Kitchen Table Electronics Repair: Tripp-Lite Regulated Power Supply

[@vwestlife]

I once put a bit too much load on a similar Tripp-Lite power supply, and it started smoking! It still worked OK for a while after that, but it eventually blew out its regulator and started putting out about 21 volts DC, with lots of ripple and AC hum. To me the "Tripp-Lite" name suggests some kind of safe shutdown in an overload or overvoltage condition, but clearly mine had neither!

[@robertmeyer4744]

I have worked on a bunch of tripp-lite supplies.. all the old ones use 723 reg ic. Even the PR 60 amp which I have. I put IC socket in. makes the next ic very easy to change. that pot on the board is for voltage adjustment. The Pyramid supplies use same ic. the diagram is close. the newer triplette supplies use SMD bord and is hard to work on.

[@Alex1M6]

@uxwbill Your probably right. It is quite old and was originally used for powering some kind of industrial applications, it is a rack mount type of design as in it has no proper casing cover and has mounting holes on the frame. Also the mains power connections are completely bare on the front of the unit right next to the output terminals! (Although I have put a piece of electrical tape over the mains terminals just in case to help prevent any accidents).

[@bratina501]

I just got the 6800 uF 35 volt filter capacitors and put them into my Tripp Lite power supply today. Its been driving a Delco car radio for about half an hour so its very much alive and well. The DC voltage on mine registered 13.82 volts so it seems more precisely regulated.

[@bratina501]

I have a bigger Trip Lite power supply capable of 25 amps with some serious AC ripple. Might dig that thing out and repair it now but sadly enough I can't remember the polarity of the filter capacitors. Also is that a Sony XR-33 I spy being tested, very nice AM stereo/FM stereo radio which actually receives all four systems if I remember right.

[@bratina501]

@uxwbill I don't have a wiring diagram for the Sony XR-A33 but did dig out my Tripp Lite and its for a large part like yours inside except more output transistors and a bigger power transformer its a PR-25A. When I had that thing working it would torque a little bit when switched on but would run just about anything I could throw at it.

[@edison700]

great job as always. any updates on the dead ps/2

[@bratina501]

I have a bigger Trip Lite power supply capable of 25 amps with some serious AC ripple. Might dig that thing out and repair it now but sadly enough I can't remember the polarity of the filter capacitors.

[@kromair22]

I too have one of these tripp lite 7A power supplies. The controller IC in mine is a EAC723E. When I look on E-bay I find several ua723pc, ua723cn, ua723k, ua723n, but no 723E. what does the letter signify and are any of these listed an acceptable exchange for the 723E in mine? Thanks for your help and your video.

[@W0uter1992]

Shouldnt there be a variable resistor to the REF pin on the IC that controls the voltage?

[@Alex1M6]

I was given an old 12V 6amp power supply not to long ago that had been thrown out becuase it had apparently stopped working, it turned out to be a fuse had blown on an internal circuit board which after replacing it the power supply works fine. Interestingly it also puts out just over 14V instead of 12V when there is no load connected to it, do you think they do that to help stabilise the voltage when a heavy load is connected to it?

[@valdarmort]

that 4 amp power supply might have been made in Canada or at least the screws anyway.cause here in Canada we have lots of square heads

[@mccunecp]

I notied on mine also it has a LM regulator on it also and it has the 2n3055 current transistor. I like to replace the transformer for a much beaffer one for a higher current but use the board to controll the voltage from 0 to 30 volts and add more of the 2n3055 transistors becaue I have a few of those. so I guess the question is why dose the transformer have so many wires for the voltage when in therory it should only need 2 sets to provided the power. any ideas.

[@armankordi]

Didn't you buy the roach palace? is it habitable?

[@timmytimmy64]

Howdy uxwbill, On your TripLite is there any V adjustment? If there is I would trim it to 13.0Volts. That always seemed to work for Me very well. I noticed Some of these power supplies give the option of adjusting the Voltage, Voltage trim, Amperage and Trip Adjustment as well as the metering adjustments. Love the videos Keep them coming I am an electronics guru as well and enjoy working in this field. I You ever need any parts(semiconductors) Let Me know and we'll go from there. Great Videos..

[@0Fluxor0]

@MAG315 I too echo that sentiment. @uxwbill Good to see another fix video Bill. I thought it was very good.

[@TheCatMilton]

Honestly when I run into these "special" or "different" screws I usually drill them out and buy new "normal" screws at a hardware store in the case that I would have to go inside it again.

