TTI TSX Series, Руководство по обслуживанию

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8. Check/Set Pre-regulator Gain - Connect CRO between 0V and OPTPO1B. Reduce
Voltage controls for 5.0/3.2V *? DC output. The voltage across R128 (generated by the
optocoupler input current) should be 175 to 200mV; otherwise switch off, discharge HV
reservoirs C9,10 and fit E12 0.25W resistor in R128 to bring the voltage into range on
retest. When the Voltage control(s) are adjusted just to reach maximum duty cycle, the
voltage across R128 should be +200 to 250mV.
9. Check HF rectifier waveforms - Connect CRO probe to DCT (D14 tab). The 160kHz
rectified rectangular PWM pulses typically exhibit similarly sized ringing recovery spikes of
20V peak and 1us half cycle basewidth decaying within 2 ring cycles as shown in Fig 6.
10. Check Switchmode Supervisory Shutdown - Connect 0V momentarily to IC9 pin 13
(sense miswire input). Switchmode activity should cease, trip LED1 on PCB come on and
the display indicate "TRIP". Reset the supervisory logic by momentarily connecting 0V to
PJ1-27. Check the secondary thermostat input by momentarily conn5V to IC8 pin
5 which should give the same result.
11. Check Overcurrent Trip Action - 4700uF is needed across the output of the 60V supply
to provide the necessary current surge. Set the Voltage control(s) to maximum then
connect a 0.47
Ω
5W resistor momentarily between VOUT- and DCVOUT ( access top
leads of R55). PWM output should cease immediately and then soft-restart. Switch off.
Remove earthing link to VRECT-.
Testing of Main PCBs at Full Voltage
1. Preparation - Remove VRECT- earthing link. Allow time or discharge HV reservoirs
C9,10. Refit leadless bridging connector to PJ4. Connect DVM between filter output at
top of R55(+ve) and D37 (VOUT-). Set the Voltage and Current controls to minimum.
Switch Output off. Switch AC on. The CV and CI LEDs should be off, the Output LED on
and both displays reading zero.
2. Control Board Adjustments (non-programmable versions) - If the control board is
suspect carry out this stage as described under Calibration stage 2.
3. Check Voltage Zero - Set Voltage control(s) to minimum and Current control for about
0.2A. Switch Output on. The CV LED should be on and the Output LED off. The Current
and Voltage displays should both read zero. Adjust VR3 until the DVM reads within 5mV
of zero. Set the Current control to minimum. The DVM should read between -0.7V and -
0.15V. Switch Output off. The DVM should read between -0.15 and -0.25V.
4. Check Current Zero - Connect 10
Ω
10W load to output terminals. Set Voltage control(s)
to display about 4V and Current control to minimum. The CI LED should come on. Adjust
VR8 for zero DVM reading within 20mV. Note and avoid saturated region below about -
20mV. Disconnect load after test.
5. Check Maximum Voltage - Set Voltage control(s) to maximum. Switch Output on. The CV
LED should be on. The Voltage display should read 35.3/18.15V. Adjust VR2 until the
DVM reading matches the Voltage display. Switch Output off.
6. Check Measured Current Display - Connect 3.75/0.9
Ω
load in series with the current
meter. Set preset VR9 fully ACW. Set the Current control to maximum. Switch Output on.
Adjust VR9 until the current display reading matches the current meter. The CV LED
should remain on. Switch output off.
7. Check HF Power Filtering - CRO check that 160 kHz ripple voltage between 0V and
DCVOUT (top R55) is less than 50 mV pk-pk. Switch Output off.
8. Check Measured Voltage Display - Connect 2.75/0.6
Ω
load in series with the current
meter. Switch Output on. The CI LED should be on. Adjust VR4 until the Voltage display
matches the DVM reading. Switch Output off. Disconnect the load.
9. Check OVP Trip - Set preset VR10 fully CW. Set Current control to about 0.5A display.
Set Voltage control(s) for about 34V display. Set the user OVP preset (VR3 on the control
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