A500 disk drive stopped!

[GadgetUK]

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:)

I can't remember but I think it was this one:-
 
https://www.youtube.com/watch?v=DXRvCnmLj7A
 
Look at his channel after you've watched that, he's got several more videos including another 2 or 3 related to that retro repair event.
 
I think he might have been specifically refering to CIA's in the 64 and 128, but I know the CIA's go for the same reason in Amigas.  The number of CIA's i've replaced far outweighs any other component, although these days it seems to be RAM - all that DRAM in older machines is finally giving up the ghost it seems.

[GadgetUK]

Incidentally, here's are the schematics for your revision PCB:-
 
http://amigarealm.whdownload.com/archives/Amiga%20Schematics%20and%20Manuals/A500_R6a_7.zip
 
It might seem confusing to start with but there's a lot you can learn by looking that these - like how each chip connects to the next chip etc, and since you've got a multimeter now you could put it on resistance and check some of the resistors - the values are on the diagram.  NOTE: You sometimes don't get an accurate measurement of resistance whilst measuring a resistor in circuit, so you occasionally have to desolder one end in order to measure it properly.
 
If you take a look at the page with Denise on you can see the _CSYNC input into Denise, and if you look at the Agnus page you can see _CSYNC as an output.  I personally suspect something wrong with either Denise or Agnus, but it might not be the chips themselves, it could be supporting resistors, or capacitors etc.  Anyway, don't bog yourself down with this stuff too much just yet, read 3 or so posts back and see my summary of where we are - try and reply to those questions if you get time.

[mrknight]

I can't remember but I think it was this one:-
 
https://www.youtube.com/watch?v=DXRvCnmLj7A
 
Look at his channel after you've watched that, he's got several more videos including another 2 or 3 related to that retro repair event.

Thank you! I have added the video to my 'watch later' section.

Laughy, when using a multimeter you should set the measuring range closer to the level you want to measure to increase accuracy. You are measuring a 12V level using a range of 200V. You can easily set your multimeter to 20V.

[Laughy]

Laughy, when using a multimeter you should set the measuring range closer to the level you want to measure to increase accuracy. You are measuring a 12V level using a range of 200V. You can easily set your multimeter to 20V.

Thanks mrknight! I did wonder what the numbers referred to exactly, but no explanation in the instructions at all! I set it to 20v and tested the power supply. It read 12v, -12v, and 5v. So it seems to be fine!

I'll hopefully be able to go through a lot of the tests that GadgetUK has mentioned, later on today

[Laughy]

Sorry for delay, didn't get to test Amiga on another TV as hoped. Have gone through the tests from GadgetUK with the TV I've got, for now until I get to another TV, hopefully this weekend..

Here is a photo of the kickstart screen in mono...
[ATTACH]2833[/ATTACH]

Picture has interference, which I hoped was due to TV not being tuned in properly. I have cleaned the remote controller, and got it working. It doesn't seem to have more functions than the buttons on side of TV, like I had hoped! Seems that it can't be more finely tuned.

Results of tests so far..

1. Haven't been able to verify if modulator working or not yet.

One good thing though! Found a friend who still has his old Amiga500!! But has lost the modulator, I'm going to see him on friday, taking my Amiga. At the very least to see if my modulator works on his Amiga, unfortunately he has no compatible TV.

3 Games the drive crashes on:

Nitro. After a few seconds, drive stops with both power and drive light on, no flashing. No signal going to TV.

Project X. Drive turns once, stops, lights on, no flashing. Drive makes one click, then 'bad disk' noise of continual clicking.

Turrican 2. Two clicks, one turn. Stops, lights on but not dim.

Workbench. Loads much more than other disks, lots of turning and clicking, sounds good. Loads for about 2 minutes, stops, drive light not on. No signal to TV.

No loading screens at all on any games tested.

Kickstart image is up, as photo shows. After 20mins, still up, computer doesn't spontaneously crash.

Drive makes it's normal, rhythmic clicking sound.


I will carry out all tests again on a different TV. Hopefully this weekend, if the modulator has not stopped working!!

[GadgetUK]

Sorry for delay, didn't get to test Amiga on another TV as hoped. Have gone through the tests from GadgetUK with the TV I've got, for now until I get to another TV, hopefully this weekend..

Here is a photo of the kickstart screen in mono...
[ATTACH]2833[/ATTACH]

Picture has interference, which I hoped was due to TV not being tuned in properly. I have cleaned the remote controller, and got it working. It doesn't seem to have more functions than the buttons on side of TV, like I had hoped! Seems that it can't be more finely tuned.

Results of tests so far..

1. Haven't been able to verify if modulator working or not yet.

One good thing though! Found a friend who still has his old Amiga500!! But has lost the modulator, I'm going to see him on friday, taking my Amiga. At the very least to see if my modulator works on his Amiga, unfortunately he has no compatible TV.

3 Games the drive crashes on:

Nitro. After a few seconds, drive stops with both power and drive light on, no flashing. No signal going to TV.

Project X. Drive turns once, stops, lights on, no flashing. Drive makes one click, then 'bad disk' noise of continual clicking.

Turrican 2. Two clicks, one turn. Stops, lights on but not dim.

Workbench. Loads much more than other disks, lots of turning and clicking, sounds good. Loads for about 2 minutes, stops, drive light not on. No signal to TV.

No loading screens at all on any games tested.

Kickstart image is up, as photo shows. After 20mins, still up, computer doesn't spontaneously crash.

Drive makes it's normal, rhythmic clicking sound.


I will carry out all tests again on a different TV. Hopefully this weekend, if the modulator has not stopped working!!

That is more than a bit of noise, that picture is well out.  Just to confirm you are connecting from mono composite out to a composite in on the TV and you arent plugging it inti a uhf / rf socket?  Composite is not 'tuned in' it just connects and you select the composite / av in/ aux on the tv and thats it.

