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inverter rebuild / troubleshooting - Voltage insulation fault P0AA6 526/614

Discussion in 'Gen 2 Prius Technical Discussion' started by tri4all, Dec 21, 2019.

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  1. tri4all

    tri4all Member

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    I am following the inspection procedure that starts on HV-424. After a lot of testing with both standard multimeter and a megameter, I have found that the inverter is a fault and possibly the frame wire as well. when I opened the inverter assembly it looked in pristine conditions and I am wondering if anyone has any experience trying to fix or troubleshoot an inverter that looks like mine.

    During the insulation test I got over 150 Mega Ohms on step 17 below which points to "replacing inverter assembly". if I were to continue testing the inverter and move to step 18, I get 2.9 Mega Ohms for all 6 terminals and this actually points to "replacing transaxle". I am planning to just replace the inverter assembly only and hope that the error code would go away.

    I am wondering if perhaps one of the conectors inside the inverter or a fuse is at fault or if I would have to replace the entire inverter assembly. Thank you for any input.

    Has anyone rebuild a inverter that appears in good overall condition that has no signs of corrosion or shorts? Is there a common part to replace to get it working again?


    upload_2019-12-21_12-34-2.png
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    #1 tri4all, Dec 21, 2019
    Last edited: Dec 22, 2019
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  2. tri4all

    tri4all Member

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    Pictures of inverter 20191221_102321.jpeg 20191221_102306.jpeg 20191221_102245.jpeg

    Posted via the PriusChat mobile app.
     
  3. ChapmanF

    ChapmanF Senior Member

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    When you're working through a troubleshooting sequence in the manual, it is very important to read carefully enough so that you know what each step of troubleshooting is supposed to be telling you, and which results are considered "OK" or "NG" (no good), and what the context is.

    In the case of step 17 in what you posted, the context is that by the time you reach step 17, you are already convinced that either the inverter or the transaxle has a ground fault, and step 17 is there for you to decide between those two possibilities. (As to why you are convinced either one of them does have a problem, that had to come from the careful reading of the sixteen earlier steps).

    Once you are at step 17, you are trying to decide whether the ground fault you think you have is in the transaxle or not. So it has you meg each of the transaxle motor leads to ground. For each of those tests, the "specified condition" is "10 MΩ or higher". So 10 MΩ, or any reading higher than 10 MΩ, is OK. A reading would have to be lower than 10 MΩ to be NG.

    So if you have just made all six of those tests and they all showed "over 150 Mega Ohms" on your meter, well, "over 150 Mega Ohms" is way higher than 10 MΩ, so these tests are all way super-duper flying-colors OK, and there is definitely no ground fault in your transaxle.

    Notice that these results do not prove that you do have a ground fault in the inverter. Rather, if you got to step 17, you presumably believe there is a ground fault in the inverter or the transaxle, and the step 17 tests have told you it's not in the transaxle, so if you are right about a fault in one or the other, then you could conclude the fault is in the inverter.

    But at this point, it would probably not hurt to run back over the 16 earlier steps just to make sure, as in this example, of what each step was supposed to be telling you, and what each one did tell you.
     
    #3 ChapmanF, Dec 21, 2019
    Last edited: Dec 21, 2019
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  4. tri4all

    tri4all Member

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    Hi Chapman, you are absolutely right. I actually went through every step of the way from step 1 to 17 to determine that the inverter was at fault. it was a lot of work testing through the hybrid battery, relays, cables, etc. In fact, the only step that I am not certain if it passed or not is the frame wire cable running from the battery to the inverter which is step 16. you can see the details from one of my previous post about a possible fault at the connector metal jacket/sleeve of the upper cable.

    Now having said all that.. I know that step 17 leads me to a faulty inverter with my current results (about 150 Mohms) and I would stop there. BUT if you look at step 18, my results (2.9 Mohms) leads me to a faulty transaxle as well. furthermore these two steps appeared to be completely independent from each other since the inverter and transaxle cables are isolated and disconnected and measuring two different separate devices. so there is a bit of contradiction if you were to look at step 17 and 18 independently even though I KNOW you need to stop at step 17. I am really hoping is just the inverter and not both.

    add edit: another irony to this step process. my original code was P0AA6 using a cheap ODT2, after I got the techstream I was able to get the full code 526/614, which in fact starts at step 19 (skipping all the previous steps although there is some redundancy), but surprisingly step 19 starts with testing the frame wire (high voltage cable) and if it is not a fault, it directly points to the inverter, and there is no mention whatsoever of testing the inverer cables or of any transaxle fault anywhere for code 614 (step 19 through 29).
     
