popping and smoke during assembly of BeePre 2 [resolved]

[denteom]

Need help.  I'm from the Philippines. Just got to work on the BeePre 2 during the easter weekend holiday. I completed the checks on the AC and the PT-9, everything was fine. I set the transformer at 235-245 volts.

Got to solder up to the 250uF 350 volts at 31 and 33.  When it was time to check the DC voltages, right after plugging a bit of smoke and popping sound occurred.  I immediately unplugged it.  Any ideas?  Hope I did not break anything.

 

[Doc B]

Look for a discolored or blown component. Check all the wiring for a miswire. Check orientation of the rectifiers and capacitors. Post some photos of the build and maybe we can spot the issue for you.

 

[Paul Birkeland]

Could you post a couple of photos of your build?

 

[denteom]

Doc B and PB:
Found the fried resistor at 34_36.  Is it because it got in contact with the T strip 35? How's my soldering? Any contact points I can improve on?  It looks like a common resistor, can I buy that in the Philippines?  Thank God it was just that resistor and not the exotic capacitors.
Dennis

 

[denteom]

more photos

 

[denteom]

AC portion

 

[denteom]

last set

 

[Paul Birkeland]

You need a proper pair of side cutters so you can trim your leads back.  I would suggest the CHP-170.

The resistor that exploded was not the correct part that was meant to go there.

 

[Paul Birkeland]

You have a 22 ohm 5W resistor where it doesn't belong.

 

[denteom]

Thanks Paul, so I'll look for the right resistor in the box and I'll be fine? But that will leave me with one less resistor of 22 ohm 5W, hope that will be an easy find. I have a side cutter, not sure how close I should trim it.

 

[Paul Birkeland]

You need to put the 22 ohm resistor where it belongs.  You need to put whatever is in place of the 22 ohm resistor where it belongs.

It looks like you put a 220 ohm 1/4W resistor across one of the power supply caps, which would indeed cause it to explode, so you'll need to replace whatever resistor that is that erupted with the correct part and obtain a replacement for what blew up.

I would recommend slowing way, way, way down on this build moving forward.

 

[denteom]

I'll be careful next time.  But from the set of resistors in the box there is no 22 ohm.  I remember checking the resistors properly 270ohm 1 watt.
 
Reading again the manual on page 34, I think my error was I soldered the wire wound resistors (270 ohm 5W) at terminal 31 and terminal 33 (with a 270 ohm 5W together with a prepared 270 ohm with a 2 UF 4007 nd rectifier 0.1 uF ceramic capacitor.), prior to the High Voltage Power Supply test.  Cause it said I  should push the probes so that the unsoldered resistors make contact with the terminal. Could soldering these resistor to the T strip terminals caused the short?

Guess got carried away by soldering the resistors from terminals 34 to 39. It would be helpful putting a note in red letter Do not solder the resistors at terminal 31 and 33 yet till further notice.
Does that mean I need to remove the soldered lead on terminal 31 and 33? Also I will replace the burnt resistor 270 ohm 1 watt.
Hope these changes will help fix the error.

One more thing how do I know if I also damaged the white wire wound resistor (270 ohm 5W)? If it still looks immaculate white does that mean it is still okay?
Thanks in advance.  Don't want to short it again, so taking precautions.

 

[denteom]

PB:
Sorry for my error, looking again on the photo.  I made the error by wrapping the ceramic capacitor and the rectifier to the wrong capacitor.  Big error.  Are those salvageable? Remove the solder and wrapping it to the right resistor.
Dennis

 

[Paul Birkeland]

I remember checking the resistors properly 270ohm 1 watt.

270K, which is 270,000 ohms.  You put a 270K across one cap and a 220 ohm across the other.  The 220 ohm resistor is the short.
 
Reading again the manual on page 34, I think my error was I soldered the wire wound resistors (270 ohm 5W) at terminal 31 and terminal 33 (with a 270 ohm 5W together with a prepared 270 ohm with a 2 UF 4007 nd rectifier 0.1 uF ceramic capacitor.), prior to the High Voltage Power Supply test.  Cause it said I  should push the probes so that the unsoldered resistors make contact with the terminal. Could soldering these resistor to the T strip terminals caused the short?

It would be helpful putting a note in red letter Do not solder the resistors at terminal 31 and 33 yet till further notice.

The manual will say attach for components that need to be placed and not soldered.  The manual will then say attach and solder when it's time to solder a connection.

One more thing how do I know if I also damaged the white wire wound resistor (270 ohm 5W)? If it still looks immaculate white does that mean it is still okay?

Yes, you have swapped a 270 ohm 5W and a 22 ohm 5W.  They need to be installed in the correct places.

 

[denteom]

Hi Paul:
Finally fixed the high voltage DC portion, took a while, had to ask someone to help me out in removing the misplaced part. DC voltage is now 240.  I can now move on, treading more gently.