[GadgetUK]

I cant help but wonder if all thats wrong is the FDD and all these video issues are your TV.  If it doesnt work on another TV its probably Agnus, that said the reason I think there might not be fault with a chip on the Amiga is I would expect the power light to flash on a crash when it dumps to the guru screen.  The behaviour looks like a disk drive read problem and its possible the display problems are the TV.

You really need to prove one way or another on a different TV.

[Laughy]

Sure, just checked, I've got the cable going from mono out on the Amiga into the ANT IN on the TV. It's the only socket it will fit into.

Tried to select AV input on the TV menu, but says 'no signal' when I try that.

Does this sound like an issue with the sync from Agnus to Denise?

[GadgetUK]

Just to expand on my comment above about where you are connecting composite out of the Amiga...

Typically composite connector is yellow in colour.  If you are connecting to a modern TV dont make the mistake of plugging into one of the 3 composite red, green or blue sockets - they are marked composite so you could do it by mistake.  Ive got no idea what the picture would look like if you did that.  You also should use a composite lead to connect - not the RF lead that you use with the modulator - the noise makes me think you are using that lead possibly??? It wont connect properly and leave the signal or ground floating.

[Laughy]

Thanks, your message came through while I was checking!

I will try it on the TV I first tested it on as soon as I can. If it does work, and turns out that this TV is the problem, do you think It's worth getting the RGB to SCART cable, and hoping it will work with that?

I ask because, I had a quick chat initially with someone at Amigakit, who told me they use the same TV for testing, and it would be ok.

I will probably need to get a new FDD in any case by the sound of it..

[GadgetUK]

I cant help but wonder if all thats wrong is the FDD and all these video issues are your TV.  If it doesnt work on another TV its probably Agnus, that said the reason I think there might not be fault with a chip on the Amiga is I would expect the power light to flash on a crash when it dumps to the guru screen.  The behaviour looks like a disk drive read problem and its possible the display problems are the TV.

You really need to prove one way or another on a different TV.

Sure, just checked, I've got the cable going from mono out on the Amiga into the ANT IN on the TV. It's the only socket it will fit into.

Tried to select AV input on the TV menu, but says 'no signal' when I try that.

Does this sound like an issue with the sync from Agnus to Denise?

OK, progress.  See my last post.  You are connecting composite mono to the RF in on the TV.  That won't work.

Next step is to either retry modulator with that same socket on TV and make sure you scan through each channel as you try to program the channel.  If you cannot do that, just order a scart cable from ebay for the a500, but make sure your TV does have a free scart socket.

I think theres nothing wrong here other than dirty heads, and possibly not even that...

Edit: how did you test with modulator to start with?  I am suspecting you just changed channels and didnt actually 'tune a channel' whilst amiga was connected and powered up?  Sorry if its a stupid question but ive got to ask.  Worst case is perhaps your TV doesnt like the modulator signal or it wasnt all connected up properly when you tuned a channel in.

[Laughy]

Just to expand on my comment above about where you are connecting composite out of the Amiga...

Typically composite connector is yellow in colour.  If you are connecting to a modern TV dont make the mistake of plugging into one of the 3 composite red, green or blue sockets - they are marked composite so you could do it by mistake.  Ive got no idea what the picture would look like if you did that.  You also should use a composite lead to connect - not the RF lead that you use with the modulator - the noise makes me think you are using that lead possibly??? It wont connect properly and leave the signal or ground floating.

Right, yes! Luckily I found I did have the Yellow, white and red composite cable lying around. I just tested it while trying with the usual aerial cable.

Took that out as you said, and put the hello cable into the video out on the modulator, and into AV in on the TV. Kickstart screen is perfect!!

Sorry for the mucking around, I had no idea the old RF cable wouldn't work as it was fine on the TV I tested it on first. Is that due to the TV's age?

[Laughy]

Just for your enjoyment! Again, I apologise for all that...


[ATTACH]2834[/ATTACH]


I have tried to clean the FDD, but now perhaps I should take it apart properly and clean the heads?

[GadgetUK]

See above.  Ive dropped u an email as well just to say also check when tuning TV into modulator that you arent looking for a digital signal - TV needs to look for an analogue signal.

[Laughy]

Edit: how did you test with modulator to start with? I am suspecting you just changed channels and didnt actually 'tune a channel' whilst amiga was connected and powered up? Sorry if its a stupid question but ive got to ask. Worst case is perhaps your TV doesnt like the modulator signal or it wasnt all connected up properly when you tuned a channel in.


Yes, that was my initial problem with the TV. I had no way of scanning for a signal to tune it in, I thought the remote would have more options than the controls on the TV itself. Now that I have fixed the remote, I found out that there is no difference!

There doesn't seem to be any option to scan frequencies with this TV. I have plugged a DVD player in, and it just finds it. However, on the TV I tested the Amiga on, which is about the same age, I had to scan and tune the signal in.

I haven't had to do anything and it's fine!

In fact I have just loaded up Workbench, and that is fine too! Can't believe it!

Perhaps the game disks I have been trying have just become dirty?

[GadgetUK]

Woohoo!  Progress!!

Yes, take FDD out. Then take lid off the drive (you dont need to take any other parts off). Some drive lids held on with 1,2 or maybe 3 ver small screws, but some amiga drive lids are taped at the sides, if its one if those just peal that tape / silver foil off and youre in.

Use a damp cotton bud with alchohol and gently rub the heads from side to side around 10 times each.  The bottom head is easy, top one usually tricker - dont bend it upwards, just lift it gently until you get cotton bud onto it.

Also clean any hair or dust out of the assembly while u are there.

If it was taped at the sides u can replace with selotape.