THE NEED FOR A QUICK TROUBLESHOOTING GUIDE FOR THE CTC 177 CHASSIS HAS RISEN IN THE PAST SEVERAL MONTHS. IN THE PAGES TO FOLLOW THIS GUIDE WILL LIST THE MOST COMMON PROBLEMS THIS TECHNICIAN HAS ENCOUNTERED FROM THE FIELD. THE INFORMATION WILL BE DISPLAYED IN A “SYMPTOM-REPAIR-PART NUMBER” FORMAT. FROM THE MOST COMMON TO THE LEAST.

AS ALWAYS, THE MOST IMPORTANT STEP IN TROUBLESHOOTING ANY DEVICE IS TO “LISTEN” AND GATHER AS MUCH INFORMATION FROM THE CUSTOMER AS POSSIBLE.

SECONDLY, TAKE A “LOOK” AT THE CHASSIS IN QUESTION, A VISUAL INSPECTION OF THE DEVICE IS A TIME SAVING STEP BECAUSE “SPOTTING” A BURNT COMPONENT OR WATER DAMAGE WILL HELP YOU QUICKLY ISOLATE THE PROBLEM TO A PARTICULAR AREA.

THE THIRD STEP IS TO APPLY POWER TO THE UNIT AND “OBSERVE” THE SYMPTOMS ON THE UNIT.

FINALLY, THE FOURTH STEP IN THIS GUIDE IS TO “MATCH” THE SYMPTOM TO THE COMPLAINTS LISTED IN THE PAGES TO FOLLOW FOR A POSSIBLE “QUICK-FIX”. IF THE SYMPTOM IS NOT LISTED HERE IT MAY BE NECESSARY TO OBTAIN THE CTC 177 SERVICE MANUAL AND TROUBLESHOOT ACCORDINGLY.

I. PICTURE “SHRINKS” AND GOES “FUZZY” INTERMITTENTLY.

A) SOLDER ALL GROUNDS ASSOCIATED WITH THE TUNER AND MICROPROCESSOR SHIELDS. THERE ARE 13 GROUNDS On THE TUNER SHIELD AND 9 ON THE MICROPROCESSOR SHIELD.

B) REPLACE Y7401 (182839) FOR INTERMITTENT FUZZY PICTURE ONLY.

II. NO RASTER, NO SOUND, HIGH VOLTAGE OK.

A) REPLACE CR4704 (207878), R4702 (215211)-CTC177AC, (215210)-CTC177BB, R4502 (215207)-CTC177AC, (190554)-CTC177BB, R4517 (215208)-CTC177AC, (215209)-CTC177BB.

III. DEAD SET.

A) R4104 (191192=1.5M_1/4W)

B) U3201, EEPROM.(218400=CTC177AA,CTC177AK), (218401=CTC177AD, CTC177AG), (218402=CTC177AF), (218403=CTC177AH), (218404=CTC177CC), (218405=CTC177CD), (218397=CTC177BD,CTC177BF), (218398=CTC177BE, CTC177BG), (218399=CTC177BH), (218542=CTC177AC), (215861=CTC177BB).

1. SEE QUICK ALIGNMENT PROCEDURE TOWARD THE END OF THIS GUIDE.

C) CHECK PINS 8 AND 10 ON T4101 FOR LOOSE SOLDER CONNECTIONS.

IV. ONE COLOR MISSING OR “SMEARED TO RIGHT”.

A) AT FIRST GLANCE THE CRT APPEARS TO BE BAD. TO VERIFY IF THE CRT IS GOOD OR BAD GO TO THE CRT BOARD AND LOCATE THE R, G, AND B INPUT WIRES. SWAP THE BAD COLOR WITH A KNOWN GOOD COLOR AND OBSERVE THE CONDITION ON THE SCREEN. IF THERE IS NO CHANGE ON THE SCREEN THE CRT IS PROBABLY BAD. IF THE CONDITION CHANGES THEN THE CRT IS PROBABLY GOOD. CHANGE THE WIRING ON THE CRT BOARD BACK TO THE ORIGINAL CONDITION. REFER TO THE “T” CHIP ON THE MAIN CHASSIS. THE LOCATION IS U1001 (215524). CHECK THE R, G, B AT PINS 36, 37, AND 38. THE VOLTAGES ON ALL THREE PINS SHOULD BE APPROXIMATELY 2.75 VOLTS. IF ONE OF THE VOLTAGES IS MISSING REPLACE THE “T” CHIP. I’VE HAD THE CORRECT VOLTAGES AT PINS 36, 37, AND 38 AND STILL HAD A BAD “T” CHIP.

V. PINCUSHION PROBLEMS.

A) THE ONLY PARTS THAT ARE DOCUMENTED FOR THIS CHASSIS ARE C4407 (214754) AND CR4403 (164589).

VI. NO AUDIO.

A) CHECK “SPEAKERS ON/OFF” SETTING IN THE SETUP MENU. AND SET TO THE PROPER SETTING.

B) CHANGE Q1903 (215495) SMD TRANSISTOR LOCATED IN THE AUDIO CIRCUIT. IT WILL CHECK GOOD, BUT WILL NOT WORK.

VII. UNUSUAL PROBLEMS.

A) UNIT MAKES “TICK-TICK-TICK” SOUND IN THE STANDBY MODE ONLY. FUNCTIONS NORMALLY IN OPERATION MODE.

1. SOLDER LOOSE CONNECTIONS AT C4103 SMD OFF OF PIN 6 OF U4101 .

B) UNIT INITIALLY DEAD. UNPLUG UNIT FROM AC TO RESET CONFUSED MICROPROCESSOR. UNIT COMES ON NOW BUT WITH EXTREMELY DARK PICTURE.

