Filter board no longer gives +5v (Dual SVF Midnight)

During the first test the reading was fine when checking on the +5v/gnd pads. Now that I’ve soldered everything on the board I went to check the controller board but it did not boot up. Checking the +5v/gnd pads again on the filter was showing 0.02v and 0.00v. I assume that means I have a short somewhere on the board.

Unfortunately I can’t see anything that looks like a short. A few places where the flux connects between two joints… could that be an issue?

I also plugged it in last night while only some of the components were soldered (the power supply + the resistors). Could that have messed anything up? It was only plugged in for a brief moment.

I hope these images aren’t too blurry to work with… And also that the fruits of my current soldering skills are not too offensive to experienced eyes…


(original size)

(original size)

(original size)

(original size)

I see lots of suspicious joints, some debris, legs cut flush to the board or to high….

Id start with removing (just reheat with a clean solder tip…) excess solder from the blobby joints and adding some to the joints that look suspicious (like the LT1054). Its a good idea to take out the Chips for this. Then id cut the too long Legs and make shure no debris whatsoever is present and try again.

Oh, and what about the -5V?

The best way of knowing if there is a short is to measure the resistance between a +5V point and ground - while everything is powered off.

Try removing all ICs one by one (except the LT1054). The short might have fried one of them, don’t make it worse!

Okay, good news (and sorry for the false alarm :/):

It turned out to be a faulty power supply that was giving out only 2.75V when set to 7.5V. Very strange, as it gave out proper levels when set to other voltages. I’ve got it replaced and everything checks out fine. Just need to find my studio cables in the moving boxes so that I can tune the filters!

Most likely you will not have to touch the trimmers - Trimpots are set to their mid position at factory, the new revision is designed to have its sweet spot right there. Try first, if it sounds OK don’t touch it.

Great news! Thanks fcd72.