Contact Us
Wuxi Island Technology Co.,Ltd
Attn: Mr.chu
Phone: (+86)18795806008
WhatsApp: 18795806008
Tel: (+86)0510-88762956
Fax: (+86)0510-88762950
ADD: No.20 Jingrui Road, Xibei Town, Xishan District, Wuxi City, Jiangsu, China
Home > News > Content
How To Repair The Charger When The DC Voltage Output Is Too Low
May 17, 2018

According to the maintenance experience, in addition to the voltage regulator control circuit will cause the output voltage is too low, there are several reasons:

(1) The output voltage terminal rectifies the three-pole , and the filter capacitor fails. This can be judged by the substitution method.

(2) The performance of the switching power transistor is degraded, resulting in that the switching transistor cannot be normally turned on, so that the internal resistance of the power supply is increased and the load carrying capacity is reduced.

(3) The source of the switching power transistor is usually connected to a resistor with very small resistance but high power as an overcurrent protection resistor.


The resistance of this resistor - generally 0.2 ~ O.8Ω. If the resistance value or open welding, poor contact can also cause the output voltage is too low.

(4) The high-frequency pulse transformer is not good, not only causes the output pressure to drop, but also causes the switch power tube to be insufficiently energized to damage the switch tube repeatedly.

(5) The bad high-voltage DC filter capacitor causes the power supply to have a poor load capability.

(6) Poor contact of the power supply output line, with a certain contact resistance, causing the output voltage to be too low.

Maintenance method: First use a multimeter to check whether the next high-voltage DC filter capacitor is degraded, whether the capacity is reduced, and whether the capacitor can be charged and discharged normally. If there is no such problem, measure the current limiting resistance of the electrode of the switching power transistor and the overcurrent protection of the source to determine whether the resistance is changed, deteriorated or open, and the contact is bad. If there is no problem, check again whether the core of the next high frequency transformer is intact. In addition to this z may also be the output filter capacitor capacity reduction, or open welding, virtual connection; power output current limiting resistor value or virtual connection; power output line virtual connection.

Do not let go of any obstacles, they should be carefully examined to ensure that nothing is lost.