STC30 Plus (v4.1) Transformer
(Rev 1.0 8/8/08)
Corporate Headquarters:
1080 North 11th Street, San Jose, CA 95112 Phone: (408) 292-2214 Fax: (408) 292-2733
www.etorque.com
Trouble Shooting
1. PL ( LED )
PL does not turn on the light when the AC power switch is turned on
Test output voltage between pin no.1 and 5 of the 5-Pin connector.
1-1. Fuse
If you read the "0" voltage, check the fuse, 220V 10A (or 6.3A). If the fuse is blown, it’s caused by the overload, overheat. This case, follow
the trouble shooting # 8 (Power shut down)
1-2. Regulator I31 (back side)
If you read the full voltage selected on the DC voltage tester, check the voltage of the input and output pins of I31 regulator (78L05). The
rated input voltage is 20VDC and output is 5VDC for I31 regulator. Replace I31 regulator, if there are any different voltages.
1-3. PL (LED) or SB21 sub-board
If it has rated input and output voltage, then finally test the voltage between one of both end leads and the middle lead of the LED. If the
voltage is 1.9V, then replace the LED. If you have "0" voltage, then replace the SB21 sub-board.
2. Buzzer is not operating in normal function
2-1. Buzzer does not stop sound when the power is on.
There are two possible problem. One is the micro processor IC. The other is the SB21 sub-board.
Push the sT button (soft start button).
If the color of LED is changed, the micro processor IC is OK.
If the color of LED is not changed, the SB21 sub-board should be replaced.
2-2. No buzzer sound when the power is on
If PL is turned on, but the buzzer does not sound, replace the buzzer itself. Or check the components of I35, Q36 which are connected with
pin#10 of SB21.
2-3. No buzzer sound and no PL light
Follow the trouble shooting # 8 (Power shut down)
3. Screwdriver does not run
3-1. PL (LED) is turn on but the driver does not run.
The possible problem can be one of two as followings:
1) Problem is with the screwdriver side
- The start signal was not delivered from the screwdriver through pin#4
- wires to Motor or motor damage
- F/R switch damage
2) There is "0V" between pin #1 and 5
- Q33 and Q31 should be checked or replaced.
3-2. PL (LED) is not turned on
Follow the trouble shooting # 8 (Power shut down)
4. Soft Start & Double hit
Soft start and Double hit works abnormally
- If PL(LED) color is not changed by pushing sT button, check and replace the sT switch (push button tact switch) .
- If PL(LED) color is changed by pushing sT button, replace the SB21 board.
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