A1200 booting but nothing displayed?

[r_varlese]

Hi,
I feel its time to repair my poor old amiga.  When i boot-up the amiga nothing displays on the screen.  It responses to key functions (quick reboot with amiga keys) and I’ve tried both the RF and s-video out connections and still nothing, is it possible that both of these are dead? If so how easy is it to fix?

Cheers

Ross

[JimS]

Have you tried the RGB output? I've seen the encoder fail on the 1200, which would affect both RF and composite. As for fixing it, well, I didn't have much luck with the one I tried to repair.

[Homer]

My questions are:
1. It sounds like you have just pulled this out of storage. Had it failed this way before the storage ? Did you see when it failed this way ??
2. Do you have a lead to connect to the RGB port such as RGB to Scart ?
3. What sort of screen are you using ? Are you sure it works ?
Another idea, does anybody know if an A500 external rf modulator module works on the back of an A1200 ? If so it may give you another chance if the internal RF is fried.
Good luck :-)

[weirdami]

does anybody know if an A500 external rf modulator module works on the back of an A1200

That's an odd question I'm sure few people have asked and it makes me curious. The A1200 has a sort of built-in A520, so probably nobody bothered to try a real A520 on it. Hmmm... my first thought is that the A1200 monitor connector is different than the one on the A500 where the A520 plugs in. I'm not sure, though. I seem to remember the A1200 (mine at least) coming with a special adapter so you could connect pre-A1200 monitors.

Someone else would need to clarify or confirm these off-the cuff ideas, though.

[JimS]

The A520 does indeed work on the A1200. You just have to make sure the A520 matches the video format of the tv or composite monitor your using. Otherwise, you'll get a B&W picture.

[r_varlese]

Homer wrote:
3. What sort of screen are you using ? Are you sure it works ?
Another idea, does anybody know if an A500 external rf modulator module works on the back of an A1200 ? If so it may give you another chance if the internal RF is fried.
Good luck :-)

Im using just a normal PAL TV, which is fine on my A500 and A600.  I tried the A520 modulator and still no joy.

I don't own a RGB to Scart cable and couldn't find one that would fit in the back of the Amiga (23 Pin right?) - i did see the plans to make them, which is quite tempting.  Do you think its worth trying an RGB to VGA adaptor?

[Framiga]

"Im using just a normal PAL TV, which is fine on my A500 and A600. I tried the A520 modulator and still no joy."

mhhh . . so the external RF modulator works fine with your A500 and A600, right? but NOT with your A1200? right?

Try to start the A1200 with both mouse button pushed and see if the "EarlyStartup" screen is showed.

[r_varlese]

I’ve tried several things now, and the only thing that seems to be producing any results is when the A520 is plugged in as the TV is receiving a signal, although nothing to get excited about.

I tried the “EarlySartup” but nothing really seems to happen – apart from the floppy drive light is on continually.  I tried a cold start and the light is still on and I now have a completely white screen??

Gonna see if swapping the floppy drive has any effect as im slowly running out of ideas.

[r_varlese]

BUT before I do swap the floppy…

Heres what happens under the following circumstances:

Connected to built in RF
No signal on TV and floppy drive light on continually

Connected to A520 RF
Screen blank, flickers and floppy drive light on continually

Connected to Composite out
Blank screen, but actually sounds like its booting up correctly with the floppy light coming on to check for a disk and then off again.

I’ve tried loading a disk but the floppy drive refuses to access the disk. Not looking good really.
 :-?

[Framiga]

its very difficult to help without seeing anythings :-(

It could be a PSU fault . . . have you tryed to feed the A500 PSU to the A1200?

ATTENTION- never owned A1200 nor A500 but IIRC the A500 PSU is A1200 compliant. ASK BEFORE ;-)

[r_varlese]

Yup the PSU works, tried and tested with A500 and A600.  Ive swapped the floppy drive over with a known working one and still it refuses to read the disks. I'm goning to completely strip the A1200 to see if I can spot anything obivous. But first, some food and maybe a strong srink is require.  Thanks for you help guys.

[Homer]

Its still worth making that RGB to Scart cable up as the picture is much clearer on the TV than the RF output. Obviously I can't tell you if it will work in your case as I don't know how much damage has occurred to the motherboard, but its still worth a try.
Do you have anything else added on to the motherboard ? Its always a good idea to remove accelerators etc etc and see what happens then on power up. Let us know what you find :-)