    #4 tri4all, Dec 22, 2019
    Last edited: Dec 22, 2019
  5. tri4all

    tri4all Member

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    the question I have for this thread: "is there anyone out there who has attempt to rebuilt a inverter or have found a way to replace any parts to get it up and running again up to specs? or do people usually replace the whole inverter and it is not worth dealing rebuilding?
     
  6. Elektroingenieur

    Elektroingenieur Senior Member

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    That’s a very old edition of the Repair Manual, and you may wish to use one that is more up-to-date and that matches the model year of your car; see the PriusChat Wiki page for where to find them. There have been changes; for example, the procedure for P0AA6, at least for some model years, now warns against using megohmmeter settings greater than 500 volts, to avoid damaging certain parts.
    Parts catalog Figure 84-31, HV Inverter, shows the internal parts of the inverter with converter assembly that are available from Toyota, including the power module intelligent transistor kit and the electric vehicle converter assembly. (Don’t read too much into the “Product Not Available” label for the top-level assembly; that may just be a data problem with the website.)
     
  7. tri4all

    tri4all Member

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    wow good to know, good catch!. I believe this is the 2006 manual and I have a 2008 prius. I was under the impression that all prius were the same between 2004 and 2009 so it didn't really matter. what manual do you recomend for a 2008?, 2008?

    Elektro, do you have any experience replacing any of this parts? is there a common part that commonly goes bad? Thanks.
     
  8. bisco

    bisco cookie crumbler

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    most people just buy a salvage inverter for cheap money
     
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  9. ChapmanF

    ChapmanF Senior Member

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    Hmm, you posted the page with step 17 but not step 18. I'm trying to follow along at home with only a 2006 manual. It does have a step 17 and a step 18, but in this version it doesn't look like you would ever arrive at both steps.

    Rather, at step 2, you would be sent to step 18 only if you had INF code 613. If you had only INF code 526, you would be sent to step 3, step 4 could send you to step 15, and from there you could end up at step 17 depending on how the SMR and frame wire tests panned out.

    But in your title, you've mentioned INF code 614, which would have sent you from step 2 straight to step 19, no? Steps 17 and 18 would have been barking up the wrong tree.

    So, there's a chance it would be easier for us to follow along if you showed more of the work with the earlier steps, what your measurements were, and which steps they led you to.

    Edit:

    Just re-read this part of your earlier post. It's actually not surprising that the steps for INF 614 don't mention transaxle fault anywhere; that's the INF codes doing their job to help you out.

    When the ECU first notices there's a ground fault somewhere, it sets only the 526 code. It uses that as a "note to self" to pay extra attention on the next drive cycle, and see if it can pin down the fault further to the air conditioning circuit (611), battery area (612), transaxle area (613), or high-voltage DC area (614). If it successfully does that and gives you a code 614, that lets the A/C and transaxle off the hook, and lets you really just focus on DC components from the inverter back to the battery, as steps 19 through 29 have you do.
     
    #9 ChapmanF, Dec 22, 2019
    Last edited: Dec 22, 2019
  10. Elektroingenieur

    Elektroingenieur Senior Member

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    Yes. The latest revision is available by subscription to techinfo.toyota.com.
    No, I don’t. Keep in mind that Toyota specifies the internal parts directly in diagnostic procedures, when replacing them would be sufficient to correct a problem. For example, instead of “Replace Inverter with Converter Assembly,” the procedure would say “Replace Electric Vehicle Converter Assembly” or “Replace Power Module Intelligent Transistor Set.”

    I also wouldn’t yet assume that there is a problem in the inverter with converter assembly. As @ChapmanF kindly points out, steps 3–18 in the P0AA6 procedure (in the old Repair Manual you’re using; the steps have been renumbered in newer editions) were written with the assumption that INF code 611, 612, or 613 has been stored, which isn’t true if you’ve only seen INF codes 526 and 614.

    In the diagram on page HV-425, the dashed lines show possible the fault areas for each INF code. Code 614 indicates a problem in the inverter with converter assembly, the frame wire, the system main relays, or the system main resistor, which is why step 2 (pages HV-426–427) has you skip to step 19 (page HV-435). In step 19, by disconnecting the frame wire at the inverter with converter assembly, the first megohmmeter test can check for faults in the frame wire, system main relays, and system main resistor, all at once.

    If the step 19 test passes, the fault is likely to be in the only part of the fault area that remains, the inverter with converter assembly. Notice that you don’t do a megohmmeter test of the inverter with converter assembly directly, presumably because the reading wouldn’t be meaningful or the test would damage it.

