[Test-Equipment] Anyone want a Marconi TF1313 LCR Bridge?

[Barry]

The plastic is just a cover.  The calibration markings are on the metal underneath and there is a pointer connected to the large knob (in front of the plastic) that turns underneath the plastic cover (I hope that's understandable).

There is felt that sandwiches the knob and its mating surface underneath the plastic so that the plastic rides between the two.  The markings and the pointer are still somewhat visible beneath the plastic but, as you can imagine, it's not nearly as easy as it was when the plastic was in good shape.

Those three screws you see support an additional metal disc where the markings for the fine adjustment (the smaller knob in the center of the plastic face).

Who knows.  You might get lucky with enough wet sanding and polishing to make it look somewhat presentable (at least be able to see all the calibration markings clearly again).  I just didn't have the "want to" after the incident occurred.

BTW, if you do undertake this, read the manual regarding disassembling the knob.  It comes apart rather easily by loosening the clamps from the rear of the spindle.  I tried removing everything from the front for a good while until I finally figured out how to take it apart properly.

Finally, the plastic sort of snaps in place into that big silver ring and is held with nibs (for lack of a better word).  It is rather easy to get the plastic (and pretty much only the plastic as I recall) out for repair.  If someone had the ability to form a new one (heating over a mold, etc.) that might also be a way to fix this.  Alternately, a flat plexiglass disc could be fashioned with an outer ring to hold it in place.  I suppose there are several options.

Thanks,
Barry - N4BUQ
> 
>      The web photos are sufficient.  I am not familiar with
> the instrument, is the plastic only a cover or does it have
> any calibrated markings on it. There appear to be screw
> heads on the surface. Unless the damaged window is part of
> the calibration I think its worth trying to fix.  Since the
> alternative is the trash I would certainly give it a go
> provided its not a totally impossible job. Tell me some more
> details of what the window works (does it just have pointers
> attached for instance) because its not possible to tell from
> pictures.