Amiga 2000 keyboard sync problems

[Cent74]

I'm using FF 3.29 in a Gotek with rotary encoder, OLED & USB stick. I'm using the files from the HxC compatibility mode folders (HXCSDFE.CFG and AUTOBOOT.HFE).

Amiga disks on USB load well, but the keyboard usually loses sync and does only recover after reset (tested with a logic analyzer directly on the CIA pins connecting to the keyboard. Looks like Amiga does not send a complete acknowledge and keyboard already sends the next character). Only in very rare cases the keyboard syncs after some time, but this is not reproducible. Almost looks like Amiga is too busy to send a complete keyboard acknowledge in time.

When booting the file selector it takes about a minute before the keyboard works, but as soon as I boot an adf-image sync gets lost and does not recover.

Disconneting Gotek and using the original disk drive and booting real disk, the keyboard works without issues.

Any experience or ideas on this issue?

[keirf]

Not reported before. What is the Amiga model?

[Cent74]

It's an Amiga 2000 REV 4.1.

[keirf]

Is this actually FlashFloppy related at all?

[Cent74]

Finally I found a solution: it was to remove the two capacitors C910 and C911 on the A2000 main board.

Thought I'd share this if anyone else has the same problem.

[keirf]

Supply decoupling capacitors? That's weird if so.

[penfold42]

i think they're on clk and data.
This was one of the C= mods to "upgrade" a rev 4.1 to rev 4.5 board

[keirf]

Makes much more sense!

[Cent74]

That's right, removing C910+911 was proposed as a mod (mainly for getting back the first keyboard character after reset). I didn't really expect it would solve my sync problem, but it did.
I found this solution in an old Amiga magazine where they said the reason was the capacitors being duplicated in both the keyboard and on the main board. Later revisions had that fixed.