HYT TC-508 User manual

8130050800200
L07157
2012-08-15

Preface
This manual describes information related with product repair. To repair the product properly, please
read this manual carefully.
This manual is applicable to the following model:
TC-508

Service Manual Contents
i
Contents
1. Introduction ........................................................................................................................................2
2. Product Controls................................................................................................................................3
3. Programmable Key Functions...........................................................................................................4
4. Software Specifications.....................................................................................................................5
5. Circuit Description ...........................................................................................................................11
6. CPU Pins...........................................................................................................................................18
7. Parts List 1........................................................................................................................................21
8. Tuning Description...........................................................................................................................41
9. Troubleshooting Flow Chart............................................................................................................53
10. Disassembly and Assembly..........................................................................................................56
11. Exploded View................................................................................................................................60
12. Parts List 2......................................................................................................................................61
13. Packing Guide ................................................................................................................................62
14. PCB View.........................................................................................................................................63
15. Level Diagram.................................................................................................................................67
16. Block Diagram ................................................................................................................................68
17. Schematic Diagram........................................................................................................................69
18. Specifications.................................................................................................................................75

Introduction Service Manual
2
1. Introduction
Intended User
This manual is intended for use by qualified technicians only.
Safety Information
The following safety precautions shall always be observed during operation, service and repair of this
equipment.
zThis equipment shall be serviced by qualified technicians only.
zUse only our supplied or approved antenna.
zTo 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.
zFor vehicles with an air bag, do not place a radio in the area over an air bag or in the air bag
deployment area.
zTurn off your radio prior to entering any area with explosive and flammable materials.
zDo not charge or replace your battery in a location with explosive and flammable materials.
zTurn off your radio before entering a blasting area.
zDo 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.
zDo not expose the radio to direct sunlight for a long time, nor place it close to a heating source.
zWhen you carry a radio with you, please keep its antenna at least 2.5 centimeters away from your
body during transmitting.

Service Manual Product Controls
3
2. Product Controls
No. Part Name No. Part Name
○
1 PTT Key ○ 10 Battery latch
○
2 SK1 (programmable) ○ 11 Accessory Jack Cover
○
3 SK2 (programmable) ○ 12 Accessory Jack
○
4 Antenna ○ 13 Strap Hole
○
5 Channel Selector Knob ○ 14 Belt clip
○
6 Radio On-Off/Volume Control Knob
○
15 Battery
○
7 Speaker Switch ○ 16 Screw for Belt Clip
○
8 Microphone ○ 17 Charging Piece
○
9 LED Indicator / /

Programmable Key Functions Service Manual
4
3. Programmable Key Functions
For enhanced convenience, you may request your dealer to program the keys SK1 and SK2 as
shortcuts to the functions listed below:
No. Shortcut Key Function
1 Adjusting the Power Level To adjust power level quickly.
2 Battery Strength Indicator To show the remaining battery strength
3 Channel Lock
To lock the channel which would disable the Channel Selector
knob.
4 Monitor Button
To adjust the condition for incoming signal match
5 Monitor Momentary
6 Squelch Off To always unmute speaker no matter whether carrier is present
or not
7 Squelch Off Momentary
8 Scanning To receive signals on other channels
9 VOX To make the radio transmit automatically when you speak.

Service Manual Software Specifications
5
4. Software Specifications
4.1 Status Indication
See the table below for LED and alert tone indications:
Item Indication
Wired
Clone
To enter Wired Clone Mode
zturn on the source radio with SK1
held down for approximately 2
seconds;
zTarget radio: turn it on directly.
The LED on the source radio flashes red once during
the power-on process.
Status of the source radio in Wired
Clone Mode
(After the target radio is turned on
and the cloning cable is connected,
press the PTT key of the source radio
to begin cloning.)
The LED glows red during cloning process.
Error occurs during cloning:
zUser Clone Mode: At the start of cloning,
frequency band and Model ID will be checked.
The LED glows orange for 2 seconds and then
goes out to indicate a failed check. If the check is
successfully carried out but error occurs during
cloning, the LED will flash orange. In this
situation, press any key to make it go out.
zFactory Clone Mode: The LED flashes orange in
presence of error. Press any key to make it go
out.
The LED glows green once cloning is completed.
Status of the target radio in Wired
Clone Mode
The LED glows green during cloning.
The green LED goes out after cloning is completed.
Power On (to enter User Mode)
When the radio is turned on, a power-on alert tone
sounds.
When the radio is currently on a blank channel, it
sounds beep tones continuously.
Low Battery Alert
The LED flashes red, and the low-pitched tone
sounds every 20 seconds (programmable by the
dealer).

