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