|Heavy duty reliable supply
||Time Owned: more than 12 months.
|I have read the reviews of this linear supply and I am quite surprised. I purchased mine about 15 years ago and it has been running steady ever since. For the past 4 years it powers my ICOM IC-7600, even on power hungry modes like RTTY without a problem. Mine is the fixed 220 volt model as I live in South Africa. I've had a look inside and as a previous reviewer pointed out, it uses discreet components unlike more modern designs but that just makes it easier to repair should I have to. I will head the warning of those that have had problems and install a crow bar circuit in my power supply for insurance. I just can't knock a product that has run reliably for years and powered some expensive gear without a single problem.|
|dangerous putting out 28 volts. dont buy
||Time Owned: 0 to 3 months.
|my friend gave me this after the power switch broke. it should be noted last month his radio had issues and had to be replaced. he ran the new one without issues then broke the power switch. i ordered the exact chinese switch on ebay and replaced it. I noticed a burnt resistor on the regulator board.i tested it without removing it to see if it was open shorted. it wasnt so powered it up and I see 28 volts out, basically means no regulation is happening. this has the 110/220v switch. basically this is a bad problem waiting to happen like the mfj 4245mv..if you see it run. they probably made the mfj one. If you own one of those mfj timebombs you need to read this. neither one are worth the risk cooking a HF radio. if your that cheap go buy a car battery at wal mart!!!|
This is cheap junk, maybe the transformer is usable but its a half wave with lots of cheap diodes and looks like 8 pass thru transistors. just weird crap.
buy a samlex sec1235m if you want small
or get a astron 35. KEEP IT SIMPLE STUPID...THATS MY MOTTO.
ASTRON ASTRON ASTRON
|Technically, it does supply power...
||Time Owned: 6 to 12 months.
|In the spirit of "0 - Awful!" I really can't think of a more flattering description for this apparatus (I think "power supply" may be too generous a term).|
After the first 20 hours of operation -- mostly some SWLing, the unit experienced some kind of surge, after which output shot up to 28.5v and stayed there, letting the smoke out of a modestly expensive rig I had plugged in.
The place I bought it from acted surprised, but was of course unwilling to provide a refund or replacement, or even a schematic for service.
Much happier with the Astron I got to replace it.
Certainly make your own decisions, but if you choose to get one of these, please be sure you have other measures in place to monitor it and to protect your equipment from harm should it fail.
|Fire hazard at best
||Time Owned: 0 to 3 months.
|These things are not rated for US voltage, like the previous reviewer had found out, the internal voltages are far to high, and they get HOT, very hot. The one I had here lasted about 3 days before it quit working. Luck it was on a glass desk, because it was so hot, I could not even tough it to pick it up, if it had been on another surface or close to paper or something else flammable, it could have caused a fire. The worse part about it, it was only powering a receiver, drawing maybe 2 amps... |
The construction is a joke, it is with out a doubt, the very worse construction I have seen. I looks like it was soldered with a cutting torch. While the other reviewer said it was OK, and his/hers may have been, this one was not. My dog could do a better job soldering.
It is built with a lot of cheap parts in a low cost way, and there is nothing wrong with that, if it would have been done with quality craftsmanship. The main transformer is in no way rated for US voltages of 115-117, and while it being 110 doesn't sound like it should be an issue, it absolutely is.
These things should be banded for sale in the US, rounded up and sent back to where ever it is they were stuck together at and dumped there. Junk, pure and simple junk. Unless you want to make a bucking transformer to knock down the US voltage, your going to have a useless power supply and potentially dangerous to you and your family. This is with out a doubt, the single most worthless piece of gear I have ever owned. I am sorry I bought one.
|Good basic value but there is a serious gotcha that is fiaxable
||Time Owned: N.A.
|This a no frills high current linear power supply. It uses all discrete components and has no fan. It is a great replacement if one has switcher noise. I am using it with by Icom IC-7410 and the slight amount of noise i had with my previous switcher is now gone along with the fan noise.|
It is essentially a steel black box with an on-off switch (neon lighted) two large binding posts on the front panel and pass transistor heatsinks, a fuse holder and AC cord entry on the rear. There is a handle on the case top as this power supply is heavy, about 30 lbs.
I opened up the case and found that the component quality is OK and the assembly quality OK as well. The circuit takes an "economical" approach to things but is sound. First, the rectifier assembly is fullwave and not a fullwave bridge. Each leg consists of seven 3A 200 PIV diodes in parallel giving about 21A capability to each side. This is OK and these diodes are only a few cents each. The filter cap assembly consists of six 4700 uf electrolytics instead of a single computer grade cap. This is also OK and saves more money. The regulator pass transistor assembly consists of six 2N3055 devices in hard parallel with each pair mounted on separate adjacent heat sinks. The power transformer is a massive beast that one would expect at this current level. The rest of the components are mounted on a single PCB and as mentioned previously are all discrete and readily available should the need arise.
I added a few cable ties to tidy things up a bit and touched up all the high current solder joints although I am sure that they ere probably OK (just to make sure).
I turned on the unit and the voltage came up to exactly 13.8 VDC. I ran the IC-7410 in receive (about 2.2A draw) for several hours. As one would expect from a linear PS, there was no noise in the receiver and no fan noise as it has no fan. After about two hours of running I touched the heat sink assembly and found that it was quite hot. I then ran it at 100W RF output into a dummy load and the heatsink became way too hot. I had read several reviews elsewhere about overheating and I became a bit concerned.
I measured the no load voltage at the input to the regulator and found that the no load voltage was at 29.7 VDC. At the 2.2A draw it had dropped to 27 VDC and at 23A draw it was down to 26 VDC. This means that at the 23A point the regulator was dissipating about 225W. No wonder it was hot. Even at the 2.2A pint the power dissipation was at 26W. Not a large number but it still heated up things pretty good.
I looked at the instruction sheet schematic and something caught my eye. There are several versions of this PS available for different AC input voltages. These are 110V, 115V, 117V, 120V, 220V, 230V, 240V, 110V/220V and 127V/220V. Each voltage had a box before it and mine had the 110V/220V box checked. My line voltage is typically 122 VAC and it became clear what the problem was. This version was obviously made for the Asian/Japan market where line voltage is 110VAC. Most of the ones for sale in the U.S. are this version (110V/220V).
I took an old 12VAC @ 4A filament transformer I had in the junk box and I put in a small chassis with a line cord and socket and connected the transformer to buck the AC input voltage. This reduced my line voltage to 108.5VAC (remember this has to pass only the AC line current, about 3A, not the DC side output current. I repeated the heat tests and now the PS runs nice and cool as it was designed to. At 23A draw the input to the regulator is now 19VDC so now the PS is dissipating 160W less!
This is actually a nice, quiet and basic supply but as supplied, at least for the U.S., it is the wrong version (we should have the 120VAC model). Adding a small buck-boost transformer on the AC side though solved the problem.