Way above my skill level but I'm always happy to meet a person that knows more than me.

@GrantsPassTVRepair

7 жыл бұрын

I try to keep it simple so anyone can follow along, but perhaps I can do a little better.

I was just searching to see how to put a multimeter to millivolts and seen this video. I finally see how diode measured to find if they aren’t working. Video is beyond excellent.

I have a digital ESR meter but I never know I could used it in other way just like what you did in this video. Thanks for sparing some time to share us your skills sir.

Great video !! And tips in the comments! When I first stared out in my 20's, my boss had a Weston 7 digit ohm meter to find shorts on boards. Boy did that work like a Champ ! 35 years later, I see this great idea using the mV meter approach !! Especially the HP concept in the comments !! I'm so grateful and embarrased I didn't think of it ! This concept in this video should get an award ! Thanks again for making this video and bringing out further comments here with further tips !

So simple yet so brilliant! Thanks for sharing.

Thanks much Grant you remind me of my uncle who had the 1st TV repair shop in the north Adirondacks.That was circa 1950? He was a communications guy in the Marines on Okinawa ww2

What a fantastic video! Over my self-educated time spent (100's and 100's of videos and some books), what no one ever said/wrote was that in repairing electronics, it all comes down to OPENs and SHORTs; with SHORTS being the "variable" cause ... meaning that there can be a SHORT ...or... a PARTIAL SHORT that's causing the problem. Once that became apparent, troubleshooting changed to "much easier" to diagnose. I have a Zapper, built a LeakSeeker, have injected voltage, and and and. This video from 7yrs ago ... I wished I had discovered earlier. It added a very valuable approach ... inject a small voltage and then look for a voltage drop in the mA's (or maybe even uA's if you can). Brilliant. Thanks for this video.

@GrantsPassTVRepair

Жыл бұрын

Thank you for the comment. It's always nice to hear when someone appreciates on of my videos. We had a period where bad capacitors kept repairmen fairly busy due to a manufacture error known as the "capacitor plague", but that's not so common anymore, so other than bad eeproms and leaky parts, I suppose shorts and opens do make up the bulk of repairs. All the best.

Great idea for locating shorts to ground; in fact you have given me an idea that I want to try out when I come across this situation again.

I've learnt something from you every video I've watched, thank you.

Excellent way to find shorts !! I had one in my house wiring that I found with your method. Thanks !!!

This technique works very well, great on logic circuits were the 5v rail might go everywhere.

Hi Dave Another great Video. Thank you for taking the time to show us your troubleshooting tricks. Keep up the great work you are doing. Cheers Willy

Also, if the short is low enough resistance, you can likewise inject a voltage of much less than the voltage than the power supply and boost the current output until the shorted component heats up enough to actually feel with your finger (no using expensive freeze spray. I work repairing cable boxes for Comcast and have been able to repair a very high percentage of boxes this way. I Have used the milli ohm method as well as the ESR Meter as well as injecting voltage and tracing with the milli volt meter, too. All have their place and merit. With Shorted chip components on a highly concentrated board with as many as 10 decoupling chip caps on a power supply line all across the PCb, it could be anywhere on the entire board. Hands down the injecting low voltage at higher current and merely feeling for heat is the most effective. I haven't had one case in hundreds of repairs where I have ever damaged the upstream or downstream components. This is mostly with buck supplies.

@hullinstruments

4 жыл бұрын

Thanks for this information. I would imagine a cheap thermal camera would help this process? I’ve had my eye on the “flir one pro” for a while now. at $400 I think it would be invaluable on the electronics bench, in automotive repair, even checking the HVAC/energy leaks in your home. A friend of mine has a cheaper model… And it immediately identified the bad wheelbearings on my vehicle in broad daylight because they were warmer than everything else. The flir one pro is pretty much the minimum priced thermal camera and resolution that one would want for electronics. Sure the $100 models work fine... but to really get down and see the smallest SMD packages and such… I think $400 is worth the extra price.

