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REPLYADDR paul.foerster@gmail.com
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MSGID:  4396a5ba
REPLY: <0d636b16-7b74-4831-bec2-4efc2c538a33n@googlegroups.com> 67a4d8e3
PID: SoupGate-Win32 v1.05
Hi Kenzo,

On 07. May, 2022 at 00:06:36 CEST, "Kenzo"  wrote:
> So my physical 1541 prevents the C128 from completing boot up when the drive
> is powered on and serial cable connected. If I kill the power to the drive
> while the 128 boot up is hung, the 128 completes booting. Same if I
disconnect
> the serial cable while the 128 is hung on bootup. And the drive does not
> respond to load command, 128 reports drive not ready.
>
> I opened the drive case, board is internally very clean, and no burnt or
> bloated caps. I am guessing one or more of the logic chips is bad. Looks like
> the MOS chips are from 1984. I am using an aftermarket serial cable, the
cable
> pins look correct when compared to online pics, and continuity pin to pin on
> each end is good. I guess these serial cables are supposed to be pin to pin
> straight wired.
>
> If I get some ambition in the next few days, I will use my scope to check for
> activity on the logic chips. My understanding is that with the scope ground
on
> a chip ground and scope lead on address or data pins, I should see high speed
> voltage oscillation, indicating logic activity...
>
> Hate to give up on all my floppies, even if I pick up an emulator...

The usual suspects are:

1. Bad power supply of the external drive.

2. If you have a 128D, you may have a drive number conflict. The internal
drive is #8. If the external drive doesn't have some other number assigned
(usually #9), then you will most likely experience exactly such symptoms.

3. The drive cable has a reset line (see below). Usually, it's wired through,
but I have seen few few cables which have no connection there. Considering
your described symptoms, it may make sense to try with a cable that does NOT
connect the reset line. The downside is that pushing the reset button on the
C128 or even powering it down and up again will not make the drive notice any
change. If you want to reset the drive too, you'd have to do that separately
then.

Reset is on Pin 6:
see http://www.hardwarebook.info/Commodore_Serial_I/O

Cheers
Paul

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