# Predator 3500 died - these photos show how - blown electrical components



## johan

Yesterday May 2, 2020, after 1677 hours of runtime, of which roughly 25% at full load, and proper prescribed maintenance, my Predator 3500 emitted a soft popping sound after starting it up and plugging in a load. Then it showed zero output voltage. Dead. Opening up the generator and analyzing the cause suggested that at least two SCR thyristors (I think) seemed to be blown and cracked open (type BT169H dJ 634, where the 'B' may be a "beta", assuming all original six where of the same type, see photos below), possibly destroying some tiny electrical components around it, judging by the black burn marks. All was immersed in epoxy so it took me the heat of a soldering iron and a scraper to excavate the components. In the process, I damaged some more despite trying to be very careful. These components are extremely hard to replace for the average Joe like me.

* Has anybody had this problem too and could I have done something to prevent this?*

Sometimes I plugged in loads (always purely resistive only) directly after turning on the generator, before the inverter reached the full 120V. The manual p11 states: "Allow the engine to run at no load for five minutes after each start-up so that the Engine can stabilize". I never did that.

Hopefully Harbor freight carries spare parts, I just emailed them.
From the manual: This is part number 103, "Inverter Assembly".

Harbor Freight SKU of generator: 63584

Update: Harbor freight can special order this part for $396. That is roughly half the price of a new Predator 3500.









_Figure 1: Predator 3500 Inverter Assembly after removing epoxy in the corner near the blown components._









_Figure 2: Inverter Assembly - close-up of blown electrical components (the two middle black ones of all six)._









_Figure 3: Inverter Assembly - close-up of electrical component type (rightmost two of the six)._


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## tabora

Yup, that's the downside of potted assemblies; you pretty much have to replace the complete assembly. That looks like a Ryobi/Kipor 3000W inverter board. Even if HF doesn't have it available (they should), you can search other sources for part number TJ838-3KS-1.


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## iowagold

salt to the wound..
this is why I spend the bucks for a honda eu series gen set!!
these clone units do not hold up to rated power..
lower cost parts...
just saying, save up for the real deal and never have to look back!

yea there is something about loading up any gen set with inrush, or loading too soon after start up..
just not a good idea...
always select a gen set that is 50% more power at rated than you need..
and watch these Jina clone gens... most do not put out the rated power for long time runs..
they get heat soak and trash parts like what happened to you...

proper cool clean air for the generator intake, this helps on the cooling too.
dry place of operation, use a gen tent or gen shack.
and make sure your connections to your load are extra heavy duty and clean so you do not have power sag issues
jerking of the power causes spikes and over heat the inverters trying to keep up with the changes.

and if you are running ac units on any gen set.
use a micro air soft start! these just help with the compressor start up issues and loading of the gen set


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## Pliskinrr

After only 26 hours of operation my inverter board has blown, any suggestions on how to replace this board, mine is the same model number as yours.


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## Pliskinrr

Why can we not find these boards cheap and easy everywhere.


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## RonJ

Pliskinrr said:


> After only 26 hours of operation my inverter board has blown, any suggestions on how to replace this board, mine is the same model number as yours.


You might try Generator Guru. I have had success with them in the past.


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## johan

Where to get this part:

Harbor Freight: approx $400, email [email protected]
Generator Guru: confirmed that they do *not* sell this part; referred to Harbor Freight.
Ebay: I tried for multiple months to get this part from a genset with e.g. a broken motor: No luck, despite broad "saved searches" with email notifications.
In the end, due to circumstances, I bought a new Predator 3500 (Harbor Freight SKU 56720, has a mechanical fuel gauge on top). As a side note, NorthernTool sells a very similar (same?) generator in blue.


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## iowagold

well at not quite 3 x the cost the honda looks pretty good..
i have never had the issue with the run for 5 min be fore the load.
heck with the hondas I start them and when the unit settles down on speed
I go right to my load.

most of the stuff from HF and a few other truck sale places is just low cost Jina stuff..
made to "look like" other brands...

a person is better of saving up for the real deal quality brands..
and stay away from the clone generators..

some of the honda eu generators in the fleet are 80,000 hours.. (not a mis print at the 80k hours)
and getting retired this year... at 10 years old.
doing the update to new honda gens.

the trick is good oil, magnetic dip stick, and run on lp or natural gas.
service them well.

we run royal purple for oil.
and I hear the same from the guys with ams oil.
these are custom gens with good large oil filtration systems.

what was the load that you were using on the gen set??
thinking maybe a power factor issue or some sort of weird spike or feedback.
at 25% of rated power for a load... something is up for sure!!

i thought the HF inverter was way too noisy on the spectrum analyzer for me...
not a good pure signal...
the honda eu 7000is is the best in class,,

these days everything is digital... and needs pretty good power to run right...