@hullinstruments

4 жыл бұрын

mister kluge Thanks a ton for the info! They’ve tried so many different terminal cameras… Are you referring to the “seek“ thermal camera? I know they’ve showed a few very nice thermal cameras but they are out of my price range. Closer to $1000....Where the flir one pro phone attachment is only about 400. And with a macro lens added… Can REALLLYYYYYY see tiny parts even the smallest SMD components clear as day. and the diy macro attachment is only a few dollars. AND makes small components 10 times clearer! Thanks for your time!

@mikeg1433

4 жыл бұрын

HULL GUITARS USA Did you end up getting the camera yet by chance? In a total novice with this stuff but I end up doing it often enough to make 400$ worth it, especially if it works for other applications. HVAC, home electrical, and car maintenance alone would justify it if it’s useable on a larger scale. I’d imagine it is, if it’s able to pick up the much higher resolution of electronics.

@violentrobot

4 жыл бұрын

@@hullinstruments how about one of those cheap laser temperature guns? you could do the same thing with the low-volts high-current and scan the components. and those are like 30 bucks

@RichardsWorld

3 жыл бұрын

And you don't buy a Flir because????

Thanx for the video very useful & educational !!! Keep them rolling my friend

Thanks for taking the time and effort. well explained.

Excellent information! Thank you for sharing your knowledge with all of us! Fred

Thanks Dave. I appreciate the video.

Big thanks for these very powerfull techniques, voltage drop is really revealing

@GrantsPassTVRepair

6 жыл бұрын

I'm glad you found this technique helpful. Thanks for the comment.

The ESR meter should be enough to find the culprit. Indeed a must have tool

This technique seems similar to 4-wire resistance measurement. Very ingenious application for repair!

Very very helpful , thank u , hope u get time to make some more videos soon , I enjoy watching them

Excellent Dave.

thanks for this, this is what i needed to see!

Thank you. Very helpful information.

Well done. I have not used this technique, but you can bet that I will.

nice tipoff about the audio frequency of switching power supplies

this is nice. thank you. I been back to watch this video several time. I also have the toneohm, which, I am in the process of making my own leads since its leads are crazy expensive, I am yet to learn how to use it though.. but I have found using a good thermal camera, though expensive but is a very effecting and fast way in finding shorts. I would call thermal camera, short finder for dummies.

Thank you! Gives me some more ideas. Shout out from Coos County!

I'm just getting into electronics learning Arduino and this video is helpful.

You need to know something about the trace geometry to accurately pinpoint the short using this method. You need to measure the voltage drops across the traces. I start by connecting the negative lead of the DMM (mV mode) to the point where the current source's negative terminal connects to the PCB. Then begin probing further from negative connection point until the voltage stops increasing. As long as the voltage continues to increase, you are following the flow of current. As soon as it stops increasing and levels off, you've passed the short. If you have a layout viewer, it really helps. Using this technique with boards that have power planes is more difficult. You'll need a high precision DMM to measure micro-volts of change on top of the millivolt voltage that is actually across the shorted component. You may need 6-digits of precision to do this. The relative (delta) button won't help because the meter will use the appropriate scale for the total voltage ("trace voltage drop" + "shorted component voltage drop"). You are only interested in the trace voltage drop. I suggest using a good cad viewer that allows you to highlight nets and has coordinates so you can calculate distance. I've used this technique to get me within about 1/2 inch of a shorted cap between Vcc and Gnd on boards with hundreds of bypass caps on them. I also use thermal LCD paper and cold spray to try to locate the shorted part thermally.

@atifservicecenter

2 жыл бұрын

In India, we mostly use rosin paste and 3.3v with few good range of amps (current) and volts depends to the supply line or supply track. And we easily find the shorting component. There are many ways to locate the shorting component and those are effective too.

