its 2 button issues too and when you move the main character left or right he pucnhes? I'm getting a new pad soon then i will be able to troubleshoot that.

[emufan]

just unpluging the cables, hmmm. you should swap the CIAs back, so see, if they are still working as expected - without the cables.
but it's good, you still have a working machine

[trydowave]

i swaped them 3 times.. cant remember which goes where now... but according to toni there both the same so it dosent matter right?
i'm going to try another 2 button pad before i take the amiga apart again just to see if the master system pad is at fault. i also read elsewhere that some people were having troubles with 2 button options in some games but not all.

[emufan]

thats ok. since chips are identical, all is good.
i only had a cd32 compatible pad in the past, but cannot recall how good it was working. IIRC, i was only using it playing Flink. cannot remember how other games were supporting all the buttons.

[john1979]

Snow bros 2 button option doesn't work for me either. All my other 2 button games work okay so maybe it's the game.