Adjusting head azimuth DCC730/951

Hello DCC users,
Sometimes I get the message clean head playing a DCC tape. When I switch to side B there is no problem. When switching back to side A the problem is gone or I need to switch again to B and back to A. The head, pinch roller and capstan are clean.
I have tested the DCC with 4 different calibration tapes from Philips. The audio perform, general purpose, 4 sector test and digital silence tape are working perfect. But these tapes have a stronger magnetic signal I think. I don’t have the mirror cassette for azimuth calibration.
Normaly the FATG and ALP can correct some misalignment, but I want it set this right. Does anyone know how to check/calibrate the azimuth.?
Regards, Pieter

FATG and ALPS are the names for the mechanical construction around the head and in DCC cassettes that work together to make sure that the tape always flows perpendicular to the head in a DCC recorder or player. Except in extreme cases where there’s a defect, you should never need to adjust these. Even if you do adjust the azimuth in a DCC recorder, you will find out that it has little or no effect because, basically, the FATG and ALPS adjust the tape flow as well as the head position.

If your recorder tells you to clean the head, it’s because it’s sensing too many dropouts from the tape. The mostly likely cause (especially if you only get it on one side) is worn out pinch rollers. They cause the tape to run at irregular speed, and if that gets too extreme, the electronics can’t keep up with the speed variations. This is a very common problem with the 730 and 951. I didn’t think my 730s had the problem but when I looked closely I saw that the rollers were all dry and irregular. They’re not expensive and they’re easy to replace. So replace the pinch rollers first and THEN maybe reconsider adjusting the azimuth or something else.


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Hello Jac, thanks for the information. The pinch rollers are maybe one year old and they look good. Maybe the tape I used is getting old, so I’ll check with other previous recorded tapes. The first thing what came in my mind was the azimuth because when I switched to side B and back to A did help. I’ve checked the azimuth by putting in an analog tape with a transparent housing. Then power off and move the head frame towards the tape. So I can see if the tape touches both the upper pins on the DCC head at the same position. I also used a magnifier glass to see it better. This was OK. Maybe my test can be useful for other users who have problems with a DCC.
Regards, Pieter