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Topic: Really universal soldering controller (Read 818659 times) previous topic - next topic

Re: Really universal soldering controller

Reply #2085
Ok, my back board died again. I wanted to fine tune my calibration so I soldered the 10 ohm resistor to SenseA and Vout-1. After calibration I switched off power but forgot to unplug the board. The switch is on the primary side by the way. I desoldered the resistor and after that the board is dead. There is only 1,3V on pin 6 and 7 of U2. I apparently fried something. What are the most likely candidates? Q10 I presume?

Re: Really universal soldering controller

Reply #2086
max0o, even if you have 0V drop on the resistor, your original problem still exist. There shouldn't be 0.68V on U16:2, it's way to high and it's causing all the following checkpoints to overflow. It may be due to leakage from U16:1>U16:2. Did you clean flux residue?

Doomedahab, it shouldn't do any harm no matter if your iron is grounded or not. Check the voltage on the emitter of Q1 and if R20 is heating up.

Re: Really universal soldering controller

Reply #2087
[quote author="afedorov"]Doomedahab, it shouldn't do any harm no matter if your iron is grounded or not. Check the voltage on the emitter of Q1 and if R20 is heating up.[/quote]

35v on the emitter of q1, no detectable heat at r20

Re: Really universal soldering controller

Reply #2088
[quote author="Doomedahab"]35v on the emitter of q1, no detectable heat at r20[/quote]
So, if you're not getting 12V rail it's Q13 and D15 left only.
And disconnect the front board until you done back board repairing.

Re: Really universal soldering controller

Reply #2089
[quote author="afedorov"][quote author="Doomedahab"]35v on the emitter of q1, no detectable heat at r20[/quote]
So, if you're not getting 12V rail it's Q13 and D15 left only.
And disconnect the front board until you done back board repairing.[/quote]

Replaced both, no difference. Yes, I disconnected the front board.

Re: Really universal soldering controller

Reply #2090
[quote author="Doomedahab"]Replaced both, no difference. Yes, I disconnected the front board.[/quote]
You could easily check both instead of replacing, and also check prerequisites for regulator to work - voltage on zener and collector of Q13.

Re: Really universal soldering controller

Reply #2091
There is only about 100mv on q13

Re: Really universal soldering controller

Reply #2092
Between Q1:E and Q13:C is R20, but if it failed it should have burn marks on it. Maybe dry solder joint...

Re: Really universal soldering controller

Reply #2093
R20 is ok, 328 ohms. I reflowed it to be sure but it makes no difference.

Re: Really universal soldering controller

Reply #2094
So, power to the 12V regulator is coming through plated hole of C8 and via near R19. There is nothing left, really.
And what about 3.3V and -0.6V on J3 - is it there?

Re: Really universal soldering controller

Reply #2095
[quote author="afedorov"]So, power to the 12V regulator is coming through plated hole of C8 and via near R19. There is nothing left, really.
And what about 3.3V and -0.6V on J3 - is it there?[/quote]

No, those voltages are absent as well

Re: Really universal soldering controller

Reply #2096
Are you sure you have 35V on the emitter of Q1? It is the lead that connected to C7 and D12.

Re: Really universal soldering controller

Reply #2097
Yes, that is the pin that had 35v on it. I said had, because I am rebuilding the back board again. Something is very wrong and it's faster to do it like this. I had almost all parts available anyway.

Re: Really universal soldering controller

Reply #2098
I'm building a UniSolder and I bought the SH1106 because it's easier to source than the original alternative.

However, I have a question: what R68 value should I use?

I found a datasheet online that lists OLED Operating Voltage as External VPP supply = 7.0V - 13.0V so am I right using a 4.7k R68 for a 9V supply voltage to the display? (Considering I'm using a FAN5331)

Re: Really universal soldering controller

Reply #2099
27k + 4.7k should give 8.3V VCC
30k + 4.7k > 9.1V
I've tried feeding 12V to the original Winstar WEO012864DLPP3N00000 and it almost doubles the power consumption with not that much increase in brightness. So, 9-10V VCC is a good compromise.