Shure U1/U1L Body-Pack UHF Transmitter
13
25C1021 (BG)
Service Procedures
Measurement Reference
dBu is a measure of voltage, and dBm is a measure of power.
For example, the HP8903 should be labeled dBu instead of dBm
because it is a voltage measurement. These two terms are often used
interchangeably even though they have different meanings.
Audio levels in dBu are marked as dBm on the HP8903.
dB Conversion Chart
0 dBV = 2.2 dBu
0 dBu = 0 dBm, assuming the load = 600 Ω
Test Equipment
Most test equipment needed is described in the Shure Wireless
Service Equipment Manual. The following test equipment (or approved
equivalent) is also needed.
Table 1
Test Equipment
Equipment Type Model
Audio analyzer *Hewlett-Packard 8903B
Digital multimeter Fluke 87
Interconnect Cable Shure PT1843
BNC (Male) Cables (2) Shure PT1838A
DC Blocker Shure PT1838W
BNC (Female) to 1/4-inch Phone Plug Adapter Shure PT1838C
20 dB Attenuator Shure PT1838T
BNC to QG Cable Shure PT1825
BNC to LEMO Cable Shure PT1878
BNC (Female) to SMC (Female) Adapter Shure PT1838S
BNC (Female) to SMC (Female) Adapter Shure PT1838S
Test Cable, Japan Version Shure PT1838–AF
Adapter, Japan Version Shure PT1838–AJ
BNC (Male) to RG–174 Cable, unterminated Shure PT1824
Frequency counter Hewlett-Packard 53181A
Rf signal generator Hewlett-Packard 8656B
Spectrum analyzer Hewlett-Packard 8590L
Shure U4S receiver Shure U4S
*Audio levels in dBu are marked as dBm on the HP8903B.
Printed Circuit Board Interconnecting Cable
This cable is provided with the standard test equipment and is used
to connect U1 circuit boards that have been removed from the case for
servicing. It is made from two custom Shure printed circuit boards, a four-
inch, 11-wire ribbon cable, and one male (Shure 170A07) and one
female (Shure 170A08) surface-mount connector. Note that the SMC
connectors face in opposite directions.
Female SMC connector
Male SMC connector
(on back side)
Figure 4. Printed Circuit Board Interconnecting Cable
To Next Page
Loading...