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## johan

iowagold said:


> well at not quite 3 x the cost the honda looks pretty good..
> i have never had the issue with the run for 5 min be fore the load.
> heck with the hondas I start them and when the unit settles down on speed
> I go right to my load.
> 
> most of the stuff from HF and a few other truck sale places is just low cost Jina stuff..
> made to "look like" other brands...
> 
> a person is better of saving up for the real deal quality brands..
> and stay away from the clone generators..
> 
> some of the honda eu generators in the fleet are 80,000 hours.. (not a mis print at the 80k hours)
> and getting retired this year... at 10 years old.
> doing the update to new honda gens.
> 
> the trick is good oil, magnetic dip stick, and run on lp or natural gas.
> service them well.
> 
> we run royal purple for oil.
> and I hear the same from the guys with ams oil.
> these are custom gens with good large oil filtration systems.
> 
> what was the load that you were using on the gen set??
> thinking maybe a power factor issue or some sort of weird spike or feedback.
> at 25% of rated power for a load... something is up for sure!!
> 
> i thought the HF inverter was way too noisy on the spectrum analyzer for me...
> not a good pure signal...
> the honda eu 7000is is the best in class,,
> 
> these days everything is digital... and needs pretty good power to run right...


Load type: A purely resistive load of approx. 2900 Watt at the time of failure. The generator is rated 3000W continuous. I used the generator 25% of the *time* at this 2900W "full load".


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## iowagold

too small of gen for that 2900 watt cont. load.
the ratings are inflated on the hf gens.

by my math 2625 watt should be the rated cont on the hf unit.
and that will be over rated... 2500 watts is a good number for the parts that hf use in the inverter.


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## Pdxry

Message sent!


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## speedy2019

People need to run in their generators slowly and not thrash the nuts of them straight away.


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## natanaelmontanezvega

johan said:


> Yesterday May 2, 2020, after 1677 hours of runtime, of which roughly 25% at full load, and proper prescribed maintenance, my Predator 3500 emitted a soft popping sound after starting it up and plugging in a load. Then it showed zero output voltage. Dead. Opening up the generator and analyzing the cause suggested that at least two SCR thyristors (I think) seemed to be blown and cracked open (type BT169H dJ 634, where the 'B' may be a "beta", assuming all original six where of the same type, see photos below), possibly destroying some tiny electrical components around it, judging by the black burn marks. All was immersed in epoxy so it took me the heat of a soldering iron and a scraper to excavate the components. In the process, I damaged some more despite trying to be very careful. These components are extremely hard to replace for the average Joe like me.
> 
> * Has anybody had this problem too and could I have done something to prevent this?*
> 
> Sometimes I plugged in loads (always purely resistive only) directly after turning on the generator, before the inverter reached the full 120V. The manual p11 states: "Allow the engine to run at no load for five minutes after each start-up so that the Engine can stabilize". I never did that.
> 
> Hopefully Harbor freight carries spare parts, I just emailed them.
> From the manual: This is part number 103, "Inverter Assembly".
> 
> Harbor Freight SKU of generator: 63584
> 
> Update: Harbor freight can special order this part for $396. That is roughly half the price of a new Predator 3500.
> 
> View attachment 7770
> 
> _Figure 1: Predator 3500 Inverter Assembly after removing epoxy in the corner near the blown components._
> 
> View attachment 7771
> 
> _Figure 2: Inverter Assembly - close-up of blown electrical components (the two middle black ones of all six)._
> 
> View attachment 7772
> 
> _Figure 3: Inverter Assembly - close-up of electrical component type (rightmost two of the six)._






 The board is so expensive it is worth fixing yourself, mine is a Generac ix800 the board is about $700.


