A4k won't start up

[doctorq]

Hi all,

at the moment I'm trying to get one of my broken A4ks to work again. The problem is as follows.

When I start the A4k up, then all I get is a green screen. According to various internet sites, and some people whom I have asked, I now know the green screen means chip mem failure. I have nicked the chip mem (the fast mem as well) from a working A4k system, but still I get the green screen.

I have tried attaching a keyboard to the system, and tried to reset the computer. The computer resets by itself after a little while, but the outcome is still the same; the green screen. I know the computer resets, becuase a hdd is also attached and the hdd led blinks for a moment, as always during a reboot.

Just to set everything straight; what's attached is a 2 MB ram module for chip mem, 4 x 4 mb ram modules for fast mem, Warp Engine 040 (yes, I have both jumpers set to EXT), daughter board with no cards in it, 1 x floppy, 1 x hdd.

Is there any place else I can look for errors? On various chips for instance? Any help will be highly appriciated.

[doctorq]

Well, can't anyone help me? Please, it's so sad with those A4k :-(

[Castellen]

Could be quite a number of things.  The green screen indicates a failed chipmem test, but things not related to the chipmem can cause that test to fail.

But for a start, simple things you could try is to clean the chip mem SIMM slot with isopropyl alchohol and an old toothbrush.  The same for the edge connector on the memory module.

Check for bad solder coints on the RAM address decoder (bridgette) or just try replacing it.

Fit a known good CPU board, or try your exsisting board in another machine.
If you have a spare A3630, fit that for testing (clock jumpers need to be on internal position).


Other devices which directly share the chipmem address bus such as Paula, or the video section could be at fault.

Check for RTC battery corrosion and repair it accordingly.

Use an oscilloscope to check the +5V supply is stable.


That's the first things I'd check anyway....

[HotRod]

The only time that I've seen the green colour for a longer time is when I've been tired and done some hw-things for my A4000D and forgot to add the CPU-card before turning the power on :-o . So maybe you shall take a look at your CPU-card.

People may say what they want about the Amiga but they're built to last :-D

[voxel]

Well,

If you're sure the simms you used are good, then it can be : ramsey, agnus - sorry alice ;-) - or some of the 74245 in the memory area, how is the battery looking? has it leaked on the mobo?

Be sure that ramsey is well seated and in the right position, try to replace it, look at the solders on alice, try to boot with both mouse button pressed right from power on, tell me what happens.

remove all fast ram, let the chip simm only, for testing you don't need more.

If you get green screen ever, then alice or the 74245 must be replaced, if it's a battery damage, the mobo needs to be reconstructed. Ask a repair shop near you or Amiga.fr.

[PhatBoiCollier]

As an initial quick try, I would try gently pressing on all your socketed chips and the daughter cards.  It only takes a little "chip creap" to loose good contact.

Best of luck.

[doctorq]

Well, I have just tried to boot it up once again, after pressing on all the chips. Still only the green screen. I have also tried holding down both mousebuttons, but nothing happens.

I don't have the right tools to measure voltage and so on, so I'm kinda stuck at the moment. I guess I better send them to Amiga.fr when I have the money for it. What do you think is the average price to get a mobo reconstructed?

[AmiDelf]

You should try another CPU board. If you hold your two mouse buttons when turning on? You get into Early Startup?

What sort of CPU card do you have?

Hope this helps,...

Regards,
Michal, www.amigaworld.org

[doctorq]

I have tried holding both mousebuttons down when I turn on the computer, but it still only gives me the green screen :-(

I have tried with an orignal 030 cpu card, a WarpEngine 040 card and with a CyberStormPPC 233&060 card. All with the same result.