Beacon Generator Repair - You Cannot Save Them All 

At 1329 you can see a hot spot at 7 aclock on the inside. And you can see it on the out side too

I have never seen a more thorough or persistent repair guy! Kudos to you.

As an electronics technician, this is exactly why I have condemned boards and assemblies that have damage to the circuit board itself. If the damage is that severe, the only proper repair is by replacement of the entire board.

The generator was never maintained and being stored outside means a lot of things can get corroded. Sad that the power head could not be saved, but this video still has a lot of useful information. Thanks. Dave.

Taylor, your subscriber donor, got two videos for his money and the rest of us got a view of how to struggle with a machine that fights back. I did learn some things James. Many Thanks.

Thanks James, I started enjoying your lectures a few weeks ago, after I purchased a generator and I was going to connect it to my house electrical system as a back up in case of a power failure, I have all the parts I need but have not done it yet, since the chances of the failure are kinda low, any way this is my new addiction, watching you trying all kinds of tricks and magic to make the systems worthy to go back to the field, excellent work, I have over 40 years of experience in electronics repairs and you are my new hero, way more patient that I would ever want to be, again thanks for posting all the wealth of materials, just fantastic, the best I have ever seen in YT! many blessings for you and your loved ones!

That tip for pulling it til compression so that the valves are closed for storage is a good one👍 I'm gonna use that for my lawnmower (the only small engine I have)

For all the gents involved with saving this unit, you did a great job and the good bit and pcs. will live on. Very nice 2 part video. Thanks guys!!

I really enjoyed the slow motion sequence. You don’t realize how much these machines rock around on their rubber mounts when they start and stop.

Mr. Condon, You provide a great resource for anyone wanting to know more about the repair and maintenance the smaller KW generators - the best resource that I have found. You hit homeruns with all of your videos but these two videos - part #1,2 - you hit out of the park. Great information. Thank you.

When my father repaired old electronics for his employer some boards had warnings that "if this blows also replace this other board" sometimes a fault in one board killed another board. You could keep replacing one board or the other but first power up would kill both boards unless you replaced both boards together.

Hello, James. That was a tough nut. It proved that you can't fix them all. It was good to add how to set up an engine for long term storage. That is very useful information. Anyway, thanks for sharing! Stay healthy!

You have a Lot more patience than me Jim! That thing would have been a boat anchor by now in my shop!

Well you through everything at it you could, Vice grips, WD-40, PB Blaster, the scissor jack and the big hammer. I always admire your grit. Lessor men would have quit long ago.

Hi Jim...Long time subscriber here. We had a power outage today and thanks to your great videos, I was able to get our house backup generator working, even though it would have preferred the day "off".... Our refrigerator/freezer (and I) Thank You!!

As always, James, magnificent! And Thank-you! Your technical skills are amply equalled by your teaching and video skills. With enough thoughtful humour to spice the tempo. Hurrah!

My vote goes to the early determination that there's a short between exciter and power windings. Chalked up as expected, if it's not, that could be a hot to ground path that the board isn't designed for. Brilliant video as always. It would be great to see a full circuit diagram.

Hi James. Thanks for this timely video. I have just had a similar issue with an old generator I was given recently. Poor condition, stored outside, uncertain history. Yamaha MZ300 engine, not running but I was told it was OK. Turned out tank and carb were filthy. I cleaned them out, engine runs now. No power. Very noisy bearing in power head. AVR had been replaced, old one supplied, the capacitor obviously blown up. I was told the AVR had been professionally replaced but when started, the new AVR "blew up." (nothing obvious to look at.) Repairer told owner to give up on the machine. It sat outside for a couple of years or more, before it was given to me. With the "new" AVR still fitted, it produced wildly varying voltage - constantly fluctuating from tens of volts to about 200 volts. (it's a 240V generator, I'm in Australia.) I followed some of your other videos, tested output with 12V applied to brushes and AVR disconnected - I got constant but low voltage, about 120 Volts. I tested the ohms of rotor and three stator windings - main output winding, exciter winding and another, very low ohms, possibly a sense winding, but it didn't connect to the AVR or anywhere else, it was just a two pin plug dangling on two green wires. This AVR connected direct to the output, it sensed the full output voltage. All windings tested perfect based on the expected ohms in your other videos. When running, with AVR disconnected, I tested the exciter winding (2 blue wires) but got half the expected voltage - only 2.4 volts AC. Well like this video, I couldn't find anything wrong but decided to pull it apart and try to source an other alternator. (this is my first generator repair so I have no spares.) When I got the stator off, I got curious and decided to go over everything. Each winding in the stator tested fine Ohms, no discoloured wire, no shorts to earth (ground.) Then I did what I haven't seen you do yet... tested for shorts BETWEEN windings... and found the answer. The main winding was shorted to the exciter winding. My theory now is that the exciter winding started the AVR supply of DC to the rotor, but as soon as the main winding produced AC, it fed that high voltage AC to the exciter winding via the short, causing damage to the AVR. I'd be interested if you can test the stator in this video and see if you have any shorts BETWEEN windings. I haven't seen you test that in any video I have seen so far. (Apologies if you have, I haven't seen it.) Thanks for your videos, they are great - entertaining to watch and very instructive.

