Another A500...another problem...

[Gavilan]

Hi People: i have managed to get a very good (at least aestethic) A500, revision 5.
Problem is, i power it on...only to get a green screen, and the power switch keeps blinking...thats all i got.
I opened, reseated all the chips....no luck...
I noticed that when i powered off, i could hear the df0 spinning and stopping shortly after i powered off...
Any ideas, comments , suggestions in order to revive what it looks to be a dead A500??
Kind Regards

Sebastian
 :-?  :-?

[redrumloa]

If you already tried reseating all the chips and it is still doing
what you say, then it sounds like it could possibly be the kickstart
chip. I've seen a few do this and it was bad kickstart chips.

[Gavilan]

Hi Jim!! so you think the light green colour means faulty kickstart??

[redrumloa]

Hi Gavilan

No actually green color usually means chip ram. However you mentioned the power light flashing, in my experience that often means a faulty kickstart chip.

When you say you reseated all the chips, does this include Agnes? Do you get green only occasionally or everytime you turn on the computer?

Do you have any spare chips? i'd try swapping out the kickstart and Agnes for troubleshooting.

[Gavilan]

Well...actually after a deepest investigation i found the 8372A chip has a missing pin...damn...i guess thats why im getting a green screen every single time i switch on the computer, right?
Is it possible to fix this? Or will i have to buy another chip? Also, the socketed place where the chip goes sitted is missing the same pin too...so i guess somebody without much experience played with this poor A500...
Lucky me uh!

 :-o

[redrumloa]

hmm, you may be screwed. They removed the socket pin altogether? Which pin #? Maybe a PAL hack gone bad.

[Gavilan]

Well..i guess its pin 13...but..no..it wasnt removed on the socketed place..just it seemes like it bended and got broken....i have it here...almost laughing at me...It was removed from the Agnes itself, but i cant see it on the socketed place. It was like glued or someting, and when i did my deepest researching, it just went away.


Say..i have a complete useless mobo now? Could i try with another chip from some of my other A500´s??
 :-?

[Gavilan]

Jim i dont know how to put pictures here, but i have taken a pic (not the best quality tough), so that can enlighten you a little more...Could i send it to you?

[redrumloa]

Gavilan wrote:
Jim i dont know how to put pictures here, but i have taken a pic (not the best quality tough), so that can enlighten you a little more...Could i send it to you?

Sure.

amigaguy[AT]bellsouth[DOT]net

[Noster]

Hi

I found this in the Amiga Guru Book:

Start-up diagnostics:

Green - error in the lowest 256 kilobytes of Chip memory. This might also be caused by a defective CIA-A (memory overlay bit, for example) or Agnus chip


I have an A2K where also a pin of the Agnus-socket has been broken, I managed to bend a tiny wire and press it between the pin of the Agnus and the remaining rest of the broken pin in the socket... and it works :-D
I think the A2K should not be shocked to hard, but it works now for nearly half a year without any further problems.

Noster

[redrumloa]

From email:

If you see the pic, just imagine that you can read  the white printed
letters in front of you. So
it would read something like

                       C=CSG
                  318069-02
                      8372A
                       5091 23

             !!!!!!!! !!!!!!!!!!!!
the missing pin would be just below the number 5. Hope this gives you a
clue!

From a quick check it looks like what I suspected is correct. It looks like someone tried to do a PAL hack. read this.
HERE

Good info on the Agnes in A500.

Maybe they phsyically damaged the Agnes or the socket in the process. Does the A500 have a memory expansion in the belly slot? If not, from my experience, then even with this pin lifted it should still work and should still default to NTSC. My experience is limited to only rev 5.A(iirc).

I'd start off trying another Agnes.

Do you have an A501 in place?

[Noster]

Hi

@redrumloa
>From a quick check it looks like what I suspected is correct. It looks like someone tried to do a PAL hack

Yeah it looks so...

> ...it should still work and should still default to NTSC.

Yes, it should still work, but default to PAL !!!

@Gavilan

What do you have in Argentina ? PAL or NTSC ?
I would try to replace the CIA 8520. There should be two of them on the board, don't know which of them is the CIA-A and which is the CIA-B, but you've said you have more Amigas, so replace both of them and test which one is defect.
Maybe the error is a missing memory expansion and the A500 is reworked to 1MB chip and the Agnus is missing the second 512kB memory ?

Noster

[melott]

On my old A1000 W/RomSwitcher (before I sold it) I did a
clumbsy job of installing the 3.1 rom and broke a pin.

I soldered a stiff piece of copper wire on the little
stub left on the chip (and installed it correctly ;-))
I never had a probelm with it after that.

Its not easy but it can be done.

[Noster]

Hi

@melott

> I soldered a stiff piece of copper wire on the little stub left on the chip

In the case of Gavilan's A500 the socket is also damaged (as in my A2000) and there is absolutely no space for a soldering iron. If it needs to be repaired, the whole socket has to be desoldered and that is not a job for a hobbyist :-(

Noster

[redrumloa]

Yes, it should still work, but default to PAL !!!

Hehe actually I didn't clarify myself good enough;-)

*IF* there is a memory expansion in the belly slot, and *IF* there 1Meg chip ram hack was properly done, then it would defualt to PAL.

*IF* there is no memory expansion in the belly slot *OR* the 1Meg chip ram hack was not properly done it will still start up NTSC(from my experience).