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## 50ShadesOfDirt

I might try to fix them, if the potting material wasn't in place ... is this stuff there for heat resistance, or to keep us from fixing it ourselves?

In the meantime, you can now take advantage of "generator recycling" (which we do with Duromax gennys), where your "dead" predator genny with a major part failure becomes a bucket full of parts for the next predator genny, as long as you keep buying the same genny model. Starters, motors, rotor or stator, carbs, etc.

This is really the only way to recycle generators ... the tapered shaft on the engine, and precise matching of generator (rotor/stator) to engine makes them throwaway items if not recycled in such a manner. It's usually a major part and/or replacement cost that drives us to this.

An open-frame genny (like the duromax and many others) is super easy to work on ...


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## natanaelmontanezvega

I can just imagin how many hours you would put on a generator for a tapered shaft to wear, I read on a site that a guy had 80,000 hours on a Honda eu2200 80k on a 10 year old machine, my understanding is that these generators mainly have problems with the inverter board when used with airconditioning units, proper use with sensitive electronics is what the generator was made for, AC units should be run on conventional generators even though they are noisy.


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## natanaelmontanezvega

50ShadesOfDirt said:


> I might try to fix them, if the potting material wasn't in place ... is this stuff there for heat resistance, or to keep us from fixing it ourselves?
> 
> In the meantime, you can now take advantage of "generator recycling" (which we do with Duromax gennys), where your "dead" predator genny with a major part failure becomes a bucket full of parts for the next predator genny, as long as you keep buying the same genny model. Starters, motors, rotor or stator, carbs, etc.
> 
> This is really the only way to recycle generators ... the tapered shaft on the engine, and precise matching of generator (rotor/stator) to engine makes them throwaway items if not recycled in such a manner. It's usually a major part and/or replacement cost that drives us to this.
> 
> An open-frame genny (like the duromax and many others) is super easy to work on ...


This is my conventional gen 4 years old with 190 HOURS RUN TIME, oil change every 30 hours. The potting is for vibration, heat, and protection and is intended to be easily removed for repair with any kind of heat gun, the chinese people are highly intellegent and don't like to throw good things away, they also don't like lazy people they expect technicians to know their field and to know by the problems symptoms which componant on the board is defective, the majority of those componants in their design are to last up to 25 years in proper use at 50% load. But at the same time take into consideration the American way,,,,,, which is,,, "throw that peace of crap out and buy a new one"....


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## OrlyP

natanaelmontanezvega said:


> But at the same time take into consideration the American way,,,,,, which is,,, "throw that peace of crap out and buy a new one"....


Well, there's some merit to that. If something will take up too much of your time than it is worth to fix it, time that would've otherwise been spent more productively on other things, I would've thrown it away, too. Or at the least, sold it to someone who has that much time on their hands.

It's all about how you put a price on your own effort. 

From purely a serviceability standpoint, I too, prefer the non-inverter gennies for their simplicity. Short of a catastrophic failure, I have very high confidence that I can fix most issues on my own. Parts are relatively cheap and easy to replace. Inverter gennies on the other hand are a wild card. They're fine and dandy when everything's normal, but on a bad day, it can quickly turn into a potential nightmare.


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## speedy2019

iowagold said:


> well at not quite 3 x the cost the honda looks pretty good..
> i have never had the issue with the run for 5 min be fore the load.
> heck with the hondas I start them and when the unit settles down on speed
> I go right to my load.


I give my gen about 30secs after starting the engine to flicking on the circuit breaker as the engine doesnt take many second to run smoothly from cold.


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## natanaelmontanezvega

OrlyP said:


> Well, there's some merit to that. If something will take up too much of your time than it is worth to fix it, time that would've otherwise been spent more productively on other things, I would've thrown it away, too. Or at the least, sold it to someone who has that much time on their hands.
> 
> It's all about how you put a price on your own effort.
> 
> From purely a serviceability standpoint, I too, prefer the non-inverter gennies for their simplicity. Short of a catastrophic failure, I have very high confidence that I can fix most issues on my own. Parts are relatively cheap and easy to replace. Inverter gennies on the other hand are a wild card. They're fine and dandy when everything's normal, but on a bad day, it can quickly turn into a potential nightmare.


