Chargery S1500 v2.1 repair

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Warning

I make this site available to people who are interested in and enjoy electronics and electrical engineering.

Devices in this category (power supplies) contain voltages that are life-threatening. Incorrect handling can therefore endanger your equipment and/or your life!

This description is therefore in no way intended to encourage you to carry out such activities on your own without the necessary specialist knowledge!

Manuals

At the time of the repair, only a user manual in a few versions (e.g. v1.1 dated 18 June 2013 or v2.0 dated 7 January 2015) was available on the internet. However, unlike a service manual, it did not contain any information that could be used during the repair.

Error description

The owner stated that the last time he tried to operate the device, a loud sparking noise was heard and later, after the device was turned over, some small black particles fell out of the device’s casing.

Error verification

The device could be powered on and the LCD and user interface worked, but the output could not be activated. This behavior indicated a problem with one of the device’s secondary circuits.

Build quality

Although the owner emphasized that the unit was purchased new and never repaired, some important components such as rectifiers and power MOSFETs were very sloppily soldered and their solder joints were not cleaned of flux.

In addition, some power components such as rectifier bridges were not completely covered with thermal paste.

Visual inspection

As usual, the check began with a visual inspection of all parts on both sides of the circuit board. The first defects were actually found very quickly – two parts in the SOT-23 package were mechanically damaged.

Q16 is part of the external circuit of power MOSFET Q20 and Q17 is part of the external circuit of power MOSFET Q21 (Q20 and Q21 are both 28N60M2 in TO220F package). In addition, some passive components in both circuits were damaged. While some damage was visible to the naked eye, others could only be detected by measurement.

The following pictures show 4 examples.

Problem #1

The mechanically damaged components belong to the circuit that controls the primary side of the main transformer.

Assumptions

The circuits for Q20, Q21, Q22 and Q23 are similar.
For damaged parts that can no longer be identified, the same type as in the neighboring, comparable circuits is assumed:

Q16=Q18 (MMBT2222A)
Q17=Q19 (MMBT2222A)

Measurements

A dying MOSFET often destroys some other components as well and in fact some random readings on parts near the dead MOSFETs were suspect. More precise measurements gave the results described in the following sections.
All resistor measurements were done using HP/Agilent 34401A 6,5 Digits bench multimeter.

Sentences such as “No component detected!” or “Part is shown as Zener diode!” in the following tables refer to the output of “Peak Atlas DCA75 Pro”.

SMDs near Q20

Resistors

PCB number	Package	Code	Expected value (Ω)	Measured value (Ω)	Replacement value (Ω)
R69	0603	200	20	19.658 *	–
R97	0603	01B	1 K	1.0009 K *	–
R98	0603	01C	10 K	21.409 K	10.025 K
R99	0805	120	12	15 M	12.151

Capacitors

PCB number	Package	Code	Expected value	Measurement result
C57	0603	–	–	Not shorted, but mechanically damaged. *
C58	0603	–	–	Not shorted. *

Although capacitor C58 was electrically unremarkable, its terminals were partially evaporated, which also made it a candidate for replacement.

Semiconductors

PCB number	Package	Code	Type	Measurement result	Replacement
D14	SOD323	S4	1PS76SB40	No connection in both directions! *	BAS40H,115
Q16	SOT-23	Unreadable	?	No component detected! Mechanically damaged package!	MMBT2222A
Q20	TO220F	28N60M2	28N60M2	No component detected!	28N60M2

SMDs near Q21

Resistors

PCB number	Package	Code	Expected value (Ω)	Measured value (Ω)	Replacement value (Ω)
R100	0603	200	20	19.658 *	–
R101	0603	01C	10 K	22.476 K *	10.030 K
R102	0603	01B	1 K	0.99879 K *	–
R103	0805	120	12	1.4949 M	12.174

Capacitors

PCB number	Package	Code	Expected value	Measurement result
C59	0603	–	–	Not shorted, but mechanically damaged. *
C60	0603	–	–	Not shorted. *

Semiconductors

PCB number	Package	Code	Type	Measurement result	Replacement
D15	SOD323	S4	1PS76SB40	No connection in both directions! *	BAS40H,115
Q17	SOT-23	Unreadable	?	No component detected! Mechanically damaged package!	MMBT2222A
Q21	TO220F	28N60M2	28N60M2	No component detected!	28N60M2

SMDs near Q22

Resistors

PCB number	Package	Code	Expected value (Ω)	Measured value (Ω)	Replacement value (Ω)
R104	0603	200	20	19.692 *	–
R105	0603	01C	10 K	45.261 * 10.006 K	–
R106	0603	01B	1 K	360.16 * 0.99769 K	–
R107	0805	120	12	1.8309 K	12.195

Capacitors

PCB number	Package	Code	Expected value	Measurement result
C61	0603	–	–	Not shorted. *
C62	0603	–	–	Not shorted. *

Semiconductors

PCB number	Package	Code	Type	Measurement result	Replacement
D16	SOD323	S4	1PS76SB40	Conducting in both directions @ 0.008V.	BAS40H,115
Q18	SOT-23	1P	MMBT2222A ?	Part is shown as Zener diode!	MMBT2222A
Q22	TO220F	28N60M2	28N60M2	OK	28N60M2

