Speedball voltage help (small circuit board)

[kill_surf_city]

I just put together the small circuit board and installed it. 3 of the LEDs turn on except the top left. Voltages are:

OA: 50.5
IA: 189.8
B-A/B: 00.3 (even when my meter isn’t clipped to anything it rarely drops to completely 0)
IB: 189.8
OB: 60.8

[Paul Birkeland]

Do you happen to have a backwards PN2907?

[kill_surf_city]

Do you happen to have a backwards PN2907?

.


Oh shit they’re both backwards. Flat part facing away from the MJE350

[Paul Birkeland]

They should survive being run backwards and can be popped out and flipped around.

[kill_surf_city]

They should survive being run backwards and can be popped out and flipped around.

Already tried and failed. I just emailed to order a new pair. Oh well. Is it possible that I damaged the eyelets where the three prongs are soldered in? I kept trying to heat up the joints to pull them out and fear I heated them for too long and possibly damaged the circuit board. I’ll post a photo.

[kill_surf_city]

here's a photo 

[grufti]

Q1A looks OK. Q1B is a bit suspect, but it's impossible to tell for certain. Buy some solder wick and use it to clear the solder away from the board.

[kill_surf_city]

Q1A looks OK. Q1B is a bit suspect, but it's impossible to tell for certain. Buy some solder wick and use it to clear the solder away from the board.

I’m surprised you said Q1A looks Ok and Q1B looks suspect. Q1B I didn’t fully clear out yet/middle and bottom lead I think are still soldered in there. I got frustrated after my failure with Q1A and left Q1B alone until later. I needed a break.

[kill_surf_city]

Is there an easier way to clear the solder from the holes? Solder wick looks like it’s just for the board itself. I’ve never used it before.

[oguinn]

I use an Engineer solder sucker. It has a flexible tube to get right in the joint.

[kill_surf_city]

I use an Engineer solder sucker. It has a flexible tube to get right in the joint.

Thanks! I’ll see if I can find one.

[oguinn]

Amazon has them.

 Engineer SS-02 Solder Sucker https://www.amazon.com/dp/B002MJMXD4/ref=cm_sw_r_cp_api_i_3WN0EbRJR5B6S

[kill_surf_city]

Amazon has them.

 Engineer SS-02 Solder Sucker https://www.amazon.com/dp/B002MJMXD4/ref=cm_sw_r_cp_api_i_3WN0EbRJR5B6S

Thanks! I think my soldering iron actually came with one of those. Didn’t know what it was really for.

[grufti]

What I really meant to write and then didn't is this. It looks to me like you may have damaged one solder pad at Q1A, not Q1B. Once you have cleaned things up you should take a close look at the solder pad next to the edge of the PCB at Q1A.

[kill_surf_city]

What I really meant to write and then didn't is this. It looks to me like you may have damaged one solder pad at Q1A, not Q1B. Once you have cleaned things up you should take a close look at the solder pad next to the edge of the PCB at Q1A.

Guess I’ll find out. Getting some solder wick tomorrow. I’ll post a pic once I have it cleaned up.