EEVblog #755 - Fluke PM2812 PSU Ebay Score

[EEVblog]

Dave checks out a Fluke/Philips PM2812 System DC Power supply he scored from ebay for 30 bucks.
Does it work?
Will the bunker hardware tin collection come through?
Service manual: http://www.eevblog.com/files/philips_pm2811_pm2812_pm2813_sm.pdf

[Yansi]

The 110/220 jumperlink only selects between full bridge rectifier and voltage doubler configuration.  The PSU works on 330DC on both voltage systems. Absolutely common input circuit, also well known from a dual system PC switchmode supplies? So why the need to change anything else on the board or even to use a stepdown transformer to those yankee 110V? :-)

The board is NOT designed for 110V only. The board can handle BOTH voltage systems. Only the jumperlink needs to be changed as you did.  The 220V position is really to be open. See below:



//by the way: someone can't draw the electrolytic caps right. The filled rectangle is always minus pole. I took the first image google returned :-)

and lol I just see, there's an error, I'll correct it for you :-)

[EEVblog]

The 110/220 jumperlink only selects between full bridge rectifier and voltage doubler configuration.  The PSU works on 330DC on both voltage systems. Absolutely common input circuit, also well known from a dual system PC switchmode supplies? So why the need to change anything else on the board or even to use a stepdown transformer to those yankee 110V? :-)

In this case you have to change both the input wiring and that jumper.
It's actually in the manual wiring diagram if you look close enough 

[quarros]

Wouldn't EM interference/radiation be a problem with a wooden case? This is a powersuply afterall. 

Edit: Never mind.

[Yansi]

Dave, I don't know what are you talking about. The voltage selection does only the jumperlink.

I have the SM opened right now and I can see that the board was possibly redesigned too. I don't see there any other spade lug there in the video. Nor is the jumperlink drawn in the SM.   

There is no way to need to change 2 wires at once. The 110/220V change is usually done via a SPST switch. If there is need to change two wires, I'd like to see the schematic how was that done :-o

In this version of board  you disconnect the wire from the bridge and connect it between the two caps.


In your version of board, the jumperlink is the selection shorting half of the bridge to make it a doubler.



What else do you need to change, than that jumperlink you have already changed? Am I missing something?

[EEVblog]

What else do you need to change, than that jumperlink you have already changed? Am I missing something?

Yes, look at your wiring diagram above, you have to change the input wiring from the mains filter and the jumper to the 220V position. It tells you right on the text on the diagram how to configure it. The extra spade lug is hidden behind the capacitor in your screen capture. It is as per the wiring diagram with the 3 lugs in addition to the jumper.

[Yansi]

I see it (there is also a whole paragraph about that in the SM), but clearly there is no reason obvious for me, why would you need to chnage TWO wires insted of only disconnecting the jumperlink.

Can you please reverse-engineer schematic of the input stage? (from the socket to the caps). I'd be quite interested to see how the Fluke guys screwed the design that 2 wires need a change instead of one as usual. O_o

[MrAureliusR]

This is the series of power supply that free_electron sent me all that time ago, albeit the single channel version. The thing has been nothing but a tank! Works perfectly every time. Mine is the PM2811. I recently picked up a PM6666 Timer/Counter and a PM3052 60MHz scope to match.

Thanks again free_electron! Dave, if you want to see inside a reference unit for any reason, let me know.

[EEVblog]

One on ebay for $159, bargain.
http://www.ebay.com.au/itm/Philips-PM2811-DC-Power-Supply-/221785830466

[EEVblog]

This one has binding posts on the bottom 
http://www.ebay.com.au/itm/Philips-PM2811-/400896940828?pt=LH_DefaultDomain_0&hash=item5d5751db1c

[MrAureliusR]

This one has binding posts on the bottom 
http://www.ebay.com.au/itm/Philips-PM2811-/400896940828?pt=LH_DefaultDomain_0&hash=item5d5751db1c

Yeah, that was an optional extra, these really were designed to be rack-mounted units. I hacked up a binding post attachment that brings them out front.

[Hamster]

Anybody know where the schematics are for the actual "Power Module" , how hard would it be to convert a 60V/5A to 30V/10A ?? The Software programming can be changed easily, but i am not sure what is different on the power module.

Looks like two power modules:

30V - 10 A
60V - 5 A , and to get 60V 10A, it just combines two 60V/5A modules. ( or Series two 30V/10A modules )

I have the tripple 60v/5a but really need a tripple 30v/10a unit.

[miguelvp]

Anybody know where the schematics are for the actual "Power Module"?

