Hi to all,
this is a very nice forum.
To my problem. I have a MKIV, which had problems in reading DVDs (allways rebooted). Having an old software version, I hoped that upgrading to V27 will help. Now I found out, that no update CD could be read. My first idea was, that the drive within the laser has a problem. But now I changed the drive inside the unit with a working one, an the same happened. The MKIV could be diagnosted by DIS, and it seems that there is no error (no faults are stored). The unit says, that software has to be reloaded (like in thread : "Nav OS CD stuck!!!" Message is : "Loading software required ..." ). It doesn't matter, which update CD is loaded (I tried V22.1, V25, V27 ..., which are working in other units), the CD will be moved out after while (the laser head is working for a while) and the message is "incorrect disc, please insert correct disc".

Now three questions :
1. Had anybody such a problem already, and what was the solution (Calvin Tan changed the whole unit)
2. Is there a basic software disc, which has to be loaded first ?
3. Is a schematical drawing or diagram available for the MKIV unit ?

best regards
rolli