Amiga 2000 - yellow screen on boot, ticking from floppy

[Ith1l]

Hello everyone.

I have multiple problems with my A2000 - mainly with unstable work.

Specs:
- A2000B v6.2PCB
- A2052 RAM expansion
- HDD expansion card

Small backstory - I have bought it about year ago in unknown condition, PCB had very bad battery leak, many traces had been eaten away, decided to change whole PCB to Remake PCB.
After soldering everything, putting chips in new sockets it started and on first glance - worked without a problem, loaded from HDD to Workbench 1.3.
After a few restarts first problem has occurred - sometimes it boots to kickstart but refuses to read floppy - drive makes some clicking and weird noises from floppy when ejecting and putting back floppy as in video in the link below.

https://www.youtube.com/watch?v=_PKnhHga89Q

I have checked KS 1.3 and KS 3.1, on KS3.1 it freezes instantly on floppy animation, checked on fresh WB floppy - nothing changed, in DiagRom every test passes ok, when it boots to WB - reads floppy without problem.
I decided to replace Agnus - again same behaviour, nothing changed. After a few weeks of fight I gave up and left it for a year.
Recently I returned to Amiga and I am trying to fix it again, but it developed another problem - HDD expansion card freezes Amiga completely on boot sequence - shows yellow screen and flashes Power LED. After few restarts and showing software failure screen it boots to workbench ok but HDD is not detectable by Amiga and after a few minutes in Workbench it freezes Amiga completely.

Any help will be appreciated because I have no clue what to do next.
Thank you for your suggestions.

[Ith1l]

Hi everyone.
Thanks for the answers.

As for ticking floppy drive problem - I can't reproduce it now so I can't really say what the problem was, I suspect it has gone away after changing Agnus chip but I'm not 100% sure.
Unfortunately Amiga developed another floppy problem. Both floppy drives work fine for a 5-10 minutes then they usually they stop reading good floppies - WB shows bad sector while reading. After a power cycle they work again for next 5-10 minutes.
I bought new pair of CIA chips, I will try to replace them to see if something changes.

Like I said in the first post, I have changed whole PCB to brand new A2000 Remake so bad traces are really unlikely.
CPU is also "new" so eaten pins are not the case. Agnus also has a new socket.

As for yellow screen problem, today's troubleshooting session left me really puzzled.
At first I suspected SCSI HDD card because after returning to Amiga it suddenly stopped working and Amiga showed yellow screen every time it was in the system.
When there was only RAM card or bare system, everything worked "fine" (no yellow screen).
So I began to re-socket every chip on board because of infamous one-side pin contact sockets on PCB. After a few tries HDD card suddenly stared working after reseating SRAM chips.
On the other hand now RAM card is not working  Every time i put it in Amiga, it hangs on immediately and shows black screen, only sometimes it start booting but shows yellow screen again.
This has left me puzzled because RAM card was working without a problem earlier and "broke" because HDD card started working. I suspect either Buster chip or bus drivers (less likely because they are brand new).

Other than that, Amiga is really unstable when it boots to Workbench, it sometimes hangs after several minutes. Also Amiga occasionally hangs when connecting keyboard while Amiga is running.

[Ith1l]

Yes, that is correct. It is Rev 1.8.5 so I think it is the latest revision.

[Ith1l]

Hi everyone, I have a small update.

After another troubleshooting session I think I found cause of random freezes. Whenever I push PCB near chip RP604-1 or the chip itself it causes Amiga to freeze and restart every time, I suspect chip itself or some problematic solder joints on PCB.

Another question - is Buster chip supposed to be stone cold? Every other chip i at least slightly warm but Buster is at ambient temperature.

I still wait for CIA chips and I will check if that fixes problem with floppy drives stopping to work after few minutes.

[Ith1l]

Hi everyone.

I think I fixed problem with freezing and weird behavior with expansion cards. After re-seating bus buffers near Zorro slots and clearing pins on 68k CPU ( two were oxidized, probably after battery leaks) Amiga stopped with random freezes after pushing buffer chips and now it boots with no problems even with two expansion cards.

Now, I’m facing next two problems:

First, I have no luck with running Amiga Explorer, I can’t get it to connect my PC with Amiga even with proper null modem serial cable. I suspect problem with serial port circuit because when testing serial port in Amiga Test Kit with correct pins shorted together it only shows two pins as good and the rest as Bad.

Second, Hdd is not detected in Workbench. Card is properly detected in Expansion board list in boot menu but hdd is not detected in HDDToolBox. I’m sure it is working properly because Hdd is reading something whenever I reset Amiga.

There are no markings on card other than MCMCOPYRIGHT 1989 B.RICKETTS

[Ith1l]

I recognize the Ricketts name, is this the card you are working with?
https://amiga.resource.cx/exp/cltd2000

Thanks for the tip. That is not that card, but I have Kronos card from the same manufacturer https://amiga.resource.cx/exp/kronos. I looked on that site for some information about drivers etc. but there is only ROM file for EPROM. This card is HDToolBox compatible because HDD showed in it when I first tried to partition HDD but now I can't get it to work - I think it needs special SCSI_DEVICE_NAME but I don't remember which one worked (neither scsi.device nor ide.device work).

It almost sounds like he has a lot of desoldered chips in sockets which may or may not be new.. lots of contact problems or bad chips from damage.

Yes, that's true, I tried to reuse old chips from old board but only working ones (I have chip tester so I knew which are in working condition). Unfortunately my 68k CPU have very corroded pin and it still doesnt work reliably so I'm waiting for a good one, new 1488 and 1489 and 74245 chips, then I will check if there is any improvement.

[Ith1l]

Hi everyone.

Small update - I have tested Serial port circuit and I think I found the issue - either EMI filters or C310-C316 capacitors are problem - I have tested new 1488 and 1489 chips and they didn't help, then I tried to short CIA pins according to Amiga Test Kit dongle schematic and then it showed pins as working, same with shorting Paula RX-TX pins.

With the kronos card in you can run SYSINFO and it should show under Devices what the scsi device name is.
then just set that in HDtoolbox icon info and it should scan it. if you want a better card with ide support you might try a BuddhaFlash

Thanks for tip, I will check it next time.

Hopefully you're only socketing the Commodore ICs, ROM, CPU.  With none of the logic gates, etc, in sockets - which is just asking for trouble, especially if using second hand corroded ICs.

It's too late now. Every chip on my board is socketed  I will just have to deal with it, I tried to use mainly precision sockets (with round hole) but some chips have normal double spring sockets.