Thank you James for a great video this one was very educational. Your explanation on how the power head works was in depth and clear. This was a great series. There was a great attempt by everybody who tried save this genarator. You have taught me how to prep the engine the proper way for long term storage. I have been enjoying your channel and content and always wait for the next video. ❤🇨🇦

Was hoping to see it in all it's glory again. But, you just can't win them all.. but, I'd dare to say you won this over and just haven't seen it yet. Another great video, another slew of information. One of the best at what you do. Blessings and respect!

I have a couple of generators. So far, I'm good but if I need to work on one of them in the future your videos provide a LOT of useful information about repairs. Repair on not only specific models but just generators in general. Thanks!

Excelent job Mr. James!!! I finally have the opportunity to see how a Generac generator repairs, I have a similar one and I was curious how to change the dynamo or power head and configure it, eager to see the 3rd part of this series of videos... thanks Mr. James for your contribution in this world of electric generator repair... always grateful... greetings from Puerto Rico 🇵🇷...👋👋👋👋👋 ( Google translate)😁

Great follow up Jim. It is strange that the board kept blowing without any obvious failure mode. We chalk those up to electronic evil spirits. Nothing a good exorcism can’t cure. 😂

A great effort James, you can't win every one. Thanks for sharing.

It may be helpful to energize the brushes independently using an external variable voltage power supply with the generator running and its stator leads disconnected. Gradually energize the rotor more and more increasing the output from the variable voltage power supply to the brushes and observe all outputs from the stator. This could rule out a problem with the control boards. That small board with the SCR is possibly damaged by a short present in the board itself between layers. Replacing components and bridging broken traces doesn't fix the entire problem so if it fails again even repaired with new components, possibly the board itself is shorted.

I was sad to see that board burn up, it fought you to the very end, thanks for salvaging the engine, made part 2 satisfying.

It's unfortunate this generator had a bad stator but like you said, you can't save them all but at least you got a good running engine out of it which will come in handy one day to save another machine, nice work James!

It freaks me out that your hands are always clean! My hands look like I played in a crankcase when I'm working!

I never thaught about pulling the starter cord until the engine had compression so the cylinder was closed off. Great idea

A shorted turns tester is a very handy device. I used them for thirty odd years testing transformers, coils and TV yokes. Great work and always look forward to watching.

Good video series and more learnings. Thanks James.

The windings testing good by the insulation tester does not mean that the windings do not have any internal shorts between turns. Internal shorts not always visible by checking resistance either. Checking impedance with AC waveform would be more helpful.

Happy Thanksgiving my friend. You had a good (and well deserved) increase in subscribers this year. You will find a home for this engine. All the best to you and the family.

Thanks for the tips on fuel and on how to store my genset. I'll take a look at mine today.

Undoubtedly you’re the best equipment resuscitation expert out there but even you can’t save all of them.

You gave it a good run and at the minimum, you have a very good engine. Happy Thanksgiving to you and your family.

An interesting gremlin. Those sort were rare ones which occurred on 1960/70 mainframe computers like the IBM System 3 range. I ran a large Control Data Cyber system back in the '80s which suffered hard drive issues caused by a zealous maintenance engineer who used an aggressive cleaning solvent on the read/write heads!!

Hi James a good follow up video You cant win them all This engine will have its day of that I am sure Thanks for sharing

I thought for sure you had it fixed. Gotta give you a medal for perseverance, however! 😉

Great example of why you should keep indoors or well covered from the elements.

Kudos and a shout-out to Gary. He really knows his stuff 👍 He's the electronics technician I'd like to be 😎 When I saw the 'flash' in the first vid and where it was I figured it was 'game over' for this one without major transplant surgery. Seems I was right but you glad tried anyhow 😊

Every time you say "thanks for watching", I say "thanks for making" Literally out loud. lol. I do all my own mechanic work (vehicles and small engine) but still learn a lot from watching these. Thanks

You gave it your best shot, happy Thanksgiving to you and your family.

