Service Model 1707B
Item Use Specification Item Recommended
Soldering tool Soldering Wattage rating: 37 to 50 Ungar #775 handle with
Unsoldering Tip Temp: 750-800 degrees Ungar #1237 Heating Unit
Soldering Tip Soldering Shape: chisel Ungar #PL 113
Desoldering tool To remove molten Suction device Soldapullt by Edsyn Co.,
solder from con- Arleta. California
nection
Resin (flux) Remove excess flux Must not dissolve etched circuit Freon
Solvent from soldered area base board material or conduc- Acetone
before application tor bonding agent Lacquer Thinner
of protective Isopropyl Alcohol
coating (100'81 dry) .
Solder Component replace- Resin (flux) core, high tin
ment content (60140 tidead).
Circuit board repair 18 gauge (SWG) preferred
Wiring
Protective Contamination, Good electrical insulation, cor- Silicone Resin such as
Coating Corrosion protectior, rosion-prevention properties GE DRI-FILM *88
should be used to obtain the very best results when 8-68. If trouble is suspected, visually inspect the
repairing and replacing soldered-in Components on instrument. Look for loose or burned components that
etched circuit boards. might suggest a source of trouble. Check to see that
all circuit board connections are making good contact
8-64. HEAT SINK REMOVAL. and are not shorting to an adjacent circuit. If no
obvious trouble is found, check the power supply
8-65. There are two types of transistor heat sinks voltages in the instrument. Prior to any extensive
used in this instrument; the friction type and the troubleshooting, also check the external power
screw-on type. The friction type can be removed by sources.
carefully pulling them off. To remove the screw-on
8-69. DC VOLTAGES.
type, proceed as follows:
a. Remove transistor from circuit board. 8-70. On some of the schematics, dc voltages are in-
dicated for active components (transistors, etc.). Con-
b. Grasp cooling fins with taped pliers. ditions for making these voltage measurements are
listed adjacent to the schematics. Since the conditions
c. Remove nut with %inch wrench. for making the measurements may differ from one
circuit to another, always check the specific condition
listed adjacent to the schematic.
8-71. WAVEFORMS.
When replacing heat sinks, especial- 8-72. Waveform measurement points (illustration 11
ly friction type, support the bottom
of the transistors to avoid lead damage on table 8-3) are placed on the schematics along
main signal paths. The numbers inside the measure-
caused by downward pressure. ment point symbols are keyed to waveforms and
waveform measurement conditions adjacent to the
8-66. TROUBLESHOOTING. schematics. Like the dc voltage measurement con-
ditions, waveform measurement conditions vary from
8-67. The most important prerequisite for successful one circuit to another.
troubleshooting is understanding how the instrument
is designed to operate and correct use of front panel 8-73. TEST POINTS.
controls. Improper control settings or circuit con-
nections can cause apparent malfunctions. Read
Section 111 (Operation) for an explanation of controls 8-74. Test points (illustration 20 on table 8-3) corre-
and connectors and general operating considerations. spond to pins protruding from etched circuit boards
Read Section IV (Principles of Operation) for ex- and do not necessarily correspond to waveform
planations of circuit theory. measurement points.
8-8 |
ACEC
