Hi all,
just to let you know that an imminent house move finally forced me to put the HMV 905 back together, perhaps before I was entirely happy with it.
When I had the chassis on the bench to do the IF sweep I had no idea that I was about to move house. So without knowing if it was really at its best, I had to pack up all the test gear and assemble the set with the CRT for the first time since I restored it...
Now, this is not all bad news as it has worked out well, with a bit of extra space in the new place. The other nice thing is seeing the whole thing back together.
The focus had been a bit uneven, so before I assembled the set I put the focus coil on a variac via a 110V step down transformer. Giving it a few minutes of AC and then gently winding it down to zero did the trick and the result is a more uniform focus across the picture.
Performance... After sweeping, the bandwidth is still quite poor in fact it might be worse, but the HF noise has disapeared unless the contrast is turned right up. So the results are quite viewable and the sound is realy crisp. There is an intermittant fault which causes wobbly line sync, it needs to be scoped really to find it.
There is a bit of IF instablilty in radio mode due to not having a metalised MHD4 (hard to find).
Overall I am very pleased with the results. After the move next week, I hope to get the chance to spend some time watching the set.
This is just about the end of a very long journey with this set
Cheers
Andy