    If the step 19 test fails, then in step 20 (page HV-436), you disconnect the frame wire at the other end (at the system main relays), so the second megohmmeter test can check the frame wire on its own. If the step 20 test fails, you’ve proved that—whatever else might be wrong—the frame wire has a fault and must be replaced. If the step 20 test passes, then the frame wire is probably OK, and the remaining steps have you test the system main relays and system main resistor.

    After any repair, you’d follow this note under “Inspection Procedure” in the current Repair Manual, to confirm that the problem is gone:

    • After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output. (Do not turn the power switch off during this inspection.)
    a. Apply the parking brake and secure the wheels using chocks.
    b. When the vehicle is stationary, turn the power switch on (READY) with park (P) selected and wait for 75 seconds or more.
    c. Turn the air conditioning system on (MAX COLD, blower speed HI).
    d. While depressing the brake pedal without depressing the accelerator pedal, move the shift lever to D and wait for 5 minutes.

    (If no DTCs are output, proceed to the next step.)
    e. Drive the vehicle for approximately 5 minutes referring to the following freeze frame data items: "Vehicle Spd" "Shift Sensor Shift Pos" "Accel Pedal Pos #1" "Engine Revolution" "Engine Coolant Temp" "Master Cylinder Ctrl Trq" "Motor Temp MG2 (No2)" "Motor Temp MG2 (No1)"
    (If DTC P0AA6-526 is output, stop the vehicle, select park (P), turn the power switch on (READY), turn the air condition system on (Lo/COOL MAX, blower speed HI) and wait for 1 minute. Then turn the power switch off and wait for another 1 minute.)
    (If the freeze frame data item "Vehicle Spd" is 10 km/h or less, drive the vehicle at 10 km/h or more.)
     
    #10 Elektroingenieur, Dec 22, 2019
    Last edited: Dec 22, 2019
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  11. tri4all

    tri4all Member

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    Chapman, if you read my previous post, also quoted above, you will find that in the beginning I just had a generic P0AA6 code with my cheap ODT2 scanner, thus I started from step 1 all the way to step 17 to find out the inverter was bad. LATER ON I got the techstream scanner and I was able to narrow it down. HAD I HAD the techstream before, it would have saved me a lot of time and skip straight to step 19.

    Chapman and all: One more point I made earlier that it is worth noting (read the above before proceeding). Perhaps the inverter and the transaxle are not fully separated/isolated from each other when you remove all the MG1 and MG2 cables from the inverter (step 17 and 18 of manual). but if we assume that they were isolated from each other, one could test the transaxle at the same time you test the inverter just like I did for curiosity. whether the results of step 18 (transaxle) are accurate or not I don't know.

    I am not sure the 2006 manual is a "very old edition" for a 2008. in fact for what I have seen here an other posts, the 2006 is the version that most priuschat users use for Gen 2 prius. especially since it covers all the 2004 to 2009 years. but you bring some very good points that we should be aware of when it comes to small but critical updates.
     
  12. tri4all

    tri4all Member

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    Elektro could you please post a picture of any part of the manual where it points to one of this problems? I would like to know which manual you are using and also what chapter of the manual you would find this: Hybrid Vehicle Control (HV chapter), Hybrid Battery Control (HB), etc. Thank you.
     
  13. Elektroingenieur

    Elektroingenieur Senior Member

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    You shouldn’t have been able to get past step 2 without INF codes. The later steps were written with the assumption that you used the INF codes to determine the fault area.
    It’s not just the model year: the manuals are under continuous revision, and even for model year 2004, the Repair Manual was revised as late as 2017. The changes are substantive; for example, the latest edition of the manual for model year 2006 includes the note I quoted in post #10, which earlier editions lack. For model year 2008, the latest P0AA6 procedure has 30 steps, and for the INF codes 526 and 614 combination, you jump to step 28, not to step 19, and do only three tests.
    I think that’s more because the 2006 version circulates (unofficially, I might add) as a single PDF document that people find convenient to use, than because it’s the most complete or current. It certainly wasn’t written to cover earlier or later model years, each of which has its own manual, though the differences might or might not be important for a particular repair.
    That’s yet another problem with the old edition of the manual. It was published before Toyota offered the EV converter or transistor set as service parts, so it lacks the “Electric Vehicle Converter” and “Power Module Intelligent Transistor” topics that explain how to replace them, and in the diagnostic procedures, once any problem is found inside the inverter with converter assembly, you’re told to replace the entire assembly, since that’s all that would have been available in the parts system.

