A500 + Floppy Drives

Okay, i told my probs earlier in IRC but since i was getting no response anymore, i'm just gonna post it here


I was fiddling around with my A500 and transfering adfs from my PC to the Amiga when at some point the floppy just stopped working. I rebooted, sometimes I got a Guru Meditation, but mostly i just got the normal bootscreen with the insert-disk picture. Note that I already inserted a bootable disk and you would expect the floppy to start reading from the disk! But then again nothing happens, the drive just wont start trying to read from disk.
Thanks to the advice from andreas & wilen, i changed the floppy 2 times. One was from another A500, where i got exactly the same problem. I thought "ok, so this might be just broken too, could be". I then took out a drive from the external drive shell and tried it, which according to wilen would work. And - oh surprise - same problem. The drives just wouldn't start doing anything. So I think this can't have to do with the drive, although I cannot confirm for any of them to work in another Amiga, however the first one worked fine until, well, some point, where I said it all started.

Any suggestions would be great, thanks.

[BippyM]

Looks the the Floppy Drive controller might have died

I think the controller is either in Gary or Paula chips.. though I can't quite remember :/

You need to establish if its the drives or the 500 that is indeed faulty :!

Are there any memory expansions etc. in the 500, if so remove them and try again!

Well seeing as they all have the same problems on that Amiga I'd say its not the drives...
And another thing how could this be related to the memory expansions? As far as i know i got a 512kb<->2mb expasnion and some 7<->14mhz thing in it, but since my father built it in when i was young and i didn't need to open up the Amiga one time up tilil now i got no experience regarding such things...
So how and where am I supposed to remove the expansions?

[jmmijo]

If you carefully remove the cover of the A500, then the metal RF shield you can check if the PAULA is socketed or not. I seem to recall that most if not all of the chips had stenceled labels near them printed on the motherboard. Also I believe it was a 40-pin DIP style package meaning that it had 20 pins on each side of the chip.

You would want to carefully use a pocket knife or if you have one, a chip removel tool to slowly pry up each end of the chip until it comes free. However if it's not socketed, meaning that it's soldered directly to the motherboard, then there's nothing else you can do

Doesn't hurt to look first and see...

But then how can I tell if its socketed? Really got no experience..

[Toni Wilen]

Could be caused by blown CIA io-port too (very easily damaged by static electricity), try swapping CIA-A to CIA-B and vice versa.

[jmmijo]

A socketed DIP chip sits a little higher then when soldered directly to the board, it looks like it sitting on/in something, usually the socket is black in color and is about 1/4" high or less.

Take a look at the pics on this site for more info on what the sockets look like you may have to save the mainboard pic to your local HD and view it manually so you can zoom in on it

Yeah well i think Paula is socketed, however I have no idea where to put on the knife to effectively remove the chip without damaging anything, can't explain this good enough probably.. Oo Maybe I'm just too anxious to break something heh

Oh and Toni, you mean I just put the CIA-A chip in place of CIA-B and vice versa? Looks like a silly question, but i dont want to break more than already is So..
And, if I'd do that (or replace Paula) would additional soldering be needed? I heard that somewhere, so..

[Overdoc]

Take a very tiny screwdriver and stick it between the socket and the chip and carefully lift the chip out of it's socket a bit. Then do the same thing on the other side of the chip, and again on the opposite side and so on, until you have removed the chip. To be exact, you have to stick the screwdriver on the small side of the chip - between it's 2 rows of pins.

As already said, it looks like a CIA or PAULA problem. The 2 CIA chips ( odd & even ) are located near the back of the A-500. You can swap them against each other for testing. But be very careful to put them into the sockets in the right direction !! There is a small vut in the chip on one side, and it must match with the white picture drawn on the motherboard. In other word. the cut on the CIA chips must look to the right side !

With PAULA, just press her into the socket firmly; might have bad contact. However, I believe it is more a CIA problem than a PAULA problem.

Hmm ok, i switched the CIA things, but well, somehow i screwed up. I got a multi-kickstart card in the miggy (at lesat i think thats what it is since its connected to a kickstart-version-switcher outside o.O dont have any experience ) as far as i can tell it replaced the chip with is near the CPU (? at least ithink thats what it is, since a "motorola" label is placed on it )

now i needed to remove it to get to the CIA chips, but when i done all that and placedit back in i screwed up some pins which broke off afterwards. (they were really shitty long pins and you couldnt tell if they plugged in right and ...i was impatient ) well i didnt test the thing out BEFORE but afterwards i got the black screen where nothing went on but the power led + caps lock led. i had this problem before and it was due to the multi-kickstart-rom thingy that didnt sit right in the socket, back then i pushed it in and then it worked. but then it wouldnt work so it could be due to the missing contact pins!? anyway i tried and got the "default" chip that is originally built there from my replacement-parts miggy, but that wouldnt work either =(
so any ideas?
maybe important to mention is that i only got the left cia chip off with more "rough" handling where i COULD have screwed the contacts which sit in the socket itself a bit.
so my question would be too - even if the cia chips had bad contact, would an A500 still boot with white screen etc? that would encircle the problem further..

i really regret i did this more hasty and dirty way but well i was in a bad mood and...maybe the poor thing can still be saved from oblivion

EDIT: heh ok, tried it with another miggy (i removed one cia chip there) and it wouldnt boot, so that is the problem - the cia chips have bad contact.
well, the problem is this - i think only on the cia chip sockets there are little metal contacts on the "inner side" of the sockets, and a few broke away, as far as i can tell. is there any way i could fix that? because this most probably prevents the miggy from booting right- at least i think so.
as i said above, kickrom could be a problem too but i doubt that - i removed the multi kickrom thingy and replaced it with another 1.3 original kickrom and it wouldnt boot right, but on another miggy it would. so it shouild be only the cia chips problem.


