The V304, V304E2, and Heathkit TO-68 Jaguar Organ - Power Supply

Figure 1. Power supply schematic for the Jaguar Organ

Figure 2: V304E2 and Heatkit TO-68 power supply

Figure 3: V304 power supply

Figure 4: Front side of power supply

When compared to the Vox Continental, the power supply of the Vox Jaguar Organ is rather rudimentary.

The power supply for the Vox Continental was a regulated design with "full-wave" rectification through a packaged bridge (M160) of four diodes. A 2000 uf and a 5000 uf filter capacitor smoothed the AC ripple. An OC35 transistor served as a current regulator, and a zener diode limited the output voltage into the -8 volt range.

In contrast, the Jaguar power supply was unregulated and had only "half-wave" rectification. Only one rectifying diode was used, which essentially chopped off the positive side of the 20 volt AC current coming out of the secondary of the power supply transformer. A twin 1000 uf capacitor smoothed the resultant pulsed DC from the rectifying diode. A zener diode drops the output voltage of the twin capacitors from about -19 VDC to the -15 VDC required by the circuits in the organ.

An eight pin octal socket on the side of the power supply is used to connect the power supply to the circuits of the Jaguar Organ. Only four pins of the octal socket are used. Pins 5 and 6 supply the -15 VDC and ground to the circuits. Pins 1 and 8 connect the 120VAC mains to the rotary power switch, which is also a part of the Bass Volume control on the control panel.

The power supply for V304E2 and the Heathkit TO-68 may be seen in Figure 2 at left. The cover of the power supply has been removed for clarity. The twin 1000 uf filter capacitor is the yellow cylindirically shaped component to the right side of the power supply. The zener diode is just to the right of the strap that holds the capacitor in place. The diode that makes the half-wave rectification is in the upper right corner of the photo of the power supply.

Figure 3 shows the power supply for the earlier V304 (or GEM) version of the Jaguar organ. The internal power supply circuitry is the same as the V304E2.

The input/output panel of the power supply protrudes from the front of the organ (Figure 4). A two prong AC recepticle receives the specially made AC power cord. If you still have your original AC  power cord, consider yourself lucky. There is no known source for replacements for this AC cord. A small .5 amp Slo Blo fuse protects the organ and power supply from shorted components.

Power Supply Repair

It isn't very difficult to repair a defective Jaguar power supply. However, the Vox Showroom and North Coast Music accept no responsibility for personal injury or damage to property while using this information to attempt an organ repair. Proceed at your own risk.

The power supply must be removed from the organ and disconnected from the 120 VAC mains to complete this repair. The 1000 uf capacitors in this circuit may retain a charge for days, even after the organ is unplugged from the wall. Again, proceed with care.

Typically, the most common (and about the only) failure in a Jaguar power supply is the twin 1000 uf capacitor in the power supply. If your Jaguar Organ is blowing fuses on power up or if the audio is distorted or hums across the entire keyboard, odds are very high one or both of these capacitors are defective. As the average life span of an electrolytic capacitor is 10 years or less, it is likely that an exchange of this part is long overdue.

Two individual 1000 uf capacitors may be used to replace the twin 1000 uf packaged capacitor. 1000 uf electrolytic capacitors may be purchased at almost any Radio Shack or Tandy store. The schematic shown in Figure 1 above will help you to connect the new capacitors. Carefully observe the polarity of the capacitors when installing.

You might wish to purchase a copy of the Vox V304 schematic to help you repair its power supply, Parts values for all capacitors, resistors, and diodes are included in this schematic. Click here to purchase this from North Coast Music.


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Photos and editorial content courtesy Gary Hahlbeck, North Coast Music

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