A500 disk drive stopped!

[Laughy]

Just to be clear, have you removed the modulator when using the black and white composite signal?  maybe you plugged the modulator in whilst it was powered up or something?  If video output is faulty it could be a problem with hybrid.  Could be denise but unlikely I think.  Try swapping the 2 x CIA chips around and check behaviour, if swapping them around changes behaviour it will be faulty CIA - i've got several spares.

Edit: when you swap them make sure they are installed the correct way around.

Modulator was unplugged when using the mono output. Just tried it again, get a picture both connected and unconnected. Just not through the modulator.
Had a go at removing the CIA chips, but they are well in and am a little worried that I will damage the chip and/or motherboard taking them out. I will have to get one of those PIL tools to grab both ends at the same time. It's going to take quite a bit of force in any case though.

[GadgetUK]

On checking again it just crashes, power light just goes dim, no flashing. Though I could swear it did flash a couple of days ago (prior to taking apart and attempted cleaning).
It's a 500, with white screen. Games I played the other day which were fine, and not now : Turrican 2, Nitro and Project X.

Modulator was unplugged when using the mono output. Just tried it again, get a picture both connected and unconnected. Just not through the modulator.
Had a go at removing the CIA chips, but they are well in and am a little worried that I will damage the chip and/or motherboard taking them out. I will have to get one of those PIL tools to grab both ends at the same time. It's going to take quite a bit of force in any case though.

The CIA will come out easily, just lever them out by putting a flat head screwdriver under the chip but above the socket and lever a little then swap to the other side.  Repeat that proccess 4 or 5 times on each side until each side has raised out if the socket.  Take your time and be careful and it should be easy.

[GadgetUK]

Do you have a multimeter? It's worth checking all the voltages are there from the PSU. Doesn't sound like a PSU issue but I am wondering if that modulator needs a 12v or -12v source or something, could explain the loading problems as well as the drive probably needs the 12v line also, whereas most if not all of the logic on the main part of the board will probably work with +5v line regardless of the +12v / -12v lines - they tend to be used for comms, and audio output.
 
EDIT: Regards my comment on the message previous to this one, see this video:-
 
https://www.youtube.com/watch?v=RkSCh53fO6Y
 
Around the 2:59 mark you can see how the guy remove the DIP chip from the socket. The smaller the blade on the screwdriver the better, he's used quite a large one there imo.

[GadgetUK]

Do you have a multimeter? It's worth checking all the voltages are there from the PSU. Doesn't sound like a PSU issue but I am wondering if that modulator needs a 12v or -12v source or something, could explain the loading problems as well as the drive probably needs the 12v line also, whereas most if not all of the logic on the main part of the board will probably work with +5v line regardless of the +12v / -12v lines - they tend to be used for comms, and audio output.
 
EDIT: Regards my comment on the message previous to this one, see this video:-
 
https://www.youtube.com/watch?v=RkSCh53fO6Y
 
Around the 2:59 mark you can see how the guy remove the DIP chip from the socket. The smaller the blade on the screwdriver the better, he's used quite a large one there imo.

I know I am quoting myself here but i've taken a look at the circuit diagram just now, and it could well be a PSU issue. +12v, +5v and -5v are used by the modulator. If you aren't getting a stable picture using the mono composite, it could be that your PSU output voltages aren't quite right.
 
EDIT: The Hybrid also takes in +12v, My suspicion is your +12v line is low (pray it isn't high or it may have damaged the Hybrid).  You need to use a multimeter set to DC voltage and check the +5v, -5v, +12v.

[Laughy]

Do you have a multimeter? It's worth checking all the voltages are there from the PSU. Doesn't sound like a PSU issue but I am wondering if that modulator needs a 12v or -12v source or something, could explain the loading problems as well as the drive probably needs the 12v line also, whereas most if not all of the logic on the main part of the board will probably work with +5v line regardless of the +12v / -12v lines - they tend to be used for comms, and audio output.
 
EDIT: Regards my comment on the message previous to this one, see this video:-
 
https://www.youtube.com/watch?v=RkSCh53fO6Y
 
Around the 2:59 mark you can see how the guy remove the DIP chip from the socket. The smaller the blade on the screwdriver the better, he's used quite a large one there imo.

No multimeter, but could probably borrow one. You'll have to forgive my lack of knowledge of electronic stuff. I'll have another go with the CIA chips.
Just so I get it straight in my head, you think that it is one of the CIA chips that has stopped the drive from loading and stopped a signal going through the modulator?

Maybe I was a little misleading with my description of the mono picture, it is there, just not great, needs a bit of tuning. No flicker or anything like that. Sorry, shouldn't have said not stable.

