View Full Version : 48V Power Supply Module cooked - what should we check before simply replacing it?

12-02-2003, 10:54 AM
This is a question I wanted to ask ShopBot by telephone today, but there is only an answering machine.

We cooked the Mean Well SP-300-48 power supply module (http://www.meanwell.com/product/sp-300/default.htm) of our very early model PRT today. A fuse replacement did not revive it. Took it to the local service agent (dealer) and they confirmed that a couple of components on the board are blown as well. A new power supply will be with us tomorrow.

Now we are wondering:

- did the SB control board cause an overload on the power supply and will our new supply also be cooked if the fault is still there?

- is there a way to check out the control board before powering it up again?

- we have a (disposable/sacrificial) 24V supply available - would it make any sense to power the control board with this 24V supply to see if smoke is generated?

12-02-2003, 10:44 PM
This is the first time in 3 years that our SB has broken down and we couldn't repair it in a few minutes by ourselves. It is rather dissapointing to find no support here at the Forum, and to find a telephone answering machine at the SB company inside normal working hours.

E-mailed the above questions to SB, and got this reply:

Sorry about the answering machine, but most of us were in training this morning and that left about two people out here to answer the phone. The power supply has very good internal protection and we rarely see any of them fail. Even when there has been a direct short on the control board the LED on the power supply will blink when connected to the board and will stay on steady if disconnected from the board. Repairing the board has always resulted in the power supply functioning normally. You can check for a short where the power supply connects to the main board, but as I said a short usually doesn't blow the power supply. It sounds like a component simply failed on the power supply.

Which still leaves us with the same problems. We have no confidence that the new power supply will be ok when we plug it in. I am still tempted to power the control board with our cheap 24V supply before we plug in the new expensive 48V supply . . . . . . . . .

12-03-2003, 06:36 AM

I have a new board running on 24V. ShopBot claims it will run a lot faster if I go to 48 Volt. I have a 48V power supply but have not taken time to install it as I have other things I feel are more important right now.


12-03-2003, 07:52 AM
Thanks Ron. We have the new power supply installed and the SB is running again. Price of new supply around US$200. Old supply been sent off for repair.