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Ian Jackson

In message . com,
writes
On 6 May, 13:10, dotter wrote:

Hi All,

I'm attempting to repair a high end DCC recorder (Philips DCC900), the
fault only seems to affect DCC tapes not normal cassettes...

On playback there is a high pitched howl, suprisingly load from the
transport mechanism, loading the capstan flywheel (with my finger, to
slow it down) didn't make much difference, pulling the rubber pich
roller away also made no difference.

When the transport is howling the audio level goes to zero.

For a while, the sequence of rewind, stop, play - howl, if followed by
a stop and play then the howl went away.

This doesn't happen when the cassete is removed or using a regular
cassette, different DCC tapes also howl.

If I press the tape lightly while playing in one corner the howling stops.

All help welcome, I'm trying to sort this out for an elderly neighbour
who has a large collection of DCC tapes.

TIA!
Paul

Sounds like bad bearnings.

NT

I had a similar howling problem. Certain tapes were worse than others,
and it depended how far through the tape you were playing.

It was caused by the slipping clutch on the take-up capstan. Instead of
slipping, it's actually oscillating between stop and go, hence the
howling sound (a bit like producing a note with a wine glass).

Many clutches have a simple torque adjustment. Changing the torque MAY
stop the howling. There are three spring fingers pressing onto a
'stepped' part of the underside of the take-up wheel. You adjust the
torque by rotating the spring fingers onto the next step.

Ian.
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