Amiga 1200 Whistling & Boot issue

[Lorfarius]

Here's an odd problem now and again when I switch my Amiga off it makes a weird humming/whistling sound for a second or two. At first I thought it was the disk drive but it does it whether theres a disk in or not.

To top it off I hadn't switched the system on for about a week (mainly due to Final Fantasy 13 taking up all my time!) and when I did get round to switching it on...nothing happened. The screen remained blank and the green light came on but no disk or HD check just a plain black screen. Reset it a few times and it fired up just fine thankfully but this has happened a few times never to the extent that it needed several restarts though Any ideas?

[Photon]

Could you try a PSU with more Wattage? Like a heavy brick A500 PSU rather than the A1200 white one. If your PSU is good, then measure the voltages (f.ex. on the floppy power connector).

If the whistling had come out of the speakers I'd suspected bad capacitors on the sound, but from your description something in the Amiga makes this sound? Zetr0 will know if there's something in there that can squeak (I can't think of anything...)

In the meantime, can you give us the complete setup? Just a bog standard A1200HD with nothing else?

Maybe bad grounding could give something like this, but I've never experienced that.

[Lorfarius]

Only have the one power supply and no means of testing voltage I have a standard A1200 with a CF card HD. The sound comes from the right hand side of the machine though and well away from where I keep the power supply.

[Photon]

Well, the only mechanical thing (something that can even make a sound!) I can think of is the floppy drive. Have you tried carfully pulling out the cables to it? When you do that, it will probably take 40 seconds longer to boot, but that's normal. That's how long the OS keeps looking for the missing drive before giving up

[Lorfarius]

Will give it a try over the weekend. Just turned it on and it booted fine but when I listened closely at shutdown it's more like something spinning to a halt making the whistling noise. It's def coming from around the FD.

[stefcep2]

disconnect the floppy data and power cables and listen again. No sound=floppy drive problem.

Originally Posted by Lorfarius

Will give it a try over the weekend. Just turned it on and it booted fine but when I listened closely at shutdown it's more like something spinning to a halt making the whistling noise. It's def coming from around the FD.

Only things i can think of is if you have an acellerator or memory card in there too or perhaps there's something stuck in the Floppy drive. Could be a spring from the metal frame that covers a floppy disk is stuck or worst case, that the metal frame has buggered your floppy drives heads.

Again not too sure but may be still worth checking. Zetr0 is defo the man to ask about your problem if there is nothing obvious.

[Loedown]

When some equipment is switched off, anything that has an oscillator, whether it be crystals, resonators or RC component networks, as power is removed, the capacitors slowly discharge through the circuitry and in the case of oscillators, they can 'whine down' for want of a better expression. Wire wound coils can also exhibit the same sort of phenominon, but this occurs when the windings come away from the ferrite former, the solution is simple, find the coil and put a generous amount of Araldite around it.

Obviously this problem has only just started and I would think that it is the start of a more serious problem, in which time that it manifests itself properly, write back and we'll solve it from there.

Paul

[Lorfarius]

Will do guys. I will add that besides the odd power on problem (which hasn't come back since I posted here) the FD and HD work just fine.

[Photon]

Well, the FD could work fine and still give a whistle when power goes off - otherwise the problem would have been quite obvious.

Coils and oscillators are electromechanical devices, but I didn't want to confuse you with them because I couldn't think of any that were on the right hand side.

Nothing but electromechanical components/devices can give a sound, when sound is not connected to the monitor/speakers.

Power-on problem could point to either bad grounding, bad voltages, or a bad floppy drive could possibly drain the 5V. If you have no means of connecting the Amiga to a grounded outlet or check the voltages, then please disconnect the floppy so we can start eliminating fault-sources

[Loedown]

Originally Posted by Photon

Well, the FD could work fine and still give a whistle when power goes off - otherwise the problem would have been quite obvious.

Coils and oscillators are electromechanical devices, but I didn't want to confuse you with them because I couldn't think of any that were on the right hand side.

Drive coils for the FDD

[Lorfarius]

Thanks for the help and suggestions just wanted to say I haven't forgotten about this! Weirdly since I created the thread the issue hasn't returned!

[fitzsteve]

Originally Posted by Lorfarius

Thanks for the help and suggestions just wanted to say I haven't forgotten about this! Weirdly since I created the thread the issue hasn't returned!

I think your A1200 was feeling neglected