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Thread: Adjustable bench power supply - buy or build yourself?

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    Pair of es460c boards in the PCSA-4 circuit board holder, connectors & crimps here...slowly getting closer.

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    Johnno (16-05-20)



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    Oh yes, replace all the RIFA caps.. I watched that Video you posted and the damn thing exploded.. /Great vision

    That would definitely Never look good after fixing the unit and that happens.. Those old RIFA caps do look great exploding thou'. lol

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    Johnno (29-05-20)

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    Two bricks refurb'd and reassembled, leaving the third board off it's heatsink for now, so it's easy to double-check the connector pinnings.




    Last edited by wotnot; 22-05-20 at 01:39 AM.

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    Johnno (29-05-20)

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    Sat down and put the necessary wires in a connector,




    Grabbed a brick, plugged it in, attached multimeter and turned it on...tiny click as the relay closed, and then straight to voltage, quiet as a church mouse..



    Put the last unit back together, get a load happening and test all three ...think more about a case, and hopefully the dps50v15 isn't too far away...

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    Johnno (29-05-20)

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    I hadn't actually taken that much notice, because the units are very similar, but I was actually supplied 2 x ES460C, and a ES460B variant. When I was testing the units for coldstart/idle, I noticed the ES460B was less than happy about something ; I figured it had something to do with the add-on voltage adj. circuit. Typically I run this old gear up first with no load for a couple of hours, and noted the B version was +/- 1.5volts every now and then, whereas the C versions are rock solid.

    Then I'll run things at about 25% load for a couple of hours, and keep adding load until I reach full output and/or the unit protection circuitry kicks in...right now, the C units are taking turns at a 50% load;




    They seem happy, however as soon as I put more than 1amp on the ES460B unit, it started shutting down/restarting....so it has a problem ~ I put it aside for a closer squizzy later, after all... I have 2 working units, so it shouldn't bee too hard to find the problem.

    I contacted the seller, to let him know I'd been supplied an 'odd bod', and passed on a bit more information about getting these things going. Without even asking for a replacement, the seller immediately said they'd send me another ES460C, and I can keep the B version. Awesome.

    Couple of things I pointed out to them.... the circuit diagram in the ebay listing, omits one very important connection -- the mains earth. Without that, all the high voltage spike/transient suppression is useless;



    Then, if one ever buys these things, the easy/quick way to refurb and get them going, requires these bits;

    *DIN41612 plug to suit units - RS Stock No.757-7942
    *DIN Power crimps to suit - RS Stock No.741-2933
    *2 x 4n7 RIFA (C4, C8) - RS Stock No.210-594
    *1 x 3n3 RIFA (C79) -- modded parallel of RS Stock No.875-2419 + RS Stock No.875-2428

    Tested the DC-DC buck converter to 10amps and it didn't explode =) Got pretty warm, but withstood the load for a good 10mins. Still, better stick that in the cooling airflow to be sure.

    The volt/amp gauge is useless... volt reading is good, amps read 2000mA high and will not zero reset/adjust within spec ; yet another ebay return =)


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    Johnno (29-05-20)

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    Right...I didn't bother mentioning the resistors above, because they're garden variety jaycar stuff...but for the record, get Jaycar RT4618 (or RT4654) for the 50K trimpot - signal input goes to a precision op-amp, so multiturn cermets like these are the go.

    Got my refund for the atrocious amp/volt meter, and bought another, which actually works - it goes by the model number D69-3049 ; same manufacturer makes them in both AC/DC in various amp/voltage ranges. This one was $26 from a local seller - you can get them for closer to $20 out of CN if you don't mind that wait.



    As reflected in the ebay sellers thread, the DPS-50V15 turned out not to be MIA in AU, but in CN instead - put in an ebay claim on that, and got $35 refund...which brings it down to about what they charge out of CN for the things a lot of the time ; Banggood have them on special at the moment for AU$50something, but I'm hoping to see RD6006 hit 50% off and buy one of those. I'll have to put some cabling together for it, and check it works as expected. Gotta check out the twin overhead parallel brick thang too, but I'm pretty sure they get along together. I've been emailing ALE requesting anything they have wrt datasheet/schematics on the bricks, but it's usually a dead-end.

