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Troubleshooting Procedure

Unit appears to be dead (no LEDs on, graticule lights off, and no
CRT display)

.  Ensure power switch on front of unit is in the “I”

position.

1.

Make sure power source to unit is live.

2.

Check that power cord is firmly seated into rear of unit

3.

Check external fuse.  If blown replace with fuse of same type.

4.

Check low voltage power supply.  The fuse on this supply has
been bypassed to ensure only the fuse on the outside of the unit
will need to be replaced.

a.

Check that AC switch on front panel is allowing AC to the
low voltage power supply.

b.

Check for +5V, ± 12V from this supply

c.

Disconnect the three DC power cables from the supply.

d.

Recheck the +5V, ± 12V from this supply.  If one or more of
the voltage from this supply are missing with no load, the
power supply is damaged.

i.

Reconnect each of the power cables one at a time.
Connect the power to the TVM-850 board first, the
TVM-851 board next, and the power cable to the high
voltage block last.  As each is reconnected, monitor the
+5V, ± 12V from the supplies.

ii.

If one of the cables causes the loss of a voltage, the
board or high voltage block may be damaged.

Front LEDs on, no CRT display.

  Make sure intensity is not turned

down.

1.

Press CAL button.  If vector centering dot appears in middle of
CRT, use the H. POS. and V. POS. knobs to return calibration
waveform to its proper position on screen.

2.

Make sure that low voltage supply 12V output is operating pro-
perly.

3.

WITH UNIT OFF, ensure that all cables inside the unit between
the boards are properly connected.  Ensure that CRT anode cap
is on the tube and that the tube wiring harness is properly con-
nected.

4.

Test points on the TVM-850 board can be used to monitor the
waveform and vector analog outputs.  The signals may be traced
through the TVM-851 board.  

IT IS NOT RECOMMENDED THAT

THE TVM-852 BOARD BE PROBED AS HIGH  VOLTAGES
(>2000V) ARE PRESENT ON THIS PCB!

5.

High voltage power supply may be damaged.

CRT display on, no LEDs.

  Cycle power to unit.

1.

A CPU cold start can be executed by holding the CAL button
while power is applied to unit.

Note:

  cold starting a unit will clear the user memories.

2.

Ensure that all cables are connected to the front panel PCB
(TVM-853).  This board uses on +5V to operate.  It communi-
cates to the TVM-850 board’s micro via a 16 pin ribbon cable.

Check that the socketed ICs on the TVM-850 board are firmly
seated in their sockets.

Serial input connected to INPUT A and or INPUT B, but CRT
display only flat lines.

Ensure that the proper input is selected on the front panel.

1.

If data error light is flashing and the EQ lights for the selected in-
put are at maximum:

a.

Check to ensure the cable BNC at the rear of the unit is pro-
perly connected to one of the serial inputs.

i.

Check that the signal generation equipment is powered
on and connected correctly.

ii.

Ensure that the looping input is properly terminated at
the end of the cable.

b.

If data error light is flashing and the EQ lights for the select-
ed input are not at maximum.

i.

Check to ensure that digital data is 601 video.  This
scope will only display 601 serial component data
(525/625).

ii.

Source of 601 data is providing data which may be
missing proper timing signals.

c.

If a known valid input signal is applied to an input, but only
flat lines are displayed, check the input sections of the TVM-
850 board.

CRT display is rolling.

1.

If external reference in ON and if both 525 and 625 reference
LEDs are OFF:

a.

Make sure that external analog reference is applied to refer-
ence input on at rear of unit.

b.

Make sure that external analog reference is properly termi-
nated at the end of the cable.

c.

Ensure that the minicoax cables are properly connected to
the TVM-851 board.

d.

Check that the analog reference is genlocked to the input
signal(s).

2.

If external reference is OFF and if both 525 and 625 reference
LEDs are OFF:

a.

Ensure that input data is 601 serial component data (-
525/626).

b.

Check the input section for the selected input on the TVM-
850 board.

3.

If viewing two inputs (A and B), the unit will always sync on
INPUT A, the B input can roll if not genlocked with the A input. 

CRT display is not starting at beginning of screen.

1.

Adjust horizontal position control knob.

2.

If external reference in ON and if both 525 and 625 reference
LEDs are OFF:

a.

Make sure that external analog reference is applied to refer-
ence input on at rear of unit.

b.

Make sure that external analog reference is properly termi-
nated at the end of the cable.

c.

Check that the analog reference is genlocked to the input
signal(s).

3.

Unit may simply be showing the timing difference between the
serial data and the analog reference.

4.

If INPUT A and INPUT B are selected, the CRT will use the A in-
put as the reference (external reference OFF).  The B input will
be display the timing difference between the two inputs.

5.

Unit may need to be calibrated.

6.

High voltage power supply (100V) may be damaged.

Содержание TVM-821D

Страница 1: ...to incompatible equipment misuses operation outside any environmental specification for the product improper site preparation or maintenance or attempts by personnel other than authorized Videotek re...

Страница 2: ...Blank Page 2...

Страница 3: ...king of the protective ground conductor within or outside of the unit or loosening of the pro tective ground connection may cause the unit to become electrically hazardous c The protective ground cond...

