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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 01:13am 25 Apr 2018
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The top chip looks ok, the bottom one I can't even get remotely close to that definition... mine looks like this for the high side 50hz... note the sag back to 12v (5v/div)... looks silly, but makes no material difference.
Now we get to the spwm first slow and it looks like this
and quicker like this
faster again..
and again
and again... why am I doing this...
because I think you have the very start of the wave form showing up, and it may be a very small time unit. On my older one I did not see this, but the Hameg does show it up some.
So... compare those slides to either spwm signal, and see if yours comes out the same as you increase the scan frequency
oh and the 50hz low side is like this
photo's of the phosphor screens have a lot of fuzz about then... so try to ignore some of it
........oztules
Edited by oztules 2018-04-26Village idiot...or... just another hack out of his depth
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 01:29am 25 Apr 2018
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Looks like I'll need a better scope.
Pin 10 top with 2110
Top pin 12 with 2110
Bottom pin 10 with 2110
Bottom pin 12 with 2110
Top pin 1 with 2110
Top pin 6 with 2110
Bottom pin 1 with 2110
Bottom pin 6 with 2110
Cheers Caveman Mark Off grid eastern Melb
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 04:44am 25 Apr 2018
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Just tried it again, but forgot to plug in the voltage feedback into the 240/12v transformer from the torroid output wires. POP blew the fets. 2110's both gone. Signals from 8010 the same as before. Put new 2110's in, and signals the same as before.
Put in new fets and tried again with 240/12v transformer plugged in this time and it operates happily as previously jumping the voltage all over the place, never getting very high.
Does that give any clues?Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 04:51am 25 Apr 2018
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Do you know anyone with a proper CRO?There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 05:41am 25 Apr 2018
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Yeah Warp has a few but it's an hour and 1/4 away, Melbourne is a big place.
I was going to get one, just missed one on bumtree this morning.Cheers Caveman Mark Off grid eastern Melb
noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 513
Posted: 08:06am 25 Apr 2018
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Mark, if your oscilloscope is new,select the " time base ( 10us etc.)" , press and hold the " ok " button.. it will show you the frequency and amplitude in real time. .. Snippet from instructions. ..
I think it works !!
noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 513
Posted: 08:08am 25 Apr 2018
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Itll come up with something like this. ..so it will tell you 23khz and 50hz if solidI think it works !!
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 08:38am 25 Apr 2018
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Thanks, reckon I'll take a break from it for a few days. Started to strip the power board and start again.
It did run without the caps, so something has gone pop or shorted somewhere.Cheers Caveman Mark Off grid eastern Melb
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 06:51am 27 Apr 2018
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BINGO!!! I changed the tip 35's and put in another set of fet drivers (2010 not 2110) and it works again. Put some caps in and it still works, it cleaned up the wave a bit too!
I'll do some loads on it tomorrow. No load current of .48A, that seems a bit low??
The voltage is only 170v for some reason, Mad said to change the 3k9 to 7k5 and that should fix it. I reckon the no load current will rise a bit then.
Cheers, cheers, time for beers.Edited by renewableMark 2018-04-28Cheers Caveman Mark Off grid eastern Melb
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 07:10am 27 Apr 2018
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Had some interesting observations, it heats up the heatsinks really bad without a choke.
One really odd thing it did a bit was it kept restarting. I just couldn't work it out, then I noticed the on off switch wires were draped over the primary cable, if they got moved a bit it would cause it to restart, it must have got some interference, once I hung the switch up in the air away from everything it stopped happening.Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 07:17am 27 Apr 2018
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No doubt you will be sleeping better tonight since you have got a good result.
Idle current will rise as you increase the voltage out.Edited by Madness 2018-04-28There are only 10 types of people in the world: those who understand binary, and those who don't.
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 10:00am 27 Apr 2018
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Mark, no need to get a new oscilloscope, that little one is perfectly OK with the right probe.
Here are two pics I took today, I was testing a spare control board for my inverter. The 8010 was set running free by feeding 12VDC where normally the little tranny's secondary connects.
Output 8010, low side:
Output 8010, high side (used special probe):
Its just a little handheld camera which I set for macro to get a good close up of that little screen.
Oztules, if you are reading this, the little cheap digital oscilloscope puts the pics of your CRO .Klaus
Mulver Senior Member Joined: 27/02/2017 Location: AustraliaPosts: 160
Posted: 10:06am 27 Apr 2018
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Awesome work Mark! Great to see your making progress!!
Klaus, what’s the special probe you use ? Edited by Mulver 2018-04-28
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 11:25am 27 Apr 2018
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In the testing section of the EGS002 manual it shown there and how to use it.There are only 10 types of people in the world: those who understand binary, and those who don't.
Mulver Senior Member Joined: 27/02/2017 Location: AustraliaPosts: 160
Posted: 12:01pm 27 Apr 2018
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Thanks Mad, I haven’t got one of these units yet wasn’t sure when I do get one if I should be buying the “special probe” at the same time.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 12:17pm 27 Apr 2018
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The special probe is just a resistor and a capacitor as described in the manual.There are only 10 types of people in the world: those who understand binary, and those who don't.
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 12:53pm 27 Apr 2018
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So it is, just download the EGS002 data sheet and you find it in the back pages.
Now, having used the resistor & capacitor just roughly soldered for a while I found it a bit clumsy to use.
I had an old oscilloscope probe and opened it up to remove the 10:1 probe & switch bits. In there I fitted a suitable small capacitor & resistor and, presto, I had my "special probe" Klaus
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 07:00am 28 Apr 2018
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Go tell your wife about your "special probe" and see what she has to say.Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 07:24am 28 Apr 2018
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I can see the sparks flying now.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 01:45am 29 Apr 2018
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I got the voltage within limits, the 7k5 was a tad too high, fitted a 5k1, but that was a whisker too low, at full travel on the pot it would go to 228v, so something in the 5k5, 6k should be fine.
With it at 228v I did some loads, a flouro lamp went on fine, a 2000w blowheater on fan went fine, put it on setting 1 heat (1000w) and the transformer gave a little hum and the fan heater very slowly spooled up and operated normally. Then tested a hair dryer on setting 1 (1200w) once again the transformer gave a little hum and the hairdryer very slowly started to spool up and BANG! blew the fets, the ones on the large heatsink blew right apart, the lower 2010 blew apart and caught fire.
I'm not sure why this happened, the dc was supplied by 4x 20ah small golf cart batteries. So either there was insufficient power going to the inverter or the driver chip or fets or all three had a problem. The sine wave looked very nice, no load draw was around 0.6A.
Tossing up whether to wait for Mads boards or push on. I don't have any more fet driver chips on hand, 4 will arrive on Monday though.
The other thing to be worried about now is what other damage got done in that rather loud and fiery demise.Cheers Caveman Mark Off grid eastern Melb
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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