Yes, and the experience can last a life time, we are entering a new age of tech,, our grandparents didn't need as much electricity as we are going to need in our future and the more knowledge we have the better off we will be being that our bank accounts are now subject to electricity, our cell phones, even a simple 250mA solar panel nowadays is enough to keep our comunication going,,,,we never know on this planet when the power outage will ruin our day the more we know the better off we will be, I currently have 5 generators a few solar panels a few power inverters,,, all with the idea of keeping up with the times. When I was a kid in New Jersey who cared about backup power¿¿¿¿ nobody!... I'll be 50 years old in January and now,,,,,"YES",,, I care about backup power.


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## natanaelmontanezvega

natanaelmontanezvega said:


> Yes, and the experience can last a life time, we are entering a new age of tech,, our grandparents didn't need as much electricity as we are going to need in our future and the more knowledge we have the better off we will be being that our bank accounts are now subject to electricity, our cell phones, even a simple 250mA solar panel nowadays is enough to keep our comunication going,,,,we never know on this planet when the power outage will ruin our day the more we know the better off we will be, I currently have 5 generators a few solar panels a few power inverters,,, all with the idea of keeping up with the times. When I was a kid in New Jersey who cared about backup power¿¿¿¿ nobody!... I'll be 50 years old in January and now,,,,,"YES",,, I care about backup power.


This is how I log the hours, oil changes, and any repairs, I don't think anybody has a good enough memory to remember if your living a real life. It's better to have documented facts for peace of mind.


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## motormonkey

natanaelmontanezvega said:


> This is my conventional gen 4 years old with 190 HOURS RUN TIME, oil change every 30 hours. The potting is for vibration, heat, and protection and is intended to be easily removed for repair with any kind of heat gun, the chinese people are highly intellegent and don't like to throw good things away, they also don't like lazy people they expect technicians to know their field and to know by the problems symptoms which componant on the board is defective, the majority of those componants in their design are to last up to 25 years in proper use at 50% load. But at the same time take into consideration the American way,,,,,, which is,,, "throw that peace of crap out and buy a new one"....


Let's get a few things straight here.

First, the potting is indeed for vibration, heat, and physical protection. Easily removable potting is the exception and not the rule. Many of us have been there and done that.

Second, the Chinese people are no more or less intelligent than any other people in the world. Likewise, their opinions about "lazy people" are not any different from the rest of the world. Their expectations about technicians are equally no different from the rest of the world.

Here's where things are different. Technicians are only as good as the technical information available on the equipment they are expected to service, AND the availablility of serviceable replacement parts. The reality is that affordable parts and service information availability, along with guaranteed longevity, are poor to nonexistent on much of the equipment coming from mainland China.

Your conclusion about "the American way,,,,,, which is,,, "throw that peace of crap out and buy a new one," is many times the ONLY option when dealing with equipment where no service information or replacement parts are available at reasonable and competitive cost. Many of us have been there and done that, too.

Your comments are not constructive, and contribute nothing to this thread or forum.


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## natanaelmontanezvega

motormonkey said:


> Let's get a few things straight here.
> 
> First, the potting is indeed for vibration, heat, and physical protection. Easily removable potting is the exception and not the rule. Many of us have been there and done that.
> 
> Second, the Chinese people are no more or less intelligent than any other people in the world. Likewise, their opinions about "lazy people" are not any different from the rest of the world. Their expectations about technicians are equally no different from the rest of the world.
> 
> Here's where things are different. Technicians are only as good as the technical information available on the equipment they are expected to service, AND the availablility of serviceable replacement parts. The reality is that affordable parts and service information availability, along with guaranteed longevity, are poor to nonexistent on much of the equipment coming from mainland China.
> 
> Your conclusion about "the American way,,,,,, which is,,, "throw that peace of crap out and buy a new one," is many times the ONLY option when dealing with equipment where no service information or replacement parts are available at reasonable and competitive cost. Many of us have been there and done that, too.
> 
> Your comments are not constructive, and contribute nothing to this thread or forum.


Very well written, I can imagine your a very well educated individual. May all our generators function at the time of need.