EDIT II: Okay, little update. Forget what i said above, thank god the thing boots again (Fiddled with CIA chips and kickrom chips i took from two other miggys, seems to work). However, still no activity from floppy. Just doesnt do anything. Is there ANY way to clearly determine if its the drive or the floppy controller thats faulty if you got no Amiga that is 100% working? Because now that i replaced / changed the CIA chips, still no change of the situation..

Ok, ANOTHEr thing...I'm not sure if I am using the original CIA chips of this machine because - if you read above - i fiddled around with it alot to even get it booting again. Toni(? I think it was him) said that it could maybe get fixed by switching their positions. I did that just now but then the thing wont boot again. Note that i somehow use 2 different labeled ones (on even its 2461 24 on the bottom line, on odd socket its 0590 24) so maybe it could get caused by this, but maybe not and then - well, any help is always appreciated.


Edit #Stopped Counting :P :
So it seems there is no definitive method to check if its the drives or sometjhing on the machine it self...so i was wondering if there is anyone in Germany with a working A500 i could send my 3 drives to and then the person would check if the drives are working, so I'd know whether its the drives or not that cause this problem. This is slowly driving me mad. =(

Thanks..

[Overdoc]

Hmm, hard to give you any advise since it seems your Amiga and it's sockets is already little bit broken, but:

When you swap the CIAs over ( the number doesn't make any difference - it is just the week/year they were produced ), and afterwards the Amiag stays black, then one of the CIAs is dead ( that is if there is no socket contact problem or other )

I suggest the folowing:

I think it is better to check dead parts or parts you think are dead in a working machine than the other way round. In your case the drive is most certainly ok, because you got the same problem with another drive and it is not very likely both have the same error.
So, what about testing the dead drive in another, working A-500 ?
Next test the CIA chips one by one in the working A-500, and next check PAULA, always from the dead A-500 in another working one.
This way you can pin down the problem to a certain chip or other part.

Well I have another A500 here problem is I COULD have used one of the CIA chips from it, (Unfortunately I lost track from which A500s (i got 3 - the main thing, one other and a third that is only usable for taking replacements like chips) i got the CIA chips - but i guess i have to look for all combinations I can find.) AND i dont know if it would be fully working either because it shows nearly the same problems as my main A500!? So I can't be sure...but I will see if i find a method.

EDIT: I replaced one CIA chip with some other that has the same label as the other and it works!!! yes! finally. i hope it WILL still work though :P thanks for your help all, without it i probably would still sit here. thanks!! =D

[whiteb]

Chips that are socketed on A500.

CPU. (68000 etc, Near left hand, beside edge connector)
Kickstart ( next to CPU )
Gary. (Ram addressing, Floppy motor, and some other logic.)
Paula. (sound, above Agnus, also contains *SOME* of the floppy control registers.)
Denise. (Graphics, top left side of the motherboard, below video port.)
Agnus. (Totally square chip, sitting INSIDE a socket not ontop of), next to Kickstart.
CIA A & CIA B (Interface I/O, timers, floppy disk I/O).

Serial IO was controlled by a Motorola MC1488 + MC1489 (not socketed.

[teh]

Originally posted by bippym
Looks the the Floppy Drive controller might have died

I think the controller is either in Gary or Paula chips.. though I can't quite remember :/

You need to establish if its the drives or the 500 that is indeed faulty :!

Are there any memory expansions etc. in the 500, if so remove them and try again!

As bippy said its most likely the controler!

Try the other floppy drives on that spare a500

Argh, I'm sorry to revive this thread but - guess what happened...the problem happened again. After some days of not using it, the thing died off again. But this time i don't even see the floppy disk start screen...just black, nothing happening...so first question does anyone have an idea why this could have happened *again*? Is it possible that there are just some Amigas with extremely crappy components, or something like that?

The fact that i see no boot screen could come from the fact that maybe the kickrom chip died...but I'm not sure, i will open it tomorrow and see if i have one left to replace it...
Maybe its just the kickrom, but maybe its the drive/the floppy controller again..(and even with a broken kickrom, wouldnt i get some floppy sounds? because i don't..)
And then, could there be something else causing this? When i switch it on, i get power led, caps lock led, etc...but then...nothing.

Any ideas/suggestions on this (Except "buy a new one", please..)?

thank you...again

[Overdoc]

Well, a black screen can be caused by almost every chip inside the Amiga, although in some cases certain chip failures are displayed by a different coloured screen at startup.

I would say check the Gary, CIA, CPU, RAM and also the Kickrom. Normally a Kickrom failure should display a red screen at startup, but this is not for 100% sure as I have also had one with bad Kickrom contact, which gave me a black screen !

In your case I would also check the power supply ! Maybe it is bad an puts out too high voltage which kills the chips after a while ? Also, push down all the chips in their sockets, because sometimes they work themselves out of their sockets becuase of temperature expansion and contraction.
If nothing helps and you have no spare chips to test then just leave the Amiga on for a while and feel if any chips ( especially the RAMs ) get VERY hot after short time ? That would be a sign for a broken and internally shortened chip.

Okay thanks, I'll try what you said later.
But one thing, how would I check the power supply and if it puts out too high voltage..?

[Overdoc]

The psu should measure 5V=, 12V= and -12V= when the A-500 is connected. Voltages shouldn't be much higher or lower than this !
If you measure the psu wothout load ( A-500 not connected ), then don't leave it on too long, as the psu might get damaged ( switching psu ) Anyway, without load you get something between 5.5V and 6V instead of 5V, and up to 14V for the 12V.