REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Monday, 1 April 2019

INFINITY IL120S SUB WOOFER - BIAS ADJUSTMENT - DISASSEMBLE

INFINITY IL120s SUB WOOFER - BIAS ADJUSTMENT - DISASSEMBLE

IL120s ADJUST BIAS PROCEDURE [Mandatory when any output MOSFET transistors Q3,4,7,8 are replaced]
SPECIFICATIONS
Frequency Response:  28Hz - 150Hz (±3dB)
Maximum Amplifier Output: 500 watts (20Hz - 150Hz with no more than 0.1% THD)
Crossover Frequencies: 50Hz - 150Hz, 24dB/octave, continuously variable
Driver: 12" C.M.M.D.
Dimensions (H x W x D): 17-1/2" x 17-1/4" x 19-3/4"
Weight: 45 lb (20.5kg)
Optional Accessory: Bass Optimization
Test & Measurement Kit: Part Number: 335852-002
BIAS ADJUSTMENT
  • Amplifier should be unplugged and OFF.
  • Remove Amp assembly from cabinet; remove rear plastic cover if present. All wires exiting the cover can remain connected unless they will prevent you from removing the amplifier or accessing potentiometers on the Linear board PCB in the following steps.
  • Locate the Linear board assembly (PCB with the output transistors)
  • Adjust R11 and R27 fully Counter Clockwise. See diagram below.
  • Apply 120 VAC power to unit, Turn power switch ON.
  • Verify LED illuminates on the front gain control dial unless you have disconnected the plug.
  • Connect voltmeter set to DC mill volt range to twin pins on terminal J7, on Linear board
  • Verify initial voltage is less than 0.1 mV.
  • Adjust R11 Clockwise until voltmeter reads 0.3 mV+ the initial current from step #8.
  • Adjust R27 Clockwise until voltmeter now reads 0.6 mV + the initial current from step #8.
  • Turn amplifier OFF. Disconnect AC power to unit.
  • Remove voltmeter from terminal J7.
  • Replace cover (if present), wires if disconnected, and replace amplifier back into cabinet.

EXPLODED VIEW