Hello Guy,
Thanks for your ( and others) reply and effort, it is much appreciated.
However I can assure you that neither of the two DVD1 units that I had converted to multiregion by the B&O dealer back in the early 2000's had any extra electronics fitted into them ( I still have both units and have checked all ). To further confirm this I have, as originally stated used the main 'monoboard' under the laser/transport mechanism from these DVD 1's transplanted into my Avant 32 DVD RF television to repair a failed internal DVD. The multiregion facility has always been transferred to the Avant along with the board from the DVD1 (previously 'converted' by the dealer in about 2 minutes whilst I waited).
This proves that it is just a matter of some sort of programming/hack that changes the stored region coding within the electronics on that board whilst remaining in the DVD1.
I know that this so called ASD-11 laser/transport/board combination was used in a few contemporary Philips machines such as DVD 612 etc. It is possible to make these Philips machines multiregion by using the OneForAll 6 universal remote control and a lengthy code input. Obviously this is one way to achieve a multiregion board by fitting it to an old Philips player, performing the multiregion hack, then re-fitting it to the DVD1 or Avant DVD of choice.
This may be the circuitous route I will have to travel to keep these machines going into the future but it it seems a shame that the clearly possible conversion within the DVD1 can not be made available to us all to keep them working.
I also have the later DVD1 mk2 (4261 Pioneer internals) which are not compatible with the Avant with Philips internal DVD. I have not yet come across one of these units that has been made multi-region. Has anyone else?
It is clear from the above that the fault that ultimately stops these players working is contained within the electronics on the 'monoboard' under the mech. I have never been able to find any visual clues of failure on any of my known failed boards. There are many surface mount components and chips on the board making a component level repair tricky to diagnose, let alone repair.
Out of approximately six machines that have failed then I have fixed, all have been due to the failure of the 'monoboard'. I have cleaned, lubed, swapped etc. mechanisms and laser units and they have never been the failure point. I have always subsequently checked all these items by marrying them to a known working board etc. All still good. Obviously six failures with board failures does not discount anybody elses alternative problems with transports etc.
As always, any further info. would be appreciated and I will be sure to post anything may help in the future.
Cheers, Duncan.