HYT TC-618 User manual

TC-618/626 Service Manual
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Contents
Introduction ..........................................................................................................................................2
Safety Information ................................................................................................................................3
Radio Overview ....................................................................................................................................4
Software Specifications .......................................................................................................................7
Circuit Description ............................................................................................................................. 11
CPU Pins ............................................................................................................................................. 19
TC-618/626 Parts List 1 ......................................................................................................................22
Adjustment Description ..................................................................................................................... 71
Troubleshooting Flow Chart ..............................................................................................................83
Disassembly and Assembly for Repair ............................................................................................86
Exploded View ....................................................................................................................................89
TC-618/626 Parts List 2 ......................................................................................................................91
Packing ................................................................................................................................................ 94
TC-618/626 PCB View .........................................................................................................................95
TC-618/626 Level Diagram .................................................................................................................99
TC-618/626 Block Diagram .............................................................................................................. 100
TC-618/626 Schematic Diagram ......................................................................................................102
Specifications ...................................................................................................................................103

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Introduction
Manual Scope
This manual is intended for use by experienced technicians familiar with similar types of communication
equipment. It contains all service information required for the equipment and is current as of the
publication date.

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Safety Information
The following safety precautions shall always be observed during operation, service and repair of this
radio.
◇This radio shall be serviced by qualified technicians only.
◇Only use HYT supplied or approved batteries and chargers.
◇To avoid electromagnetic interference and/or compatibility conflicts, turn off your radio in any
area where posted notices instruct you to do so. Turn off your radio before boarding an aircraft.
Any use of the radio must be in accordance with airline regulations or crew instructions.
◇For vehicles with an air bag, do not place a radio in the area over an air bag or in the air bag
deployment area.
◇Turn off your radio prior to entering any area with explosive and flammable materials.
◇Do not charge or replace your battery in a location with explosive and flammable materials.
◇Turn off your radio before entering a blasting area.
◇Do not use any portable radio that has a damaged antenna. If a damaged antenna comes into
contact with your skin, a minor burn may result.
◇Do not expose the radio to direct sunlight for a long time, nor place it close to a heating source.
◇During transmission, hold the radio in a vertical position with its microphone 2.5 to 5.0
centimeters (1-2 inches) away from your lips, and keep the antenna at least 2.5 centimeters
(approximately 1 inch) away from your head.
◇If you wear a portable radio on your body, ensure that the antenna is at least 2.5 centimeters
(approximately 1 inch) away from your body when transmitting.

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Radio Overview
TC-618
(1) PTT (Push-to-Talk)
Key (2) SK1 (Side Key 1) (3) SK2 (Side Key 2) (4) Speaker
(5) Microphone (6) Antenna (7) LED Indicator (8) Channel Selector Knob
(9) Radio On-Off/Volume
Control Knob (10) Battery Latch (11) Accessory Jack (12) Accessory Jack Cover
(13) Belt Clip (14) Battery (15) Screw of Belt Clip (16) Charging Piece

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TC-626
(1) PTT (Push-to-Talk)
Key (2) SK1 (Side Key 1) (3) SK2 (Side Key 2) (4) Speaker
(5) Microphone (6) Antenna (7) LED Indicator (8) Channel Selector
Knob
(9) Radio On-Off/Volume
Control Knob (10) Battery Latch (11) Accessory Jack (12) Accessory Jack Cover
(13) Belt Clip (14) Battery (15) Screw of Belt Clip (16) Charging Piece
PTT (Push-to-Talk) Key
Press and hold down the PTT key to transmit, and release it to receive.
SK1 (Side Key 1)
SK1 is a programmable key that can be assigned with long/short press function by your dealer.
SK2 (Side Key 2)
SK2 is a programmable key that can be assigned with long/short press function by your dealer.
Note: Short Press means key press shorter than 1.5s, while Long Press means key press not shorter
than 1.5s.
LED Indicator