I’ve never tried testing diodes in circuit we were taught to always pull one side to open the circuit so no feedback loops. Good Information and well put together video! I’ll keep that trick on the shelf one day I may need it.

Finally.....thank you SIr

Thanks for sharing your knowledge

This was really helpfull, thank you.

Thank you i have been trying to do a similar check with sm caps in parallel☺

Your really good at explaining

Nice job. I'm working on a small board with a short somewhere. I'm going to apply a small voltage (3 D batteries, 4.5v) with a small current limiting resistor and try to get closest to the short with digital voltmeter readings OR allow more current and feel for a hot component.

Usually to find shorts of that kind, i usually plug a lab supply across the shorted rail and inject some power and look for the hot parts.

@GrantsPassTVRepair

9 жыл бұрын

***** I've used the same technique, but sometimes it takes quite a bit of current to get the component to warm up.

Thank you for sharing this technique. Subscribed

Very helpful video! Thank you!

Thanks! helped me find the needle in a haystack.. bad SMT cap

Thank you , great tip!

Thank you for a good video!

thank you nicely explained.

Very good teacher.

@GrantsPassTVRepair

9 жыл бұрын

MrMac5150 Thanks.

@MrMac5150

9 жыл бұрын

send some more of your skills this way.

Thanks very much for sharing. I too use my ESR meter for finding shorts but you've intrigued me with the short sniffer that I saw it costs quite an insane amount of money. 10 minutes later, I have one up and working just great, it's just a prototype of course but more or less I made myself and idea of what values of components I have to use. If you need any help, just ask. Cheers :)

@yugimkl6938

4 ай бұрын

Tap on a clip to paste it in the text box.

very informative , thank you sir

Thank you so much. unfortunately, my bench power supply doesn't control current that accurately so I created a simple constant current supply circuit that I use now for this method.

Great video

another excellent video. although in my experience finding a short to ground is a lot tougher than you have shown especially if you have a bunch of smt noise caps or the short is between layers.

@GrantsPassTVRepair

9 жыл бұрын

Roger Kerr I agree. Finding shorted diodes and large transistors is fairly simple in comparison to what you describe.

Good info. Thank you.

Very useful. Thank you.

Great Video . Thanks

Thank You very very much sir this works excellently,

very informative video

GREAT VIDEO & A GREAT LITTLE TRICK! My Teague ESI will measure down to micro-ohms, and uses a 4 lead shielded Kelvin clip lead set. That Teague is around $3000-$5000, used. The time it saves testing caps, & diodes in circuit are kind of worth it. I really love having it, and don't know how I lived without one as long as I did. I have used this method too. I liked the LCR bridge so much, I bought a spare one. It is a Chinese made no name that cost $700, but it works, despite only having 4 test frequencies, 4 test voltages & 4 test current. The Teague has 100s. I fixed up a Samsung plasma TV only to find it puts out excessive RF interference into the mains, making my amateur radio station noisy. Plasma TVs are notorious for backfeeding RF noise into the power lines.

excellent, thank you for sharing your hard earned knowledge, much respect!

super video , congratulations

Yes it helped, Thank you so much

Great video, thanks! There's a potential (little) goldmine out there if you can get the "throwaways" before the "scrappers". And if they are repairable. I bet most are.

@Skipperj

5 жыл бұрын

I like the ones with broken screens, if they come on ther usually some fairly good boards inside.Sometimes it's deceiving.

Good video. Thanks!.

Great Video

cheer's another couple of top tip's

One can also pour some Butane on the suspect component. The S/C will obviously generate some heat, which in turn will cause the Butane to evaporate (boil) at a rapid rate in comparison to the normally operating components. Of course a Power supply is used for the power source as described in this video. The Current (I) may have to be increased to 5A so that enough heat is generated, As the S?C component is already defective 5A will not be of a concern, and power rail components are quite durable for obvious reasons. For those just learning, it is important to understand how Power rails work, and how lower voltages are derived from the source power rail(s) Not knowing that would be chasing one's own tail and wasting time. Good luck everyone.

