JVC 370 SC, 330, 340 SC Measure the number of millivolts between pins 3 and 4 on SPS J505

Chapter 3---Service Adjustments

2. Measure the number of millivolts between pins 3 and 4 on SPS J505.

NOTE: This circuit is designed so that the number of millivolts between these pins (for Models 340 and 370, it is millivolts divided by 10) represents the lamp current in amps.

3.Multiply the two (2) figures from Item 1 and from Item 2 together.

4.Divide the product from Step 3 by 1 for Model 330 wattage. Divide the product from Step 3 by 10 to get wattage for Model 340SC or 370SC.

5.Adjust the Lamp Current Adjust pot (see CAUTION below Table 3-1)on the top of the SPS (refer to Figure 4-3) until this result is within the appropriate HJT model spec indicated in Table 3-1).

Example (for Model 370SC): Voltage measured between J503 and J504 = 28V and voltage measured between pins 3 and 4 of J505 = 1070mv.

The product of this is 29960÷10 = 2996W. This result is within the Model 370SC spec of 3000W ± 25W and would not require adjustment.

Table 3-2Arc Lamp Current and Amp Specs

Model 330

Model 340SC

Model 370SC

1500 Watts ± 25W	2000 Watts ± 25W	3000 Watts ± 25W
68 Amps Normal	80 Amps Normal	100 Amps Normal
70 Amps Maximum	85 Amps Maximum	110 Amps Maximum

CAUTION! Make adjustments in small increments to ensure lamp integrity (lamp overheating may occur if current is abruptly increased). Do not increase the current beyond the maximum levels listed in Table 3-2.

3-22 Model 330, 340SC, 370SC Service Manual