    You don’t have to look far for examples—in the current Repair Manual for model year 2008 on techinfo.toyota.com, in the P0AA6 procedure, see step 18 for an example of “Replace Electric Vehicle Converter Assembly” and step 27 for an example of “Replace Power Module Intelligent Transistor Set.” Neither of these helps you, of course—for INF 526 & 614, you’d go to step 28, which still says to “Replace Inverter with Converter Assembly” if the megohmmeter test of the frame wire, system main relays, etc., passes. Depending on the results of the other tests, it’s the system main relay, system main resistor, or frame wire, by the way.
     
  14. tri4all

    tri4all Member

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    That is not correct. the generic code here is 526 for P0AA6. and this is where most people start if you didn't have a fancy scanner to get a more specific subcode. You can see in the diagram below that 526 covers all the issues and it goes from step 3 through step 17. if you look at the remaining steps (18 through 29) they are all the same previous steps but put in a different order to address the specific issue or condition.

    upload_2019-12-22_23-21-3.png

    upload_2019-12-22_23-18-43.png


    unfortunately that is the version available to most of us. the price of the manual ($1300) is outrageous and triggered to the full mechanic shop, no the common diy priuschat user. Toyota - New Subscription . There really should be a more affordable price for the common diy user who is not running a shop.

    Finally, are you able to provide any pictures or screenshots of this small part of the manual which according to you there is only 3 parts to address the 526/614 error code, so it is probably only 2 pages long. or if you don't feel comfortable sharing, perhaps you can expand on the new updated version that talks about this “Electric Vehicle Converter” and “Power Module Intelligent Transistor”, which by the way as of today, you will not find any references on priuschat and even if you google search you only find the two recent inverter recalls on the new prius where Toyota is providing shops with the tools for them to service them so they are not overloaded with inverters rebuild jobs at the dealership. interesting articles online that come up on this last recent recalls.
     
  15. Elektroingenieur

    Elektroingenieur Senior Member

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    I didn’t see anything that says to proceed, if you don’t have a way to read INF codes, as though only INF code 526 has been output. Just as later steps require a megohmmeter, steps 1 and 2 require the Intelligent Tester (Toyota’s hand-held unit, now obsolete) or in later editions, the Techstream system.
    Standard subscriptions to techinfo.toyota.com start at $20 for two days, during which you can save or print as many topics as you wish, though there isn’t a button or link to download or print an entire manual at once. Many people can also get access to reasonably current versions of the Repair Manual text and illustrations at no charge through public libraries, as I explained on the PriusChat Wiki page.
    I’m glad to share brief excerpts verbatim (as in post #10), but posting much more would be difficult to defend when the manuals are available from sources licensed by Toyota.

    Steps 28–30 aren’t anything really new; for INF code 614, the main effect of the reorganization is that you don’t continue unnecessarily with tests in other areas. Step 28 is like step 19 in the older edition, with added notes to check the inverter for coolant, water, etc., and to use the megohmmeter’s 500 V setting. Step 29 is like step 22 in the older edition, but you disconnect only the frame wire and system main resistor from the system main relays. (I imagine the authors realized that the battery side of the relays can stay connected, since with the car not in READY, the contacts should be open.) Step 30 is like step 23 in the older edition, but the outcome if the test passes is to replace the frame wire, not to continue with another step.

    About the internal parts of the inverter assembly, the examples I gave are the only places in the current P0AA6 procedure that call for their replacement. In step 18 (for INF code 611), if the electric inverter compressor and its cable pass a megohmmeter test, you’d replace the EV converter assembly. Similarly, in step 27 (for INF code 613), if the transaxle and its cables pass a megohmmeter test, you’d replace the transistor set. In either case, you also have to inspect the inverter with converter assembly for “coolant leaks, water intrusion, excessive deposits and damage,” which if found mean replacing the whole thing.

    Considering the hazards of high voltage and the risk of damage to the vehicle, I strongly recommend using the actual Repair Manual, not my summary, of course.
     
  16. tri4all

    tri4all Member

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    well, P0AA6 526 is in fact your INF code that you can read with a generic OBD2. But regardless, I think the diagram I posted above speaks for itself.

    Is this what you did?

    The information here was the most helpful so far. Thank you for your willingness to share some information on the updated version.
     
  17. tri4all

    tri4all Member

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    SOLVED. here is the UPDATE.

    Short version: yesterday I found a good working framewire at the junkyard. this morning I hooked it up and I didn't get any error codes after running the car for 15 minutes and changing gears! Big thanks to Wardtp who previously had this same problem. I do want to add to future readers that Wardtp and I found this voltage fault at the frame wire by experimentation, because if you follow the repair manual procedure for diagnostics you will think the wire is good. so read the previous post carefully and look at the pictures previously I posted to check where you need to test.

