Shure T2 Service Manual page 28

Excessive Current Drain:
Deviation:
ETSI
25C1018 (CC)
Shure T2 Vocal Artist Microphone Transmitter
n If the power is slightly low and the spurious level is high, check
for wrong or open coils at L205, L207, and L210.
n Check the collector bypass capacitors for the
C227, and C234) and the collector bypass capacitor for Q203
(C228), which can also affect the tuning and power gain of the
stages:
RF
S
If level is not the same on both sides of one of these ca-
RF
pacitors, that part is probably defective.
S
The level between the collector of one transistor and the
RF
base of the next should drop approximately 10 dB. Check
any stage that drops more than 12 dB.
ETSI
n Try readjusting C226 for lower current drain while maintaining
output power to specification. If the current drain is still exces-
sive (the factory setting is 35 mA), check for the following:
S
short
S
wrong resistor value
S
defective capacitor
S
value of R218 (that it is correct for the frequency group)
n As a last resort, try changing Q204.
-Approved Units
n If R201 cannot be adjusted to obtain a "15 kHz deviation, try to
isolate the problem to the audio or
lowing:
S
If 1 on the
TP
measure –2.2 dBV (775 mV), refer to the "Audio" section,
page 23.
S
If the preceding level is correct, check R201, C201, C202,
R202, R203, D201, L201, and C203. Also make sure that
the cathode of D201 is being supplied with a 5 Vdc bias from
the 5 V line through R202 and R203.
n As a last resort, try replacing D201 and Y201.
n Make sure the carrier is good: you need that to get any devi-
ation.
27
-Approved Units
section by doing the fol-
RF
board (or I109 on the audio board) does not
RF
stages (C220,
RF
Bench Checks