Genius ISO XFR-75W, 2093, 1493, 2793, 3693, 1793, 1993, ISO XFR-100W Excessive, color, No Picture, Sync

Problem

Tests

Probable Solution

Excessive

1.

Turn down M. Gain.

If pin 1 still different

Measure voltage of K-Film pin 1

replace K-Film.

color.

for each color. If affected color

If pin 1 voltage same as others,

Turn down

has a .3V difference then others

Desolder pin 1. Make open to trace.

replace IC

241

.

G2 (bottom

pot of FBT)

2.

Measure voltage across cap.

.

If this voltage is less than 5V,

846

if excessive

check filament pulse. If OK

color is too

replace capacitor

.

857

bright.

3.

Turn up M. Gain.

Refer to the

Measure voltage,

Red

837

If the voltage is greater than .7V

schematic for

of affected color,

Green

842

or 0V , Replace the transistor.

the specific pin

base to emitter:

Blue

954

numbers of

each color.

4.

Ohm check,

Red, pin 8

If resistance is below 2K, replace

Tests should

CRT socket.

Green, pin 6

preformed in

pin of effected

the

CRT socket.

order to reduce

color to pin 12.

Blue, pin 11

chance of

5.

Measure voltage, of affected color,

If voltage is 3-8V replace the

replacing

wrong

K-Film pin 4.

2SC3467 & the PNP transistor pair.

component.

If voltage is less than 2V replace

PNP transistor connected to pin.

Problem

Tests

Probable Solution

No Picture.

1.

Note; Blanking should be > 5V.

The vertical booster pulse supplies

Measure blanking voltage on

part of vertical sync to the auto bias

Check that the

jumper

215

. If .6V to 1V check

IC

927

. With no sync to pin 8 of

vertical output for waveform.

, vertical blanking is not reset.

927

master gain pot

is turned up.

2.

Check light from filament.

If FBT waveform is the same on both

If no light check FBP before and

sides of the filament adjustment cap.

after capacitor

.

, ohm out the filament circuit.

854

854

3.

Measure voltage on Blue K-Film

If this voltage is over 10V, replace

pin 7. This voltage should be 9.3V.

transistor

.

942

4.

Measure G2 voltage on

If this voltage is under 100V, check

that the FBT bottom pot is turned

CRT socket

877

pin 7.

up. Replace CRT Socket if GND to

G2 is less than 100KΩ .

5.

Measure voltage on LM324

If this voltage is 9-11V, replace the

920

pin 8.

C-Film

and or LM324

.

917

920

Problem

Tests

Probable Solution

No

1.

Vertical osc. frequency adjustment;

Add or remove V solder connection. p30

Sync.

2.

Check H. free running freq. (Hfo)

If out ±500Hz of sync, adj. Hfo. p75

Tests should

3.

Check sync waveforms at input of

If input sync to the LA7851 is OK

preformed in

order to reduce

LA7851. Hs=pin 1, Vs=pin 19.

and picture roles replace IC

.

415

chance of

4.

Check voltage, LM339,

pin 14.

Also should check other voltages in this circuit.

replacing wrong

355

If outside range replace IC

.

component.

Normal range is 5V to 7V.

355

96