you're taking the proper way to turn the card. Even with the the clock modification you mentioned it seems that the cleaning of the screen is the correct event. To me it happened that I had to press the CR on the keyboard. If I remember correctly the eighth bit of the keyboard connector must be connected to ground because the system knows forever to use the keyboard parallel. I'm not having keyboards parallel I built a PS2 adapter to parallel for to use any ps2 keyboard. If you are familiar with the RS232 signals with the help of rs232 interface analyzer you can check the correct jumpers to do and connect to the card using sw like teratem via RS232. I have created a special selfbuilt cable to use a 3.5 "drive that I use normally. On Bitsavers you can find magazine Microcornucopia whose good part of the first issues was scanned by me wanting to delve into the context of those old times of the board. At that time an Italian compait first turn on http://www.vintagesbc.it/wp-content/uploads/2011/12/Foto2858.jpg
. Here and below , however, you can see other cards that have made further changes as i said http://www.vintagesbc.it/?page_id=305
All pages have a flag in the upper right to get the not perfect, but (right for me ;) ) automatic translation by google service.