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Burn spot on panel.

I would have moved the MC4 connector wire to the next terminal if it is just a single string. Surprised to see where the burn is at the junction box.. They must have made a really long fold. And it the connections were all made on the same side, why don't I see the other two panel strips on the connector?
Sorry I did not give the whole setup. It is my #3 Solar Array with a 3S2P configuration of 200w panels (sorta*) so removing 1 string is not a big issue but I decided to toss in an old shattered glass 200w panel that I know works to a degree to keep it producing.

*The non affected string is 2-200w panels in series with 4 panels of dubious ratings in parallel (claimed 100w when bought but the size of panels makes anything over 75w impossible and they test out at about 67w max). I have some Frankenstein setups.
Diode scale typically will show about 0.7V for forward polarity, "overrange" for reverse.
(0.4V for germanium vs. 0.7V for silicon)

Old analog meters deliver positive voltage from black negative lead.
Modern DMM deliver positive voltage from red positive lead.

Can't judge diode with ohms scale because don't know voltage applied.
If you have two DMM, try measuring voltage with one and ohms with the other. Then reverse connections of ohms meter. See what voltage applied in each case.
I haven't tried it, so tell us what you see.

Calibration hat on here - the higher the range the higher the voltage applied. For the 200k range it can be 9 volts. For the 1k range more like 1.5 volts. That is on analog meters. On digital autoranging meters it is typically 1/10th that voltage on the upper end and 1/100th on the lower end.

BUT - depends on the meter - Ohms in one direction will have a very high reading and the other will a blip of value then a near short reading. This is why you get a beep then tone or just a beep and nothing.

On meters with a straight diode position and toner for shorts you get a beep and nothing. On meters with the ohms meter shared it is usually a beep then solid tone (assuming it tones when you touch the leads together)

Your 0.4 is the volts required to forward bias the PN junction in the diode.
(0.4V for germanium vs. 0.7V for silicon) Hedges is having a senior moment. 15SQ045 is about 0.27V and the higher current ones oddly are much higher till they get quite hot.
Hedges, I have a couple germanium diodes socked away that might pass for "power" because I've been in electronics for nearly 60 years. When was the last time you saw a power germanium diode?
The Seller did message back overnight with a question of if there was a cover over the panel when in operation. Seems a bit of a odd answer to my if there is any warranty for panel failure. My response was to say no there is no cover over the panels and also include a picture of the opened junction box so they could see the damage there. I will see if I get any follow on.

"We are so sorry but we do not guarantee our solar panels if you put them out in the sun."
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Hedges, I have a couple germanium diodes socked away that might pass for "power" because I've been in electronics for nearly 60 years. When was the last time you saw a power germanium diode?

Last time I took the seat off one of my Hondas.

I have to admit I was a toddler when they were built.
Their next response to me just now was to measure if the panel has any voltage and current. Bunch of nonsense it has a burn spot on it and melted junction box. Which was my reply and another request if the panel has a Warranty or not.

I did not expect much but I hate dealing with nonsense and runaround. Werchtay has made a critic out of me. I don"t recommend things but I will speak out against products and companies I find to have bad practices.

Edit: No further response overnight so I expect that's that. Funny that they could not simply state that there was no Warranty. Why waste effort with meaningless back and forth?
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