    The replacement es460C brick turned up, and it reworked and ran-up just fine -- the rifa caps in it were really shot, and it makes me want to wire them up to mains, just to see how long it takes them to go critical. Might set that up, and do it in the workshed on a different circuit than the house =) One of the es460c bricks is making a hiss noise...one of those sounds like HV is leaking type hiss =) I -think- it's coming from the input filtering stage, I'll have to sit it on the bench later & take the cover off. The whacky es460B unit will be part donor for the repair.

    If you want to see that rework of the last brick (somebody not here did) using a shitty old soldering iron and .38mm 1.1% flux leaded solder...


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    Johnno (09-06-20)

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    One of the es460c bricks is making a hiss noise...one of those sounds like HV is leaking type hiss =) I -think- it's coming from the input filtering stage, I'll have to sit it on the bench later & take the cover off.
    Huh, interesting debug, not what I was expecting ~ it's actually the big DC output inductor having a sing. It's exactly the same part# etc etc as the other units, and the only visible difference is the type of enameled wire used in the windings - all the others have the usual copper colour wire, whereas this inductor has a green enameled wire that looks suspiciously not copper. If I could be bothered (I can't =), I'd swap it out, but the brick works fine, and it quietens down once you get 100+ watts of load on it.

    The DPS-50V15 works fine, so no complaints there;










    Everything tests good, so I'm now into the final furlong, and just need to fashion a case for it all ~ I'll have to pattern out the pieces and get some cutting done.

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    Johnno (09-06-20)

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    Looking good there wotnot.. As a kid I built a psu case out of clear Perspex. Drilled holes for the analog amp & volt meters a few switches, terminals and lights were added.

    It bloody worked (12v5a) and looked good.. My CB Radio mates loved it.. lol

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    wotnot (10-06-20)

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    Haha, thanks ~ so many years ago since I played with CB (mid/late 70's)...I had a variable 18volt supply back then, I must've blown up I dunno how many RF power transistors by injecting DC to obtain extra TX range..so much magic blue smoke =)

    I'm at that blasted aesthetics of case design stage, where apparently I've supposed to have learned something from every last time I did this, to not stuffup again <grin>...you know, none of those "I wish I had've ..... " type thoughts you have after you finish, when in use you discover you could've done something a little better... }shrug{...that interface where function meets fashion.

    I think the easy way, was to mount the brick in a case, and have a clean front panel, but that's les_boring. I've decided the showcase the brick front panel somehow, and get a Cherenkov radiation motif happening...should be fun.

    Had another look for more data on the bricks ; nominal full load max temp is 65C, but they will withstand excursions up to 75C for 2hours minimum. The cooling air flow must sink 180BTU continuous away from the case/heatsink assembly. Some of the docs are enlightening in ways you don't expect, like the inrush current control/relay I noted on the PCB, turns up in the installation guide as 'all rectifiers incorporate specialized circuitry to control switch-on inrush current, and thus minimize false-tripping of 3rd-party supplied mains circuit breaker junction boxes'.
    The 4 holes in the case at the back for instance, are for alignment/guide pins to position things so the connectors mate when inserting units into the frame.

    I've got a small Sunon maglev blower coming to do the cooling, I think a mezzanine idea will work. The DPS-5015 has it's own fan&heatsink, and someone thought about it and mounted the heatsink so it also blows air around/thru the output inductor. Also turns out the DPS-5015 I have, is a newer version again than what's described in the OpenDPS docs, so it may not be applicable to this model. It still has the (nostuff) JTAG & UART ports available, but meh...firmware it ships with seems to work fine.

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    Just touching back on those cheap chinese switchmode bench power supplies, I found this little pearl of deft hacking to clean-up the DC output on those things;




    I'm just waiting for a buddy to squeeze my foreign order of cutting the case pieces into his workflow, might get closer this w/e.

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    lsemmens (03-07-20)

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