I will have to look up PSU as I don't know what that is. I wouldn't know where I would have to test to find out the voltages. Shall I see if I can get a multimeter, and get back to you? I'm not sure what the hybrid is, sorry, I assumed you meant the RGB to SCART cable. I don't have one yet. But then, if the RGB output is buggered, no point getting one until I fix it?

[Zac67]

PSU = Power Supply Unit - the power brick
If you're using a multimeter, measure the voltages loaded, i.e. while the PSU is plugged in and the machine is running (or trying to). Just clip the black cord to ground somewhere (e.g. RF shielding), easy access to +5V & +12V is on the floppy power connector. DO NOT short circuit any power pins with their neighbors!

The "Vidiot" hybrid is that black card right next to the Denise chip (upper left corner). It's converting the digital video signals to analog ones for RGB output. Have never seen one die but you never know.

Apart from trying the very easy CIA swap my guess is on one the RAMs or the Agnus socket.
Is the floppy spinning up?
Is the head moving?
How long does it take from inserting the disk to the flashing LED? Anything on the screen then?
Have you tried removing the trapdoor expansion to see if it makes any difference?

[mrknight]

The pinout of the PSU can be found here:
http://www.hardwarebook.info/Amiga_500/600/1200_Power_Supply

And for a photo:
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/body_amiga_power_supplies.html

When using a multimeter, hold the common ground probe of the meter (usually black) to pin 2 - common ground. Then use the other lead (usually red) and hold on the voltage pins (1, 3 and 5) one at a time. You need both probes to touch one pin each to get a reading. Sorry for sounding too informative but I do not know how much electric/electronic skills you have.

Maybe that you can borrow a multimeter from can help you to check? Ask for help but stay with that person during the test and see what he/she does. And ask questions. Learn. And then get your own multimeter. For just checking basic voltages you do not need an advanced one. I paid ~AU$20 (~GBP14) for the one I have. And it's a decent one to to basic stuff.

Good luck!

[GadgetUK]

No multimeter, but could probably borrow one. You'll have to forgive my lack of knowledge of electronic stuff. I'll have another go with the CIA chips.
Just so I get it straight in my head, you think that it is one of the CIA chips that has stopped the drive from loading and stopped a signal going through the modulator?
 
Maybe I was a little misleading with my description of the mono picture, it is there, just not great, needs a bit of tuning. No flicker or anything like that. Sorry, shouldn't have said not stable.
 
I will have to look up PSU as I don't know what that is. I wouldn't know where I would have to test to find out the voltages. Shall I see if I can get a multimeter, and get back to you? I'm not sure what the hybrid is, sorry, I assumed you meant the RGB to SCART cable. I don't have one yet. But then, if the RGB output is buggered, no point getting one until I fix it?

Yes, the CIAs can cause all sorts of weird behavior as they connect to various other chips. I've seen for example CIA's cause the green screen error typically associated with bad RAM when it was the CIA, i've also seen CIA's interfere with floppy loading although you would expect it to be more likely to be the Gary chip or the floppy drive itself.
 
Swapping the CIA's is a nice easy check just to rule it out as they are identical chips and swapping them should result in no change in behaviour. If you get a significant change after swapping them around you know one of them needs replacement.
 
The other guys have given you some good advice there on checking the voltages - just borrow or buy a cheap multimeter, you will probably get one on ebay for £5 to £10 and the benefit is you can use it to check fuses around the house when things fail, or check voltages on batteries, test bulbs etc etc - everyone should learn to use one for those basic uses.
 
The hybrid as mentioned by one of the other chaps is the black ceramic package that is connected to the board at a slanted angle, just behind Denise and before the RGB socket. They seldom fail but they have rarely been known to fail, normally caused when connecting the modulator or monitor connection whilst the Amiga is powered up - but it is very rare tbh - i've accidentally wiggled the modulator around many many times and never damaged one. CIA's go for the same reason, disconnecting and connecting things whilst its on. I watched a great video recently by one of the head engineers from Commodore and he explained why that occurs - something to do with differing ground levels.
 
Start with the simple stuff, checking things are firmly in sockets, remove RAM expansion, check PSU voltages, try it without keyboard connected - does it boot and not crash then etc. Hopefully its something simple like the power supply, you could at least then get one off EBAY or something for £5 to £10 probably.
 
EDIT: When you want to check the voltages on that power connector, be careful not to short the pins on each other with the probes or you could damage the power supply.

[mrknight]

I watched a great video recently by one of the head engineers from Commodore and he explained why that occurs - something to do with differing ground levels.

