Maisheng MS-605D Power Supply

[tristate]

Hi,
bought this from taobao China for 339RMB + shipping
performs well with no overshoot (load /no load)
I traced the schematic for repairs
Here is a similar one on youtube from user  Elecifun:

All four of the front potentiometers failed, reading far too high.
There are 2x10K and 2x1K single turn pots. The failure is due to poor manufacturing I think, because the resistive track still measures correctly with a meter, but after the joint between the solder post and the track the value is very high.

tristate

[Cliff Matthews]

Everything OK? You say "performs well with no overshoot (load /no load)"  So then, you're happy with it?
Then you say, "I traced the schematic for repairs" So then you are studying it expecting a future failure?
Then you say, pot values are too high, without giving info or pics for the front panel board connected to 8-pin CN5/6.. (between TL431's and LM324)

What is it that you expect here? Your subsequent post (which you should delete) just says "test"     

[tristate]

I posted the test message, after my original message posting failed but with no error message from the forum (turns out due attachments being too big).

After posting worked, I tried to delete the post 'test', it wouldn't let me, it seems to be gone now.

Expecting nothing, after I replaced pots, everything fine (excellent value).

Just uploaded schematic because it doesn't exist online and others may find it useful.

Here are pics of the control board and a failed pot.

tristate

[DTJ]

Very nice work on documenting, I'm sure others will find this info very useful for repairs.
It also helps others like me who are in the market for a low end bench supply.

Cheers!

[Harvey17]

Just a quick note to anyone who has one of these, the rear left foot is held in with a screw which if overtightend will come in contact with the PCB right at the point where the mains input connects.  "Interesting" results would occur.

They also are fairly awful at any form of constant current limiting, being switchmode they jitter between CV and CC, especially at low current settings.

[Robert99d]

Hi sorry for opening up an old topic.
New here nice to meet you all
I've just got this power supply from eBay the 10A version, model ms3010D seems to be the same PCB
All seemed to be fine but when trying to current limit both CC and CV LEDs come on and it emits a high frequency buzzing ( from the transformer I think)
Is this normal for them to not current limit very well, as stated above?

On opening it up to have a look noticed R47 is snapped
Think seller is going to offer a partial refund but wanted to know if anyone can tell me what R47 does and is it likely to have caused any damage or can I just replace the resistor
Thanks for any advise
 Robert

[belvoir]

hello sir,
I have a problem with a Maisheng MS3010D when switched on the output voltage is at 39.00 volts and slowly goes down to zero, nothing adjusts, I have replaces fets but still the same I have also solderd front pots like you say... I wonderd if you new how to obtain some service information as I am a fully qualified tv engineer thank you so much for your help all the best kev…. cornwall england

[josephgut]

Hi, I have basically the same power supply, but the 10A version. Mine does not power up properly. When I turn it on a hear a high-alternating high-pitched noise. No display is active. I've heard that on a power supply this noise is typically from not enough voltage to the transformer? I've looked at the soldering and re-soldered things, tested the capacitors and don't see anything obvious. Any suggestions would be greatly appreciated.

Thanks,
Joseph

[xavier60]

I can't make much sense of the driver circuit. I wonder if Q4, Q5, Q6, Q7 are really all NPN?

[flindersit]

Hello reading on from the post I've been searching high and low for a replacement transformer marked on the board T3. The closest thing I found was a transformer called ERL 35 found on Ali Barbara link below (https://www.alibaba.com/showroom/erl-35-transformer.html)
I believe this is for the 30 V version and I'm needing the 60 V. The pinout is slightly different as seen pictures in AliBabaa.com
is anyone able to assist me to locate a new transformer after mine has gone short-circuit the primary site and it also took out IRF 840? Surely appreciate your assistance, I am an amateur electronics enthusiast learning as I go.

Kind regards Adrian.