XA1541 adapter + cable PC troubles

[GilesGoat]

Ok "don't shoot me now" ( yet ) I know I should first try all this with a real CBM before to get to any conclusions.

But just a few questions/doubts/things to know.

Yesterday I built this :

I used 4K7 resistors and 2N3904G transistors, despite they say 'it may or it may not work' I cannot see reasons why not (*) as this transistor even when used like switching is rated for quite some MHz

The cable I made out from that is this one :

However I have some doubts like :

1) how can a thing like that work unless somewhere ( in the drive ? ) there are some pull up resistors ?

2) should I test levels with connector inserted in the disk ?

3) getting confused a bit about this, is this the cable that should work 'with any system/sw' or should I swap some clock/data line ?

I am trying to use opencbm, I first installed the 'drivers' but when I try some stuff like :

cbmctrl reset

It takes a couple of seconds and then 'nothing happens'

when I try

cbmctrl detect

it seems to hang .. ( until I disconnect the parallel cable )

"Something" seems to happen/be active because normally I can see only the power green led on the 1541 disk but the moment I insert the parallel cable I hear like a motor spinning and the red led going on.

Maybe something is wrong in the cable I am using ?

Anything I could use as 'test' ? I tried the XCDETECT.EXE but all seems to hang.

Thanks in advance for help.

[edit] - checked and rechecked, the cable seems correct .. mah ..

 

[timbob]

ah, a cable problem

I've got a topic in here where I'm trying to get a cable working as well, And i had loads of problems as well, but I'm getting some better results already...

Do you try to acces the drive with windows?
I had much better results when i booted my computer on MS-dos, and used Starcommand from there.
When i tried it in windows, the lights on the drive just turn on and the drive keeps on spinning.

You can easily make a ms-dos diskette in windows, if you still have a floppy drive...

 

[GilesGoat]

I contacted the guy that made that article.

He sent me to a link where some people made extensive studies on that cable and transistors.

I don't know exactly "what they want to obtain" ( i.e. I suppose the idea is to avoid using some buffer chips that would require an external power source ).

Basically they did test a bunch of transistors and various parallel port modes, it also seems that the PC parallel port drives the output differently if configured like SPP or EPP ( I think one of the two is totem pole and one is OC ).

The bottom line seems to be "that thing works *ONLY* with the BSV 52 transistor and almost nothing else" and the reason seems to be "raise time" and "delays" the transistor introduces.

The 2N3904 I used seems to be a bit of a 50% 50% chance it could work with some parallel ports but not with all.