Big BOB Posted March 16, 2021 Share Posted March 16, 2021 Power Jack version 7.0 signal board led not lighting, with switch on fan starts when powered on. No output 110v or 220vac. back light but no display info. Once the unit powers up fan does not turn off when power switch is turned off. You have to remove power to get fan to turn off. Tried unplugging the blue an black cable from the display board, no change. The power source board also has no led light. Mosfets are fine. Don't have enough info to diagnose this problem please advise of any thing you come up with. Not familiar with this circuit need help. I am an electronics tech but as you know it takes a while to figure out what they where thinking when they designed this unit. Thanks for any help BigBOB Quote Link to comment Share on other sites More sharing options...
wonka Posted March 16, 2021 Share Posted March 16, 2021 Not sure if this will help, but I remembered watching one of Sean's videos about a similar problem. Maybe this will help: Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 16, 2021 Share Posted March 16, 2021 3 hours ago, Big BOB said: Power Jack version 7.0 signal board led not lighting, with switch on fan starts when powered on. No output 110v or 220vac. back light but no display info. Once the unit powers up fan does not turn off when power switch is turned off. You have to remove power to get fan to turn off. Tried unplugging the blue an black cable from the display board, no change. The power source board also has no led light. Mosfets are fine. Don't have enough info to diagnose this problem please advise of any thing you come up with. Not familiar with this circuit need help. I am an electronics tech but as you know it takes a while to figure out what they where thinking when they designed this unit. Thanks for any help BigBOB Looks like you've seen the "no power video"...I see that you've tried unplugging the blue/black cable from the LCD board, etc. This gets a bit harder; we will need more info to figure out exactly what's going on. Obviously the power switch works. And something on the power source board seems to work. Any repair history on this inverter (blown FETs)? I assume it used to work...what caused it to stop working? (Now's not the time to forget about dropping that 1lb bag of screws into the inverter 🤪. The more info we have about the inverter...even if embarrassing...the better our chances of diagnosing what's wrong.) Could you provide a photo/short video showing the inverter and how it behaves? Any info is extremely helpful. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 16, 2021 Share Posted March 16, 2021 Can't say whether the LCD board is at fault here or not; is the backlight coming on all the way, or is it dim? Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 7 hours ago, Big BOB said: Power Jack version 7.0 signal board led not lighting, with switch on fan starts when powered on. No output 110v or 220vac. back light but no display info. Once the unit powers up fan does not turn off when power switch is turned off. You have to remove power to get fan to turn off. Tried unplugging the blue an black cable from the display board, no change. The power source board also has no led light. Mosfets are fine. Don't have enough info to diagnose this problem please advise of any thing you come up with. Not familiar with this circuit need help. I am an electronics tech but as you know it takes a while to figure out what they where thinking when they designed this unit. Thanks for any help BigBOB thanks for the info just finished reversing the L.F Driver for my info. Idon't if you know but there is no 0.1uf capacitor across pins 5 and 8. Thanks i didn't check the output fet's my fault I'll try that next. Again thanks for the feedback. It was given to me as is so i can't say what happened. BigBOB Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 17, 2021 Share Posted March 17, 2021 Does the inverter power on if the LF Driver is unplugged? There should be a 0.1uF cap across pins 5-8 of both TLP350 chips. Not that this would prevent it from powering up, but damage spreads pretty easily on that little board. 1 Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 Got some pictures for you, tell me if any are to blurry to see and i will send another ok. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 17, 2021 Share Posted March 17, 2021 Seems to me that there's more than just a few things wrong with that inverter. Power supply appears to be working. All of the CPU outputs that I can see are "on" (all 3 LEDs, as well as the LF Driver LED being out). That together with the LCD board being unusable...kinda points to a destructive surge on the 5v rail, blowing out the CPU. How the LCD processor is failing to function (nothing visible) could be a slightly different problem--or similar. If you measure from the big solder tab on the LM7805 below the CPU board...what voltages do you get on either leg? Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 3 hours ago, Big BOB said: Got some pictures for you, tell me if any are to blurry to see and i will send another ok. Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 Sid I have +12vdc and 5vdc on those two points Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 that was from the big solder blob. and again thanks for your help BigBOB Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 17, 2021 Share Posted March 17, 2021 OK, so that part is working perfectly. At this point, I'm not sure what further to pinpoint. Appears that the CPU is not functioning...and whatever took it out also seems to have taken the LCD out as well. They are not connected (except by the 12v power supply), so that's really weird. Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 i'll check the crystal to see if it's oscillating next. I have some boards coming so i can figure out which boards are bad. Is the display board a separate processor or does it get its info from the cpu board ? Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 where can i get a block diagram or flow diagram of what does what. I looked to see what the dc input board does but it doesn't make sense. looks like they are interconnected between the dc and the ac side I don't understand am I looking it wrong. Normally they step up 24vdc to 360vdc then chop that with the power fet's But that doesn't seem to be what they are doing here. Unless i missed something. Please advise. Thanks BigBOB Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 17, 2021 Share Posted March 17, 2021 27 minutes ago, Big BOB said: i'll check the crystal to see if it's oscillating next. I have some boards coming so i can figure out which boards are bad. Is the display board a separate processor or does it get its info from the cpu board ? It won't be oscillating. Gotta love PJ...they have a crystal soldered to the CPU, but the CPU is running on it's own internal oscillator. You could rip the crystal off the board and it wouldn't make any difference. 21 minutes ago, Big BOB said: where can i get a block diagram or flow diagram of what does what. I looked to see what the dc input board does but it doesn't make sense. looks like they are interconnected between the dc and the ac side I don't understand am I looking it wrong. Normally they step up 24vdc to 360vdc then chop that with the power fet's But that doesn't seem to be what they are doing here. Unless i missed something. Please advise. Thanks BigBOB This would be the case for a HF (high-frequency) inverter. These Power Jack inverters are LF (low-frequency) inverters...all of the switching is done at battery voltage. Mainboard is nothing more than a FET H-bridge. 28 minutes ago, Big BOB said: Is the display board a separate processor or does it get its info from the cpu board ? LCD board has a separate processor...there is no connection to the CPU board. It just gets voltage/current feedback from completely separate sensors. If I had to take a stab in the dark at diagnosing fault, it seems the CPU is faulty. If I recall correctly, there's no place in the code where it holds all 3 lights on. The only thing that could blow the CPU would be the FETs through the LF Driver. In a PJ inverter, if the FETs are blown, the LF Driver 99 times out of 100 is also blown. Without testing the FETs, we can guess they're good...but not so sure about the LF Driver. LCD board also appears faulty, as it's lighting up, but not displaying anything. (A similar failure mode would do the same thing: processor is holding everything high.) You could try adjusting the little potentiometer on the LCD board above the LCD (should be LCD contrast)--see if that helps at all? Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 17, 2021 Author Share Posted March 17, 2021 thanks again for the info, when i get my replacement boards in i'll start fresh and see what happens and the can figure out which boards are bad. so i think i'll order a new lcd screen. wait i have a 6000w inverter is that the same lcd display ? again thanks BigBOB Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 18, 2021 Share Posted March 18, 2021 2 hours ago, Big BOB said: wait i have a 6000w inverter is that the same lcd display ? Yup. Same LCD for every PJ LF inverter... Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 18, 2021 Author Share Posted March 18, 2021 no it doesn't have a display board rrrrrrrrgh. where can i buy a display for a pj inverter ? genetry ? Quote Link to comment Share on other sites More sharing options...
Big BOB Posted March 18, 2021 Author Share Posted March 18, 2021 do i really need the display or will it run without it, i will use it in one place one load and leave it Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 18, 2021 Share Posted March 18, 2021 It will run without the display, no issues--it has absolutely no connection to the control circuitry. Newer PJs don't even have the display. Sean should have replacement PJ LCD boards. Quote Link to comment Share on other sites More sharing options...
Big BOB Posted April 9, 2021 Author Share Posted April 9, 2021 Update, I found a resistor burned up. It is R228 on the bottom of the I/C board two components away from the ic. Don't know what that ic is . I think it's a ST 324 op-amp ic but not sure. I have received my upgrade board from powerjack. So i will upgrade the 8k unit. Any Ideas, the unit is a 24v unit an i have received a 24v board with the display and board with the switches on it. Any help will be appreciated. Thanks again BigBob Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted April 9, 2021 Share Posted April 9, 2021 4 minutes ago, Big BOB said: Update, I found a resistor burned up. It is R228 on the bottom of the I/C board two components away from the ic. Don't know what that ic is . I think it's a ST 324 op-amp ic but not sure. I have received my upgrade board from powerjack. So i will upgrade the 8k unit. Any Ideas, the unit is a 24v unit an i have received a 24v board with the display and board with the switches on it. Any help will be appreciated. Thanks again BigBob That would be an LM324...and R228 being burned up kinda indicates that something SERIOUSLY went wrong. It's part of the AC INPUT voltage divider...the part AFTER the 8 megohm "isolation" bed of resistors from the AC line (per side...16 megohms total). I don't know how you could possibly get enough power to blow a 1/8w SMT resistor through 8 megs... Quote Link to comment Share on other sites More sharing options...
Big BOB Posted April 9, 2021 Author Share Posted April 9, 2021 What gets me is the lm324 seems to be ok, I question what happened ? Lightning maybe that to me is the only thing that i can see what could cause it. I'll check the 8 megohm isolation bed of resistors. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted April 10, 2021 Share Posted April 10, 2021 That kind of fault points further to significant damage in the low voltage side of the board (perhaps not visible)--which is kinda indicated by all 3 LEDs being on simultaneously, with no beeper or any other indication of fault. There is no possible way for that resistor to get blown out by any sort of normal operation--or abnormal operation, for that matter. Honestly, I'm not sure that this inverter is worth repairing. Quote Link to comment Share on other sites More sharing options...
Big BOB Posted April 10, 2021 Author Share Posted April 10, 2021 It looks like something flashed metal around the resistor. I get 138k in one direction on r228 and 270k the otherway ??? Quote Link to comment Share on other sites More sharing options...
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