SMDs near Q23

Resistors

PCB number	Package	Code	Expected value (Ω)	Measured value (Ω)	Replacement value (Ω)
R108	0603	200	20	19.646 *	–
R109	0603	01C	10 K	10.035 K *	–
R110	0603	01B	1 K	0.99 K *	–
R111	0805	120	12	11.946 *	–

Capacitors

PCB number	Package	Code	Expected value	Measurement result
C63	0603	–	–	Not shorted. *
C64	0603	–	–	Not shorted. *

Semiconductors

PCB number	Package	Code	Type	Measurement result	Replacement
D17	SOD323	S4	1PS76SB40	OK, Vf=0.244V	BAS40H,115
Q19	SOT-23	1P	MMBT2222A ?	Part is shown as Zener diode!	MMBT2222A
Q23	TO220F	28N60M2	28N60M2	OK	28N60M2

MOSFET Gate Driver

U10 and U11 are TC4424AV (dual 3A MOSFET Gate Driver in SO8 package). U10 controls Q20 and Q22 while U11 controls Q21 and Q23.

Partial circuits

Warning! I do not have a service manual for this device. The circuits in this section are the result of reverse engineering and may be incomplete or even incorrect!

Q20 and Q22

Q21 and Q23

Electrolytic Capacitor Check

Not all capacitor measurements were necessary for this repair, but since the device was already opened I performed these measurements as well.
The measurements were performed as In-Circuit measurements using Peak Atlas ESR PLUS ESR70 (Equivalent Series Resistance Meter). E8 and E9 were also additionally measured outside the circuit.

Part	Parallel connection	Manufacturer & model	Value	Measured value
E1	E1||E2||E3||E4	CapXon P1610	1000µF/35V/+105°C	?µF, ESR=0.04Ω *2
E2	E1||E2||E3||E4	CapXon P1610	1000µF/35V/+105°C	?µF, ESR=0.04Ω *2
E3	E1||E2||E3||E4	CapXon P1610	1000µF/35V/+105°C	?µF, ESR=0.03Ω *2
E4	E1||E2||E3||E4	CapXon P1610	1000µF/35V/+105°C	?µF, ESR=0.04Ω *2
E5	–	CapXon ?	1000µF/25V/+105°C	1086µF, ESR=0.04Ω
E6	–	CapXon ?	100µF/25V/+105°C	?µF, ESR=0.08Ω *2
E7	–	CapXon P1604	100µF/35V/+105°C	113.0µF, ESR=0.24Ω
E8	E8||E9	Jianghai CD294	330µF/450V/+105°C	602.6µF, ESR=0.10Ω *1 304.3µF 0.12Ω
E9	E8||E9	Jianghai CD294	330µF/450V/+105°C	603.6µF, ESR=0.08Ω *1 298.8µF 0.14Ω

Not all measurements in the circuit produced a useful result, but at least they did not indicate a problem. So there was no need to desolder in this case.

Additional measurements

Part number	Package	Type	Result
D24	TO220	1F32AV	OK Vf=0.435V @ 5.00mA IV Chart
D25	TO220	1F32AV	OK Vf=0.435V @ 5.00mA IV Chart
Q30	TO247	47N60C3	OK, further data in the table below.
Q31	TO247	47N60C3	OK, further data in the table below.
C58	0603	4.7 nF	Mechanically damaged!
C59	0603	4.7 nF	Mechanically damaged!

	Q30	Q31
Type	N-Ch Enhancement mode MOSFET with body diode	N-Ch Enhancement mode MOSFET with body diode
Vgs(on)	2.985V at Id=5.02mA and Ig=3µA	2.998V at Id=5.03mA and Ig=1µA
Vgs(off)	2.305V at Id=4.9µA	2.327V at Id=5.2µA
gm	40.8mA/V at Id=3.0mA to 5.0mA	38.8mA/V at Id=3.0mA to 5.0mA
Rds(on)	<1.0Ω at Id=5.0mA and Vgs=8.0V	<1.0Ω at Id=5.0mA and Vgs=8.0V
Charts	Id/Vds, Id/Vgs	Id/Vds, Id/Vgs

Replacements

Replaced parts #1

Part	Package	Part numbers
28N60M2	TO220F	Q20, Q21, Q22, Q23
MMBT2222A (1P)	SOT-23 (SMD)	Q16, Q17, Q18, Q19
1PS76SB40 (S4)	SOD323 (SMD)	D14, D15, D16, D17
10k	0603 (SMD)	R98, R101
12Ω	0805 (SMD)	R99, R103, R107
4,7 nF	0603 (SMD)	C58, C59

Q22 and Q23 passed the test, but I usually replace all power MOSFETs of an affected H-bridge.

Problem #2

During the measurements I have noticed that the output resistance of the PSU is very low (less than 1 ohm). So there was also an error on the secondary side.

The search for the defective component using a thermal imaging camera led to nothing. Even after injecting 8.5 A, no component became significantly warmer and the leads were shown as the warmest components. I assumed that the defective component was on a cooling plate and was therefore not easy to find using this method.

