Amiga 2000 doesn.t boot up, Black Screen

[amigaman2000]

Hi

I need your help guys. I have just received my new Amiga 2000 computer, standard one, revision 6 motherboard, one floppy, 2MB RAM on A2058 and a GVP SCSI card with a hard disk.

When connected I can ear one disk drive click, the power led is always on and the Caps Lock led keyboard isn´t blinking, and a black scrren on my TV, I connect it via an A520 video adapter in perfect working order.

I noticed a bit of battery lacking, so I remove the battery and clean the board with isopropylic alcohol.

I disconnect the hard disk card and the memory expansion and try again, no luck, same black screen.

So I tried every chip on my Amiga 500, 68000, ROM, Paula, Denise, Gary and CIAs, and all chips from my Amiga 2000 works perfectly on my Amiga 500. So What more can I do?

Thanks in advance

 

[r0jaws]

Have you tried hooking up the composite output to see if there is any picture at all?
Is there any damage around the leaked battery?
Are the caps looking Ok? Is the PSU sound?
I would leave all the expansions out while diagnosing at this time, just have the mobo and PSU at first until we get a result.
Have you removed and re-seated the Chips you mentioned, or did you replace them with spares?

 

[amigaman2000]

No picture via composite or A520, only a black screen.
Caps looks OK for me, PSU is fine too.

I only have the mobo, PSU and floppy at this tine.

I re-seated the chips at first place and replace then in second place.

Thanks for your help

 

[r0jaws]

Have you measured the output of the PSU? The 2000's is notoriously weak and usually the first point of major failure.

 

[rkauer]

How warm is the CPU? If stone cold or devilish hot the CPU chip is dead.

Otherwise try to move jumper J300 from 1-2 to 2-3, this will force the tick signal from PSU to Denise V-blank. A common problem as the tick signal generator fail rendering the computer dead as a dodo.

 

[amigaman2000]

Have you measured the output of the PSU? The 2000's is notoriously weak and usually the first point of major failure.

Yes, the output is 5.12 and 12.24.

How warm is the CPU? If stone cold or devilish hot the CPU chip is dead.

No, the CPU and all chips works perfectly in my Amiga 500.

Otherwise try to move jumper J300 from 1-2 to 2-3, this will force the tick signal from PSU to Denise V-blank. A common problem as the tick signal generator fail rendering the computer dead as a dodo.

Interesting, with the J300 in 2-3 the Amiga doesn´t startup either, but now instead of black screen I have a red-brown screen

I attach a photo of the Battery area.

 

[r0jaws]

superficially, that looks Ok.
I'm sure a red screen is a ROM issue. Which ROMs are you using?
Have you also tried re-seating the Agnus?

 

[amigaman2000]

superficially, that looks Ok.
I'm sure a red screen is a ROM issue. Which ROMs are you using?
Have you also tried re-seating the Agnus?

The ROM, 1.3, is OK because works perfectly on my Amiga 500.

I have re-seated Agnus with no luck, but this is the only chip that can´t test in my Amiga 500, I can´t pull out of It´s socket.

 

[r0jaws]

Hmmm, tricky. If the chips are all as good as you say they are, I would tend to be still suspicious of the PSU myself.
Either that or there maybe a problem with the CPU socket. The corrosive products of the battery could have damaged the socket where we are unable to see, a really thorough clean of that area might help.

 

[John58]

I would go with r0jaws on the probable problem being damage to the CPU socket from battery acid. This link to boot error code colours points to a black screen being a CPU problem.




These before and after pictures of my A1500 shows the nasty green stuff from the battery had got into the CPU socket, lucky for me it hadn’t done any damage.

If this was my 2000 I would remove the CPU and ROM then give the area around the battery and CPU socket a good soaking with distilled vinegar, or lemon juice, wash of the vinegar , when dry check the CPU socket near the battery with a continuity meter. The acid may have damaged one or more tracks.

My own A1500 had been working fine until yesterday. When I switch on now I get a red screen which goes out of sync after about a second.


John

 

[psodas]

@amigaman 2000

Please look at the picture.
In yellow mark. In the edge of cpu is this corrosion ? If yes maybe has run in under side and damage the pcb.
In red mark. I dont see very good, but can you check this pcb trace for continuity?

 

[rkauer]

Remove carefully the CPU from the socket (the chip itself may get one or more pins snapped because the corrosion may get into the pins), then you need to desolder the socket and check the traces under it.

A vast corrosion as this one normally affects both the traces under the CPU as well the ones under the ROM chip.

The yellow area is just a spot on the CPU, nothing to worry about.

 

[amigaman2000]

Hi

Thanks for your help, I agree with you the problem is the 68000 socket so I must desoldered it and check tracks.

Regards

 

[robin-elvin]

What happened? Did you fix it?

I'm looking forward to a happy outcome to this tale