"B" tone generator card (see "B" on side of tuning coil case).
|If your V301H Vox "American" Continental is missing tones, chances are you have a problem with one of the six divider circuits found on each tone generator card. Even if you have no test equipment, this web page is designed to help you diagnose, and possibly even repair this V301H Continental problem on our own.
The Vox Showroom and North Coast Music accepts no reposnsibility for personal injury or damage to property while using this information to attempt an organ repair. Proceed at your own risk.
You will need the three Radio Shack items shown at left plus a 9 volt battery and a mono audio cable with 1/8" plugs to diagnose this problem.
First, turn on the organ, connect to an amplifier and pull out the 16' and ~ drawbars. All the other drawbars should be pushed in. Starting with the low C, which is called "C1", test each note from the lowest to the highest key of the organ, which is called "C5". Listen for any note that seems to be an octave or more higher than adjacent notes. This symptom points to a problem in the divider circuitry.
Here is an hypothetical example of a typical divider problem. When testing the organ, you find that the frequency of the "B2" tone is the same as the "B3" key. This symptom points to a defective divider on the "B" tone generator card.
Start by turning off the organ and locating the "B" tone generator card in the organ. The B tone generator card can be identified by the letter "B" stamped on the tuning coil (see photo, lower left). This card will have the defective divider. Based on the hypothetical problem described above, this "B" card will have the defective divider. The tone generator will be held in place with one screw, located on the end of the circuit board near the tuning coil. After the screw is removed, gently pull the card out of the ten pin socket opposite the "screw" end of the board. Completely remove the tone generator from the organ.
Carefully connect a 9 volt battery to the board, as shown in the illustration above. I use "alligator clip" leads from Radio Shack for this purpose (see picture and part number at left). The positive side of the battery goes to end pin on the right (see photo above), the negative side of the battery goes to fourth pin to from the right. Check and double check this againt the drawing before connecting the battery. Use care that you do not short the alligator clips onto adjacent pins on the tone generator.
Next, connect one end of a 1/8" plug audio cord to a small battery powered audio amp, such as the Radio Shack unit shown at left (approximately $15). Connect one end of an alligator clip test lead to the sleeve of the other end of the audio cable and the other end to Pin 4 of tone generator card. This is the same pin on the tone generator that the negative wire of the battery is connected.