Excellent upgrades👍 I was looking to buy one of these from gigs parts for $150 but after seeing how cramped the build is will probably opt for the Pyramid 30a power supply for the same price. I have had good luck with Pyramid supplies.
Just bought a new one. Many of the problems of the early model seems to have been address. The soldering is limited as they went to crimp on connectors for most connections. They have added caps to the DC outputs. They still use a two prong cord, they must have there reasons. The only thing missing is the meters are not lit but I don't know if that was a add on. Easy to do once the warranty runs out.
We used this power supply at our CW station for Field Day in 2016, and received poor signal reports. I replaced it with my Samlex switching supply and cleaned it up. I am planning to icorporate the suggested RFI mods, thanks for posting this video! Lou KT1R ... look for us as N1ME in 2017 -- 73's
I have 2 of these MFJ4035M supplies and have not experienced any issues. I have tested to 24 A, not just 6A. I do thing adding AC safety ground a good idea. The output caps on the DC are too small to do much of any RF suppression. Only issue I have had with this supply the variable voltage knob had setting for 13.8V and there is pot inside to adjust the voltage so when the panel pot is set to 13.8V the output will be 13.8V. I have had the internal pot get flaky and the adjustment be off. I also have had to replace the panel pot. IMHO this is much better supply than any Astron. I also have 2 RS35M Astron supplies. The MFJ is much better built. Astrons are about as cheap one can get, but they do work.
I worked pipeline back in the 80's, doing so as a plastic pipe fuser and welders helper. what gets me Is those who must see beautiful welds/solder joints. my mentor, welding teacher; an alaskan pipe line welder, exclaimed it's not the look of the weld after it done. it's visually watching the puddle for penitration. that take time to learn. as for what looks like a cold solder joints. if you wrench on the wires and it doesn't snap loose. enough said.
Pretty much why I left it alone. They felt solid and did their job. I don't get all hung up over it, but I do try to be a bit neater when I do the work. There's a degree of self-discipline that's evident in clean results.
Kevin Loughin ,,, some might call that anal or ocd. but it is what it is. I try to keep my solder jobs minimalistic. that way I save solder. being single, disabled, on a fixed income; well below the poverty level, no formal skills, but not a blubbering idiot, but I get by on the education I didn't pay money for: on the job training or just simple hobbyist education. like my interest in monatomic gold. I've never used it, i cant afford it, so i read, then filter the opinion from fact. just the facts, ma'am. reading being the fundamental for most educations. but I'm more audio visual. if I can find it here or other outlets, I do so. kinda like with my mentors, when I was pipelining mains and services in towns across n.c. and s.c.. or being Elmered with radio and circuitry. one last thing that rides under my skin is how many will demean amplifiers. a amp is a simple circuit. but so many look at a c class amp and say it's junk. I say it's a starting point. even if the basics of the amp is broad banded. it only need simple tuners to cut the band spread. I see the everything from being educated as a wagon wheel. in my thought process, work gets done at the core or hub. then there are short cuts, those are spokes. and all roads go to the same place. thats the rim or tire. and that's where progress advance.
I hear ya, school of hard knocks, hands on. There's value to that, practical, real-world experience can teach things that just can't be fully covered in a book. You had me looking up monoatomic gold. I was given pause when I saw it bottled. Since elements don't become 'monoatomic' until they are pushed to their gas state where the atoms can separate to a point where they exist alone. Gold has to be heated to over 5000 degrees Fahrenheit to pass from boiling to gas and enter a monoatomic state. Kind of hard to drink a 5000+ degree vapor!
Thanks for a very useful video! I've performed the mods you demonstrated and it has vastly improved the usefulness of this power supply. While in there I also cleaned up the solder joints on the rectifiers and performed the "fan mod" to reduce the fan noise (I see the unit you displayed here already has that mod.. the resistor going from one of the rectifier leads to the fan). I really enjoy your videos, keep up the great work!
My MFJ4035 has been in service for 14 years now, I have not seen this problem, nor have I had any issue with this supply during this time. I would buy another should the need arise.
I have the same power supply, bought from the family of a silent key. First thing I did was ground the cabinet. How could anyone not use a 3 prong power cord? Thanks for the video, I will add your other updates. Thanks.
I have this same power supply, which was stored in a box for over 10 years. Previously it was working well. But now the voltage meter fluctuates and does not stay as set with the voltage adjustment knob.I did open the unit up to blow any dust in there but the problem persist.Can you tell me why this is happening?