Sorry for going a bit off topic here, but is this video available online? And if so, do you have a link? It sounds very interesting and I'd like to learn more:)

[Laughy]

Thanks all, suggestions taken on board. I will try swapping the CIA chips in daylight, I don't want to damage my computer! Have taken out RAM expansion. No change as yet.
Will also get hold of multimeter asap. As soon as have done chip swapping, will get back to you..

[Laughy]

Have swapped the CIA chips, that was a bit nerve wracking! Especially as one of them was really hard to get out. It all popped up in one go really quickly, and all the pins on one side were still in the socket, and got bent!!

Straightened them out, turned on. No picture through the modulator, so went back to the mono output. Get the white usual hand and disk screen. Tried loading a game, drive the same, makes two turns with the disk, then stops. Difference now seems to be that the power light doesn't dim!

There is something showing on the screen, it turns blue as the disk stops, and then, goes to what could be a white screen with something small being displayed. It is unstable at this point, diagonally flickering..

RAM is out too.

What should I try next? Getting the multimeter and checking power to RGB socket?

[GadgetUK]

Have swapped the CIA chips, that was a bit nerve wracking! Especially as one of them was really hard to get out. It all popped up in one go really quickly, and all the pins on one side were still in the socket, and got bent!!

Straightened them out, turned on. No picture through the modulator, so went back to the mono output. Get the white usual hand and disk screen. Tried loading a game, drive the same, makes two turns with the disk, then stops. Difference now seems to be that the power light doesn't dim!

There is something showing on the screen, it turns blue as the disk stops, and then, goes to what could be a white screen with something small being displayed. It is unstable at this point, diagonally flickering..

RAM is out too.

What should I try next? Getting the multimeter and checking power to RGB socket?

You could try cleaning the drive heads first.  Use a cotton bud with alchohol and rub the heads lightly, just to rule floppy drive out.  Then check power using multimeter, and if that doesnt reveal anything you are looking at a faulty chip probably.  Sounds like you can rule the CIA chips out, my next guess would be the RAM, which is soldered on board and hard to remove if you dont have experience.   Have you pressed the Agnus chip down to make sure its firmly socketed?

Edit: Ignore comment about RAM for now, its probably not that - I was forgetting that your modulator isnt outputting.

[gertsy]

It could be a dozen things.  Load Workbench first (if you have it) and then insert the disks they could come up as bad and that might be normal depending on the disk. But at least you should get an error of some type.

[Laughy]

The pinout of the PSU can be found here:
http://www.hardwarebook.info/Amiga_500/600/1200_Power_Supply

And for a photo:
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/body_amiga_power_supplies.html

When using a multimeter, hold the common ground probe of the meter (usually black) to pin 2 - common ground. Then use the other lead (usually red) and hold on the voltage pins (1, 3 and 5) one at a time. You need both probes to touch one pin each to get a reading. Sorry for sounding too informative but I do not know how much electric/electronic skills you have.

Maybe that you can borrow a multimeter from can help you to check? Ask for help but stay with that person during the test and see what he/she does. And ask questions. Learn. And then get your own multimeter. For just checking basic voltages you do not need an advanced one. I paid ~AU$20 (~GBP14) for the one I have. And it's a decent one to to basic stuff.

Good luck!

Thanks mrknight,

Got myself a multimeter, think you are right it is a PSU problem. Tried black lead on pin 2, and put red lead on pin 1,3 and 5. Nothing at all showing. So tried black lead on pin 4, signal ground (going by the diagram). Results:
Pin 1, 10.9v
Pin 3, 26.2v
Pin 5, 0.0v

Pretty scary! Does this explain why modulator not working, does it mean that there is no 5v supply going into the computer?

Would getting a new PSU solve all my problems?

[Laughy]

It could be a dozen things.  Load Workbench first (if you have it) and then insert the disks they could come up as bad and that might be normal depending on the disk. But at least you should get an error of some type.

Put in workbench disk, it does load for quite a while, can't remember if this is normal. When it eventually stops, there is something showing on the screen, but the picture is so bad can't see if it is anything, or just more static!

[Laughy]

You could try cleaning the drive heads first.  Use a cotton bud with alchohol and rub the heads lightly, just to rule floppy drive out.  Then check power using multimeter, and if that doesnt reveal anything you are looking at a faulty chip probably.  Sounds like you can rule the CIA chips out, my next guess would be the RAM, which is soldered on board and hard to remove if you dont have experience.   Have you pressed the Agnus chip down to make sure its firmly socketed?

Edit: Ignore comment about RAM for now, its probably not that - I was forgetting that your modulator isnt outputting.

Have cleaned the heads on the drive as best as I could, I reckon you are right, and that it is a PSU problem, tested outputs. Don't think they are what they should be!
Pressed the Agnus chip, it was fine. If it is as simple as the PSU not working, problem may be solved, just have to look on ebay!