A format transfer project I took on for a new client has been delayed twice now due to problems with AU-65 decks.
The latest deck to become disabled is an AU-65 with low hours.
It was working excellent, with high RF readings.
Now, it is displaying (suddenly) a "Low-RF" warning; despite the fact that the tape runs through the machine and the audio sounds great. However, the picture is not there and the RF needle is dead to the left.
The same tape was played back on another MII unit and played without distortion.
I have tried cleaning the heads with an inert fluorocarbon solution and chamois swab. No difference. I do not possess an MII cleaning cassette; though I know where to get one if it would help.
I do not know how to preform head cleaning with compressed air; however I have heard great things about this technique from reliable sources.
Perhaps this is simply an electrical problem on a replaceable board?
It may just be a severely clogged head(s). MII is metal particle tape from what I remember and sometimes when the heads clog, it practically welds metal particles across the gap in the heads. I had a problem with an MII machine a while ago and no amount of cleaning with freon or head cleaner worked. I finally got it cleared up using Ampex head cleaner (nasty stuff) along with a Panasonic head cleaning tape. These tapes are pretty abrasive and will wear the clogged heads down a bit to clear them out. Don't run it very long. A little goes a long way. If the tape plays on a different machine, it can't be the tape at fault and is most likely clogged heads. It's possible that the machine just finally gave up, but I'd look into a good head cleaning first. It takes some effort.
Life moves pretty fast. If you don't stop and look around once in a while, you could miss it.--Ferris Bueller