Help. Can’t get past the power supply test. [mostly resolved]

[last lemming]

I’ve double checked everything and my solder joints and direction of all components look correct. My test on the power transformer came up correct, but when I test the +6.3v and -6.3v I get 13.2v. What do I do?

 

[Paul Birkeland]

Can you post some photos of the top and bottom of the power supply board?  I would be willing to bet you have some cold solder joints and the regulator isn't doing any regulating.

 

[last lemming]

this is where I am so far

 

[Paul Birkeland]

Those are teeny, is there any way to get something a bit bigger?

 

[last lemming]

hope these are better

 

[Paul Birkeland]

Can you confirm that there's a 1085 regulator on the PC board and not an MJE5731A?

You could certainly reheat all your solder joints, but they don't look like I would expect them to in order to end up with no regulation.

 

[last lemming]

Are you talking about the two Cree 1060’s?

 

[Paul Birkeland]

No, the three legged regulator that mounts to the heatsink.

 

[last lemming]

Oh yeah. Yes that is what is on there

 

[last lemming]

Would a bad connection at T7, T9 or T11 or T12 do this?

 

[Paul Birkeland]

I would go ahead and reheat all of the solder joints on that PC board.  You are unlikely to damage anything on there from overheating. 

If you have 12V coming out of the 6.3V pads, you power transformer connections are unlikely to be a problem, but the 1085 regulator isn't doing its job.  This could occur due to soldering issues, an MJE5731A swapped in instead of the 1085, or possibly you have a meter that isn't working properly.  To rule out the meter, you can try measuring a 9V battery with it.

 

[last lemming]

I pulled the power supply off and retested the transformer. I got 9.2
V on the first test and 144v on the second. I also reflowed the joints. I will try soldering the PS board back on and see what happens

 

[last lemming]

Well not sure where to go from here. I’m still getting 13.2v. My meter is good, I reflowed all the joints, they didn’t look bad, but I reflowed them anyway. I also double check the transformer it checks out, so I’m not sure what to do now?

I don’t know enough to know how to trouble shoot.

Can the 1085 be over heated by the solder?  I didn’t really put too much heat on it. I did notice that on each leg on the top side of the board, I used a bit too much solder and each leg had a small ball of solder at the base.  I tried to remove after I tested but really couldn’t get the solder off.

 

[Paul Birkeland]

Can you post a photo or two looking at the 1085 and what you're seeing?

 

[last lemming]

here you go

 

[Deke609]

The right leg of the bottom capacitor could use some more solder.

cheers, Derek

 

[last lemming]

Would that not being fully soldered cause my issue?

 

[Paul Birkeland]

Yes, if the cap on the output of the regulator isn't well soldered, the regulator may not function properly.

 

[last lemming]

Ok reflowed that one capacitor and triple checked the others, but no change.

At this point I’m not sure what I’m supposed to do.

 

[Paul Birkeland]

If you'd like, you can mail me the board and I'll get it working for you.  My e-mail is pb(at)bottlehead(dot)com.