Since there was no free access to the MOSFET screws, the MOSFETs and heat sinks had to be desoldered together for further tests. To protect the circuit board, the original solder was first vacuumed out, replaced with a solder with a low melting temperature and then vacuumed out again.

The short circuit disappeared after removing the third (middle) heatsink, which carries the power MOSFETS Q3 and Q4 as well as the temperature sensor.

The out-of-circuit power MOSFET measurements confirmed the malfunction of Q3. This was also consistent with the images previously taken with the thermal imaging camera, which were not meaningful on their own. During the IR study, coil L2, which has direct connection to Q3 and Q4, was slightly warmer (1 to 2°C) than coil L1.

Part number	Package	Component type	Model	Check results
Q1	TO220	N-Channel Advanced Power MOSFET	RU1H150R	OK
Q2	TO220	N-Channel Advanced Power MOSFET	RU1H150R	OK
Q3	TO220	N-Channel Advanced Power MOSFET	RU1H150R	Failed! All 3 leads shorted.
Q4	TO220	N-Channel Advanced Power MOSFET	RU1H150R	OK
Q5	TO220	Bipolar Junction Transistor (BJT)	1508 J13009-2	OK

Replacement Q3, Part #1

The RU1H150R is a Chinese semiconductor, but it was not easy to find.
To avoid getting a fake, I wanted to buy the part from companies that specialize in it. Although the component was listed in the webshop in some cases, my request was rejected with the note that it was currently not available.

After a long, unsuccessful search, I finally tried one of the sites where almost everything is sold. The item description indicated that it was guaranteed to be an original.

	Original Q3	Replacement part #1
Type	N-Ch Enhancement mode MOSFET with body diode	N-Ch Enhancement mode MOSFET with body diode
Vgs(on)	3.478V at Id=5.01mA and Ig=0µA	3.581V at Id=5.01mA and Ig=0µA
Vgs(off)	2.279V at Id=5.1µA	2.781V at Id=5.1µA
gm	34.0mA/V at Id=3.0mA to 5.0mA	37.2mA/V at Id=3.0mA to 5.0mA
Rds(on)	<1.0Ω at Id=5.0mA and Vgs=8.0V	<1.0Ω at Id=5.0mA and Vgs=8.0V

In my opinion, the results of these spare parts deviated too much from the original and I therefore decided to replace them with parts from a known good source.

Replacement Q3, Part #2

As described in previous section I have decided to go for another part from a trustworthy source.
After comparing the parameters of many available components from well-known electronics suppliers, I am convinced that I have finally found a component that will do its job perfectly for years to come:

CSD19536KCS N-CH MOSFET 100V 150A TO220-3

	Original Q3	Replacement part #2
Type	N-Ch Enhancement mode MOSFET with body diode	N-Ch Enhancement mode MOSFET with 0,57Vf body diode
Vgs(on)	3.478V at Id=5.01mA and Ig=0µA	2.843V at Id=5.00mA and Ig=0µA
Vgs(off)	2.279V at Id=5.1µA	2.059V at Id=5.1µA
gm	34.0mA/V at Id=3.0mA to 5.0mA	341.3mA/V at Id=3.0mA to 5.0mA
Rds(on)	<1.0Ω at Id=5.0mA and Vgs=8.0V	<1.0Ω at Id=5.0mA and Vgs=8.0V

R22

R22 is the gate resistor of Q3 and it was also destroyed. The selected replacement part is Yageo RC1206FR-134R7 (4R7/0,25W/1%/200V/100ppm).

PCB number	Package	Code	Expected value (Ω)	Measured value (Ω)	Replacement value (Ω)
R22	1206	4R7	4R7	2K9	4R696

Replaced parts #2

Part	Package	Part numbers
CSD19536KCS	TO220-3	Q1, Q2, Q3, Q4
4R7	1206 (SMD)	R22

As mentioned before, I usually replace all power MOSFETs of an affected H-bridge and in this case I also selected a new power MOSFET type. Therefore, the non-defective power MOSFETs Q1, Q2 and Q4 were also replaced.

Verification

Power-On

The function was confirmed by measurements at the output at different output voltages.

Load Test

The power supply can deliver 1500 W and therefore cannot be fully tested with my “Rigol DL3031A Electronic Load 150 VDC/60 A/350 W” due to its limited power, but this test is at least better than pure idle measurements.

The connection between the D.U.T. (=Device Under Test) and the electronic load was realized using 2 cable sets suitable for 20A each and separate measuring cables.

No problems were detected even after a longer period of operation with a load of 300W. After a short time, both fans of the power supply started up, so that no excessive temperature increase could be detected in the test.

Digital obsolescence

The power supply is relatively well built and can be maintained or repaired relatively easily. I would have given the manufacturer almost 10 out of 10 points if he hadn’t taken a step towards digital obsolescence.

It is true that a service manual is almost never available for modern electronics, but in many cases you can live with that.
What I can’t stand, however, is the grinding off of the ICs. There are 3 ICs in this power supply with sanded off labels.