Amiga600 Floppy led keeps lighting up?

[brostenen]

Hi...
I have a slight issue with the floppy led on my A600. For some reason, the light has started to be active continiusly. Even though there are no floppy disk in the internal drive. The issue is the same, if I have an external drive connected or not, or if that external drive is turned on or off.

The issue is present whenever it starts to load the workbench.

My 600 is not stock, as the only upgrade that have been made, are an kickstart upgrade from 37.300 to 37.350 and I have a CF adaptor with a Transcent 512mb card. Partitioned at 2x256mb partitions and WB 2.10 installed.

The machine is working as it should, only that the drive led is constantly active. And I have absolutely no idea on to what I should look for. Any suggestions?

Cheers

[Oldsmobile_Mike]

Short in the wires? Check the ones running to the LED, also disconnect the floppy completely from the motherboard - does it still happen then?

[mechy]

Hi...
I have a slight issue with the floppy led on my A600. For some reason, the light has started to be active continiusly. Even though there are no floppy disk in the internal drive. The issue is the same, if I have an external drive connected or not, or if that external drive is turned on or off.

The issue is present whenever it starts to load the workbench.

My 600 is not stock, as the only upgrade that have been made, are an kickstart upgrade from 37.300 to 37.350 and I have a CF adaptor with a Transcent 512mb card. Partitioned at 2x256mb partitions and WB 2.10 installed.

The machine is working as it should, only that the drive led is constantly active. And I have absolutely no idea on to what I should look for. Any suggestions?

Cheers

dirty switches on the disk drive could be causing it.

[brostenen]

Yes. None of the suggestions seem to resolve the issue.
The wires to the led looks ok. Nothing suspicious.

[Oldsmobile_Mike]

So what you're saying is, even with the floppy drive and floppy drive cable completely disconnected from the motherboard, the floppy LED still lights up and stays lit?

Edit - I have a vague recollection that some CF adapters "trigger" the floppy LED as a way of indicating activity on the CF card.  I only have a very vague idea that this is possible with some of them.  Could it be a possibility with yours?  Did the issue start the same time as you installed the CF adapter?

[brostenen]

Ahhh... I have only had the drive disconnected from both of the cables. I guess I was too lazy to remove screws. Will try again.

The issue has arrived a couple of hours, after I tried an SD card adaptor, instead of the CF adaptor. I have had the machine for a recap, and when I got it home, I installed the 37.350 rom instead of the 37.300 that was in the machine.

I have had the original installed back, just to test if that was the cause of the issue as well. Hmmmm.... Should the led issue be anything to worry about, in terms of the machine failing completely if not fixed?

[magnetic]

I would bet your board needs to be recapped.

[brostenen]

I would bet your board needs to be recapped.

That's the thing... I just got a recap. :-)

[Castellen]

The machine is working as it should, only that the drive led is constantly active. And I have absolutely no idea on to what I should look for. Any suggestions?

The floppy drive LED is driven from the MTR0 signal, the same signal that tells the drive motor to switch on.  Meaning that while the line is low to activate the motor on the internal drive, the LED turns on as well.

So the question is that when the floppy drive LED is on, then is the internal drive motor on as well?  It's very quiet and you may have to put your ear directly on the A600 to hear it.

If the drive motor is turning on and off as it should but the LED remains on, then look at the LED driver circuit.  Which is simply a PNP transistor, Q632.  The circuit is configured so when MTR0 is low, drawing current from Q632 base, it causes the transistor to conduct 5V to drive the LED.

If the transistor has been damaged, it'll usually fail short circuit, which could explain the LED being permanently on.

In which case the solution is to replace Q632.  The original device is a 2N3906 or MMBT3906.  I don't have one in front of me, but it's probably a SOT-23 package.  i.e. the slightly larger surface mount type, not the smaller SOT-323.  Any other general purpose PNP transistor in the same package will be fine as well, e.g. BC857. They're easy to source and cost a few cents each.

[brostenen]

I have had it dismanteled now, and had it running without the following stuff:

 - Keyboard.
 - All data cables.
 - Floppy power cable.

And the led pcb removed from the upper case and connected to the header.

When powering on, the floppy led is still active, yet it still powers off for a brief moment. And then it comes on again. No activity is aprox a split second, while active is some 10 or 20 seconds a time. (I have not taken any time how long it stays on). This cycles all time, untill I power off the entire machine.... So far so good... It is like normal operation, just in reverse, if anyone can follow me.

Now for the drive motor.
There are no motor sound, only drive click. When I push down the right pin out of the two pins found on the left side inside the drive (pin number two from left, inside the drive), the motor spins up and the issue does not go away. So... As I am a total noob on electronics, I think it might be a resistor that are dead. Yet as I have no real experience, this is only a vague guess from my side. As it seems like the most logic explanation.

What resistor to measure, and what rating it need to be, I have no clue on.


EDIT:
New issue have turned up. The bluish "film" on the RGB output have returned. (the issue it was recapped for)
Yet as the bluish color have returned, the floppy led issue have resolved it self for some odd reason.
Now I really need to get that internal scandoubler, as I can live with bad signal from the RGB output.
The Floppy led issue might return after some time. I don't know... :-(

[Castellen]

New issue have turned up. The bluish "film" on the RGB output have returned. (the issue it was recapped for)
Yet as the bluish color have returned, the floppy led issue have resolved it self for some odd reason.
Now I really need to get that internal scandoubler, as I can live with bad signal from the RGB output.
The Floppy led issue might return after some time. I don't know... :-(

Since the floppy drive LED is working intermittently, then it's not a problem with short circuit Q632. Though if it has been exposed to leaking capacitor electrolyte in the past, then it can cause unusual things to happen.  If the area around Q632 has been visibly corroded (solder joints not shiny and silver) then I'd suggest replacing Q632 anyway.  Very unlikely to be a resistor problem.

Failing that, you'll need to take some measurements while it's in a faulty state in order to work out where the problem is.


As for the (intermittent) discoloured RGB video, the most common cause of this is damaged transistors Q321, Q232, Q233 which are the RGB signal output drivers.  Usually as a result of leaked capacitors.  I'd suggest replacing all three transistors.  They're NPN devices, so different from Q632 driving the floppy LED.  Originals are 2N3904, but I expect the likes of a BC847 would be a drop-in replacement.

If that's outside of your abilities, contact me for a repair estimate.

[brostenen]

Since the floppy drive LED is working intermittently, then it's not a problem with short circuit Q632. Though if it has been exposed to leaking capacitor electrolyte in the past, then it can cause unusual things to happen.  If the area around Q632 has been visibly corroded (solder joints not shiny and silver) then I'd suggest replacing Q632 anyway.  Very unlikely to be a resistor problem.

Failing that, you'll need to take some measurements while it's in a faulty state in order to work out where the problem is.


As for the (intermittent) discoloured RGB video, the most common cause of this is damaged transistors Q321, Q232, Q233 which are the RGB signal output drivers.  Usually as a result of leaked capacitors.  I'd suggest replacing all three transistors.  They're NPN devices, so different from Q632 driving the floppy LED.  Originals are 2N3904, but I expect the likes of a BC847 would be a drop-in replacement.

If that's outside of your abilities, contact me for a repair estimate.

Sounds like my 600 will require too much money to restore again. So I might resell it at a low price, as a machine to fix up. You know... A do it yourself. What will perhaps be a reasonable price to sell it for? It is after all in need of a serious overhall, if all these things need to be fixed.

Update...
Found a working board online, bought though not recieved yet. Looking forward to recieve that board and get my 600 working again. Thanks to all who gave me tips and input.