A really interesting video. I purchased a Home Depot 5200 Watt generator, but couldn't find the information I needed at the time, to check the rotor and stator. I noticed, when I pulled the back to expose the slip rings and brushes, that there was the same type of discolouring on my stator. Even though I purchased a new voltage regulator board, I didn't want to risk blowing it out if there was a fault in the stator. I have learned a lot from your video, and maybe I'll have another shot at identifying the problem.

Although the bell housing has an unusual bolt pattern, you can easily take it off and see if there are extra tapped holes in the engine cover that could be used to mount another generator head but you would still have to find on with a rotor to fit the non-standard length tapered end of the crankshaft.

You would need one other meter to your collection: An inductance measuring device. That generally comes as a part of so called LCR meters. If there is an internal short in a winding, the inductance collapses, but the DC resistance probably changes only a token amount. Or we might say the the "Q" or quality factor of the coil also collapses. The LCR meters tend to be fairly expensive, but you might check the offerings of BK Precision, or what is more capable, DER EE meter model DE-5000 that is my favorite with a wide measuring range due to especially 100 Hz to 100 kHz frequency range. Cheaper meters may be limited only to 1 kHz fixed. I believe the generator windings require measurements at 100 Hz.

Thanks for the interesting content James. Happy Thanksgiving to you and your family.

Never mind James, There are NOT many situations that beat you (you're a fighter to the end). I'm sure that, at some point, a Phoenix will arise out of the ashes of this machine (pun unintended). Happy Thanksgiving to all your end. Wayne & Nina (Ipswich, Suffolk, UK) ❤️❤️❤️❤️❤️👍👍👍👍👍

Jim, another great video. Happy Thanksgiving to you and your family.

Well done James, maybe someone may have a spare powerhead lying around for you and you'll be able to get another machine functional again. Keep it up.

As you said, you cant fix them all. It was very entertaining watching you try. Happy Thanksgiving!

That was an impressive flame out. Even if you had got it to produce power I don't think you could trust it long term with that amount of corrosion on it but kudos to you for giving it a damn good go.

Thankful for a video on Thanksgiving and wishing the best holiday to you and yours, Jim. 🦃 Sorry that you and Gary spent as much time and effort as you guys did only to have it continue to fail.

That engine would be well received by someone doing custom go-kart shenanigans.

Like you said James, you can't save them all. but you did get to save some parts for later on. great video. making great video's.

Thank you for the thanksgiving gift today.

Hi James. Such hammering on the motor shaft destroys the bearings. The rod and thread or hydraulic pressure method is much friendlier to the motor shaft bearings.

You could check the iron of the stator for a short. Rap the stator with some welding cable and connect this cable to an AC welder and set the welder to the lowest setting and run the welder for a few seconds and check for hot spots on the stator iron. I think you will see a spot that will start to glow red this is because the iron has shorted out and cause high current in the motor. The only wat to fix it would be to separate the iron at the hot spot and insulating it by varnish or cutting out the short with a cutter or grinder. Also when you power up the welder you should be able to check the voltage coming off the winding, all the voltages should be the same , you can check the the voltage to groung of the stator and winding neutral. Great videos keep up the good work.

well done thanks for sharing learned a LOT

Ah well, you can't win 'em all. As a by the by, I'm guessing you're upstate which is a pity as I'm on long island visiting my mum and sister this week. But work calls and I head back to Blighty Monday evening, so it'll have to be another time. Thanks for another great video Jim.

Well sometimes things don’t work out sorry about your luck . I learned something so thanks .

Wow, this was very educational👍👍👍

At least you got a decent pressure-lubed engine out of the deal. Maybe a powerhead that will fit will show up in the future. Happy Thanksgiving!

I reckon, on a second viewing, at least, buying that voltage regulator board new is worthwhile, then a try-out with the existing stator (and another stator) . . . It's such a lovely machine (ok, rusty frame, lost towing handle and foot . . . ). Again, thanks!

Well its unfortunate it wasn't able to be fixed but at least you get to dig into it and find out what failed. I work on similar stuff to this and see if I can get it going and why it was put away sometimes I find the reason other times I don't. Id say the thing that is the most cool about it is I run a RU-vid channel as well, people can watch our videos we upload and see what we're working on and say Hey I'm having that same issue and follow what we do instead of taking it somewhere to have it worked on, Plus even if you don't end up getting what ever your working on running taking it apart to see what failed is a good learning experience. Keep up the good work and keep the videos coming I also enjoy seeing when youtuber's help other youtuber's out.