That Mfj 4035mv doesn't come with lighted meters from the factory which means someone was in there mucking around which might explain the sloppy solder job. I bought one of these new a couple of weeks ago and get great signal/Audio reports! I also popped the hood on it and everything looks clean and professional. Did the owner of the supply ever let you know if your improvements worked? Dave
Yes, it was much improved for him, he's quite happy with the results. His was an earlier unit, and the solder points were all original where they were messy. MFJ has people doing the work, so it probably depends a great deal on which individual did the assembly on your particular unit. I'm sure some workers take more pride in their work than others.
Hey Kevin, I was talking to a tech at Mfj last week and from what I gathered, this supply is made overseas but apparently some of their supplies are made here in the states. The tech I spoke with has the 4035mv at his work station and he said his supervisor has one at his as well. He says their built like a tank and he likes them. Dave
The owner had five that were all a little different. Only one matched this exact model. I'm not sure where he got them. I sent them back along with the unit, so I don't have a copy. Sorry.
Hi Kevin. I need some help. I 've bought this power supply but the issue is I have 220Vac in my country. How big should be the power voltage converter. How many watts? Thank you.
I'm really disappointed you didn't do the proof at the end by measuring the transient a/c voltages at the load like you did at the beginning. You stated the problem, but never quite showed that you solved the problem you stated.
It's fine. Max current draw on the mains side will be around 4.02 amps. Even if you managed to hold the power supply at 35 amps for any length of time, that cord shouldn't get warm. It came with a 600 watt computer power supply. The MFJ under it's max 35 amps on the DC rail is drawing 483 watts. At it's nominal 30 Amps DC side, only 414 Watts.
Kevin Loughin Yeah i recognized the style of cord. it just looks to me like one of the way too thin ones that sometimes ship with chinese equipment. If its only going to draw 4 amps yea it should be fine.
With the few MFJ products I've had my hands in so far, I'm not buying their stuff any more. I just fixed my MFJ SWR meter, bad diodes on the VHF side thanks to a bad amp that had been hit by lightning. It had similar poor work. Gotta work on my analyser next. Once in awhile it needs a thump on the side to start working....
Great video -- I am a total HAM beginner and have a general question: Could I not directly use an Automotive battery together with a DC-DC converter to avoid all problems of other power supplies -- especially if I am transmitting max. 1h a day. After usage I would recharge the accumulator over night. I would need to check the effiency of the charging process (for slow charging it should be fitting to the free energy of the double cell reaction of the accumulator). What would be the disadvantages of such an approach ? Cheers and thanks for all your videos. Stephan
Oh yes, you could absolutely use a battery with some kind of trickle charge or intermittent charge like solar. I have a battery system in the house that my QRP radios run off. It's charged by a small "wall wort" transformer to keep it up and I can run for days off the battery if need be.
Well done video Kevin and very informative. Curious what you would/could do to reduce the RFI further if you were trying to be super anal about your power source?
I cannot believe that that wiring is legal in the US. If there's a transformer failure and live connects the chassis then chassis is live and potentially lethal.
I believe that you know by now that MFJ is building their equipment in Taiwan. I have a SWR meter from MFJ. Back in the day (up to 90s) we had to raise money to get a high quality device depending on the brand of course first and the model second (any device, e.g. I was buying audio-video equipment then), now even if you have the money to buy an equipment from a well known brand, you don't really know if its quality made.. Sad really.. I saw a studio monitor (in 2016) from FOSTEX that had a cost of $150 and got my attention. (for crying out loud, Beatles were recording with Fostex equipment in the 60s/70s), and that 2016 model was a piece of junk! You take it out of the box and throw it to the garbage..
most mfj equipment, including ameritron, goes all flimsy when you take one part of the encasement off/apart. shame on mfj for such poor/minimalistic engineering.
Excellent upgrades👍 I was looking to buy one of these from gigs parts for $150 but after seeing how cramped the build is will probably opt for the Pyramid 30a power supply for the same price. I have had good luck with Pyramid supplies.
*This is one of my favorite channels have been binge watching for a few days now!*
Just bought a new one. Many of the problems of the early model seems to have been address. The soldering is limited as they went to crimp on connectors for most connections. They have added caps to the DC outputs. They still use a two prong cord, they must have there reasons. The only thing missing is the meters are not lit but I don't know if that was a add on. Easy to do once the warranty runs out.
We used this power supply at our CW station for Field Day in 2016, and received poor signal reports. I replaced it with my Samlex switching supply and cleaned it up. I am planning to icorporate the suggested RFI mods, thanks for posting this video! Lou KT1R ... look for us as N1ME in 2017 -- 73's
Good stuff Kevin,amazing the corner cutting to save pennies in production.
The 'L' on the mains plug is 'Live' or 'Line' both mean the same.
