UNIVERSAL HORIZONTAL ANALYZER (HA2500) TRAINING. HA2500 Universal Horizontal Analyzer

UNIVERSAL HORIZONTAL ANALYZER (HA2500) TRAINING

HA2500 Universal Horizontal Analyzer

Test output currentfrom H. Driver stage

Dynamic HoirzOutput Meter

Load Test &Sub DriveFrequencyAdjust

Load Test checksH.output -chassisoff

Ringer TestDetects shortedturn in IHVT,yokes, coils

Substitute H.Drive to Horiz.Output Transistor

SubstituteB+ voltageto Horiz.Output stage

Universal Horizontal Analyzer Tests

HORIZONTAL STAGES IN HI-RESOLUTIONCRT VIDEO DISPLAYS

1. Horizontal Output - Produces current in flyback and/oryoke resulting in HV and/or deflection2. B+ Power Supply - Powers horizontal output & driver stageswith voltage ranging 30-190 volts.3. HV/Deflection Regulator - Varies B+ to horizontal outputto keep HV and/or deflection constant.4. Horizontal OSC/AFC - Generates sync-locked drive at thehorizontal scanning frequency.5. Horizontal Driver Stage - Amplifies weak drive to levelneeded by the horizontal output transistor.6. X-Ray Shutdown - Disables horizontal output stage by removing drive or B+ when the HV is at an unsafe level.

Basics of Horizontal Output Stage

Horizontal Output Stage in Multi-Resolution CRT Video Display

Horizontal Output Stage in Hi-Resolution CRT Video Displays

Horizontal Output Stage Types In Hi-Resolution CRT Video Displays

T503

HST +D511

C538

Q519

H. Yoke

Linearity Coil

S-CapacitorsSelect

Horiz. Drive

H. DeflectionRegulated B+

+ 15 V

Q518 Q520 Q522 Q523 Q524

C523

Q527

2.2uFdC554

S-Capacitor and LinearityCoil Switching

HLCL506

Switched by mode control as horizontalscanning frequency (resolution) increased.

Understanding Horizontal Troubleshooting Difficulties

Technicians indicate more than 50% of failures are horizontal related.

* Excessive horizontal current (loading) decreases the SMPS output voltage (limiting) or damages SMPS circuitry.* Excessive horizontal output current stresses or burns out, HOTs, HV/defl. Regulator & SMPS components.* A flyback or horiz. yoke shorted turnor flyback secondary circuit short cause excessive current (loading) not evident with ohmmeter.* HV/deflection regulator interacts with horizontal output stage.* Horiz. Drive defects cause horizontal output transistor heating often resulting in failures.* Flyback pulses feed back to AFC, these circuit loops can cause unusual drive and picture symptoms.* X-ray shutdown results in momentary operation with no effective

means to make measurements to isolate the cause.

HA2500 Universal Horizontal Analyzer Features

* Chassis Off Horizontal Output Stage Load Test: Isolates defects with power off (PS loading, shutdown, HOT burn outs).* Dynamic Horizontal Output “METER”: Tests output operation & finds horizontal drive and B+ supply problems. * Exclusive Horiz Driver Test: Measures driver stage output current- detects weak drive or intermittent drive.* Horizontal Output Transistor Base or Gate Sub Drive:Subs missing or suspect drive to prove output stage good or bad. * Substitute B+ Power Supply: Subs chassis B+ supply to isolate SMPS, HV/Defl. Regulator, X-ray, or output stage. * Flyback, Yoke & Coil Ringer Tester: Determines is component good or bad from a shorted turn(s).

Horizontal Output Load Test Introduction

Provides a functional test of the horizontal output stage at the proper frequency & 1/10th B+ voltage to detect loading (high B+ current) anddefects that do not permit power on testing.

Benefits:

Identify horizontal output stage defects before replacing and burning out replacement output and P.S. parts.

Quickly determine if horizontal output stage defects exist before applying AC voltage.

Determine if the horizontal output stage is the cause of PS defects or improper operation.

Block Diagram of Load Test andConnections To Horiz. Output Stage

Orange clip to B+ Input to FlybackYellow clip to Collector of H.O.T.Black clip to Horiz. Circuit Ground

Load Test Setup

Load Test SetupGuides you to setting frequency & 1/10 B+ voltage to test the horizontal output stage. Confirms proper load test with VPP readout.

1. Remove AC to chassis - start with LOAD TEST B+ VOLTS at “MIN.”2. Connect the LOAD/RINGER test leads to proper chassis points.3. Set the LOAD & RINGER TEST Switch to “LOAD TESTS SETUP.”4. Set the HORIZONTAL FREQUENCY COARSE and FINE Controls for a frequency near the displays highest horizontal scanning frequency.5. Increase the LOAD TEST B+ VOLTS Control to approximately 1/10 of the normal B+ to the horizontal output stage. 6. Read the VPP readout - 1/10 of normal - 100VPP typical.

Load Test Connections & Readouts

ANALYZING THE HORIZONTAL OUTPUT STAGELoad Tests Readouts

Interpreting Load Test Readings

Typical uS range or horizontal pulse times for multi-frequency (resolution) video displays.

A display’s pulse time should be in the range of its highesthorizontal scanning frequency or scan format capability.

Relationship of flyback pulse tohorizontal blankinginterval in under-scan and over-scan displays.

Horiz. Flyback pulse is retracetime which occurs during video horiz.blanking interval.

Ringer Test

Provides a test to determine if the flybackor yoke has a shorted turn defect.

* Confirms if flyback, yoke or coil must be replaced.

* Saves time replacing components and doing added testing to determine flyback, yoke or coil is defective.

* Proves the flyback, yoke or coil does not have a shorted turn and repair is likely feasible.