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Status indications and alert tones are shown in the table below:
Operations/Functions LED Indications and Alert Tones
To enter Wired Clone mode
(For the source radio, hold down
SK2 while powering it on; for the
target radio, turn it on directly)
The LED on the source radio flashes orange once
upon power-on.
Status of the source radio
(After the target radio is turned
on and the cloning cable is
connected, press SK2 of the
source radio to begin cloning.)
The LED flashes red during the cloning process;
The red LED goes out once cloning succeeds;
The red LED goes out once cloning fails.
Wired
Clone
Status of the target radio The LED flashes green during the cloning process;
The green LED goes out once cloning is completed.
Power On (to enter User Mode)
When the radio is turned on, it sounds the power-on
alert.
When the radio is currently on a blank channel, it
sounds beep tones continuously.
Low Battery Alert The LED flashes red, and a low-pitched tone sounds
every 10 seconds.
Transmitting
The LED solidly glows red.
When the TOT timer expires, the radio sounds beep
tones continuously.
A TOT pre-alert tone sounds before the TOT timer
expires.
Receiving The LED glows green when carrier is present.
Scanning
The LED flashes green once every second during the
scanning process.
Scan Start Alert (programmable by the dealer): one
beep.
Scan End Alert (programmable by the dealer): one
beep.
Priority Scan Alert (programmable by the dealer): one
beep if the radio is currently on a priority channel.
Writing/Reading The LED flashes red during reading.
The LED flashes green during writing.
Adjust Power Level
A low-pitched tone is heard when the radio switches
from high power to low power.
A high-pitched tone is heard when the radio switches
from low power to high power.
VOX
A high-pitched tone is heard when the VOX function is
enabled.
A high-pitched tone is heard when the VOX function is
disabled.
Channel Selector knob
Rotate the knob to select your desired channel.
Radio On-Off/Volume Control Knob
Rotate the knob clockwise to turn the radio on, or counter-clockwise to turn it off (a “click”will be heard).
After the radio is powered on, rotate the knob clockwise to increase the volume, or counter-clockwise to
decrease the volume.
Accessory Jack
Use the jack to connect accessories such as speaker, microphone, external PTT, earpiece, PC
programming cable and wired cloning cable, etc.

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Software Specifications
Description of Features
1. Channel Capacity: 16
2. Channel Spacing: 25KHz/12.5KHz
3. Channel Step: 5/6.25/10/12.5KHz
4. Channel Scan
5. Tx/Rx Status Indication (red/green LED)
6. CTCSS/CDCSS Encode & Decode (38 groups of standard CTCSS; 83 groups of standard
CDCSS; optional CTCSS Tail Revert of 180/120 degrees, and supporting non-standard
CTCSS/CDCSS).
7. Low Battery Alert
8. Auto Battery Save
9. Unlock Detection and Emergency Alarm
10. Nine Selectable Squelch Levels
11. Monitor
12. Time-out Timer (TOT)
13. Squelch Tail Elimination
14. PC Programming (manual/automatic adjustment)
15. High/Low Power Switch (2.0/5.0W)
16. Wide & Narrow Bandwidth Compatibility
17. Busy Channel Lockout (transmission prohibited in busy status)
18. Wired Clone
19. Battery Strength Indication
20. Manual Adjustment
21. VOX and Five Selectable Sensitivity Levels
Mode Description
User Mode
It is a conventional communication mode. After the radio is turned on, it enters the User Mode.
PC Programming Mode
The radio in User Mode enters PC Programming Mode through specific protocol based communication.
Wired Clone Mode
1. Description
Wired Clone Mode is an independent mode. To access other modes, you must restart the radio.
Wired Clone Mode includes User Clone Mode and Factory Clone Mode.
1) User Clone Mode:
Connect two radios using a cloning cable. Then hold down SK2 on the source radio while

