Rickenbacker Bass from Reverb.com Looks Great But Doesn’t Play Fair

Craig found this incredible Ric bass on Reverb, and thought he could flip it. When he unboxed it, he discovered several electrical problems that needed to be fixed to protect HIS reputation as a seller. Could The Unbrokenstring track down the electrical issues?

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Can anyone tell me what the model number is?

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I never get to see the tuners up close on cool instruments like this.

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The bound and sealed fret board is just outstanding on this instrument.

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Rickenbacker calls the neck pickup “Bass” and the bridge pickup “Treble.”

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This model comes with a built-in thumb rest. Not.

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The bridge and saddles are just massive.

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Each pickup is wired to separate outputs e.g. The Rick-O-Sound system. We will fix the issue of the jacks extending past the nuts like this. Anyone who has played out knows that the extended jacks makes it much more difficult to plug the cable from the amp into the instrument when you go on-stage. And it’s dark. And you are nervous. And the jacks are on the other side of the instrument where you can’t see them. This is a pet peeve of mine.

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One pickup is completely dead, and one of these controls will not rotate at all, and these controls are all out of order. What’s up with that?

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The pots have been changed from the original 330k units, but these are the Correct tone caps.

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The pick guard and bass pickup are from your favorite parts vendor, located right here in Houston, Texas.

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Inside the control cavity, we see some signs of human presence. The 4001 is the model number. The rest of it…?

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Well, this explains a lot. The wires are literally tied in a knot, and shrink-tubed together.

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Here is more Boy Scout knot-tying merit badge material.

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The connection to the switch is wrapped, not soldered, and it also appears to be glued with a clear adhesive.

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I detached one end of each of the tone caps to check them for value and leakage at stated working voltage. These are in perfect shape.

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Here is more of that clear glue. It’s not Super Glue, but some sort of crystal clear hard plastic adhesive, I guess.

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Here is more glue. Now, it just hit me. The reason that the pot doesn’t turn is that some of the glue leaked inside the control and locked it in place. Oh boy.

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Here is another connection made with glue. If it were silver rather than clear, I’d say that someone used Liquid Solder. Which has actually happened, but that’s a long story involving a Heathkit home stereo from the 1970s that is best saved for another day.

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The output jacks are mercifully unmolested. These were cleaned and checked OK.

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The blue material is the automotive heat shrink tubing that can be shrunk with a cigarette lighter. The presence of soot on the blue tubing confirms this.

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Our Boy Scout was here too, wiring up the bass pickup to the rest of the electronics.

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The treble pickup (next to the bridge) had a broken wire. The small wires were broken from the stress from moving the larger wires.

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While we’re here, let’s see what happened to the bridge ground. No, I’m not taking the strings off, just leaving them slack. Nobody changes bass strings.

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This takes the cake. Duct tape. Or is it Duck Tape?

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A dab of non-conductive hot glue secured the ground wire and the duct tape removed. We’re about done with our exploratory surgery, so the bridge can be reinstalled.

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500k pots are ‘pretty close’ to the original 330k pots, which are only available on the used market for Big Money. All the wiring is soldered correctly. The location of the controls is marked as shown. You can see, from the earlier picture, that this layout is different.

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A marker was used to clearly identify which jack goes with which pickup. The output jacks are ready to be installed. The blue heat shrink in the foreground is some of mine, properly shrank with hot air, not a cigarette lighter.

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Note that the output jacks are flush with the nuts. This makes it a lot easier to plug in when you walk on stage.

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The wiring is done and the bass is set up. It’s actually a lot of fun to play!

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Here is the correct knob layout, in case you don’t download the Users Manual.

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Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626

Ampeg BA115HP Combo Rescued from Pawn Shop

This pawn shop find doesn’t work, parts are rattling around inside, and a knob is missing. Watch The Unbrokenstring Crew get this into the practice room!

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St. Louis Music moved their production to China, which IMHO was the beginning of the end of this fine brand. Que sera sera.

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I had always wondered if stuff from a pawn shop with obscured serial numbers was a ‘little warm to the touch,’ if you know what I mean. But who would steal something this big?

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The electronics are out of the cabinet for inspection. A replacement Gain knob is on order from eBay, because someone cranked it up and ripped off the knobs. The ‘Style’ switch, which was broken internally, was put on order as well.

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This amp sports three band EQ and a Master Volume

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You can play your CD through the Line Input RCA jacks on the top, and mute the amp to play through headphones. In the muted mode, a built-in chromatic tuner comes on. Neat!

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The internals of the tuner was one item rattling around inside the unit.

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The translucent lens over the LED array diffuses the individual LEDs that illuminate when each note is played. This was very dirty for some reason.

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The tuner electronics and LEDs are one assembly, which makes me think that this was an option for this model.

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This power cord needs attention. All I need to do is unclamp it, shorten it, and re-clamp.

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The Chinese did not go cheap on the power transformer. This is the power supply section, with the filter capacitors seen on the left.

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The power amp is all bipolar transistors. The large white objects are wire-wound resistors. Some of these resistors are open-circuit, but the transistors are all intact. This is interesting…

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Removing the preamp board, we note that these spacers are required behind the input jacks. The gain control, which needed a knob, is fine.

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Speaking of spacers, this toothed washer is required behind the Style switch (the white and green item in the center of the picture) to properly set it’s geometry. This is the new switch. The original switch was defective.

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The ‘sleeve’ contact on this input jack was open-circuit, which caused hum with nothing plugged into the amp. Do you see anything?

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The contact on the right is not closing when nothing is plugged into the jack.

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The easiest way to fix this is to just replace the jack, although these can be carefully disassembled and bent back in place. These are inexpensive enough to just replace.

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The open resistors were identified and removed. Note the round holes in the circuit board.

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These round holes are for air circulation. I believe that there is a relationship between the plugged holes and the defective resistors.

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Some of the holes were plugged. The material plugging the holes is adhesive that helps to mechanically support the resistors when the amp is moved. Someone at the factory was sloppy with the hot glue gun!

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The new replacement resistors are modern high-temperature resistors, spaced above the circuit board for additional heat dissipation. All of the holes in the circuit board are clear now.

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This part of the circuit board is all cleaned up and ready to reassemble.

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The raw corners around the mute button can be stained to match the black anodize aluminum. A permanent Sharpie pen works well for this task. A little blending with a finger, before the marker fluid dries, makes the repair invisible.

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The front view of the finished unit is pretty unremarkable, since the controls are on the top and back. The control in the lower center is a pad for the tweeter. This unit is now 100% and ready to get back to the practice room!

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Thanks for reading all the way to the bottom!

CONTACT – David Latchaw EE
281-636-8626