Qw ms-305d input power swap

Thread Starter

Mrstude

Joined Feb 27, 2022
3
I was given an Ms-305d . The tester is wired for 220v European. I would like to change it to 110v without using an external step-down unit. Can it be done ? The attached schematic is for a 605d. The power input circuit appears to be the same.
 

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MisterBill2

Joined Jan 23, 2018
13,793
What I see in the schematic diagram is that a you need to do is change the 20V/110V switch to the 110 V position. Probaby you will also need to change the mains power connector. I am not certain where that switch is located, so you will need to search a bit.
 

Thread Starter

Mrstude

Joined Feb 27, 2022
3
What I see in the schematic diagram is that a you need to do is change the 20V/110V switch to the 110 V position. Probaby you will also need to change the mains power connector. I am not certain where that switch is located, so you will need to search a bit.
Unfortunately, this 305 unit does not have a power conversion switch. It is wired only for 200 volt.
 

Thread Starter

Mrstude

Joined Feb 27, 2022
3
Unfortunately, this 305 unit does not have a power conversion switch. It is wired only for 200 volt.
I do not see any switch for voltage change in the schematic
Unfortunately, this 305 unit does not have a power conversion switch. It is wired only for 200 volt.
After re inspecting the CB, I found the connection pads (K1 and K2) for the 220/110 switch (K). It appears the company who copied this power supply decided the leave it out of their version and sell them in a 220 or 110 version. All I need to do is connect the pads (close the switch) and it should then work on 110. Thanks for the advise !20220227_213142.jpg
 

MisterBill2

Joined Jan 23, 2018
13,793
I have a similar power suppy, at east I think it is simiar, max ratings are 50 vots at 50 amps, with a 15 amp 40 volt mains connection. I have been using it with my 120 volts mains for over a year now without ever changing anything. Of course I do not get max power, but as I have not yet required that, no problem.
I was given my supply because others could not make it work.The problem, as I explored it, is that with the current imit set to zero, or with the over-voltage trip set to zero, there is no output. So the "repair" was fairly simple. It often is handy to examine the instructions book for new equipment.
 
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