Re: Teledyne Gurley DRO

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

>
>
> abenedro wrote:
>
> >Hi,
> >I have a Teledyne Gurley DRO from the 70's which will only read in
> >metric although the thumbwheel switches should allow it to read
> >imperial as well as metric. I suspect it may have been configured
> >this way since new to prevent mistakes as it was off a Swedish

milling

> >machine used on a Sandvik production line. The readout is a
> >Pathfinder model 8770 and uses TTL updown counters (74192) and
> >minitrons for the displays.
> >
> >Anyone got a schematic for this box so I can work it out or heard

of

> >this before?
> >
> >
> I talked to an old Teledyne Gurley rep quite a few years ago when I
> inherited
> a pile of DRO bits and pieces. Sometime in the early 70's they

went to

> all-metric
> scales, and stopped production of imperial scales. The older,

imperial- or

> metric-only readout boxes would then only display the native

resolution of

> a given scale. I think this is what you've got there, a native-

only box and

> a metric scale. What Gurley did after that change was to

incorporate PROMS

> in all readout boxes to perform the metric to imperial conversion.

If

> your DRO
> box only has standard SSI and MSI components like gates and decimal
> counters,
> it won't do the conversion.
>
> Jon

Jon,

Thanks for the ideas. I had presumed that because the reader head had
two light sources and detectors which swopped when imperial and
metric were selected that the reader head did the conversion before
it got into to the box. The reader heads produce a buffered sine
wave same as the modern Gurley scales.
I have contacted Gurley about a schematic and they are helpful but
reckon that there master circuit was sent out by mistake instead of a
copy some years ago. I thought if there was a diagram about or
someone recognised the box I may have been in with a chance.
There is certainly plenty of everything in the box and it difficult
to re-draw the circuit with the double sided boards used.

Peter