My take is keep the rotor with the unit . It's old & very much obsolete but should work as a Franken-gen for a few more years . Just document the parts changes for the next fix ! Ditch the original avr , it's trouble . Find a stator that fits use the end carrier casting , end cap & avr from that donor unit . Fit a small battery tender in the plug panel ( running off the a/c out ) . Relabel the 12 v out as charger input or just delete it ! Some you win Some you lose Some you break even Some you make it up as you go along ! Sometimes you just go home …...........

before risking the repaired boards i would exite the rotor with a variable DC power supply and measure output voltages from the stator to eliminate any internally shorted stator windings James!

Another great follow-up video.

Hi first if you get a centre drill and drill in the centre of the draw bolt the pullers will stay put when you pull the end cover off. While you are pulling give the end cover some heat around the bearing and the outside. Get two 12v batteries in series 24v and connect to a 24v pulse width modulation dc motor speed controller and connect to the Brushes. With your test lamp and a multi meter slowly ramp up the excitation to check the output from the alternator. If ok i think the kidney shape avr fits those units. Use 500 volt to test not 1000, 1000v bit to much. Good luck. Grind a shiny patch on the laminates to give you a better connection.

I keep non ethanol fuel in mine and it's the same premix I run for weedeater and lawn mower. I change it annually and run it to warm up then under load. It stays stored in garage and I've never had problems like this.

James can't tell you how much I enjoy your videos to say they are excellent is an understatement! I have a question for you: I have an excellent but inexpensive 4KW generator for emergency purposes that runs great, but I'm concerned about harmonic distortion from it damaging my high-end appliances. Short of buying an expensive inverter generator is there a reasonably priced device i.e., line conditioner etc. that would reduce this harmonic distortion to an acceptable level or am I just domed to pay out the bucks for an inverter generator.

A air hammer would be very helpful in separating rusted powerheads. South Main Auto uses Big Nasty. That's overkill for a power head. A smaller air hammer is all that's needed. Happy Thanksgiving

You can partially prefill the oil filter even if it mounts upside-down. The oil will soak into the filter element if you give it a few moments. For long term storage run engine with fresh oil until fully warmed up. Spray fogging oil into the carburetor and smoke it heavily. Stall out or shut off and drain all the gas out of everything. Spraying fogging oil into the carb bowl will coat the interior. Spraying fogging oil through the carb lubes the valves and guides. Leaving the engine on the compression stroke is a good idea. Won't work on a multi cylinder engine. Close the choke and Spray exterior bare metal with fogging oil to stop corrosion.

Good video as usual Jim. One note of caution on hammering on the bolt that threads into the crankshaft...hammer too hard and you could break/crack the crankshaft Ask me ho I know. Also, I have a rotor I can't get off the tapered shaft. I was hesitant to pound on the bolt...but now it's the only alternative.

good try James, you worked hard to save it .. happy Thanksgiving my friend

Why don't you use the black box power supply for your DC. You can then load the gene and see if the stator holds while monitoring DC amps from power supply. That way you will know if it was the board

Anytime there are sparks and stuff burning up but not in a dangerous way of course, makes for a good video. You should re-purpose the engine since it is so good like, I don't know, a go kart or something. I used to put two stroke oil in the pistons of my machines at work because it would at least burn up on startup, did not know about that spray or the idea of making the engine seal by having it top dead center.

I say lesson learned...... do not leave your stuff outside uncovered.

A thought for actively testing stators. Maybe an old TV degaussing wand? It will induce AC magnetism into the stator to help check for shorted turns etc

Thanks for the vid. I am impressed with your attention to detail. Why haven't you been using the lift you got in a previous episode. I would have thought you would use it and not have to work on the floor.

I was intrigued that the panel on that beacon generator had a light on it ~ and was looking forward to you testing it and turning on the light, ☹️ I’ll have to wait until you repurpose the power unit to another generator/replace the power head on that generator

If James can’t find the problem, no one is going to find it, machine is just too stubborn to work that’s all

Has a flying short. Short is only active once the rotor starts spinning. While stopped it all appears o be fine but once it gets up to speed or it starts spinning the short connects it self, when it stops the short clears or otherwise disconnects itself. The issue is extremely rare maybe 1 in 10 thousand chance that you would/could happen. When the stator is energized the magnetic force pulles or otherwise shifts the windings into a shorted condition when power in cut it loses contact and clears the short. It happens once in maybe 10k issues. Extremely rare problem. Could happen in the rotor but even less if a chance think I've seen that problem maybe twice in 20 years I worked rebuilding generators. That it is in he stator is maybe a 1 in 5k chance kinda problem.

