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Reviews For: MFJ-4245MV

Category: Power Supplies

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Review Summary For : MFJ-4245MV
Reviews: 73MSRP: 150-200.
Description:
Switching and Non-Switching Power Supplies
Product is in production
More Info: http://www.mfjenterprises.com/products.php?prodid=MFJ-4245MV
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00733
WA5BDU Rating: 2001-06-28
Great little PS Time Owned: 3 to 6 months.
After getting my IC-706, I realized I didn't want a boatanchor class PS to go with it, since my intent is to lug it around. This little (and light) MFJ switcher is great for the job.

I don't know if MFJ has made improvements or not, but on mine the fan runs all the time and is quiet. I hate fans that go on and off and I also just hate fans in general, but they're in my computer and in my FT-1000 and the one in the MFJ PS is quieter than either of those by far.

Also--mine doesn't have a detent on the voltage control--but when I set it to the 13.8 V mark on the meter, it's dead on with my DVM.

No switching noise and the voltage doesn't move a bit with 20 amp keying.

73--Nick, WA5BDU
W3JJH Rating: 2001-06-08
Good Performance--But with a Safety Issue Time Owned: 6 to 12 months.
Let me start this review by saying that I design power supplies for a living. My present project involves low-voltage DC/DC convertors for a satellite. My last project was a high-power AC/AC convertor (yes, there really is such a critter) for use as a ballast for HID lamps.

This supply works quite well. Out of the box, the only "problem" was that the output potential was only 13.65 V instead of 13.8 V when the level control was in the reference detent.

When I removed the cover to find the trimpot to tweak the output level, I found that the safety ground (green wire) on the line cord was not properly connected to the chassis. It was connect, but the method was wrong. The grounding lug was on one of the mounting screws for the input potential selector switch. This is a clear violation of the safety agency requirement either to attach the ground lug either on its own chassis mounting point or to place it at the bottom of a stack of items on the screw with its own lock washer and nut.

The supply is grounded as shipped, but it would be better if the supply were built according to good safety practices. The supply is not safety agency listed (eg., UL, ETL, CSA) nor could it be as shipped. It may not be legal in CE countries.
OH2GBA Rating: 2001-03-23
nice! Time Owned: 3 to 6 months.
I bought the MFJ 4125, and I think it's a very nice power supply. Even with high power the voltage remains clean. No noise on my radio at all. The only noise is the Fan. And because the fan is just always running, it's a real dust collector too. So guess it's better to, every now and then, open the supply and take the dust away. I'm wondering how long the power supply will live actually.....
JAMES_BENEDICT_EX_N8FVJ Rating: 2001-02-17
No Problems! Time Owned: 0 to 3 months.
Purchased the #4125 power supply due to being the most compact 22/25 amp unit available. The power supply and my FT-100D will fit together in one compartment of my computer soft-bag! The output is 'clean' DC without 'birdies' in the receiver. Some switching type power supplies are poor performers in this area. The #4125 is advertised with over-current and over-voltage protection. After reviewing the schematic, I did not find the ultimate over-voltage crowbar on the output. The over-voltage must be managed by the regulator IC. If the IC fails, your radio may suffer damage. I will install a SCR 'crowbar' type over-voltage protection on the output! As for fan noise, the #4125 is quiet enough that the noise does not interfere with receive audio. I would have rated the #4125 a '5' if an over-voltage 'crowbar' type circuit on the output was standard from the factory.
AA1UY Rating: 2000-12-20
4225 MV : Decent unit but fan is noisy Time Owned: more than 12 months.
I got a 4225MV when they first came out. Neat little unit for tight-spaces and has a nice array of features. Worked well for me with no problems at all. However, noise from the on-all-the-time fan would definitely make me want to place the unit away from the operating position. I subsequently sold the unit when it was no longer required. Recently, I had the need to purchase a new supply and opted instead for a Samlex SEC-1223 which has a quiet, thermally-switched fan, a 3 year warranty and can be found for a little over half the price of a 4225MV.
KC4TXR Rating: 2000-12-20
Great Supply, Great Value Time Owned: 0 to 3 months.
It's inexpensive! It puts out a clean 22 amps without breaking a sweat! It has a quality board and cabinet! No EMI/QRM which is rare for a switcher! The fan sounds like... well... a fan. It's not loud and it's no big deal, get over it! This is a very high quality supply with a "no way you can lose" warrenty. God bless MFJ (I wouldn't be on the air otherwise). BTW, I have the MFJ 4225MV
W3AIR Rating: 2000-10-27
Buy other Time Owned: 6 to 12 months.
Switching Power Supply MFJ-4225MV:
I always get on the air reports of cooling fan noise. MFJ does not respond to help inquiry regarding an inherent design problem. Their ads
say the supply is "whisper quite". I say BALONEY.
W7NEW Rating: 2000-10-25
My Fan Isnt Noisy Time Owned: more than 12 months.
I have a Mfj 4245mv and the fan stays on all the time and doesnt make any real noise. I dont know what supply everyone is talking about but it cant be the same modal I have. I have had this supply for a year, after my Alinco Liner supply craped out and have had no problem with it at all. I love this supply. It is lite small and has been a releiable unit. I do however think that the supply is a dust collector with that fan on all the time but I cant hear it thats for sure.
N1KFC Rating: 2000-10-25
awful Time Owned: 0 to 3 months.
After 2 hours trying to put up with the noise of the 45a switching power supply, I ordered another Astron. The MFJ makes a nice paper weight... at least then it is quiet.
KE5UT Rating: 2000-10-24
Good Supply; Noisy Fan Time Owned: more than 12 months.
I bought this supply in 1998. The fan died shortly after purchase. I sent it back to MFJ and they replaced the fan -- and simply connected it to run all the time! The supply then ran cold, but loud. Recently, I connected a 50 ohm, 10 watt resistor in series with the fan. Now the supply runs cool, even after long QSO's, and quiet. I didn't measure the regulation, but it appears fine under 25A load. A good, solid supply made ear environmentally friendly!