Another great education. Thanks! 11:03, *smaller* voltage drop. I know you knew that... (c:

I'm a retired avionics tech. 30 years ago HP published a trick not unlike your own, using the mv on the DVM, but with no guessing. To find the short connect a current limited supply to the shorted supply rail at the spec voltage but with a safe current limit. Now connect the positive lead to the rail, and we'll use the neg probe to chase down the short. Clearly the millivoltage will grow towards the short, and if you probe past a node, the voltage will stop increasing.

@GrantsPassTVRepair

7 жыл бұрын

I'm not to surprised. Unless you own a low ohm meter capable of 1000 divisions it's a great option.

@RickNickel

5 жыл бұрын

That's how I used to find shorts until I got a $200 FLIR that connects to my phone. Now one of the first things I do is take pictures of the board temperature signature when I first power up the item. Sometimes it pinpoints the problem without any troubleshooting.

@mchaves7663

5 жыл бұрын

@@RickNickel hi Rick would you post a link to this?

@jettramel

3 жыл бұрын

@@RickNickel Looking at one today for the same purpose.

@tonytrilex2555

3 жыл бұрын

it kinda like the opposite of what he is doing very smart!!!

Awesome vid.

Thank you very much

good information

Thank you!

Awesome, thanks.

NICE . ThanX !!!

I think this is the most professional method to isolate the shorted component. I want to know about if this method can be applied to computer boards. If possible, can u make some video on that?

Nice idea ;-)

Thanks for this vedio

nice video

VERY GOOD

whats the type of the "paper" that connects resistors you use for simulation? thank you!

@challenger2ultralightadventure

7 жыл бұрын

Adhesive copper tape. Available everywhere, here is a link to one site that sells it, there are other sites, or outlets in your country as well. www.sparkfun.com/products/10561

very good most helpfull tip haow can you check for a winding short in a transformer do you have to use a micro ohm meter and know what a good one would read?

@GrantsPassTVRepair

Жыл бұрын

I do have a micro ohm meter, but when I test the primary side of a transformer I often use the my blue ring coil tester. Here is video on how they work. kzread.info/dash/bejne/fa1mtpNmnsKsm9Y.html

how value voltage and current to charge? for not damage the other component

Wow! Now I know. Thanks

ESR meter can also read very small value resistors.

this is a great way to find bad connections on car battery leads

Thanks!

Got that trick from (How to diagnose and Fix everything electronic) by Michael Jay Geier.

Great way to test for shorted components BUT that's IF you have more than one of the same component [with which to compare it with - like three similar values diodes]. But how can this work, when the components are of different values to each other AND altogether different components? Ex: a transistor, a cap [tear shaped - tantalum], an electrolytic cap, few resistors and maybe a diode. What can you possibly achieve test-wise with this method [ESR meter]? You would never be able to find the shorted component. But I have so much more to learn about electronics [I'm a complete NOOB in this field] so, PLEASE correct me if I'm wrong - I truly am trying to learn. Your videos have been a great source of education for me. Thank you kindly.

You can use a Seek Pro thermal imaging camera to see what heats up the most to find it fast too!

@Heathmcdonald

3 жыл бұрын

91% IPA (isopropynol aka isopropyl alcohol)pour on suspect components then inject voltage and you will know what is shorted by how quickly it evaporates. Much cheaper than thermal cameras

@stevenbedoya9920

3 жыл бұрын

@@Heathmcdonald That's the way to go!

Great video and explanation. I thought I seen a video of someone looking for a short with a battery maybe it was a 9 volt and a multi meter. Is it possible or even safe to do?