1. TURN G2 SCREEN CONTROL UP ENOUGH TO MAKE OUT MENU.

2. GO TO VIDEO MENU.

3. CHECK BRIGHTNESS LEVEL FOR “MISLABELING”. SEE ILLUSTRATION BELOW. (TRUE CASE).

COLOR -. . . . . . . . . . . .+

TINT G. . . . . . . . . .... . .R

BRIGHT G. . . . . . . . . . .R

SHARP -. . . . . . . . . . . . +

AUTOCOLOR: ON

THE BRIGHTNESS LEVEL SHOULD NOT HAVE A “G” OR AN “R”.

4. SOLUTION. GO TO BRIGHT LEVEL. INCREASE LEVEL TO HIGHEST SETTING. IF YOU CONTINUE TO HOLD DOWN THE VOLUME UP BUTTON THE BRIGHTNESS WILL RETURN TO NORMAL WITH PROPER GRAPHICS AND EFFECT.

5. IT MAY BE NECESSARY TO DO THE SAME FOR THE COLOR LEVEL IF INSUFFICIENT COLOR OCCURS.

6. TEST ALL OTHER FUNCTIONS FOR PROPER OPERATION.

VIII. QUICK ALIGNMENT PROCEDURE.

A) THIS PROCEDURE IS A MUST AFTER REPLACING U3201. ALL VALUES LISTED ARE FROM A KNOWN GOOD WORKING CHASSIS. THIS PROCEDURE WILL GET YOU IN THE BALL PARK HOWEVER, YOU MAY NEED TO DEVIATE FROM THESE VALUES. IT MAY ALSO BE NECESSARY TO ACTUALLY GO THROUGH A COMPLETE ALIGNMENT AS LISTED IN THE CTC177 SERVICE MANUAL.

“QUICK ALIGNMENT PROCEDURE”

THE VALUES LISTED IN THE ALIGNMENT SHEET WERE TAKEN OFF OF A KNOWN WORKING CTC 177BD CHASSIS. THE PARAMETERS WILL GET THE UNIT VERY CLOSE TO FACTORY SPECIFICATIONS. IN ORDER TO ACCESS THE SERVICE MODE THE UNIT MUST BE ON. PRESS AND HOLD THE MENU BUTTON AND THEN SIMULATANEOUSLY PRESS THE POWER BUTTON. WHILE CONTINUING TO HOLD THE MENU BUTTON, RELEASE THE POWER BUTTON AND THEN PRESS THE VOLUME + BUTTON.

 

PARAMETER#	PARAMETER NAME	VALUE RANGE	COMMENTS
00	PASS NO. FOR SERV. ADJUST	MUST SET TO 76	MAY NOT ADVANCE UNTIL VALUE SET
01	HORIZONTAL FREQUENCY	10	SYNC IS KILLED. DON’T GO BELOW 9
02	HORIZONTAL PHASE	08
03	EW DC (WIDTH)	09	27" ONLY
04	EW AMPLITUDE	02	27" ONLY
05	VERTICAL DC	07
06	VERTICAL SIZE	17
07	RED BIAS	29	PRESS MENU BUTTON FOR SETUP LINE
08	GREEN BIAS	35	PRESS MENU BUTTON FOR SETUP LINE
09	BLUE BIAS	45	PRESS MENU BUTTON FOR SETUP LINE
10	RED DRIVE	32	PRESS MENU BUTTON FOR SETUP LINE
11	GREEN DRIVE	28	PRESS MENU BUTTON FOR SETUP LINE
12	BLUE DRIVE	25	PRESS MENU BUTTON FOR SETUP LINE
13	SECURITY PASS NO. FOR CHASSIS ALIGN PARAMETERS	MUST SET TO 77	MAY NOT ADVANCE TO HIGHER PARAM. UNTIL VALUE SET.
14	PLL TUNING	41
15	4.5 MHZ TRAP	03
16	VIDEO LEVEL	04
17	FM LEVEL	07
18	B+ TRIM	07
19	RF AGC CHAN 6	27	MAN. TUNE CHAN 6
20	D-PIP CHROMA	60
21	D-PIP TINT	25
22	D-PIP CONTRAST	16
23	D-PIP BRIGHT	18
24		30
25	SECURITY PASS NO. FOR TUN. ALIGN.	78	MAY NOT ADVANCE TO HIGHER PARAM UNTIL VALUE IS SET.

IN ORDER TO EXPEDIATE IN HOME REPAIRS ON THE CTC 177 CHASSIS EVERY OUTSIDE TECHNICIAN SHOULD HAVE THE FOLLOWING PARTS ON THEIR TRUCKS.

FOLLOWING THE CTC 177 “CHEAT SHEET” WILL DEFINITELY CUT DOWN ON THE OUTSIDE SERVICE TECHNICIANS TIME SPENT IN THE HOME. IF THE PROBLEM WAS NOT LISTED IN THIS GUIDE IT MAY BE NECESSARY TO OBTAIN THE ACTUAL SERVICE LITERATURE PERTAINING TO THE CHASSIS IN QUESTION AND GO THROUGH A FULL TROUBLESHOOTING DIAGNOSTIC OF THE UNIT.

IF YOU COME ACROSS ANY NEW INFORMATION REGARDING THIS CHASSIS PLEASE LET ME KNOW SO I CAN UPDATE THIS GUIDE FROM TIME TO TIME. GOOD LUCK AND HAPPY TROUBLESHOOTING!