BAMA (The Boat Anchor Manual Archive) has a lot of documents for Philips (Fluke) pm power supplies:

http://bama.edebris.com/manuals/philips/

But the closest to the PM2812 is the PM2811 but it covers both, but I'm not sure it has the schematics for everything inside, but the other ones might use the same modules.

[lewis]

Real schoolboy error on that power supply Dave, that configuration is not only very common but almost universal in non-PFC dual voltage switched mode supplies. Can't believe you haven't seen that before!

[EEVblog]

Real schoolboy error on that power supply Dave, that configuration is not only very common but almost universal in non-PFC dual voltage switched mode supplies. Can't believe you haven't seen that before!

Meh. With hindsight of course I have seen it before, it just didn't come to mind. But it seems it's not that common because it's a combo of both the jumper and the input wiring config.
If I had bothered to check the actual layout, I would have twigged.

[lewis]

Not to worry, everyone makes mistakes, that's why the put rubbers on the end of pencils. And that's why I edited my post 

[EEVblog]

BAMA (The Boat Anchor Manual Archive) has a lot of documents for Philips (Fluke) pm power supplies:
http://bama.edebris.com/manuals/philips/
But the closest to the PM2812 is the PM2811 but it covers both, but I'm not sure it has the schematics for everything inside, but the other ones might use the same modules.

Nope, same one I posted. No PSU or control circuit

[EEVblog]

Not to worry, everyone makes mistakes, that's why the put rubbers on the end of pencils. And that's why I edited my post 

There are mistakes in every one of my videos, I guarantee it. My care factor has always been pretty close to zero, if it wasn't I'd go insane and/or never finish anything.
I press record, I talk about what I see at the time, I check hardly anything during edit, then I upload.

[Mark Hennessy]

I do a lot of work with power supplies, and as has been pointed out, the link (or a SPST switch) is pretty standard. In 240V mode, the link is O/C and the bridge does the usual thing. With the link in place, two diodes of the bridge cease to do anything, and the other 2 form a voltage doubler. In both modes, you get ~325V across the series combination of the smoothing caps.

Looking carefully at the manual - and without the actual thing in front of me - I can only assume that the Input Module has changed from that detailed in the manual (common with Philips/Fluke gear of that era). For that version, I bet that when in the 120V position (X4106), Neutral is going to the junction of the smoothing caps, whereas in the 240V position (X4102), it is going to one of the AC inputs of the bridge. Functionally, it's the same change that adding the link does in the example schematic in post #2 - just another way of implementing it.

I have *never* seen a PSU that requires both a link and an input change. But, there's a first time for everything; if you're sure that this one does, can I add my voice to those who wish to see a reverse-engineered schematic (won't take 5 minutes - just the stuff up to and including the big caps).

Is the spade post behind those caps labelled X4106? If so, perhaps it's a "legacy" thing? If my guesses are right, then the Neutral wire can be left on X4102 when the link is made (120V position). With the Neutral on X4106, the link status would be "Don't Care" - it is 120V operation, whatever the link says. Perhaps a bit risky! Maybe that spade post now serves some other primary-side function - AC fan, extended hold-up, DC operation? Who knows?

[Wim_L]

I think the EEVblog has a new slogan: "More couch feet!" 

[MrMetthew]

Dave, or somebody else, how do you keep finding these deals? Do you just search for random electronic related searchterms? Do you complete some kind of list, eg first search for scopes, than for sources, ... Or is there some kind of ebay sub catogory with most of these things in it? Cause I really wanna get in on some of this action!

[ornea]

Dave, or somebody else, how do you keep finding these deals? Do you just search for random electronic related searchterms? Do you complete some kind of list, eg first search for scopes, than for sources, ... Or is there some kind of ebay sub catogory with most of these things in it? Cause I really wanna get in on some of this action!

I am also at a loss where people find these deals.  I did see a condition subcategory of Faulty - Not Working on ebay.com.  Cant find it now and never found it on ebay.com.AU.  I believe it is an option when selling something so you should be able to filter on it as a buyer.

[miguelvp]

The keywords should be "parts only" or "repair only"

I guess you can combine them, like "power supply parts repair"

[kcozens]

Early on in the video I noticed that daisy chain cable wasn't connected to the board. I also noticed that the 4 screw terminal block on the rear of the chassis for output 2 is missing two screws. Comparing it to channel 1 it is missing the shorting wire between -S and -V. You may be able to fix the channel 2 stability issue by replacing the two missing screws and adding a bit of wire to short the two terminals.

[Hamster]

I picked up a 2813/1103, 2811,2831 for $300 for all 3 . ( Yankee Dollars )