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ms660 · 7th Nov 2019, 8:34 pm

I've never worked on one of these machines, and I might be wrong but to me it looks like the top of the upper head segment is too high in relation to the top edge of the tape so far as I can make out from the photo's. When I used to service Sony decks at Sony the top edge of the upper segment was always set slightly below the top edge of the tape thereby leaving a guard band, the head heights for record and playback heads were the same as far as I remember. The top of the erase head segment was always above the top edge of the tape which ensured that any recorded info on a tape that had made it into the guard band was fully erased.

If I remember at Sony the top edge of the upper segment was adjusted to be exactly in line with the top edge of the tape then the head height adjusting screws were turned anti-clockwise by so many degrees, Sony used to give a figure for the number of degrees the head height adjusting screws had to be turned (anti-clockwise) to drop the head height down so that the correct distance between the top edge of the tape and the top edge of the upper head segment was achieved.

That might or might not be of any use....but good luck with it whicheverways.

7th Nov 2019, 8:34 pm	#5
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Philips N4520 alignment problems I've never worked on one of these machines, and I might be wrong but to me it looks like the top of the upper head segment is too high in relation to the top edge of the tape so far as I can make out from the photo's. When I used to service Sony decks at Sony the top edge of the upper segment was always set slightly below the top edge of the tape thereby leaving a guard band, the head heights for record and playback heads were the same as far as I remember. The top of the erase head segment was always above the top edge of the tape which ensured that any recorded info on a tape that had made it into the guard band was fully erased. If I remember at Sony the top edge of the upper segment was adjusted to be exactly in line with the top edge of the tape then the head height adjusting screws were turned anti-clockwise by so many degrees, Sony used to give a figure for the number of degrees the head height adjusting screws had to be turned (anti-clockwise) to drop the head height down so that the correct distance between the top edge of the tape and the top edge of the upper head segment was achieved. That might or might not be of any use....but good luck with it whicheverways.