Actually, most head alignment is done optically to begin with. If you have some clear leader tape, just thread it up and do a rough alignment using the leader as a guide. You don't actually have to play the tape, just thread it among the guides and heads. The tape should touch the head as it normally would during playback. If you cannot defeat your tape lifters with a cue lever, then thread the tape OUTSIDE the capstan/pinch roller and hit play.
Once it's mostly aligned that way, play back a multi-track tape (not full-track), preferably with test tones of 1 KHz and 10 KHz, that was recorded on your machine (assuming it was well-aligned before removing the heads) and adjust the head height using equal turns on all three screws to get the highest response at 1 KHz. Re-check optical alignment. Then adjust azimuth with the test tape to get the most response at 10 KHz. If you have a 2-channel oscilloscope, you can then connect the output of two channels from the deck and display it as X-Y on the scope, and further adjust the azimuth to get a straight diagonal line (no oval). This step isn't ultra-critical, but if you have or can borrow a 'scope, I recommend it.
Once the playback head is aligned in this manner, and the record head is optically aligned, thread up some GOOD blank tape (one that won't suffer from dropouts or poor frequency response) and start recording a 1KHz tone at 0 dB. While monitoring the tape from the playback head, adjust the height of the record head until you get even, high levels. watch the VU meters and make all adjustments slowly. Haste makes waste. There will be a fraction of a second delay between making an adjustment and it's effect showing on the VU meters, because it takes a finite amount of time for the tape to travel from the record head to the playback head. Once you have the record head mostly aligned at 1 KHz, you can do finer adjustment with 10 KHz, and also adjust azimuth with 10 KHz. 10 KHz @ 0dB input at 7.5 IPS and slower will more than likely saturate the tape on your machine, so don't be worried if the playback level isn't anywhere near 0dB. You can increase the output to make it more readable. We're simply trying to get the highest levels.
From here you can do even finer adjustments to things like playback reference level and playback EQ as long as you have an alignment tape from a place such as MRL. DO NOT USE HOME-BREW TAPES FOR PLAYBACK LEVEL AND EQ ADJUSTMENT!!! I cannot stress this enough. I have attempted to align several decks many times, and this is NOT an accurate way to do it, even if you make the tape from a "known good" machine. TRUST ME! MRL charges a lot of money for these tapes for a good reason. They are very accurately made, much more accurately than your own machine can ever hope to accomplish.
As always, if you have one available, consult the service manual for your deck. If you don't have one, get one. They're worth their weight in gold.
:thmbsp:
