Electronic Component Removal; Checkout And Troubleshooting; General; Operational Ch Eckout - Vivitar 283 Service Manual

·· ,
3.7
ELECTRONIC COMPONENT REMOVAL
Automatic Electronic Flash
Model 283
When removing and replacing electronic components, observe the following precautions.
A. When applying heat, use a heat sink to avoid damaging the components or circuit board due to heat
conduction of component leads.
B. Apply heat sparingly to the component lead to be removed and lift the lead clear of the junction.
C. Ensure that new components are placed and dressed the same as the originals.
SECT ION 4
CHECKOUT AND TROUBLESHOOTING
4.1 GENERAL
When checking out or adjusting the Vivitar Model 283 Automatic Electronic Flash, ensure that all electrical
connections are good, that main capacitor C1 has been formed, and that the battery or power supply is of
the correct potential.
4.2 OPERATIONAL CHECKOUT
4.2.1 TOO LS AND TEST EQUIPMENT.
No special tools are required for maintenance of the Model 283 Auto-
matic Electronic Flash. Screwdrivers, diagonal cutters, long nose pliers, soldering irons, and other common
hand tools are adequate for repair and replacement of parts.
The following test equipment is required:
Volt-Ohm Meter
DC Power Supply
Pulse Photometer
4.2.2 MAIN STORAGE CAPACITOR FORMING.
Before performing any operational checkout, form the main
storage capacitor C1 by switching the unit on, and, after the ready light glows, firing the flash 5 times by
depressing the open flash button. Wait at least 20 seconds between flashes. If the flash cannot be operated,
form the capacitor with power supply as described in Section 4.2.5.
4.2.3 EXTERNAL CHECKOUT.
Before opening the unit, establish or verify the nature of the trouble. For a
quick external check of operations, use a rel iable DC power source, and first check whether the bat tery saver
is functioning as indicated by a blinking ready light. Check recycle times in the manual and automatic modes.
Check that the sufficient light indicator is functioning and that the calculator dial light works. Test the trig-
ger voltage - across the hot shoe or the PC cord terminal - it should be 200 volts or more. Check t he polar-
ity of the hot shoe - the metal ball on the base of the shoe should be positive, the springs on either side of
the mounting grooves, negative. Make certain that plugging in the PC cord disconnects the hot shoe.
If you find that the trouble appears to be in the circuitry, first look for obvious signs of defects such as
broken wires, broken or discolored components, and arcing or burnt-out transistors or transformers before
going through a detailed circuit checkout. Common circuit troubles can often be isolated through voltage,
current, and resistance measurements. Circuit checkpoints and normal voltage readings are given in Fig. 4-4,
and Section 4.3.5, Pages 25 and 24.
Vivitar 37460598 (11/80)
17