    Long version: yesterday I went again on a expedition through the biggest junkyard jungle in town with my machete (the megger) looking for a prius that had a decent frame wire. most outlets were still very wet from the recent rain so I had to shake them up and dry them prior to megger testing, this is what the pacific northwest has to offer for 9 months, I tested a total of 3 prius and the third one was the charm. the first one was sitting there for awhile and perhaps water got inside the wire and had similar readings as mine, the second one was slightly better, the third one was great and also very easy to take out since most of the parts of the front of the car was removed. overall it took me about 15 min max to uninstall something that will take like couple of hours on a prius with complete engine. This morning I got up at 4:30am very excited to try the wire out, I didn't even want to waste time removing my old frame wire which it will take some time. I instead ran the frame wire from outside of the car just for testing purposes. as soon as it was hooked, I set up my scanner and started the troubleshooting, I turn ignition on and I was not expecting any error codes as I have not gotten any codes on this code previously (if you were to get the error code at this phase, this would point out to a voltage leak in the battery area). so I proceeded to get the car into "ready" and shift to neutral right away, I waited several minutes and I was so happy at this point as that is when I the error code always would pop up and this time was clear. then I shifted into gear and move the car for several minutes and the code never came back.

    I will report back after a few weeks of driving and also what I find out about the bad frame wire. I am planning to dissecting the wire to look for shorts or see if the connector is at fault. but for now I have to catch up with family, kids and my biking buddies. merry christmas and happy holidays to everyone and thanks to everyone who have helped me and others on the chat.
     
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  18. tri4all

    tri4all Member

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    Now, I do would like to keep this thread alive as I think it is worth looking into inverter rebuilds and find ways in which the inverter can be used. regardless of how cheap is to buy a used one, it is a very impressive piece of technology and yet quite simple that would be easy to troubleshoot.

    Perhaps, we can find other uses like turn it into a prius HV battery charger, I am talking from complete ignorance as I am not a electronic guru.
     
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  19. ChapmanF

    ChapmanF Senior Member

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    I'm glad the problem is solved, but in fairness to the repair manual, it's not clear on this record that you really quite did follow the procedure for diagnostics. If you had followed step 2 (read the INF codes), the 614 code would have sent you straight to the section where the frame wire would be the first thing you would test.

    I understand you had a reason for not following step 2: if a step says "read the INF codes" and you don't have a way to do that, you're not going to follow the step. Ok, but we can't fault the manual for that.

    Instead, you followed the procedure for finding no INF code other than 526, which probably was the next best option if you couldn't read the codes. That sequence of tests did get you eventually to the frame wire, just after a dozen or so other tests that reading the INF codes would have spared you. And when you got to that step you did report:

    so you may have been quite close to finding the problem right there, but possibly distracted enough by the other tests in the unnecessary sequence you were following that you didn't focus on running down that lead.

    It seems like the other thread you mentioned in connection with the frame wire was Wardtp's thread, but even there it's not completely clear what was going on with your test. Wardtp reported an unequivocal megger test result on the 2005:

    The megger test you were reporting in that thread looked like the VC60B+'s "overrange" display, which would represent a passing, not a failing, test. But it seemed like unfamiliarity with a new instrument could have been a factor, and also it's hard to see your exact test setup and procedures over the internet. It would be interesting to see further test results on your old frame wire to see the fault clearly shown.
     
  20. tri4all

    tri4all Member

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    I already mentioned several times in this thread that I only had a generic scanner with P0AA6 so I had to start from the 526 generic INF. LATER ON I got the techstream and I was able to narrow it down but by the time it arrived I already have gone through most of the generic steps.

    not sure you are quite following this thread or Wardtp's thread. First of all the frame wire test is step 16 which is towards the end of my testing (step 17 is the inverter) so I was not distracted, I did have to go through all the generic steps with my generic code scanner. now to the core of the problem and to clarify: step 16 in the repair manual should be rewritten after Wardtp's thread and my testing, there exist a possible fault inside the frame wire that it will NOT show up with the current testing in the repair manual. You need to look at the thread more carefully. My success at fixing this problem is further proof that sometimes the frame wire cable could be faulty even after following the steps in the repair manual. this random fault in the cable is on the outer steel jacket of the internal wire, you can read and see the pictures on that thread.

    Again look at the thread more carefully. the test will pass but it is a FALSE pass because of what we have discussed already.

    also, please post on Wardtp's thread any related frame wire issues or questions. I would like to keep this thread open for only "inverter rebuild" questions and ideas.