@GrantsPassTVRepair

9 жыл бұрын

TakeTheNarrowPath GloryIsHisName I suppose you could use a 9 volt battery if you added a 27 ohm resistor to drop the current a little, but it would sure be hard on the battery..You might see the power drop so quickly that your reading might be undependable. It would be better to build yourself a small power supply out of an inexpensive transformer, a resistor and a bridge rectifier.

Have any idea how I can force yt to put up your newest videos? I go out of town and upon returning yt seems to "retire" subscriptions to the back burner. I imagine just finding and watching a few is the only way.

@GrantsPassTVRepair

9 жыл бұрын

madisonelectronic I put an index to all my youtube videos at www.tvrepairinfo.com/

The $1 diy diode tester is the bees knees

New subscriber here.

Short-Circuits (in their natural state) on PCB's have already done the damage to the equipment! I am an amateur (self-taught over 50 years). I can say that Grants Pass TV repairs have taught me that you can check out 'shorts' by the use of a DMM on the milivolt scale. I have followed the same procedure as shown in this video, and that is - to first determine WHICH CIRCUIT BOARD is faulty. Sometimes, there are five or six separate PCBs in a Home Theatre System. Narrow down the fault to just one specific PCB. Write down every step that you take! Magnification of the PCB and its' components is a must! Look for the obvious first. I do this by powering-up the suspect PCB independently, with the same voltage / current that is rated for the particular Board. I will not reduce the voltage (or current), because a 'short' is present. Remember that the Board cannot suffer more damage! At this point (when the suspect Board has been disconnected from ALL other Boards and Feeds), the 'short' begins to show itself........... Yes, components (even the printed copper track) will get warmer than others, because many other parts of the circuit are not being fed with their correct voltage - due to the 'short'. Have a smoke, have a coffee - but leave the suspect Board powered for 5 minutes. THEN, pinpoint every component such as diodes, capacitors, resistors, voltage regulators and transistors etc WITH A LASER BEAM. I am talking about the (very cheap) Hand Held Laser Pyrometer. The Laser Pyrometer detects the smallest amounts of heat (from or near to the shorted component), and you will definitely see results! As an amateur, I have had many hours of frustration and heartache in trying to detect a 'short'. I have no idea why all of the professionals have never mentioned this method of heat detection on You Tube. In many cases, it isn't possible to detect small amounts of heat with the human hand - from many components that have radically shrunk in size - and mass - from two or three decades ago. If I was a professional Electronics Technician, a Laser Pyrometer would be a very important part of my arsenal. Thanks to Grants Pass for a great Tutorial. Greetings from Australia.

Could you also use nS to measure conductance and then convert it to ohms? For small resistances. The fluke 87v has nS but is kinda hidden.

@GrantsPassTVRepair

2 жыл бұрын

I don't understand your question.

@user-hh4ly2xy6s

2 жыл бұрын

Never mind. I was thinking you could use Nano Siemens which can be used to measure very hi resistance. In this case your measuring very low resistance. My fault. Thanks

A thermal camera would have being really nice

Thanks for this great video. I learned something new today. It just happens that I have an incredibly expensive board that has a short on it's power bus. I am dying to try out this new method of tracing it. Please let it not be the CPU, because then it's fucked.

Nice

Hey, you can just supply this troubled PCB not with ordinary high input voltage but with low voltage and high current capability power supply. And just use your fingertip to locate a shorted component(s) by its temperature. )) Any advanced multimeter needed, but ATC 300W power supply in tact is strongly recommended to have in your workbench.

very interesting info.🥳 i use fluke equipment, however i also have some wonderful hobby equipment that i go to 1st. 😊🧐 thanks a lot. 🤩

Thanks

hi, is there a difference between a bad diode and a shortened diode when checked with a meter what i am asking would a shortened diode measure as bad with a meter ? thank you

@GrantsPassTVRepair

2 жыл бұрын

I don't quite understand your question, but I think you meant to say shorted diode rather than shortened diode. ;-). When the short out they generally become like a piece of wire with almost no measurable resistance. Less than 1 ohm.