Dobson Troubleshooting Guide

Table of contents

(1) - Dobson Troubleshooting Guide
(2) - Definitions
(3) - Theory of operation
(4) - What can go wrong?
(5) - Getting started.
(6) - Photomultiplier Tube Problems – There aren’t many.
(7) - R-dial (optical attenuator readout) and Q-levers (Wavelength selectors)
(8) - Ground Quartz Plate (GQP) and inlet window
(9) - Cleaning
(10) - Removing the Encoder
(11) - Barrel (Bellows) connector access: Note that there might be two setscrews.
(12) - Leveling the Encoder to the R-dial
(13) - Problems with Encoder/Counter
(14) - There are pins at each end of the lid (under the rings)...
(15) - Removing the lid – After removing the encoder.
(16) - Fuses – 3amp slow-blow.
(17) - AC Power and switches – each section is independently switched.
(18) - Block Diagram of Electronics
(19) - Block diagram of the amplifier circuit.
(20) - Block Diagram of the High Voltage Section.
(21) - 1999 vintage amplifier circuit
(22) - Locating the amplifier
(23) - Amplifier Section
(24) - Another view of amplifier card
(25) - Quick Test of the amplifier
(26) - PMT Circuit, Showing Dynode chain and AC coupling Cap.
(27) - Measuring the PMT Voltage
(28) - Bottom View – the instrument must be tilted back on to bean bags or other supports
(29) - High Voltage section mounted on right bottom plate.
(30) - View into high voltage bay.
(31) - Motor and shutter removed from instrument.
(32) - Before removing shutter and motor….
(33) - Shutter wheel and PCI