May 3, 2015
Today I broke the best tool I ever had, the Hakko 808 Desoldering gun. Trying to clean it after quite some time of inactivity, I got everything done and put back and plugged it in. Magic smoke came out and the smell of my stupidity. Somehow I shorted the two red heating element wires.
I started sweating and searching online. One source I found on badcaps forums (never heard of them) but read a post with a problem similar to mine:
Hakko 808 too hot! The pictures were especially helpful but the post ended on a bad note: replacement of the board - a $60.00 expense and an intellectual drawback. Surely I can fix this.
First, I changed the power resistor at the bottom ( the 1Ohm resistor located underneath the HAKKO logo in this picture) and it is at this point that I put everything together and the tip got really hot. Red hot that is. I could not believe it. The original resistor I switched got burned and I couldn't make out the colors. Looked like a 2 Ohm but after looking in my parts bin I could only find the 1 ohm. Power rating seems similar. Close enough.
Next, I switched the triac located on the back of the board. Found a replacement in the parts bin; again. After I put the "new" triac, the heat element didn't get hot at all. The pump worked fine, but the gun was cold.
After measuring the the voltages for the triac driver (taken from the datasheet) everything checked out. Up to this point I did everything as described on the badcaps forums. This is where they gave up. But I didn't. After more measuring I found R4 resistor shot and looking carefully it was burned also. Again, I could not make out the colors. I think it was a Red, Black and Brown? 200 Ohms? ? So I replaced with something close, a 220 Ohm resistor.
And this was it. This fixed it.
Two resistors and a triac found in the parts bin, which I got through desoldering with the Hakko 808 in the first place, fixed the desoldering gun. Ironic! The Hakko fixed itself and at no cost.
After a thorough cleaning (and not shorting the heating element leads) I checked the heat at the nozzle tip with a thermistor. The readings I got were 360 to 470, ten degrees lower than the datasheet. Works for me. Some testing was in order and after desoldering half the pcb's from a projection TV I can say that the gun is fully working and then some. I am very happy. I hope this helps someone.
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| Snapped this picture after I changed the 1 Ohm resistor - R1 i believe. |
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| The original power resistor that got replaced. |
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| The original and the replacement resistor. |
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| Burned triac. Upper left corner in this picture. |
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| Replacement triac. |
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| Replacement triac in flashlight. |
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| R4 and R1 after replacement |
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| Top of the board after repair. |
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| Triac placement after repair. |
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| New triac fits perfectly when the board is in place |
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| Burned parts that got replaced. |
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| Two resistors and triac got replace to fix the Hakko 808. |