Ringer Test

Ringer Test Detects Shorted Turns

To Ringer Test a Flyback

1. Remove AC to the chassis2. Set the Load & Ringer Tests Switch to “Yokes & Flybacks.”3. Connect the Ringer/Load Test leads to the primary winding. (Use the orange and black test lead clips)4. Read the rings indicated by the HA2500 center display.

Note: 10 or more rings indicates the flyback does not havea shorted turn. Rings less than 10 indicate a shorted turn.

DYNAMIC TESTS - METER

Provides automaticmeasurements at horizontaloutput transistor to ID horizontal drive,B+ supply or horizontaloutput stage symptoms and defects.

Check horizontal drive VPP and Freqeuncy.Check for missing or improper B+ volts.Check for horizontal output stage flyback pulse VPP.Check flyback pulse time in uS automatically.

Collector Or Drain METER Readouts

Base Or Gate METER Readouts

To Use the Dynamic Tests Meter

1. Remove AC to the chassis2. Connect the Dynamic Tests Leads3. Set the Dynamic Tests Switch to “Collector Or Drain.”4. Apply AC to the chassis.5. Read the DCV, VPP and uS readouts in the center display.6. Set the Dynamic Tests Swtich to “Base or Gate.”7. Read the kHz and VPP readouts in the center display.

Horizontal Driver Test

A measurement of the output current capability of the horizontaldriver stage. The test simulates a base/emitter HOT junction andmeasures output current during positive drive cycle.

Benefits

* Determines if the base drive current is adequate for normal HOT function. *Indicates when driver stage is suspect of HOT heating or repeat failures.

* Displays drive current to ID intermittent drive defects without damaging

replacement horizontal output transistors.

HORIZONTAL DRIVER & OUTPUT STAGE

The horizontal driver stage produces output drive currentto the base/emitter junction of the horizontal output stage.Defects reduce this current causing H.O.T. heating, failuresand improper horizontal output stage operation.

Methods used to control driver stage output currentwith horizontal scan frequency changes.

Adjust V+ toDriver Stage

Switch resistancein base of H.O.T

Horizontal Driver Test - Push & Hold Red Test Button

How To Perform the Horiz. Driver Test

1. Remove AC voltage - unsolderH.O.T. base or open base circuit path.2. Connect Dynamic Test Leads3. Set DYNAMIC TESTS Switch to“HORIZ. DRIVER TEST.”4. Apply AC voltage to chassis - PushPower switch to ON.5. Push & Hold the HORIZ DRIVERTEST OR SUB DRIVE Pushbutton.6. Read the mA reading & compare to typical mA range chart.

Block Diagram of Horiz. Driver Test

Base Sub Drive & Gate Subdrive

Provides substitute horizontal drive, optimized to drivethe base (bipolar output)or gate (MOSFET output)

transistor.

Subs for missing or suspect horizontal drive to test thehorizontal output stage or to isolate subtle reduced deflection,noises or unusual picture horizontal tearing defects.

Display Before & During Base or Gate Sub Drive

Be sure Frequencymatches signal source.Be sure B+ voltageis proper or regulated.

During Subbingcollector DCV, VPPpuse uS readings are displayed.

Substitute Horiz. Drive To The Base or Gate of Horizontal Output Transistor (Base -Bipolor, Gate - MOSFET)

Block Diagram of HA2500 Base Sub Drive

Output drive current is dynamically adjusted.

Gate Sub Drive Block Diagram

To Substitute Base Drive to the Horizontal Output Transistor (Bipolar)

1. With AC power removed unsolder the Horiz. Output transistor base or open base circuit path.2. Connect Dynamic Test Leads - Blue to base of H.O.T. Yellow to H.O.T collector, Black to Horiz. Ground.3. Set the Dynamic Test Swtich to “Base Sub Drive.”4. Apply AC to the chassis and read the DCV readout to confirm proper B+.5. Read the display kHz readout to confirm the proper drive frequency.6. Push & hold the Horiz. Driver Test or Sub Drive push button.7. Read the DCV, VPP and uS readouts to test the horizontal output stage. Note: Proper readings indicate normal output stage operation.

Synced With Generator A Locked Picture Appears

SUBSTITUTE B+ SUPPLY

A variable DCV power supply to substitute for the B+ voltageto the horizontal output stage or to the HV/Deflection regulator.

Determines if the horizontal output stage is good or bad by subbingfor a dead or suspect B+ power supply.

Isolates defects to B+ supply, regulator, or horizontal output stage.

Permits slowly increasing B+ voltage to isolate HV breakdownfailures, troubleshoot current shutdown and regulation defects.

Isolate X-ray or HV shutdown symptoms.I

Typical B+ Voltage Path In Multi-Frequency CRT Display

Using The Substitute B+ Supply

To Substitute B+ Voltage To a Horizontal Output Stage

1. Remove AC to the chassis and open a jumper wire, coil or resistor in the B+ power supply path to the flyback.2. Set the HA2500 VOLTS Control to “off” and the POWER LIMIT control to 1/2 scale (40W).3. Connect the B+ Supply Leads to the chassis.4. Connect the Dynamic Test Leads to the chassis horizontal output transistor.5. Set the Dynamic Tests Switch to “Collector Or Drain.”6. Apply AC Power to the chassis.7. Increase the VOLTS Control to apply substitute B+ volts. (Increase the B+ sub voltage until the Collector Or Drain meter indicates normal VPP for the chassis)

B+ Substitution to the Input of HV/Deflection Switching Regulator

Using the Substitute B+ Supply and Sub Drive Together

Congratulations- You are now an experiencedUniversal Horizontal Analyzer (HA2500) User!