Yellow screen with a4000...
 

I have almost finished my a4000 tower project, but I am running into a few problems. When I first turned the machine on, everything seemed fine and I was able to boot into workbench from a floppy. However, now I am getting a yellow screen at boot up, and the machine will just reset itself repeatedly until the yellow screen disappears (sometimes it does, sometimes it doesn't), however, it will not always show the yellow screen. Sometimes it will show up, sometimes everything will be fine. Another quirk I noticed is that sometimes when the yellow screen does not appear, it will fail to detect my harddisk. If I reset the machine, sometimes it will find it again. When I can boot into workbench, it runs fairly stable (long enough to partition, format, and install workbench).

The only thing I can really think of is the fact that I'm using an AT power supply, however, I checked the voltages with a volt meter and they seemed to match up pretty well.

Any ideas?

a4000/040
GVP A4008 SCSI Z3 card

A bit of an update:
I took the SCSI card and the Zorro3 daughter card out, and this seems to have fixed the problem. (I've only got the yellow screen to show up once without it, but it quickly rebooted itself and I haven't been able to get it to reappear) I've just noticed how fast this thing boots up without any cards installed. (starts loading OS from floppy the moment I let go of the reboot keys, however, it takes a while to start with an initial powerup).


I looked on the back of both cards for pins that were shorting, but I haven't found any. I really want to use this card since my cd-rom is scsi, plus the card adds an extra 8meg ram.

Colour code
 

A short site note: If you boot up your Amiga, the machine runs through some hardware-checks. If a hardware error occurs, the screen will show a colour which represents the error with a hardware device. Pity I don’t know what error the yellow colour represents – does anyone know a list which explains these colour- messages?

Well when I have a Yellow screen on my A600, it is when my 1MB Upgrade card works loose:confused

I've found only this link:

http://www.nethkin.com/bmori/amiga/f.../tech/test.htm

Thanks for the help, guys.


It turned out to be a loose SIMM :rolleyes

I get yellow screen on my A4000d, when I use the Os reboot command ( Os 3.9; all boingbags installed).
If I do keyboard reset, everythings fine.
I recall the reboot command worked before.
Could it be something with my new A3660 card ..?!
Or maybe the flash card contents ..?! ( a couple of devices, Rom update and some libraries )

Ok, it was the Flash Rom card ( eFlash ) contents.
When I reduced them, problem disappeared ( expect for reboot command causes it if ran without loading Wb).
Will start another thread, regarding the eFlash card use.

Generally speaking, is the yellow screen necessarily Always a hardware problem..?!

Something crashes exec.library before it's gotten far enough to be able to create a guru. Before this is has done a checksum of the kick rom, which produces a red screen when fails. So yeah, since the firmware is verified ok at this point, no user code is running yet, it's a hardware problem that makes the machine fail.

For 1.x I don't see a red screen failure in the exec.library disassembly, so "not always" but I think we can safely say "always in 3.x".

Could also be a memory Configuration problem..?!

Yes it can. I have had a yellow screen many times when having an issue with the Buster-11 seating (if socketed), SIMMs making bad contact or having a problem or the accelerator having some problem like bad contact or configuration problem.



macce2, for you based on your various threads, I think you should get acquainted with a memory test program. Maybe run mbrtest-2 on your Fastlane RAM that despite not knowing whether your Fastlane supports 16MB SIMMs, 4 of them show up as 40MB. I'm going to guess if you run mbrtest-2 on your 40MB of Fastlane RAM you'll have one of the following happen:
1) Simple test like March, pukes immediately saying error in your Fastlane RAM
2) Simple test like March, pukes after 4MB on your Fastlane RAM

Ok thanks once again for your help, grelbfarlk !
I do agree I would better test my Fastlane memory.
From where to get the " mbrtest-2 " program?!
Aminet, perhaps ?!

You can get it from the floppy from here:
http://amiga.resource.cx/exp/mbx1230


M1230XA-101.dms
I've carried so much stuff from one Amiga to another I forget where I got some of this stuff. There are other memory testers for sure, some are likely better but this has served me well.

I can also recommend mbrtest-2, it is a reliable piece of software.

Ran Memory tester v 1.0 ( by P- O Yliniemi v 1.0) two times, with different settings. No errors occured.I found the MemTest program from my old Aminet Util cd-rom.

Well then, I was totally wrong! If this tested 40MB on the Fastlane and passed then it should be fine. I am not familiar with this software but running it on UAE it looked as though it tested all of the extra Z3 memory, so I would expect it would go through all the Fastlane RAM too.


I guess this is a pretty useful configuration for the Fastlane you've found, chasing down 4x16MB 30-pin SIMMs has got to be easier than finding 10x4MB 30-pin SIMMs. Maybe you should try some other configurations with it, maybe there's some combination to increase it a little further, say to 52MB or to the full 64MB.

Well, when running a particular demo, I get the message that says" Mmu tables are incombatible or not enouhg memory for page.." . I have about 300 Mb Ram total. But I noticed that my hardware configuration has changed, and the Mmu configuration file may propably be incorrect / out of date.
So, question 1: Is it possible that improper Mmu setup could cause yellow screen ( and some other instability) occasionally ?
Question 2: I have a Fastlane scsi controller ( with some memory onboard) and BigRamPlus card installed on my A4000. It seems that extra Ram is seen as "one" memory " area"; according to SysInfo.
So, is it possible that the Ram with those cards somehow isnt recognized properly ?
Q3: if I removed all the extra memory from my Fastlane card, but kept the BigRamPlus card, would my Scsi transfer speed & overall performance suffer, or would the FL card automatically use the Ram on the BRP card instead, without any noticeable Scsi performance loss ?!
Q4: How about the A3660 card; should the enable mapRom setting/ jumper be enabled ( curremtly it is)or disabled ?
Q5: How to test the Mmu is " physically" ok ?
Q6: Would it be possible that I would be better off in using some other version of 68060.library, instead of the Mmulib package ?!

Ok; it seems like I got rid of the yellow screens. I re-installed and configured my Fastlane memory properly. Now it has total 16 Mb available.
I'm just running a memory test program and all seems fine, so far ( expect for some problems with my new KTRL CD32+ joypad; which does have some weird occasional problems.
I suspect those problems to be caused by power supply problems.)

Update: As soon as I wrote here of getting rid of the occasionally appearing yellow screen, it happened again.
Soon after succesfully testing all available memory on my A4000 and running some demos, yellow screen.

I got a strange feeling.
If it is not a power supply problem, it may be almost anything..?!
Will check the order of my Zorro cards etc.

Sorry if I've suggested this already but if you have a socketed Buster-11 you should at a minimum try reseating it. When you remove it try to clean the socket and the Buster as well as you can with at least some isopropyl. If you reseat it without cleaning everything and immediately see more yellow screens then you might have one of your culprits. That or you broke the socket, at which point you should just remove the socket and solder it down.