Rebuilding my A3000: video doesn't work!

[McVenco]

I've just started rebuilding my A3000 after a few months of it being scattered in parts all over the attic, but I immediately bumped into a tiny problem that renders the computer completely useless: there no video output

The Amiga seems to boot just fine from both diskette and harddrive (vanilla WB3.1 install). The sound also works (booted from a game disk to test that) and the keyboard responds just fine to Ctrl-A-A and continuously pressing Caps Lock.

However, I get a NO SIGNAL message on a TFT screen, and a 1084 monitor displays a grey screen with vertically scrolling/flickering artifacts on the sides of the screen. The 1084 works just fine on my A1200, so that's not the problem.

So, what could this be? Broken Denise? Something else perhaps?

 

[Ed.D]

Hi McVenco,

Does the A3000 have a SONY RGB encoder? I got a scrambled picture on an A1200 board and it was the encoder at fault, everything else worked fine.

There's a screenshot in post #9 in the following thread:


https://www.amibay.com/showthread.php?t=38507

 

[roy_bates]

Hi McVenco,

Does the A3000 have a SONY RGB encoder? I got a scrambled picture on an A1200 board and it was the encoder at fault, everything else worked fine.

There's a screenshot in post #9 in the following thread:


https://www.amibay.com/showthread.php?t=38507

theres no cxa1145m in the 3000,but there may be a problem related to amber.

 

[McVenco]

there may be a problem related to amber.

Wouldn't that only affect the output on the VGA port? The standard RGB output hasn't got anything to do with Amber does it?


Anyway, I've just ruled out the Denise as a problem. I tested in in my A500 and works without problems. The 8362 OCS Denise from the A500 doesn't work in the A3000 either. Also, I have plugged in another keyboard, and now the artifacts on the side are gone . Still no picture though...

 

[McVenco]

I'll be darned. I've disconnected and reconnected everything three times, removed the mainboard from the case, tried again and hey presto, it works! Then I connected the harddrive and it didn't work anymore. I turned the machine off, unplugged everything and replugged everything (including the harddrive) and then it worked again!

I don't know what's wrong really, I think a bad/loose contact somewhere, though I don't really know where. Every chip, socket and connector seems pretty solid to me, the only thing that's a bit wobbly is the daughterboard.

I'll try to gently bend the pins from the daughterboard connecter to make it a bit tighter, but I'm glad that nothing's actually broken (or so it seems).

These old computers, eh? icard

 

[geminister]

You could try to clean the contacts with rubbing alcohol. It usually fixes problems like these.

 

[roy_bates]

I'll be darned. I've disconnected and reconnected everything three times, removed the mainboard from the case, tried again and hey presto, it works! Then I connected the harddrive and it didn't work anymore. I turned the machine off, unplugged everything and replugged everything (including the harddrive) and then it worked again!

I don't know what's wrong really, I think a bad/loose contact somewhere, though I don't really know where. Every chip, socket and connector seems pretty solid to me, the only thing that's a bit wobbly is the daughterboard.

I'll try to gently bend the pins from the daughterboard connecter to make it a bit tighter, but I'm glad that nothing's actually broken (or so it seems).

These old computers, eh? icard

the custom chips come loose sometimes when you insert cards into it or anythng really that involves pushing down on the motherboard.

my only suggestion is to reflow all the solder joints on connectors and ic sockets(as you know theres lots) as a precaution action.

because it may get to a state where just simply moving it makes it unstable with odd effects just like this.

 

[bdb]

Or it is just an Amiga acting up to show you who is in charge!