Software Specifications Service Manual
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Item Indication
Transmitting
zThe LED glows red during transmitting.
zWhen TOT timer expires, the radio sounds beep
tone continuously.
zA TOT pre-alert tone sounds before the TOT
timer expires.
Receiving The LED glows green during receiving.
Scanning
zThe LED flashes green once per second during
scanning.
zScan Start Alert (programmable by the dealer):
one beep will sound.
zScan End Alert (programmable by the dealer):
two continuous beeps will sound.
Writing/Reading
The LED glows red when the PC is reading data
from the radio.
The LED glows green when the PC is writing data
into the radio.
Power Adjustment
A low-pitched tone sounds when the radio switches
from high power to low power.
A high-pitched tone sounds when the radio switches
from low power to high power.
VOX/Channel Lock
One audio alert for enabling;
Two audio alerts for disabling;

Service Manual Software Specifications
7
4.2 Function List
zChannel Capacity: 16
zChannel Spacing: 25KHz/12.5KHz
zChannel Scan
zRX/TX status indication (red/green LED)
zCTCSS/CDCSS (38 groups of CTCSS, 83 groups of CDCSS, and CTCSS Tail Invert by 180
degrees.)
zLow battery alert
zBattery Save
zUnlock Detection and Emergency Alarm
z2 Selectable Squelch Levels
zMonitor Button
zTime-out Timer (TOT)
zSquelch Tail Elimination
zPC Programming (manual/ automatic tuning)
zHigh/Low Power Switch (4.0/ 2.0W)
zWide & Narrow Bandwidth Compatibility*
zBusy Channel Lockout (transmission prohibited in busy status)
zWired Clone
zBattery Strength Indicator
zManual Tuning
zVOX and 5 Selectable Sensitivity Levels
Note
* indicates optional functions.
4.3 Description of Modes
4.3.1 User Mode
It is a conventional communication mode. The radio will enter this mode by default after power-on.
4.3.2 PC Programming Mode
The radio in User Mode enters PC Programming Mode through specific protocol based

Software Specifications Service Manual
8
communication with the programming software. In this mode, radio functions and adjustment parameters
can be set through the programming software (including User Version and Factory Version).
4.3.3 Wired Clone Mode
Description
Wired Clone Mode is an independent mode. To access other modes, you must restart the radio.
Wired Clone Mode includes Clone Mode and Factory Clone Mode.
1) User Clone Mode:
Connect two radios using a cloning cable. Power on the source radio while holding down SK1; the
radio will enter Clone Mode in approximately 2 seconds. Then directly power on the target radio to enter
the User Mode. In this mode, data stored in EEPROM of the source radio will be cloned to EEPROM of
the target radio. The data transferred only involves channel data and common parameters, excluding
tuning data, version and serial No. of the model.
2) Factory Clone Mode:
Connect two radios using a clone cable. Hold down both SK1 and Power On/Off Key of the source
radio, it will be turned on and will enter User Clone Mode by default after 2 seconds. Press SK
afterwards to switch to Factory Clone Mode. The target radio can be directly turned on to enter user
mode. The data transferred covers all data in EEPROM (including settings for the Manual Tune Switch),
other than the serial No.
Process
Step 1 The LED flashes red once after the source radio enters the Wired Clone Mode. Press PTT to
begin to clone data to the target radio.
Step 2 During cloning, LED of the source radio solidly glows red, and LED of the target radio solidly
glows green. When cloning is completed, LED of the source radio solidly glows green, and the
green LED of the target radio goes out, which indicates the preparation for another clone.
Step 3 If any abnormal situation occurs during cloning, the source radio will stop cloning and its
LED will flash orange, which indicates the preparation for another clone.
Step 4 When cloning is completed, the source radio goes back to standby status. Press PTT again to
begin another clone.
4.3.4 Manual Tune Mode
In this mode, you can manually tune the frequency deviation, power level and squelch level and etc.
Description of Tuning: