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Reviews For: MFJ-4035MV

Category: Power Supplies

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Review Summary For : MFJ-4035MV
Reviews: 52MSRP: 150.
Description:
35 Amp Adjustable Power Supply
Product is in production
More Info: http://www.mfjenterprises.com/products.php?prodid=MFJ-4035
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00523.4
AG4GT Rating: 2002-12-11
Good Supply-Not the best quality Time Owned: more than 12 months.
I have one of the MFJ-4035MV’s. I have found it to be a good supply although I have never really loaded it up, about 10 amps is all I have ever drawn from it. I bought it because I wanted to be able to use it with HF equipment at some time in the future, which has not arrived yet. I do not think that it is built with the most up to date design, and some of the soldering tends to be a little clunky but the design is straightforward and robust enough to do the job. I also bought it because it is a linear as opposed to a switcher. I can work on a linear, a switcher, well perhaps not.

The thing is VERY heavy, they tell you that in the add. I solved the moving around problem by putting a robust handle on top. I placed the handle over the center of gravity, which is almost centered over the transformer. It looks a little funny being off center on the cabinet but is certainly makes moving it a lot easier. Also when you pick the supply up, it stays level and doesn’t try and twist out of your hand.

The supply also has a unique cooling fan arrangement; the more power you draw from it, the faster the fan runs. This is controlled by a simple comparator circuit, which biases a transistor on and off. The only problem with this system is that at idle, the fan does not run at all and the supply gets quite warm. I solved this by paralleling the transistor with a large power resistor (around 180 ohms at about 5 watts I think). This keeps the fan running at a slow speed all the time. When you draw power, the transistor kicks in and runs the fan as designed. A second small problem that is unique to my setup is the air intake vent. The supply is sitting on a shelf with the back to a wall. It wants to suck the air in from the back. I put some tape over that vent to force it to draw air from the side.

With all this said, I have a suggestion for limited budgets. I have found several sites on the net that tell you how to modify and parallel old computer power supplies to get up to about 30 amps at 12 volts. I have wanted to try this. If I did not have the MFJ–4035 I would have already tried it. This may be something you can do on the cheap if you can find about three supplies and you feel like tinkering.
K4CDK Rating: 2002-10-24
Great Service Time Owned: more than 12 months.
Purchased this power supply with my first radios, it is 19 lb. piece of equipment and hard to move around. Has been in place running two radios almost around the clock for two years. Easy to use and quite running. Power adjusted to 13.8 and has not dropped down any since being put in use.