Tube Time

Yep, that's me. On Mon, Aug 22, 2022, 7:50 AM David Given ***@***.***> wrote: > Are you Tube Time on Twitter (who just reported the same thing)? > https://twitter.com/hjalfi/status/1561325934204096512 >...

i have not had a chance to dig into it in any more detail other than the screen shots on Twitter. would it help you to see the two SCP...

see attached. [mac_400k.zip](https://github.com/davidgiven/fluxengine/files/9419869/mac_400k.zip)

Are you using sbdiag for that test? It will likely take some more detective work to track this down. Do you have a logic analyzer?

Look at ISA_RD, ISA_WR, DSP_WRITE, DSP_READ to get an idea of the timing of the mailbox reads and writes. I have a feeling the issue is with the mailbox (U19/U18)...

Yes, you will want a CRT with a P11 phosphor (see [the list of phosphor types](http://www.bunkerofdoom.com/tubes/crt/crt_phosphor_research.pdf)). There are types other than P11 that are blue, but it is the most...

Since you had it working for a short time that makes me suspect either the drive itself or the Filer disk you're using, or perhaps the floppy data cable. You...

Is this a standard combo floppy drive that you want to fit to a PS/2 system? It might work; this floppy adapter wires both drive select lines through, but it's...

Thanks for going through this, it's a good clue about the root cause of the problem, which is probably the bus timing of the SRAM chip. The fetching of the...

There may be another card/resource in the system that can either use 140-170 or 220-260, meaning that you can't have the combination of the 3 devices in the system at...