Help: possibly destroyed my A1200

[Marco]

While attempting to replace the original 3.0 ROM chips in my 1200 with some 3.1 chips I got from ebay I may have done something to fry my 1200. After we finished installing the new chips we attempted to power up the Amiga but nothing happened, none of the lights for power, f.disk or h.disk lit up, there was no activity from either the floppy or HD, nothing. We followed the instructions that came with the ROM chips to the letter, I even got an anti-static wristband just in case.

At first we thought it was a problem with the power supply but I tried the PS from our old A500, didn't work, then I tried the 1200s PS with the 500 which immidiately worked. So obviously that is not the fault.

We did remove the stickers that were on the ROM chips (they were stickers with Eyetech written on them and had instructions on which ROM chip was which (u6A and u6B) but we removed the stickers after installing the chips so there's no chance we put them in the wrong way round.

The 1200 is otherwise completely stock, no other mods have been made before. Does anyone know what the cause of the problem might be, and is it something reperable or is the 1200 dead?

[amigakit]

Have you put the original 3.0 ROMs back in to check if the motherboard is still working: ROM 391523-01 (bottom/socket U6B) and ROM 391524-01 (top/socket U6A).

Be careful as the ROMs are shorter than the actual ROM socket so they should be put in correctly with the space at the left hand side looking front-on to the motherboard

The Kickstart 3.1 ROMs should have 391774-01 in the top socket (U6B) and 391773-01 in the bottom socket (U6A) with the space on the left looking once again straight on to the motherboard.

[amigagr]

here you can see how the roms must be on the motherboard. take care at the left side of the chips. the first pin on the socket must be left free.

-edit-
take a look here too: rom

[Marco]

Yes, I followed the instructions and made sure the notch in both was on the left (towards the PCMCIA slot) and that the contacts left free were also on the left. The ROMs themselves were also placed in u6A towards the bottom of the keyboard, u6B behind 'A'. I am too annoyed at this time to do any more, tommorow I'll try putting the 3.0 ROMs back in just to make sure. One thing that I did find odd - the ICs I got, they had a small, what looked like a 'window' in the centre, through which you could see the inner workings of some sort. Also they were manufactured by AMD, which I just thought was odd in and of itself.

I'll report back tommorow after trying the 3.0s. :-(

[_yak_]

If the chips have window, that means they are not normal ROM chips (which are "programmed" by the manufacturer) but EPROM chips which can be programed using special hardware programmers and a computer. Taking that into account, it's not strange that they were made by AMD. The window is used to erase the contents of the chip by using ultraviolet light. After that they can be reprogrammed using the hardware I've mentioned before.

[odin]

Heh..so Eyetech sold EPROMs as genuine Kickstart ROMs?

[Amiga4k]

EPROMS were the logical choice for future AmigaDOS chips. Remember, Commodore was dead, it's manufacturing mechanism gone. The rapid spin thru the holding companies, and several owners did little to further chip manufacturing.

[Ohforf]

Note on EPROMs :
cover the Window to prevent
the Data from being deleted.
(a few Days or Weeks of Sunlight will do that)
I use black duct Tape for that.

[rockape]

Hi,  

Also, after you have covered the window on each ROM, make sure you label them Top and Bottom, so you'll know which way to install them if you remove them again.

Regards, Michael

aka rockape

[orange]

but its easy to recognise top, it has the 'slot'

[motorollin]

Marco, I would suggest putting the original 3.0 ROMs back. It sounds like you have been very careful to orient the chips correctly, so I assume you have done this correctly.

If the 3.1 ROMs you bought are indeed on flash roms, then it is possible that the chip has been erased which is why the Amiga won't boot with those chips installed.

If the Amiga works with the 3.0 ROMs installed then send the 3.1 ROMs back!

--
moto

[Ral-Clan]

motorollin wrote:
If the Amiga works with the 3.0 ROMs installed then send

Yes, but even if they were corrupt out of the package, now that he has removed the stickers from the 3.1 EPROM windows the original seller will probably not take them back --- as they have 'tampered' with.

Lesson: Do not remove stickers from EPROM windows (voids warranty and can result in erased EPROM over time).  Of course, you did not know about EPROMs at the time, so live and learn.

[amigakit]

Why would EEPROMs be needed for Kickstart 3.1 ROMs?  Even today, we have stocks of new unused Original Amiga 3.1 ROMs manufactured by Commodore and ESCOM.

Picture of original Amiga ROMs are:
http://amigakit.leamancomputing.com/catalog/images/amiga-roms.jpg

I cannot remember Eyetech selling EEPROMs burnt under licence.  They sold the same stocks as us AFAIK. Was this stock really from Eyetech or has someone stuck an Eyetech label on it?

[Boot_WB]

I would still have expected the A1200 to show some signs of power (LEDs) - even with corrupt/blank roms (or even none at all) as this is just the 5v rail powering up, and has nothing to do with the ROM information being read.

Have you tried removing everything from the mainboard (floppy, hard drive ribbon/power cables, etc

Is the A1200 in the desktop case, or towerised - if in desktop make sure you have not bent the metal shielding somewhere which could be shorting the mainboard out.

As a test you could try using a PC power supply to supply power through the floppy power header on the motherboard.

[Boot_WB]

Have just checked - an a1200 motherboard power LED will still light up even with no ROMs attached.

Check your LED cable is securely attached ;-)