Sony TCD D7 DAT recorder tape path problem.

[chriswood1900]

I Have been over hauling my DAT machine, started off not working at all with the usual gummed up mechanism, I have cleaned the mechanism up and it now laces up properly and feeds the tape through and plays for a short period with a few errors.
Then the tape starts to ride off the fixed guide after the head and TGI guide as per the picture. I had to adjust the SGI and TGI guides as they were lose so tightened the grub screws and adjusted to get a reasonable play back. I have not yet checked the eye pattern as the tape rides off the path before I can get a reading usually after about 20-30 sec. I have not touched the fixed guide adjustment as it still has a seal on it but the tape tends to run off the bottom of the lower flange.
Ha anyone else had experience of this problem and been able to fix it, I would be grateful of some advice

[jamesperrett]

How is the tape tension? Some of the Sony mechanisms stop driving the reels properly with age. I remember hearing a suggestion to insert a shim in a vital place although I've never tried it with mine because just about everything was worn on it when I stopped using it.

[murphyv310]

Hi
I used to repair these during my days in Sony service. A few things come to mind but remember this was mid 90s so a lot has faded. Take up torque was a problem back then with it rising which gives the symptoms you have, there was a kit of parts to fit and then you did the set up. Pinch roller I'm sure caused the issue as well as could back tension, in bad cases would baulk the head drum. Back tension and take up torque tend to rise after some hundreds of hours use from what I remember.
I have to say I wish you well with the repair, I did find them awkward to do and now with sore fingers and less than good eyesight I'd not consider opening one up now
Good luck.

[Ted Kendall]

There's a fellow on an auction site offering mechanical overhaul of these for what seems a modest fee. I've bought a machine from him, which is OK, but have no other knowledge. I'm OK with full size DATs, but try to make fixing these Sony compacts SEP. It is as well to bear in mind that spares stocks are now next to non-existent.

[chriswood1900]

Thanks for the replies, Trevor you were in the right area.
After watching the mechanism operating and few tests I discovered it was a lack of back tension on the supply reel. There is a small friction pad shown in the first photo and this was sticking against the roller stopping it controlling the supply reel. Freeing it up and a small application of white silicon grease got it working again. It has now been playing for an hour fault free.
I have now done 3 of these Sony units and this was the hardest.
I also discovered a way of setting up the gear timing which worked better than others I had seen on the net and I will post this in new thread.
Picture 2 shows the RF output after repair and setting up the alignment.