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powering it on, and the radio enters User Clone Mode in 2 seconds. The target radio can be
directly turned on to enter the mode. In this mode, parameter data stored in EEPROM of the
source radio will be cloned to EEPROM of the target radio. The data transferred only covers
channel data and common parameters, excluding adjustment data, version and serial No. of the
model.
2) Factory Clone Mode:
Short the SELF pin of the source radio's MCU, and connect the two radios using a cloning
cable. Then hold down SK2 on the source radio while powering it on, and the radio enters
Factory Clone Mode in 2 seconds. The target radio can be directly turned on to enter the mode.
Data transferred covers all data in EEPROM other than the Serial No., with the flag of Tune
Switch included.
2. Process
Process of Wired Clone:
1) The LED flashes orange once after the source radio enters Wired Clone Mode. Press SK2
again to clone data to the target radio.
2) During cloning, the LED on the source radio flashes red, and the LED on the target radio
flashes green. When cloning ends, both the red LED on the source radio and the green LED on
the target radio go out, indicating both radios are ready for another cloning operation.
3) If any abnormal situation occurs during cloning, the source radio will stop cloning and the red
LED on it will go out, indicating both radios are ready for another cloning operation.
4) When cloning ends, the source radio goes back to the standby status. Press SK2 again to
begin another cloning operation.
Manual Adjust Mode
Hold down PTT and SK2 on a radio while powering it on, and the radio enters Manual Adjust Mode.
(Note: This operation is subject to the option Tune Switch in the programming software.) When this
option is unchecked, the radio is unable to enter the adjustment mode, which helps avoid change of
parameters and degradation of radio performance caused by user’s misoperations. )
Keep this option unchecked after values are well adjusted from factory, to avoid any unexpected change
of values. The adjustment values can be reset and changed in Factory Mode only.
Description of adjustment:
1) To enter Manual Adjust Mode
Hold down PTT and SK2 on the radio over two seconds while powering it on, and then the LED
glows orange, indicating entry into Manual Adjust Mode. When the keys are released, the radio will
enter item N of Tx group (N depends on the position where the Channel Selector knob locates).
The radio enters an item of Tx group by default, and the LED glows red. (CH16 is used to switch
between Tx group and Rx group. When the Channel Selector knob locates on this channel, there is
no LED indication.)
2) To switch between Tx group and Rx group
Rotate the Channel Selector knob to CH16 and long press PTT to switch between Tx group and Rx

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group. If the LED glows red, Tx group is entered; if the LED glows green, Rx group is entered.
The LED solidly glows red for adjustment of Tx group items.
The LED solidly glows green for adjustment of Rx group items.
3) To switch between items of Tx group/Rx group
This operation is done through the Channel Selector knob.
Tx group: CH1~Ch15 respectively stand for Tx Preset Power, Tx Low Power, Tx Medium Power, Tx
High Power, CDCSS Deviation, CTCSS Deviation (low), CTCSS Deviation (medium),
CTCSS Deviation (high), MSK Deviation, VOX Level 1, VOX Level 2, VOX Level 3, VOX
Level 4, VOX Level 5 and Tx Low Voltage Threshold. (Note: Tx Medium Power is not
required to be adjusted and can be skipped. For radios without the ATIS function, MSK
Deviation is not required to be adjusted and can be skipped. )
The LED solidly glows red during adjustment of CH1~CH15.
Rx group: CH1~CH8 respectively stand for SQL On 1, SQL On 5, SQL On 9, SQL Off 1, SQL Off 5,
SQL Off 9, Rx Low Voltage Threshold and Rx Bandpass Filter.
The LED solidly glows green during adjustment of CH1~CH8.
CH9~CH15 are invalid, and the green LED goes out when the Channel Selector knob
locates on one of these channels.
4) To switch between wide and narrow bandwidth
When adjusting a certain item, long press PTT (orange LED flashes indicating valid press) to switch
between wide/narrow bandwidth. And the first frequency of the current bandwidth is the frequency
for adjustment by default.
5) To switch between frequencies
Short press PTT (orange LED flashes indicating valid press) to switch between frequencies orderly
under certain bandwidth and certain adjustment item.
6) To adjust the value
Short press SK1 under certain bandwidth and certain adjustment item to increase the adjustment
value in steps of 1; hold down the key to increase the value continuously in steps of 1. The
adjustment value will remain unchanged once it reaches the allowed maximum value.
Short press SK2 under certain bandwidth and certain adjustment item to decrease the adjustment
value in steps of 1; hold down the key to decrease the value continuously in steps of 1. The
adjustment value will remain unchanged once it reaches the allowed minimum value.
7) Measures on special items:
Tx group: CH10~CH15 respectively stand for VOX Level 1, VOX Level 2, VOX Level 3, VOX Level 4,
VOX Level 5 and Tx Low Voltage Threshold. These adjustment items are related to AD
sampling. Press SK1 or SK2 after entering the above items, to activate AD sampling
(including calculation) once. Rotate the Channel Selector knob to save the current AD
sampling value. If neither of SK1 or SK2 is pressed, the adjustment value will not be
updated, and AD sampling will not be activated.