PSU for test

Hello

I'm looking for a "labo" PSU

what do you guys use?

option are new like this one:
http://www.ebay.com/itm/1-X-DOUBLE-ALIMENTATION-DE-LABORATOIRE-2-x-0-30V-5V-2-x-0-3A-QUATRE-AFFICHEU-/321265514097?pt=LH_DefaultDomain_23&hash=item4acceab671

or second hand like this, better qualities ?:
http://www.ebay.fr/itm/HAMEG-7042-Alimentation-laboratoire-Triple-2X32V-2A-1X2-7-5-5V-3-3A-/121229776670?pt=FR_YO_MaisonJardin_Bricolage_ElectroniqueComposants&hash=item1c39db971e

I need two output minimum (for +/-15)

Zam

I have two HP 6205C dual supplies that work great for bench work.  They can be setup for dual or single supply by configuring a terminal strip on the back of the unit.  They are 0-40v at 0.3A or 0-20v at 0.6A.  Got them on Ebay for about $40 each!

Regards,
Jeff

I have two old HPs and one old Acopian bench supply.  They go for next to nothing on ebay and work well.  But, it's also not impossible to build your own for cheap.

I never had much use for fancy variable bench supplies. I used to sell +/-15V PS kits so just kept one laying around with clip leads on it for easy hook up. THe modern 3 terminal regulators have short circuit protection.

JR

tks all for input

A symmetrical PSU don't fit my need, i have gear in +/-15, but also 24v in some rack and -22v for my desk.
I don't know about amperage, I can say most of what I have to fix are under 500mA per rail, 2A will fit 99% of my need.

still looking for low cost second hand

Not rocket science to roll your own... too...

JR

deveng said:

I have two HP 6205C dual supplies that work great for bench work.  They can be setup for dual or single supply by configuring a terminal strip on the back of the unit.  They are 0-40v at 0.3A or 0-20v at 0.6A.  Got them on Ebay for about $40 each!

Click to expand...

Took your advice and grabbed one off eBay. Should be here Wednesday. I'm hoping I can use it to check before/after current draw on a mic pre I'm modding.

Thanks!

You can still get the full manual from the Agilent website (HP now part of Agilent).  Look for "06205-90004.pdf".  There's a section in the manual that describes how to setup the rear terminal strip for the modes of operation.  Since you'll be getting a used unit you should set that up first to make sure you have the proper mode before connecting to your circuit.

Regards,
Jeff

Thanks Jeff, got it!

Man, looking through that PDF, I think I'm just going to have to cross my fingers and hope that thing's still somewhere near spec., or maybe see what Agilent charges for tune-ups. Not sure how much of it you really need to do, but one of the tests actually involved sticking the darned thing in an oven.   

The Agilent/HP gear is really well built and documentation is comprehensive.  That's why I bought 2 of them.  My supplies worked right out of the box with no issues.  I wouldn't worry too much about them.  Put a scope on the outputs and look for normal noise levels.  If it doesn't work as expected, verify the terminal block connection on the back is setup correctly.

These things are built like tanks.  I'd wager you'll just be able to unwrap it and use it!

Regards,
Jeff

deveng said:

These things are built like tanks.  I'd wager you'll just be able to unwrap it and use it!

Click to expand...

That's what I'm hoping too. I should know on Wednesday. I'll do the scope thing you suggest. I've also got current readings I took from one of those old timey Heathkit meters. If it's too far off from that, I guess I'll look into it.

Thanks,

George

These rock!

http://www.ebay.com/itm/Tektronix-PS280-DC-Power-Supply-8602E-/111161519312?pt=LH_DefaultDomain_0&hash=item19e1be2cd0

Got mine for much less.  Make an offer.

Best,
Bruno2000

Disclaimer:  This is not my auction.  Just an example.

...yuck 

This HP thing looks great, but I have a feeling it's non-functioning. All the controls are gunked up. The pots are stiff and seem to rotate endlessly (they are supposed to have stops, right?), and the switches either stick in, or won't stay in and slowly drift back out.

Not looking forward to the near future with this one.

George

deveng said:

Since you'll be getting a used unit you should set that up first to make sure you have the proper mode before connecting to your circuit.

Regards,
Jeff

Click to expand...

