Troubleshooting Boss CE-5 DC jack

[PeterJ]

I have a Boss CE-5 that has been working fine, but just stopped working when powered by the DC jack. According to the label, it uses a PSA adapter, so it's 9v, not 12v.

Board power is a One Spot Pro CS6. The CE-5 has its own 9v connection (no daisy chain). I tested it by taking it off the board, plugging in cords in the in and mono out jack, and powering it with a One Spot wall wart, still nothing. Then I tried putting in a 9v battery and it turned on.

Opening it up, I saw that the pad for the lower leg of the PC-mount jack had lifted -- it came completely off, so a solder touch-up was a no-go. I cleaned the area w/alcohol and carefully scraped clean a bit of the trace, then used the leg of a resistor to connected the lug to the trace. I have continuity from the lug to the next solder point on the board.

Without power, battery removed, the other two lugs on the jack have continuity to their respective connections on the board, and to each other. With power, I get 9.3v between the two horizontal lugs, 2.0 mv from the top lug to the vertical one, and 5.2 mv from the vertical lug to the lower lug. But still nothing from plug-in power, only with a battery. I don't see any broken traces, errant strands of wire or corrosion on the jack.

I'd appreciate any ideas. Thank you in advance.

[Rob Strand]

I'd appreciate any ideas. Thank you in advance.

If you have a multimeter the first thing to check would be that 9V appears across the DC jack pins.  You can measure the voltage across the two pins - top most and bottom most on the solder side of the board.   You can get bad *external* connections when the hole in the external DC jack is 2.5mm and not 2.2mm.  Try wiggling or partial insertion.

If that looks OK then, given the battery works the + rail seems fine and the problem is on the 0V/gnd rail.

It is possible the solder joints on the repair aren't connecting.  Perhaps because the solder mask hasn't been scraped off enough. If you have a multimeter check the continuity from the DC jack to a point past the repaired solder joint.

It could also be a break in wire 6 (DC jack ground) between the PCB and the jack - possibly a brown wire.   Again check continuity with multimeter.

[PeterJ]

Thanks, Rob -- here's what I've done:

I'd appreciate any ideas. Thank you in advance.

If you have a multimeter the first thing to check would be that 9V appears across the DC jack pins.  You can measure the voltage across the two pins - top most and bottom most on the solder side of the board.   You can get bad *external* connections when the hole in the external DC jack is 2.5mm and not 2.2mm.  Try wiggling or partial insertion.

I'm getting 9V across the pins, so that seems to be working

It is possible the solder joints on the repair aren't connecting.  Perhaps because the solder mask hasn't been scraped off enough. If you have a multimeter check the continuity from the DC jack to a point past the repaired solder joint.

Yup - I'm getting continuity to the next point on the board past the repair

It could also be a break in wire 6 (DC jack ground) between the PCB and the jack - possibly a brown wire.   Again check continuity with multimeter.

I'll check that out -- thanks for the tip!

[ElectricDruid]

Could the actual DC socket itself be busted? They have a normally-closed connection that allows the battery power to go through when there's no power jack inserted. Perhaps that's never opening and screwing things up?

If the power socket has been hammered so much it's lifted pads off the board, I'd certainly be suspicious of it. The "lifted pads" thing is pretty common though with those PCB mounted sockets. There's nothing holding them down except solder, so any wiggling on the DC plug sticking out stresses the solder joints fairly directly.

I've certainly managed to fix a few doing what you've done - run resistor leads from the DC socket pins to the next-nearest solder joint to reinforce/replace broken or cracked tracks or lifted pads. If that hasn't sorted it, that makes me think the socket itself might be at fault. It still sounds like a mechanical failure at this point.

[PeterJ]

Could be, @ElectricDruid. It's weird that I have continuity with the jack, but that might be the problem. Thanks

[Rob Strand]

Could be, @ElectricDruid. It's weird that I have continuity with the jack, but that might be the problem. Thanks

If you can measure 9V on the jack (from the bottom of the PCB) when using the external DC supply then the power is getting to the jack.  The problem must then be further along the power circuit.

Hopefully you can see the debugging logic.    The aim is to find where the voltage stops.

[PeterJ]

Makes sense -- this may be where my limited abilities fail. Tracing where the power stops might be beyond me. I'll look for obvious things, like disconnected wires or blown components

[Rob Strand]

Makes sense -- this may be where my limited abilities fail. Tracing where the power stops might be beyond me. I'll look for obvious things, like disconnected wires or blown components

If you put the +ve meter probe on the + terminal of the DC jack (on the back of the PCB) you should be able to move -ve meter probe along the ground connections until it disappears:

First insert jack into the 6.5mm jack sockets.

Ground path:
- DC Jack -ve terminal (on back of PCB)
- Wire terminal 6 on the PCB   ; ground from  DC jack to 6.5mm socket
- The ground nuts on the 6.5mm jacks
- Wire terminal 4 on the PCB   ; ground from 6.5mm socket to PCB

Given the battery works you should find the problem at one of those points.

[PeterJ]

Thanks, Rob — I'll give that a shot

[PeterJ]

If you put the +ve meter probe on the + terminal of the DC jack (on the back of the PCB) you should be able to move -ve meter probe along the ground connections until it disappears:

First insert jack into the 6.5mm jack sockets.

Ground path:
- DC Jack -ve terminal (on back of PCB)
- Wire terminal 6 on the PCB   ; ground from  DC jack to 6.5mm socket
- The ground nuts on the 6.5mm jacks
- Wire terminal 4 on the PCB   ; ground from 6.5mm socket to PCB

Given the battery works you should find the problem at one of those points.

Everything tested okay at these points but when I was maneuvering the board around I saw the brown wire from point 6 was now hanging free (as you mentioned much earlier — I didn’t think it was loose before but no doubt I missed it). Reattaching will be fun — the lug on the output Jack is missing! The lug for the output B Jack is still there so I can see the difference— the A Jack has a crater of solder. It’ll be a stretch to reach the lug on the B Jack.

Thank you for the help and patience! I will let you know how this works out.

[PeterJ]

And... fixed!  I extended the brown wire with an additional bit of wire— hooked together, soldered, heat shrinked (shrunk? Shrank?) and soldered it to the B Jack lug. Thank you again Rob, and everyone else who jumped in to help. I've been away from this board for a long time but I'm getting back into building, so I really appreciate this community!

[Rob Strand]

And... fixed!  I extended the brown wire with an additional bit of wire— hooked together, soldered, heat shrinked (shrunk? Shrank?) and soldered it to the B Jack lug. Thank you again Rob, and everyone else who jumped in to help. I've been away from this board for a long time but I'm getting back into building, so I really appreciate this community!

Cool,