Problem booting A600

[Philski]

Hey all! (VERY) Long time, no post.

I’m looking for a little advice...

Got my A600 board back from being recapped and PCMCIA being replaced last week. After putting it back together I turned it on and all I got was a flickering/rolling, black screen and buzzing coming through the speakers. 🙈

I’ve tried removing the shielding from the bottom and powering the board with only the ROMs (which are on a switcher) connected.

The flickering seems to no longer be happening, but the screen is blank and the buzzing is still happening.

Any thoughts on what the problem could be and if the board can be salvaged?

All the best

Phil

[paul1981]

You didn't forget the insulation layer on the shielding then? It certainly sounds like a short and it's easily done. If it has shorted then who knows what has happened.
Where did you send your Amiga? Was the box damaged or motherboard poorly packaged in the post? Did you connect anything else to it upon first test besides the floppy drive? The bracked of the floppy can short out too if it's not correctly screwed in place.

It sounds like I'm assuming you have shorted it out...honestly I'm not! But it is easy to make these mistakes! Even plugging a mouse in can short something out if you're not careful.

[Darin]

A few things to try. 
- Try reseating the ROMs and ROM switcher.
- Check all the solder points on the caps and PCMCIA to make sure there are no shorts and everything is secure. 
- Try using a set of ROMs without the switcher
- Make a close inspection of the board and chips to make sure nothing got jarred loose during shipping.
- Check to see if there are any popped resistors or caps.  In case there was a short during initial power on.
- See (or more appropriately, listen) to see if you can determine where the buzzing is coming from.
- Get a set of diag ROMs to see if that will report where the issue is.
- If you have a logic probe or oscilloscope, you can check to see if the CPU is getting timing signals.
- If you have a multimeter you can check Vcc points to see if there are voltages where there needs to be.

[paul1981]

Another thing to check is the power connector socket. Apply a slight force in each direction to see if makes a difference (you'll need to power on each time of course) and inspect it closely with a magnifier for dry joints. I've had that problem before.

[beller]

I can vouch for the problems caused by a bad power port on the A600.   Mine was not supplying enough power and the machine was responding with bad Kickstart and memory errors.  Hard to chase down until I started moving the supply cable around and it booted.  Mine is being shipped off to repairs tomorrow...