- How to measure FET?
- How to test the transistor with 3-terminal measurement?
- What are the conditions that the capacitors, resistors, inductors and diodes unable to be measured?
- Can JET-300 be extended to dual press down unit?
- How to judge if the TestJet sensor has been properly installed?
- What could be the problems if it is unable to execute the auto test when the head of the press down unit has been lowered?
- How to measure the small resistance?
- Does JET-300 provide functional test?
- How to measure the two paralleled diode?
- How to judge the fail relay board when the error message appear during debugging relay board?
- How to check the polarity of electrolyzed capacitors?
- How to measure the β value of the transistor?
- How to measure the regulator IC?
1. How to measure FET?
There are JFET, Depletion MOSFET and Enhancement MOSFET.
a. Enhancement MOSFET
Following is an example program:
Control the voltage of gate from 2V to 3V till it turns on completely then measuring the Vds.
b. JFET and Depletion MOSFET
Following is an example program:
Control the voltage of ACTVAL (Vgs) from 2V to 3V till the FET pinches off.
2. How to test the transistor with 3-terminal measurement?
|Only measure the two ends of the diode of BC and BE for the transistor of Japanese’ transistor (ex : 2SAxxxx) to know if the diode is false soldering or wrong insertion.( ex: program step 1and 2). But for US transistor (ex : 2Nxxxx ), measure the transistor with three terminals (program step 3) to detect the wrong insertion is necessary due to the pin of base is in the middle. Following is an example program:
Control the base voltage to saturate the transistor.
- When R1>10R2, R1 cannot be measured.
- When XL >10R2, L cannot be measured; XL=2πfL
- When R2>10XL, R2 cannot be measured.
- When the capacitor is with a relatively large capacity, prolong the delay time or make it in CV mode to measure the resistance. When 10R2<XC, C cannot be measured.
- When R2>10Ω, the misoriented inserted D is detectable.
- When L2>10L1, L2 cannot be measured.
- When 10XL<XC, C cannot be measured; when 10XC<X L, L cannot be measured.
- When RL<10Ω, D cannot be measured.
- When C2>10C1, C1 cannot be measured. CAUTION! This feature is opposite to those of R and L.
- When C2 is large, to measure D1 need long time. When D1and D2 are paralleled at the same direction, apply CM mode to measure them.
4. Can JET-300 be extended to dual press down unit?
|Yes, Just rename jet300n.exe as jet300d.exe and take off the jumper of the retest on the mother board. The ICT will become a dual press down unit.
5. How to judge if the TestJet sensor has been properly installed?
|When measuring the voltage (Vdc) between two terminal probes of the TestJet sensor and getting the values as listed, the sensor might be in the bad condition. Below are the reasons.
a. If Vdc=0V,
i. the probe number setting is wrong in test program.
ii. the cable of MUX board is bad.
iii. the cable is not well connected.
b. If Vdc=5V, the sensor plate might be open.
c. If Vdc=0.7V, the system board or MUX board go wrong.
d. If Vdc=4.5V, the mechanical function is fine.
a. Check if the Fix Auto flag in the status table is set “ON”
b. Check if the Proximity Reed Switch on the air cylinder is properly adjusted.
c. Check if the system control board, the cable and the fixture control board failed or not.
d. Check if the fixture control cable is properly plugged.
7. How to measure the small resistance?
|For small resistance measurement (0.1Ω~2Ω), regard it as jumper measurement. It is only for measuring if any missing components occur on the board. For more accurate measurement, four-wire-mode measurement is necessarily to be applied. The theory is as below:
|Signal sources and measurement has different loop individually so that the voltage on RX could be correctly measured.
Each relay board was set as two-wire-mode, thus you need below steps to modify to four-wire-mode:
a. Take out the jumpers marked JA, JB and JC and make them open.
b. The short jumper is as
for JA0, JA1, JA2, JA3, JB0, JB1, JB2, JB3, JG0, JG1, JG2 and JG3.
Make them open and short as
c. There are only 32 points left on relay board, because the second connector has been
functioned as sense . To measure RX, set A as 1, B as 2 and pin 33 will set as sense
of pin 1 and pin34 as sense of pin 2 automatically.
d. The program should be set as below:
e. The modification is completed.
8. Does JET-300 provide functional test?
Yes, JET-300 does offer functional test. So far, we provide +5V, -5V, +12V, +3.3V power.
Add one more board with a 7-pin molex socket on the back of the fixture and set the program as below:
Press [Alt] + [k] simultaneously in the edit screen to show the relay code. Fill No.4 and e with 1 and turn
on the relay to send out the proper voltage. Be sure to turn off the power after measuring. ( as step. 3 )
9. How to measure the two paralleled diode?
Use CM mode to measure the paralleled diode. Following is the example program:
Programming for Step 2 is to apply ACTVAL voltage (0.6v) to make the current about 40mA.
10. How to judge the fail relay board when the error message appear during debugging
Open on B130 (B3: P2)
The message indicates that it is open on the P2 relay of the 3rd board belongs to the No.130
point of the B switch. Replace the P2 relay of B switch of the 3rd board so that the job is done.
11. How to check the polarity of electrolyzed capacitors?
(a) Leakage current measurement
If C1 were 100uF 25V, rewrite the program as STEP2, press F9 to measure the normal leakage
current of the capacitor and fill the value in the STDVAL field. If C1 were misoriented inserted,
the current value will be amplified.
Remark : Each capacitor bears different durability, so the voltage under ACTVAL is not fixed.
(b) Three-terminal measurement:
This method is used to measure the electrolyzed capacitor. Plant a probe on the top of the
capacitor (as drawing shown) and rewrite the program as below:
12. How to measure the β value of the transistor?
Set N in MD, 1 in RG and tune the Vb voltage in ACTVAL (start from 0.7V) until the utmost
and stable βvalue is measured and fill the measured value in STDVAL. (ref. to STEP 1)
Set P in MD, 1 in RG and tune the Vb voltage in ACTVAL (start from 4.3V and downward), until
the utmost and stableβvalue is measured and fill the measured value in STDVAL (ref. to STEP 2)
13. How to measure the regulator IC?
Add external power and modify the hardware as following steps and attached drawing A.
a. The existing fixture should be added with a Molex 7 pin socket which will be connected
to JP9 of JET IC SCAN BOARD for power supply.
b. Pin 1 for +5V, Pin 2 for GND, Pin5 for -5V, Pin6 for +12V and Pin7 for +3.3V. Please refer
to the attached drawing B and program below to test its regulator IC output voltage VCC2
VTT)If the STEP 8, 10 and 12 cannot release the voltage lower than 0.1V, increase the TM
value to the STEP 7, 9 and 11 till the STD value of STEP 8, 10 and 12 lower than 0.1V.