All three PSU's I have were sold online as not functioning. 1 on ebay, 2 from a test equipment company.  All were $50 or under, and all were fine when I got them.

In all cases the "not functioning" problem was that they were racked in the LAB and they had remote sense wires connected.  When they were pulled from the lab rack those wires were disconnected by nobody ever replaced the little screw jumper that connects the PSU output to the sense input.

So they would not regulate properly.

All were fixed with a couple of 5 cent jumpers.

One is a beautiful dual voltage programmable Fluke supply.
two were big old beautiful HP linear dual supplies

Shipping was about $50 per unit (they are heavy)

Anyway, I think most broken supplies for sale on line might not be broken.

bruce0 said:

Anyway, I think most broken supplies for sale on line might not be broken.

Click to expand...

Yeah, I'd probably be using it right now if I had bought one of the "as is" ones. This feels like somebody sprayed WD-40 or something in it and it glued everything shut. The auction lists "Passes basic power-on tests.", but I can't see that happening. In the picture, both meters are up past the halfway point. They did that here when I first plugged it in, but after I pushed a couple panel switches it never showed any further activity. The knobs occasionally grab the pot shaft, but they usually just slip as the pots are so stiff. I couldn't even get the lock screws in the knobs to move to try to get them off.

Sucks. I'm wondering if I should just try to get in it and clean it to avoid having to ship it and track down another (assuming the seller is cooperative).

George

On a positive note: I opened one of those eBay "case" things last night to contact the seller and let him know of the troubles, and this morning there was an automated "case is now closed" email notifying me that the full price plus shipping was recredited via Paypal.

Not sure what I'm supposed to do now as eBay is making it a bit more difficult to interact directly with the other party, but there's no mention of how to proceed. He appears to be a new seller and sent a personal note with the unit asking me politely to remember to leave feedback as he's just starting out.

Re: The supply- I did manage to see voltage output from it last night on both sides, but still no meter activity and the output voltages dropped to almost nothing the minute a small load was attached. Terminal strip looks to be in the default state going by page 3-1 in that manual.

Do any owners of that (or similar HP's) know how difficult it is to clean out their style of pushbuttons or the voltage pots? It's got a "void if removed" calibration sticker sealing the case and I'd rather not mess with it until I can track down the seller and see what he wants me to do.

Thanks,

George 

Sorry to hear about the condition of your HP supply!  Both of the ones I got worked fine with no issues other than the terminal strip jumper settings on the back.  They've been work horses for the last 7-8 years.  I wouldn't worry about the void sticker unless you're going to return it to the seller.  When I purchased my supplies I made sure the Ebay descriptions included "fully working".  I had to be patient and wait for a good price as many of the working units sold for much more than the $40 I paid.  But they did pop up here and there.  Unfortunately, with any electronic equipment purchased on Ebay you run the risk of issues unless the seller guarantee's full operation and its been checked.

You may be able to find replacements for the switches and replace them but that will take some time and effort.  As for the pots, those may be more difficult. 

Hi Deveng,

Well it turns out the seller is nice as crap. He said he's "leaving it in my care", as it's not worth the hassle of trying to do a return or fix the unit. I'm going to see if I can at least get him to take the shipping cost back so he hasn't paid just to give it away.

The pots turn out to possibly not be as bad off as I thought. They're a bit stiff, but they're a type I hadn't yet run into with that weird >360 degree rotation thing. I'm going to look into the switches and see how hard they are to clean. I guess if the mechanics of the switch aren't the only thing gunked up, they may not be making clean electrical contact either, but I probably won't be that lucky. Like I said, there's no meter movement at all and the output supply doesn't seem to hold up under any sort of load. When I get in, I guess I can see if there's any of that weird custom "current limit mod" stuff done too, but it's acting too screwy to just be that.

George

There are not that many controls, maybe pull it apart and clean it with alcohol and maybe add some tuner cleaner.

Push on push off toggles come apart usually, and sometimes go back together, given the vintage you might be able to replace them cheap (the only problem is that HP stuff is built like a brick sh*thouse and some of the stuff is so nice that you won't be able to replace it, but you might be able to clean it).

Be careful of caps that are not discharged (HP stuff usually is very maintainable and has drains, but put a voltmeter on any large caps).