NJD Spectre theatre stage light, 2003 date
 

Gives fully variable total spectrum floodlight output under remote control.
Or it would but nothing now. Full of dust and fluff in the control area and
a long term heat damaged , so presumably dramatically raised ohmage
resistor.
The bands are not discoloured , I think, reading 100 ohm , 5 percent and 1W
size. Currently reading 47K, but scraping back the end thirds of the metal
oxide spirals , the outer section thirds to each end are about 500 ohm each.

This resistor connects mains live to in-series opto-coupler, then small 3W
mains transformer primary (supplying just a 7805 for the microcontroller)
then neutral.
The opto is 4 pin P620 , presumably Toshiba TLP620 , current going through
back to back LED of 50mA rating with transistor receiver.

For the UK a 3W transformer would take about 12mA so 1.2V dropped across 100
ohm, does that seem about right ? presumably uprating to 2Watt, 100R. The
LED side of the opto seems ok at 1V diode drop either way.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

NJD Spectre theatre stage light, 2003 date
 

N Cook wrote in message
...
Gives fully variable total spectrum floodlight output under remote
control.
Or it would but nothing now. Full of dust and fluff in the control area
and
a long term heat damaged , so presumably dramatically raised ohmage
resistor.
The bands are not discoloured , I think, reading 100 ohm , 5 percent and
1W
size. Currently reading 47K, but scraping back the end thirds of the metal
oxide spirals , the outer section thirds to each end are about 500 ohm
each.

This resistor connects mains live to in-series opto-coupler, then small
3W
mains transformer primary (supplying just a 7805 for the microcontroller)
then neutral.
The opto is 4 pin P620 , presumably Toshiba TLP620 , current going through
back to back LED of 50mA rating with transistor receiver.

For the UK a 3W transformer would take about 12mA so 1.2V dropped across
100
ohm, does that seem about right ? presumably uprating to 2Watt, 100R. The
LED side of the opto seems ok at 1V diode drop either way.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/





According to www.njd.co.uk the schematic was available via email request.
Nothing received so far though, so I will suck it and see.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/