Страница 4: ...4 BLANK PAGE...

Страница 5: ...s 12 Theory of Operation 14 Block Diagram 18 Block Diagram for TVM 850 Board 19 Block Diagram for TVM 851 Board 20 Performance Check 22 Calibration Procedure 24 Troubleshooting Procedure 25 Interconne...

Страница 6: ...hematic 63 Parts List 65 Exploded View of TVM 821D 77 Exploded View of Control Panel Assembly 78 Exploded View of CRT Ass y Connector Panel Ass y 79 Dimension Drawing of Standard Case SSC 1 80 Dimensi...

Страница 7: ...verlay makes routine tasks such as synchronizing timing and level setting easy to perform Other functions include LED alarms to alert the operator of EDH EAV and SAV data problems Add this to Videotek...

Страница 8: ...x10 TIMING ACCURACY 1H H Mag 0 5 s div 2 2H H Mag 1 s div 2 of 1H Mag 3H H Mag 1 5 s div 2 of 1H Mag LINEARITY 2 or less over complete horizontal position range ex cluding first and last major divisi...

Страница 9: ...of the unit CUSTOM INSTALLATION All installations must provide adequate ventilation and mechanical protection Top openings should not exceed 0 15 inches in diame ter Other openings should not exceed...

Страница 10: ...scoded component format waveform displays VMAG Toggles waveform vertical x5 magnification on and off SAV EAV Enables viewing of SAV and EAV timing signals while in YCbCr format waveform display FILTER...

Страница 11: ...ents Y Cb Cr 3 Vector display is an X Y representation of the Cb and Cr compo nents respectively 4 Low Pass LP and Differential Step DS filter the selected Y Cb Cr channels 5 Bowtie displays a two lin...

Страница 12: ...of each other 2 If all three channels are selected a In parade view the channels appear next to each other and each channel is an overlay of both inputs b In overlay view the channels and inputs all...

Страница 13: ...RESET If the CAL button is held in while the power switch is cycled on the unit will execute a system reset forcing the front panel and all memory locations to the factory default state Input A only...

Страница 14: ...both data for EDH and Data errors 5 Provides all timing for real time control of beam and analog switching This timing is derived from either input A input B the external analog reference or is genera...

Страница 15: ...ed to CN14 The beam intensity control R29 and the focus control R98 are buf fered by U35 before entering the CRT deflection board In addition a small amount of intensity voltage is added into the focu...

Страница 16: ...ngent so that the higher voltage transistors required do not have to be as those in the vertical deflection amp Also since the amplifiers are operated from the same 100V supply the outputs can be easi...

Страница 17: ...TVM 853 BOARD Sheet 1 An 8 bit bi directional data with control strobes is used to interface the TVM 853 board with the TVM 850 board The data bus is only driven when the TVM 853 board is addressed by...

Страница 18: ...cal Horizontal Rotation Pot N O and N C Dry Contact Blanking x1 or x5 Vertical Mag Vertical Position Control Waveform Analog Filters Vector DC Restores Stereo Audio Analog Input x1 or x5 Horizontal Ma...

Страница 19: ...vector adjustment Y delay Bowtie filter Demux Y Cb Cr Programmable Device Mux Timing Extraction and EDH Data Error Detection Deserializer Deserializer Cable EQ RCVR Cable EQ RCVR Internal 27 MHz Clock...

Страница 20: ...n Gain Vertical Deflection Selection Input Waveform Amplifier Analog Waveform Input from TVM 850 Bd CR Analog Vector Audio Y Input CB Analog Vector Audio X Input Timing Signals from TVM 850 Bd Sweep F...

Страница 21: ...21 NOTES...

Страница 22: ...phase with one another The audio pattern should pass through the 10E audio mark on the CRT f Return to video mode by pressing the DISPLAY and AUDIO buttons 5 Missing bits check a Change INPUT to A b...

Страница 23: ...F int int ext ext DISPLAY wfm vec wfm wfm SWEEP line line line field FORMAT YCbCr YCbCr RGB YCbCr SAV EAV off off off on FILTER off lowpass ds bowtie CAL off off off on VIEW par par overlay par CHANNE...

Страница 24: ...elect field sweep and 625 rate input signal Adjust field rate R213 on the TVM 851 for approximately 1 small timing mark between channels Verify 625 LED is on 16 WFM x5 Use 5 step signal Select V Mag U...

Страница 25: ...oard are firmly seated in their sockets Serial input connected to INPUT A and or INPUT B but CRT display only flat lines Ensure that the proper input is selected on the front panel 1 If data error lig...

Страница 26: ...only mode may be selected 6 High voltage power supply may be damaged Reference LEDs are both off 1 If external reference is selected check that an analog reference input is properly connected the to...

Страница 27: ...2 CN7 Fan 15 Pin 2 Pin 3 3 TVM 852B Graticule Lights TVM 851B Control Knobs 16 Pin 2 Pin 14 Pin 4 Pin 4 Pin 16 Pin Low Voltage Power Supply 2 Pin 2 Pin 6 Pin CN8 3 CN1 CN4 CN5 6 8 7 CN3 High Voltage P...

Страница 28: ...28 NOTES...

Страница 29: ...83 Addendum...

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