Mojotone Blackface Vibro Champ Style Amp Kit Instruction Manual

Transcription

1 Mojotone Blackface Vibro Champ Style Amp Kit Instruction Manual Tools needed for build: 40 W Soldering Iron Wire Cutters / Stripper Needle Nose Pliers Phillips Head Screwdriver Small Flat Head Screwdriver AC/DC Multimeter with Resistance Reading 44 Rosin Core Solder Lay out parts for a quick inventory (Photo 1) Compare physical inventory to the included bill of materials. Packaging mistakes are rare for Mojo but double check us before you start your build. Photo 1 - Lay out parts for quick inventory Install chassis mounted hardware Tube Sockets - Install so that they all face the same direction (noting pin #1 orientation) Power Transformer - Make sure to mount the PT so that the label faces toward tube sockets. This will be helpful for anyone looking at the transformer model number without having to take the chassis out of the amp. Output Transformer - Feed wires through grommets and note wire locations. Install Potentiometers. Install Input, Output Jacks, and Switches. Fuse Holder - Install fuse at same time so you won t forget. Pilot Light Assembly (Lens and Bulb) Install can capacitor mounting ring onto chassis. Install can capacitor into the mounting ring. Gently tighten the ring so that the capacitor is snug and not able to rotate or shift. Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 1

2 Photo 2 - Installing Chassis Mounted Hardware Photo 3 - Installing Chassis Mounted Hardware Photo 4 - Installing Chassis Mounted Hardware Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 2

3 Fiberboard Assembly Tech Tip - Always use a clean tip on your soldering iron to make positive, clean solder joints, ( cold solder joints can be a major problem in hand-wired amps) Always try to rely more on the schematic than the wiring diagram in any circuit. Be sure of component placement and orientation, especially capacitors (positive, negative) It is recommended to place the components on the fi berboard and the wire leads before soldering. This step can help prevent cold solder joints by eliminating the need to push wires through an already established solder connection. Check and double check the traces on the back of the fi berboard. (this is one of the most common areas that mistakes are made). If you plan on doing modifi cations such as hot-rodding (adding a bright switch etc.) and have never put a kit together before, it is suggested that you assemble the basic amp and have it functioning properly, to have an understanding of how the amp works before you start modifying it. Photo 5 - Fiberboard Assembly (Top View) Photo 6 - Fiberboard Assembly (Bottom View) Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 3

4 Internal Wiring Follow the color coded wiring diagram closely, twist the fi lament wires (6.3v heater wires) together from transformer and between tube sockets to reduce hum from 120ac voltage. Have enough of the power cord inside chassis to reach fuse, switch and ground Affi x the fl oating fi berboard, noting it is held in place by the wires, attach backing with rubber cement if necessary (or mount directly to chassis) Place entire fi berboard inside the chassis noting the orientation (see schematic) Connect corresponding wires to hardware, try to keep wire short and runs as neat as possible. This will help make future troubleshooting and repair easier. Solder (2) ½ W 100 Ohm resistors - solder from the pilot light to ground Solder (1) ½ W 1 Meg resistor from Input 1 to ground tied to Input 2. This grounds the input of the amp so that no hum or noise picked up by the amp when the guitar cable is unplugged. Note the letters on the can capacitor and the orientation of the capacitor before wiring the fi berboard. Solder a wire from terminal labeled - on the capacitor to ground. Connet the yellow wire coming from the output transformer to the tip connection on the speaker output jack. Tie off the end of the green wire coming from the output transformer with either electrical tape or heat shrink. Try to avoid crossing wires over each other. Before you plug the amp in check and re-check your wiring. If you are not clear on any part of the circuit, ask someone. Photo 7 - Internal Wiring Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 4

5 Photo 8 - Internal Wiring Photo 9 - Internal Wiring Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 5

6 **WARNING** The Voltages found inside your amp can cause serious harm or even death. Never attempt to service your amp while a power source is connected. Testing the Amp *WARNING* Never stick your hands inside amplifi er especially while power is on! Plug in speaker Turn amp on without tubes installed fi rst, checking transformers and components for shorting, excessive heat, arcing, smoking, etc. Test tube socket voltage with a multimeter to ensure correct operation. Turn Amp off before putting tubes in proper location, and allow tubes to heat up for approx. 30 secs. Before playing at volume. Listen. The best way to tell if there any problems with the circuit of the amp and/or tubes is just to listen... excessive noise, popping/ crackling, hum, loud squeals, as well as ghost- echo sounds. These are all symptoms of many common problems in tube amps. If you need to service the amp after having it on, you must discharge the capacitors. This is done by unplugging the amp, turning the power and standby to the on position and letting it sit for 30 mins. or so. Always use a multimeter to check the residual voltage in the cap to make sure it is fully discharged. Feel free to call Mojo at Mojo (6656) at any time if you any questions regarding your kit. Thanks for choosing Mojo and don t forget to crank it up!! **WARNING** The Voltages found inside your amp can cause serious harm or even death. Never attempt to service your amp while a power source is connected. Online Resources Grounding principles: & Signal Flow Diagram: ow.htm Printed Resources The Tube Amp Book by Aspen Pittman A Desktop Reference of Hip Vintage Guitar Amps By Gerald Weber All About Vacuum Tube Guitar Amplifi ers By Gerald Weber Mojotone Blackface Vibro Champ Style Amp Kit Manual 2012 Page 6