Kenwood TM-281A Service Manual page 21

Adjustment Mode
This mode is used to replace or readjust the EEPROM (IC708).
In Adjustment Mode, the transceiver can be adjusted us-
ing its panel keys.
■ Items that can be adjusted in Adjustment Mode
1. Frequency Tune
2. Transmit High Power *1
3. Transmit Low Power *1
4. DCS Balance *2
5. Max Deviation *2
6. CTCSS Fine Deviation *2
7. DCS Fine Deviation *2
Note:
*1: Adjusted in 5 points in the transmission operating fre-
quency range.
*2: Adjusted in 3 points for the Wide bandwidth in the
transmission operating frequency range.
Adjusted in 1 point for the Narrow bandwidth.
*3: Adjusted in 3 points in the reception operating frequen-
cy range.
*4: Adjusted in 3 points for the Wide bandwidth in the re-
ception operating frequency range.
Adjusted in 1 point for the Narrow bandwidth.
■ How to Enter Adjustment Mode
To perform adjustments with the transceiver panel keys,
the transceiver must be set to "Adjustment Mode".
While shorting two lands (GND, ADJ) on the component
side of the TX-RX unit (A/2) using a pair of tweezers or simi-
lar tool, turn the transceiver power ON to enter Adjustment
Mode.
TX-RX UNIT (X57-8130-XX) (A/2)
: TX-RX section
Component side view
ADJ
GND
Short these two lands
■ LCD Display in Adjustment Mode
Example of Frequency Tune. See "Table 1" for an LCD
display list.
The value stored in the EEPROM (00~FF)
Blink in adjustment mode
Adjustment item Current adjustment value (00~FF)
ADJUSTMENT
8. DTMF Fine Deviation
9. Band Pass Tuning *3
10. Squelch Tight *4
11. Squelch Open *4
12. S-Meter S1 Level
13. S-Meter Full Level
■ Panel Key Operation Method in Adjustment Mode
q Power switch/Volume control
w When the Tuning control is pressed once, the adjustment
value display blinks. (Select an adjustment item with the
[VFO] or [MR] key before performing the operation. It
cannot be performed while transmitting.)
When the Tuning control is rotated while the adjustment
display is blinking, the adjustment value changes. (Adjust
transmission items while transmitting.)
When the Tuning control is pressed again, the adjustment
value stops blinking and lights, and the adjustment value
is saved in the memory of the transceiver. (For transmis-
sion item adjustment, enter receive mode before per-
forming the operation.)
e Changing between adjustment value display and frequen-
cy display
The display changes as follows: Adjustment value display
→ Transmit frequency display → Receive frequency dis-
play → Adjustment value display.
The frequency for adjustment can be confi rmed.
r Moves the adjustment item backward. (If it is operated
when a frequency is displayed, the adjustment item dis-
play returns.)
t Moves the adjustment item forward. (If it is operated
when a frequency is displayed, the adjustment item dis-
play returns.)
y If it is pressed before determining the adjustment value,
the adjustment value of the Adjustment item returns to
its original value.
u Not used in Adjustment Mode.
Note:
If Max Power for transmission is low, check the DC cable.
If the DC cable connector has poor contact due to rust or
stain, a voltage drop may occur frequently and correct trans-
mission power may not be supplied.
In this case, polish the DC cable connector. If the problem
still persists, replace the DC cable with a new one.
TM-281A
21