Thank you for trying to show your anilitics are best wishes to you n yours peace

Hi, James. I'm sorry I am so late with my comment, but I thought I would share my thoughts on this power head. The fact that the main windings were disconnected when the power module blew up would indicate to me that the load on the engine was due to excessive current in the DPE winding supplying the power module due to a short in the power module itself. Looking at the slo-mo footage of the module destroying itself, it is clear that there was a huge amount of current involved. This could only have come from the DPE winding. My next step would have been to remove the power module and supply 12v to the brushes from a battery. If the engine still went under load doing this, then definitely the stator is bad, with an internal short somewhere. If not, then the issue is only with the power module. Another option would to use the DPE winding with just a bridge rectifier to supply the brushes. Again, if the engine went under load, then there is an issue with the stator. There is no way a bad stator on its own could cause the failure of the power module. The only way the rotor could contribute to the failure is if it suddenly went short circuit, in which case the magnetic field from the rotor would collapse, stopping any power generation from happening. IMHO, the only villain in the piece is the power module. It has a fault causing the DPE winding to short out.

Some you win some you have to beat like it owed you money. Great video.;)

You need a "ring tester" they are commonly used to check coil windings on transformers and electromagnets. All that energy had to be going somewhere and I suspect that's why the stator windings are a different color they were getting hot and you could hear them kind of crackling and popping in the first video when it went under load.

Good job bro 🌹🌹 I’m Gues if The power head is still make power with a Dc very well which is mean still happy it should just need a correct pbc.

I'm curious if a rod with a few o-rings on it could be used with water to pop off rotors? Acts like a piston down the center of the rotor. Would strike it with a hammer.

Hi James , I was field service industrial for over 35 years and have accumulated a lot of tools etc. I retired a little over a year ago. I have a few items I think you could use, possibly several,. I will have to go snooping around the garage to see. Is there an address I could send a care package to ? It may take me a little while to get it sent out. Thanks for all the great videos you make and share with us. I'm sure all us viewers learn some good tips from them.

James, It is not over... You could install a universal AVR such as the SX460 (about $20) or GAVR-8A. These units do not require an excitation circuit. This would allow you to abandon the damaged (DPE) winding and both circuit boards. Wire a lamp cord to the SX460 and connect F1 and F2 to the brush pack. A 9 volt battery works well for the first "flash". If the genset produces power it will be a creative recovery, if not it will make for great footage.

Good day from my experience repaing and rewinding generator my guess was the second board was part of voltage regulation In Japanese and Chinese small generators if the sensing wire coupled with the main winding disconnect it will ramp up over voltage which lead to damage the regulators just my guess

An alternative to fogging oil is a 2 cycle mineral TC-W3 oil at about a 16 to 1 gas to oil fuel mix. Fill the fuel line and run the engine a few seconds, it should smoke when it gets a gulp of that 2 cycle fuel mix. Choke it down instead of running it dry. Leave the choke closed on the stopped engine.

You did not see the shaft on stater jumping up and down..The berrings are DONE from sitting outside i suspect.the shaft looks like an oval rotation

Hi James, l also watch the regulator rebuild and I think that if the regulator is not connected to the 3 pin connector the rotor will be full FIELDED. As the 3 pin connector was bad in first place that could've been the original fault. Just a thought JS

In your 1st video you got the generator to work by supplying 12 volts to the brushes and got power, which should indicate the generator is sound. With all the corrosion on this generator could it not have a proper ground though out the generator body and frame. IF this is the case I wonder if your getting a back feeding though the boards. I have seen this many times in the automotive field there circuits will back feed though anything turning radios on when the reverse light come on or lights turning off and on by pressing the brake pedal that are not the brake lights.

Good morning. Have you ever considered getting a growler to test the rotor or stator ? I am not a specialist in electric motor or generator repairs and have never used a growler myself, but a friend of mine had one, and he used it all the time for that kind of tests. What my friend said was that sometimes you ran into situations where you could measure to no end and not detect the problem, but with the growler he always cound the problem. He used a hacksaw blade to detect the vibrations.

looking forward to a follow up with this one....!

Hay I’m fixing one just like it and so far it’s turning out great Rats ate fan and all wires Carb was terrible but cleaned up Still trying to get fuel tank gleaned Metal tanks are terrible ideal

James, I love the way you present these videos, just a quick question, have you had any experience with Honda ME500 Generator, and if you do what would the resistance for stator be for a 500W generator (generally) ?