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## natanaelmontanezvega

johan said:


> Yesterday May 2, 2020, after 1677 hours of runtime, of which roughly 25% at full load, and proper prescribed maintenance, my Predator 3500 emitted a soft popping sound after starting it up and plugging in a load. Then it showed zero output voltage. Dead. Opening up the generator and analyzing the cause suggested that at least two SCR thyristors (I think) seemed to be blown and cracked open (type BT169H dJ 634, where the 'B' may be a "beta", assuming all original six where of the same type, see photos below), possibly destroying some tiny electrical components around it, judging by the black burn marks. All was immersed in epoxy so it took me the heat of a soldering iron and a scraper to excavate the components. In the process, I damaged some more despite trying to be very careful. These components are extremely hard to replace for the average Joe like me.
> 
> * Has anybody had this problem too and could I have done something to prevent this?*
> 
> Sometimes I plugged in loads (always purely resistive only) directly after turning on the generator, before the inverter reached the full 120V. The manual p11 states: "Allow the engine to run at no load for five minutes after each start-up so that the Engine can stabilize". I never did that.
> 
> Hopefully Harbor freight carries spare parts, I just emailed them.
> From the manual: This is part number 103, "Inverter Assembly".
> 
> Harbor Freight SKU of generator: 63584
> 
> Update: Harbor freight can special order this part for $396. That is roughly half the price of a new Predator 3500.
> 
> View attachment 7770
> 
> _Figure 1: Predator 3500 Inverter Assembly after removing epoxy in the corner near the blown components._
> 
> View attachment 7771
> 
> _Figure 2: Inverter Assembly - close-up of blown electrical components (the two middle black ones of all six)._
> 
> View attachment 7772
> 
> _Figure 3: Inverter Assembly - close-up of electrical component type (rightmost two of the six)._



























I guess those reached their limit and blew out.The datasheet shows their limit.


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## natanaelmontanezvega




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## natanaelmontanezvega

Found these photos online, this guy repaired a Honda eu2000 inverter board.


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## Winnipegmike

80,000 hours is a bit over 9 years of continuous operation (and this is stated for a 10 year old machine). Similar to approximately 5,000,000 miles on a car at 60mph. 
Have the good people at the Guinness book of records been contacted in regards to these numbers?


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## natanaelmontanezvega

Winnipegmike said:


> 80,000 hours is a bit over 9 years of continuous operation (and this is stated for a 10 year old machine). Similar to approximately 5,000,000 miles on a car at 60mph.
> Have the good people at the Guinness book of records been contacted in regards to these numbers?


Read it for yourself 80k.


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## Winnipegmike

Cool. I did read that. That's what I replied to. Exceptional service life. Congrats to the owners


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## natanaelmontanezvega

johan said:


> Yesterday May 2, 2020, after 1677 hours of runtime, of which roughly 25% at full load, and proper prescribed maintenance, my Predator 3500 emitted a soft popping sound after starting it up and plugging in a load. Then it showed zero output voltage. Dead. Opening up the generator and analyzing the cause suggested that at least two SCR thyristors (I think) seemed to be blown and cracked open (type BT169H dJ 634, where the 'B' may be a "beta", assuming all original six where of the same type, see photos below), possibly destroying some tiny electrical components around it, judging by the black burn marks. All was immersed in epoxy so it took me the heat of a soldering iron and a scraper to excavate the components. In the process, I damaged some more despite trying to be very careful. These components are extremely hard to replace for the average Joe like me.
> 
> * Has anybody had this problem too and could I have done something to prevent this?*
> 
> Sometimes I plugged in loads (always purely resistive only) directly after turning on the generator, before the inverter reached the full 120V. The manual p11 states: "Allow the engine to run at no load for five minutes after each start-up so that the Engine can stabilize". I never did that.
> 
> Hopefully Harbor freight carries spare parts, I just emailed them.
> From the manual: This is part number 103, "Inverter Assembly".
> 
> Harbor Freight SKU of generator: 63584
> 
> Update: Harbor freight can special order this part for $396. That is roughly half the price of a new Predator 3500.
> 
> View attachment 7770
> 
> _Figure 1: Predator 3500 Inverter Assembly after removing epoxy in the corner near the blown components._
> 
> View attachment 7771
> 
> _Figure 2: Inverter Assembly - close-up of blown electrical components (the two middle black ones of all six)._
> 
> View attachment 7772
> 
> _Figure 3: Inverter Assembly - close-up of electrical component type (rightmost two of the six)._











Inverter circuit board


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www.powerequipmentforum.com


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