Here in the U.K we have Earth, Live and Neutral mains connections.
I have 2 of these MFJ4035M supplies and have not experienced any issues. I have tested to 24 A, not just 6A. I do thing adding AC safety ground a good idea. The output caps on the DC are too small to do much of any RF suppression. Only issue I have had with this supply the variable voltage knob had setting for 13.8V and there is pot inside to adjust the voltage so when the panel pot is set to 13.8V the output will be 13.8V. I have had the internal pot get flaky and the adjustment be off. I also have had to replace the panel pot. IMHO this is much better supply than any Astron. I also have 2 RS35M Astron supplies. The MFJ is much better built. Astrons are about as cheap one can get, but they do work.
I worked pipeline back in the 80's, doing so as a plastic pipe fuser and welders helper. what gets me Is those who must see beautiful welds/solder joints. my mentor, welding teacher; an alaskan pipe line welder, exclaimed it's not the look of the weld after it done. it's visually watching the puddle for penitration. that take time to learn. as for what looks like a cold solder joints. if you wrench on the wires and it doesn't snap loose. enough said.
Pretty much why I left it alone. They felt solid and did their job. I don't get all hung up over it, but I do try to be a bit neater when I do the work. There's a degree of self-discipline that's evident in clean results.
Kevin Loughin ,,, some might call that anal or ocd. but it is what it is. I try to keep my solder jobs minimalistic. that way I save solder. being single, disabled, on a fixed income; well below the poverty level, no formal skills, but not a blubbering idiot, but I get by on the education I didn't pay money for: on the job training or just simple hobbyist education. like my interest in monatomic gold. I've never used it, i cant afford it, so i read, then filter the opinion from fact. just the facts, ma'am. reading being the fundamental for most educations. but I'm more audio visual. if I can find it here or other outlets, I do so. kinda like with my mentors, when I was pipelining mains and services in towns across n.c. and s.c.. or being Elmered with radio and circuitry. one last thing that rides under my skin is how many will demean amplifiers. a amp is a simple circuit. but so many look at a c class amp and say it's junk. I say it's a starting point. even if the basics of the amp is broad banded. it only need simple tuners to cut the band spread. I see the everything from being educated as a wagon wheel. in my thought process, work gets done at the core or hub. then there are short cuts, those are spokes. and all roads go to the same place. thats the rim or tire. and that's where progress advance.
I hear ya, school of hard knocks, hands on. There's value to that, practical, real-world experience can teach things that just can't be fully covered in a book.
You had me looking up monoatomic gold. I was given pause when I saw it bottled. Since elements don't become 'monoatomic' until they are pushed to their gas state where the atoms can separate to a point where they exist alone. Gold has to be heated to over 5000 degrees Fahrenheit to pass from boiling to gas and enter a monoatomic state. Kind of hard to drink a 5000+ degree vapor!
Thanks for a very useful video! I've performed the mods you demonstrated and it has vastly improved the usefulness of this power supply. While in there I also cleaned up the solder joints on the rectifiers and performed the "fan mod" to reduce the fan noise (I see the unit you displayed here already has that mod.. the resistor going from one of the rectifier leads to the fan). I really enjoy your videos, keep up the great work!
Seeing this MFJ PSU w/o a chassis ground just removed MFJ as a potential source for PSU for Ham use.
My MFJ4035 has been in service for 14 years now, I have not seen this problem, nor have I had any issue with this supply during this time. I would buy another should the need arise.
I tape my wire nuts with electrical tape to prevent wire nut from coming loose.
I have the same power supply, bought from the family of a silent key. First thing I did was ground the cabinet. How could anyone not use a 3 prong power cord? Thanks for the video, I will add your other updates. Thanks.
what was the ac voltage from neg to chassis ?
different tests were preformed before and after...
tnx Dan kb7uxe
Actually, this is a re-branded Zurich DPS-3012M power supply. Remove the MFJ sticky labels and you'll see..
The 'L' on the new AC plug denotes 'LINE' side or HOT.
Live
I have this same power supply, which was stored in a box for over 10 years. Previously it was working well. But now the voltage meter fluctuates and does not stay as set with the voltage adjustment knob.I did open the unit up to blow any dust in there but the problem persist.Can you tell me why this is happening?
That Mfj 4035mv doesn't come with lighted meters from the factory which means someone was in there mucking around which might explain the sloppy solder job. I bought one of these new a couple of weeks ago and get great signal/Audio reports! I also popped the hood on it and everything looks clean and professional. Did the owner of the supply ever let you know if your improvements worked? Dave
Yes, it was much improved for him, he's quite happy with the results. His was an earlier unit, and the solder points were all original where they were messy. MFJ has people doing the work, so it probably depends a great deal on which individual did the assembly on your particular unit. I'm sure some workers take more pride in their work than others.
