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Need Help : MCP355 pump dead

1061 Views 3 Replies 4 Participants Last post by  rakesh_sharma23
Hi guys, does any of you out here knows how to repair a dead mc355?

what happened was, it worked before maybe for 24 total hours of use

then it was left for about 2 months with coolant in it.

then i fired it up today it wont power on.

i opened it, there was some mildew build up on the magnet core

i cleaned it put it back on, still nothing

i'd pay for shipping to and back, and also compensate you for your trouble

i just dont want to buy a new one.

PLEASE HELP! because i have to finish SCARLET!
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There really isn't all that much in one that can be easily fixed, just the impeller that rides on the ceramic bearing under it and then the PCB underneath that.

Did you pull the impeller all the way out? If you didn't just pull straight up on it and see if there is more crud under it. Be sure to check your molex connector also, if you haven't already, to make sure your making good contact.

The armature is underneath that in the bottom of the pump case, just pull up on that and you can look at your PCB and see if you have a burned spot or widened out traces.

And as suggested you can always RMA it.

Here's a pic of a old 18W orange impeller that died on me with obvious burns and enlarged traces. I had another one die that I could see no reason for it going out at all.

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My friend Ashish(mav2000) from India had MCP 355 Pump and it went dead few days ago and i am trying my best to make it alive. So here is what fault i found. I like to share this so that if any one can found some thing usefull which can be shared and help in making this pump alive again.

Some breifing:-
Three Power MOSFETs sections are ok. MOSFET are APM4532 Dual Enhancement Mode MOSFET (N-and P-Channel).
Main Control chip is giving a load resistance of only 10 ohms, which in turned overloaded the small regulation chip(the three pin chip) resulting in shorting 12 volts power line and burning the chip and the filter coil.

Voltage regulation chip is ST-H7805 (5v regulation chip). I have few replacements to replace this chip.

Control chip is ST-(7FLITE35F2Mb /991) this is what I can read out. (Unable to kind it on ST site)

Here is the pic.

Rakesh Sharma

Found the link of the Datasheet of the Controller chip http://www.st.com/stonline/products/...7lite35f2.pdf.

This is a 8 Bit Programmable chip. So this particular chip has been programed to run the pump.

In short, even if i got a free sample from ST or any other place. The chip will not have the particular programmed in it as the MCP355 pump chip have. So replacement of chip will not work and this pump cant be repaired.

Sorry friend. This is the best i can do.

Rakesh Sharma
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