[@TheCatMilton]

@uxwbill mine has two settings hot or cold so i hop i get it right or the circuitry could be damaged.. :3

[@mccunecp]

I Have had the same ic go bad on me but it was because I back fed 30 volts in to it and it poped the LM23CN regulators and after replaceing it it worked but I put a blocking diod to keep that from happeing again I work on solar stuff and test my eq with the power supply. now whey dose the transformer have more than one out put if you only have one voltage out put unlike mine I changed it to change the voltage from 0 to 30 volts and changed the caps to all 35 volt

[@richthecardude94]

could u run a cb radio off this unit ?

[@Sdnaurs]

That's good, but my grandad gave me a regulated power supply he built in 1956 with a tube regulator circuit, he told me he got the capacitors from a radio he dismantled (god knows how old that was) and it's in perfect working order.

[@807radioman]

I have 2 of the GSC 20 amp supplies and neither of them use the 723 regulator control IC .

[@Bandicoot803]

I was wondering: Would it make sense to add an IC holder to facilitate the matter of replacing it in the future?

[@uxwbill]

+Bandicoot803 So far it hasn't, but if it fails again, I will certainly do so.

[@Bandicoot803]

I love good points concerning repairing stuff of (almost) any kind. This world clearly needs more repair-encouraged guys like you, it would drastically shrink the landfills. Btw, I also love to disassemble, analyze and if possible, repair/improve electro-mechanical appliances, as well as to watch the episodes of "KTER".

[@Kujokouklos]

Awesome video indeed. Just got a free Q6600 my brother in law was throwing away. Just needed a PSU fuse replacement, been running 24/7 for three months now. I just do not know what these people are thinking.

[@ronnywmedia6950]

ua723 is a voltage regulator with 150ma internal limit, that is used to protect the short circuit. probably it was blown due to repetitive "spikes" after the shot was lifted. its rated to 40V, but a sudden spike over that voltage due to a short circuit or inductive load, can fry it. (specially deenergizing a coil that produces a negative voltage!)

[@OlegKostoglatov]

@uxwbill Actually it is called a Robertson Socket Head Screw, if you look at the screwdriver tip it actually has a taper and the screws have a tapered slot to match. The square head screws are not the same, the hole and the driver it uses has no taper, everything is 90 degrees so a Robertson screwdriver does no fit properly, still better then Phillips screws and all the look alikes that don't fit each other though.

[@807radioman]

The PR25A transformer has 8 wires . The white and black ones on the bottom of the transformer are the AC primary .the 3 heavy white ones on the top rear side are the 35 vac centre tap for the regulated high current output . The 2 white and 1 black wires on the top side where the AC primary wires are supplies the low voltage to the regulator board .

[@cutpow]

Bill, I managed acquire a Tripp-Lite pr12 power supply as a freebie from a friend, upon inspection I noticed that it puts out about 28vdc when it's supposed to put out 13.8 vdc (I was able to surmise why it was free). Before I spend a lot of time digging into this supply. Where would be a good place to start. The filter caps seem to hold a good charge after removing power. Any help would appreciated. Larry

[@cutpow]

+uxwbill tnx Bill

[@stevenking2980]

Nice video

[@artbonales7968]

Can someone out there help me I need my triplite pr-40 repair cannot find one

[@uxwbill]

Unfortunately, you're almost certainly on your own. Tripp-Lite won't provide schematics or any service literature. You'll have to trace the circuit, have a basic understanding of what components in a circuit do, and the knowledge to work on line powered electronics safely. A multimeter will also be needed.

[@807radioman]

brattina501 The PR25A supply capacitor board the outside foil around the edge is the B+ and the centre foil is B- . the capacitor value in mine is 6800 ufd 25 vdc .

[@TheCatMilton]

Cold that power the Drink-O-Matic

[@JosephLorentzen]

Many old cars were regulated at 13.6 for the charge voltage to the battery and many new ones use 14.8 volts. Looks like the power supply is happily in the middle.

[@chemicallust77]

I have a PR-20 that outputs exactly .56v DC....I suspect it has the same problem

[@eternalblue2119]

Glue a heatsink on that IC, its driving 2 pass transistors

[@cowsongs]

Yeah, it does look that way (that the regulator is directly driving the big power transistors). I have PR10, which also has two big TO-3 style pass transistors, and the LM723 regulator, but on that one, they put intermediate transistors in between the IC and the big TO-3's to buffer it - a much better design.

[@8592291613]

my astron rs-7a has the same lm723cn

[@jpbrown1963]

My 10 amp like yours is no volts out so first thing i buy. Regulator ic thats for the help

[@UnderTheBigOak]

5 years til a reply but I got one of these free at a swap meet, same thing. 723 IC brought it back to life.

[@TheCatMilton]

@uxwbill I have one of those and it would be great to run my drink o matic off of...(when i had the swine flu and used it to have drinks by my side its powersuppply died :( )

[@ACA332]

STUPID squarehead screws? Nothing grabs like a squarehead screw does. You know darn well how easy it is to strip a phillips.