Hey Kevin, I was talking to a tech at Mfj last week and from what I gathered, this supply is made overseas but apparently some of their supplies are made here in the states. The tech I spoke with has the 4035mv at his work station and he said his supervisor has one at his as well. He says their built like a tank and he likes them. Dave
Kevin, thanks for the excellent video. Do you have a proper schematic? I have one, but it doesn't match most of the components. - Bob
The owner had five that were all a little different. Only one matched this exact model. I'm not sure where he got them. I sent them back along with the unit, so I don't have a copy. Sorry.
Hi Kevin. I need some help. I 've bought this power supply but the issue is I have 220Vac in my country. How big should be the power voltage converter. How many watts? Thank you.
I'm really disappointed you didn't do the proof at the end by measuring the transient a/c voltages at the load like you did at the beginning. You stated the problem, but never quite showed that you solved the problem you stated.
Yeah, thought about that this morning. I did measure it and it was less than 1 Volt.
l stands for line. That mains cable seemed awfully thin.
It's fine. Max current draw on the mains side will be around 4.02 amps. Even if you managed to hold the power supply at 35 amps for any length of time, that cord shouldn't get warm. It came with a 600 watt computer power supply. The MFJ under it's max 35 amps on the DC rail is drawing 483 watts. At it's nominal 30 Amps DC side, only 414 Watts.
Kevin Loughin Yeah i recognized the style of cord. it just looks to me like one of the way too thin ones that sometimes ship with chinese equipment. If its only going to draw 4 amps yea it should be fine.
nice fix. but as long as you had the case open didn't you feel it was worth re soldering some of that original slop ?
MFJ - Mighty Fine Junk ;)
With the few MFJ products I've had my hands in so far, I'm not buying their stuff any more. I just fixed my MFJ SWR meter, bad diodes on the VHF side thanks to a bad amp that had been hit by lightning. It had similar poor work. Gotta work on my analyser next. Once in awhile it needs a thump on the side to start working....
LOL
ground shouldn't be soddered, must be mechanical connection. Also neutral is also hot in AC. It's part of same power circuit
Why would the casing have had a PD of 61V? Simple due to impedance from the transformer?
Bleed through from the bypass capacitors to the chassis. Voltage, but no current. It wouldn't shock you.
Great video -- I am a total HAM beginner and have a general question: Could I not directly use an Automotive battery together with a DC-DC converter to avoid all problems of other power supplies -- especially if I am transmitting max. 1h a day. After usage I would recharge the accumulator over night. I would need to check the effiency of the charging process (for slow charging it should be fitting to the free energy of the double cell reaction of the accumulator). What would be the disadvantages of such an approach ? Cheers and thanks for all your videos. Stephan
Oh yes, you could absolutely use a battery with some kind of trickle charge or intermittent charge like solar. I have a battery system in the house that my QRP radios run off. It's charged by a small "wall wort" transformer to keep it up and I can run for days off the battery if need be.
Did you try a pure battery approach also for a 100 W radio ? Would this work too ? Thanks for your answers, Kevin and 73 from Zuerich, Switzerland ...
I WAS LOOKING A SCHEMATIC FOR THIS PS I CAN NOT FINE ONE ,DOSE ANY ONE HAVE A SOURCE MFJ ONLY HAVE A USER MANUAL MINE LOOKS IDENTICAL TOO YOURS.
Well done video Kevin and very informative. Curious what you would/could do to reduce the RFI further if you were trying to be super anal about your power source?
I cannot believe that that wiring is legal in the US. If there's a transformer failure and live connects the chassis then chassis is live and potentially lethal.
You know your hand is in the way all the time, right? So when you say "it goes here, and uses this wire...." all we see is your hand.
I believe that you know by now that MFJ is building their equipment in Taiwan. I have a SWR meter from MFJ.
Back in the day (up to 90s) we had to raise money to get a high quality device depending on the brand of course first and the model second (any device, e.g. I was buying audio-video equipment then), now even if you have the money to buy an equipment from a well known brand, you don't really know if its quality made.. Sad really.. I saw a studio monitor (in 2016) from FOSTEX that had a cost of $150 and got my attention. (for crying out loud, Beatles were recording with Fostex equipment in the 60s/70s), and that 2016 model was a piece of junk! You take it out of the box and throw it to the garbage..
most mfj equipment, including ameritron, goes all flimsy when you take one part of the encasement off/apart. shame on mfj for such poor/minimalistic engineering.
L = Line...
L should have been the Black lead.