SCR 850 Repair

On this Alba SCR 850 unit,  one tape deck had a fault, which resulted in the tape not winding. This type of fault can manifest in either one or both decks.

A quick inspection without inserting a cassette revealed that the take-up spindle was not turning, however the pinch-roller and capstan were. This obviously indicates a problem with either the clutch mechanism, which usually powers the take-up spool, or the secondary drive belt. In any case, this means taking the dual deck mechanism out to gain access to the reverse side.

Opening the unit, the first thing I discovered was a large spring stuck to the speaker magnet. At first, I thought it must belong to one of the terminals in the battery compartment, but further investigations later revealed that it was a part of the clutch mechanism.

I was able to take the dual-deck mechanism out without having to take apart the tuning string mechanism. Luckily, the manufacturers have placed the tuning string and its pulleys on a separate panel, which can be detached from the tape transport mechanism. All the wires are on sockets, which are also easily removable.

Comparing the two decks and their clutch mechanisms I noticed an obvious difference. The side that did not work had a missing spring and retaining cap. Whilst shaking the unit up side down the plastic retaining cap made an appearance. A close inspection of the plastic cap revealed a hairline crack that prevented it from locking the spring down in compression. I simply used a tiny drop of super glue to repair the crack and reinforce the cap. It works fine now.

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