Double check to ensure no missed or cold solder or shorts
Close JP2 for the time being (even BOB3 is installed)
Keep JP3 JP4 open
、
Close JP1 if no BOB2
Keep JP1 open
Make sure BOB2 in
Power up. Check voltage
at +5V test point. Is it +5V?
Power off. Close JP4
Power up and check +5V
again. Is it still +5V?
LCD backlight on
？
Adjust contrast. Can you
see display?
Press buttons. Do you see
reaction on screen ?
Set cursor to timebase. Turn
[ADJ] dial. Do you see
timebase change ?
Powering-up Test 1
Yes
No
USB powered
Battery powered
Make sure BOB4 and BOB5 have been installed
Follow "No Power"
flow chart to check
Check for soldering mistakes.
Wrong polarity, shorts, etc.
Follow "LCD Dark"
flowchart to check
Check U5 and soldering
of button related pins
Follow "No display"
flowchart to check
Check U5 and soldering
of rotary encoder pins
V4
V1
V2
V3
AV-
AV+
V-
+5V
VT
VB
SYSCLK
VA
Contrast
Adj.
JP4
JP3
JP1
JP2
JP6
USB
Connector
(About +5V)
Signal Input
Reference point for
voltage measurement
*
All voltages are measured with volt meter's (-) pole at reference point (indicated
in photo below) and (+) pole at points of measurement.
1.
2.
*
Notes:
VBUS
V+
(Volt. range: 2 - 5V)
Battery
Connector
VS+
Without BOB3 VS+ = V+ (due to JP2 closed)
：
With BOB3 VS+ depends on state of BOB3 (On or Off)
：
LCD pin18
Is V- normal (-5V) ?
Check BOB5 and C27
Check L1, C28, C11, and C12
Check L5, C16, and C17
Set SW1, SW2, SW3 to GND,
10mV, and X1 respectively
Is VA normal (+5V) ?
Check L4, C29, C9, and C10
Is V2 measured 0V
？
Check SW1, SW2, and R1
Is V3 measured 0V
？
U1 may have been damaged
is V4 measured ~1.6V
？
Check SW3, R9, R10, R11
Adjust VPOS. Can you see
trace displayed ?
Follow "No Trace"
flowchart to check
2
1
Install Batter &
Enclosure
USB powered
Battery powered
Battery voltage ok ?
Is VBUS measured ok?
Is V+ measured ok ?
Is V+ measured ok
？
Is VS+ measured ok ?
Is +5V measured ok ?
BOB3 installed ?
Power good
Check BOB3
Check JP2
Check batt.
Check BOB2
Check USB
Check D4
Check BOB4
Is voltage at LCD
pin 19 5V?
Check related
connections
Short C and E of Q2.
Does LCD light up?
Check Q2, R30 and
connection with U5
Possible LCD
issue
Press SW12. Does LED blink as it should be ?
U4 and LCD connection good ?
LCD defective
Fix bad connections
Check Y1, C21, C22
Re-program U4
Volt at U4 pin20 too low ?
Is contrast changeable by POT1?
VEE.at LCD pin18 negative?
Check POT1 and related
Check all connections between
U4 and LCD for opens or shorts.
VT and VB normal?
U3 damaged
Connection between U4
pin17 and U3 pin12 good ?
U3 has bad soldering
or has been damaged
Check out
the cause
Ensure all analog voltages
are normal (see photo)
Power Up Tests
Troubleshooting
A.
B.
C.
D.
E.
F.
G.
H.
Press SW12. Do you see LED
blink once (if bootloader
installed) and then twice ?
Check Y1 C21 C22
、
、
LED reversed ?
U4 pin 20 voltage low ?
Continue to install
parts on the front
Powered by USB: V+ VBUS - 0.7V
≈
Powered by Batt.: V+ VBAT
≈
（
）
+5V
（
）
-5V
（
）
+5V
（
）
-5V
（
）
0V
*
（
）
0V
*
（
）
~1.6V
（
）
0.6V
（
）
2.6V
*
（
）
0V
（
）
+5V
（
）
About -5V
(Battery voltage)
VBAT
（
）
2.5V
V5
（
）
~1.6V
www.jyetech.com/forum
JP5
Adjust Compensation
Capacitors
Compensation capacitors can be
adjusted using the built-in signal
generator. Follow steps below:
C5
C8
Temporarily connect test signal output to
scope input with a piece of wire
No t en ou gh
通 电检 查
G oo d
通电 检 查
To o mu ch
通电 检查
1.
Connect test signal output to scope input
(see photo below) and set SW1 to DC.
2.
Power up. Set test signal to 10KHz and
5V. Set scope timebase to 20us.
Set SW & SW3 to 1V & X2 respectively.
Adjust trigger level to make display
stable if necessary. Change C8 to obtain
waveform as the middle of photos left.
3.
Keep signal frequence unchanged and
set amplitude to 1V. Set SW2 & SW3 to
0.1V and X5 respectively. Make display
stable. Change C5 to obtain waveform
as the middle of photos left.
4.
5.
Remove connection between test signal
output and scope input. Adjustment is
done.
JP7
JP8
- www.jyetech.com -
This is by-pass of charger BOB2. If battery
is not used (i.e. no BOB2) keep JP1 closed.
This is by-pass of switch BOB3. If BOB3
is not used JP2 should be closed. In order to focus
on the main circuit JP2 can be temporarily closed
at power-up test even BOB3 is installed. Keep it
open after the test.
JP2
：
This is by-pass of step-up converter BOB4.
Usually JP3 should be kept open.
JP3
：
This is the connecting point of power supply
to the rest circuits. For safety JP4 should only be
closed after power supply is tested good.
JP4
：
Step 2
Step 3
Step 4
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
Is AV- normal (-5V) ?
Is AV+ normal (+5V) ?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No Power
LCD Dark
No Display
No Trace
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
Yes
Yes
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Voltages with " " are measured when SW1 (couple) is placed at GND position.
Major Jumpers Explained
JP1
：
Install BNC connectors
and place silicone pad.
Cap slide switches. Insert
board to connector holes.
Hold board tight towards
USB end and push in.
Connect input signal BNC
to main board as shown.
Connect test signal with
shielding wire provided
Tight two screws and attach
batt. to center of back cover
Put on back cover. Tight
the two screws as shown.
Put dial cap on and you
are done.
Tech Support:
JYE Tech Ltd.
JP9
Central
conductor
Outter
conductor
Tight
Screw
Tight
Screw
Scope input
Test
signal
output
Powering-up Test 2
Done
Note:
JP9 must be closed
before power-up test 2
Note:
Keep JP2 open
after the power-up tests
Quick Waveform Diaplay Test
Touch probe tip with a finger to
show introduced main line signal
This jumper should always be closed.
JP9
：
Power Supply Options
Source
BOB2 JP1
Remarks
USB
Yes
Open
No
Close
Int. Batt.
Yes
Open
Ext. Batt.
(J2)
Yes
Open
Close JP5
Ext. 5V
(J2)
Yes
Open
No
Close
Install D5 (D5
is not provided)
Note:
Do not simultaneously connect
external and internal batteries.
