With the past few days being overcast it hasn't been too frustrating not having an operative system. However, all is now working again with much assistance from my friend John who is far better at applying some logic to electronic problems than I am. After a lot of trial and error the additional pulse timer circuit was also ready for its first test on the scope. Unexpectedly last night, though too poor for any serious imaging, was good enough to see if the extra circuitry was going to work. After all the trouble getting it to operate properly in the first place it seemed natural to expect further problems in actual use. It was therefore quite a surprise when it appeared to perform very much as hoped for and didn't cause the guiding software to go ballistic in some way as I had expected. The apo is much more forgiving of guiding errors so I won't know for sure how good any improvement is until I can test it with the main scope....At least I can now turn my attention to re-building the errant spider.