ページを印刷する15A. Verify that the panel switches are set up to the conditions as given in PREPARATION at the beginning of this section,
(JR 5347-2) FILAMENT at 6.3 volts. Set the BIAS and the ENGLISH controls to zero. Connect a 1K 1% 10 watt resistor
to the anode lead of a 1N4005 silicon rectifier. Connect the cathode of the rectifier to pin 8 of the octal socket. Connect the
other lead of the resistor to pin 3 of the octal socket. Adjust the ENGLISH control to 86. Press the P1 DIODE test button.
Verify that the meter reads at or slightly above the DIODES OK line on the meter. Release P1.
15B. Adjust the ENGLISH control to 53. Press the P3 RECTIFIER test button. Verify that the meter reads at or slightly
above the DIODES OK line on the meter. Note: for actual rectifier tube tests the REPLACE ? GOOD scale is read for the
test results. Release P3.
15C. Replace the 1K resistor with a 10K 1% 10 watt resistor. Adjust the ENGLISH control to 46. Press the P2 0Z4 test
button. Verify that the meter reads at or slightly above the DIODES OK line on the meter. Note: for actual 0Z4 rectifier
tube tests the REPLACE ? GOOD scale is read for the test results. Release P2.
GAS TEST
16. Obtain a 6L6 tube that is known to be free of gas. Put the tube in the tester and set it up for the standard 6L6 test. Set
the ENGLISH control to 73. Press P5, the gas 1 test button. Adjust the BIAS control for a reading of 100 on the 3000 scale.
Hold P5 and press P6, the gas 2 test button and verify that the reading moves up by less than one small division. Release P6
and P5. Connect a 1Meg resistor between pin 5 and pin 7 of the nine pin miniature socket. Repeat the test. This time verify
that the reading goes up by 4 to 5 small divisions on the meter when the P6 button is pushed. Release P6 and P5.
This completes the testing and calibration procedure. For adjustments and problem resolution refer to the
ADJUSTMENT CHART section below.
ADJUSTMENT CHART
1. LINE ADJUST: The 150 volt plate supply is used as the reference when setting the AC line voltage adjustment. The AC
line control is adjusted until the plate voltage is 150 volts as read on the meter. All of the other operating voltages follow
along and are assumed to be correct. If the plate supply is abnormally high or low then adjusting it to the nominal 150 volts
with the line test will cause all of the other operating voltages to be shifted. This is because the line adjust will be
compensating for an abnormal plate supply and also affecting every other operating voltage.
If the plate supply voltage is normal and all of the other voltages are wrong by the same percentage, look at the
plate supply for problems. If the AC line test circuit itself is bad the plate and other voltages will all be wrong. Earlier
versions of the 800/800A had a fixed resistor in the AC line voltage metering circuit. This was a 215K fixed resistor
mounted on the terminal side of the pushbutton switch deck. In that case check the 215K resistor for proper value and
replace it if necessary in order for the meter to read the line test correctly when the plate voltage is 150 volts.
Later versions of the 800A had a calibration adjustment for the AC line test. Adjustable resistor R24 / 100K is used
for that. If the plate and other voltages are not correct after setting the AC line adjustment, perform the PLATE VOLTAGE
TEST 6 and adjust the LINE ADJUST control for a reading of 150 volts. Follow this with the LINE ADJUST test but do
not change the LINE ADJUST control. Adjust R24 instead of the LINE ADJUST until the meter points to the LINE TEST
mark in the center of the meter.
Also check the meter movement and verify that it indicates full scale when passing the nominal full scale current of
500 microamps and has a movement resistance of 233 ohms. Other values may have been used as production changes were
made through the years. The metal plate mounted on the side of the meter is a factory applied magnetic shunt. By loosening
the mounting screw and sliding the plate back and forth, small adjustments can be made to the full scale deflection of the
meter. Bear in mind though that changing the meter adjustment will effect the mutual conductance reading too so rule out
everything else before adjusting the meter.
2.ENGLISH POSITION: Loosen the set screw on the knob and reposition the knob to the correct location. Retighten the
set screw.
3.BIAS POSITION: Loosen the set screw on the knob and reposition the knob to the correct location. Retighten the set
screw.
4. SHORTS TEST: There is no adjustment for this function. Check the meter movement accuracy, R11 / 112K resistor and
the 56 volts low screen voltage as measured in SCREEN VOLTAGE TEST 7.