Sony DTC-A7 DAT tape guide adjustment

[rogic]

Hi all,

This is my first time posting so hope I do this right. I have a Sony DTC-A7 DAT recorder which worked perfectly for a about year until the tape transport started giving me trouble. So I took the transport apart (several times), got that fixed so the tape was now wrapping around the head, and put it all back together just to have no audio.

So then I decided to replace all the capacitors in the RF amp and now was getting a distorted sound. I figured I had knocked the alignment off, so I adjusted the tape guides with a small screwdriver to see if I could get the tape back on track with the head, but it was still distorted. This was a tape that I know had sounded great before. So after fiddling with it for a couple days, I decided to record onto a new DAT tape and play it back, and it sounded great! So that tells me record and playback work perfectly, it's just that the tape alignment is just off from its original position.

I have about a dozen tapes I recorded over the past year and instead of re-recording them with the new alignment, is there a secret to getting the old alignment back? Especially without a scope? I turned the tape guides with a small screwdriver but was never able to get them aligned as before, although I feel I was close.

I've attached a file of the tape guides, circled in red, for reference.

Thanks!

 

[hdrobien]

Unless major damage on the transport, tracking settings do not need to be adjusted, even after 30 years.

Once that has been said, you can try to adjust tracking by ears even if a scope would be of great help:
- First you need a "reference" tape, a tape that has been recorded on a perfectly aligned deck.
- Fully screw the left guide (supply guide S1) then unscrew 1 turn 1/2.
- Play the reference tape and adjust the right guide (take-up guide T1) to cancel any digital noise. Find a medium setting between both directions where digital noise appears.
- While playing the tape, press the fast forward key (>>).
- If the T1 setting is good, you should hear a chopped sound but without digital noise.
- If you hear digital noise, slowly rotate T1 (~1/16 step) in either direction until you can hear a clean chopped sound
- If you can't reach such a result, rotate S1 1/4 turn in either direction and try again to adjust T1

Next step would be to record a tape an play it on another deck to check full compatibility with "standards".