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!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday, 11 December 2019

JBL SUB350 DOLBY PRO-LOGIC SURROUND AMPLIFIER/SUBWOOFER STK4151 – HOW TO DISASSEMBLE THE SUB-WOOFER, SCHEMATIC DIAGRAM, GENERAL TROUBLESHOOTING


Please do not try to attempt any repair work; if you’re not well experienced in service field.
The troubleshooting described here is the only thing you can do as a user.
Total System Output - 200 watts
Front channels – 35 watts x 3 @ .1% THD
Surround channels – 15 watts x 2 @.1% THD
Subwoofer – 65 watts @ .1% THD
Frequency response - 35Hz – 20kHz
Dimensions - 15 1/8 x 13 x 14 ½” (384 x 330 x 368mm)
Input Impedance - 20k Ohms
Audios output IC – STK4151
Weight - 34.5 lbs. (15.7 kg)
Troubleshooting
If there is no sound from any of the speakers, check the following:
• Make sure the subwoofer is plugged into an active AC wall outlet.
• Make sure the Master Power Switch, located on the rear of the subwoofer, is in the “On/Standby” position.
• Make sure there is a source – for example, a VCR or television – hooked up to the TV or tape/aux input jacks on The Source.
• Make sure that the program material is playing.
• Re-check the hookup connections.  
If most of the sound comes from the center-channel speaker, with little or no information from the surround channels, note the following:
Although most of today’s televisions are equipped with stereo audio output jacks, some stereo televisions have poor audio sections and are unable to provide a Dolby Pro Logic encoded signal. In the unlikely event that you experience this problem, connecting the audio outputs from your Hi-fi VCR, laser disc player, DVD player, or Satellite receiver directly to one of the inputs on The Source will provide a proper audio signal and allow you to enjoy true Dolby Pro Logic surround sound.
If there is no sound from the surround speakers or sound is very low, check the following:
• Check all connections between the amplifier and each of the speakers.
• Raise the surround volume  with the remote control.
• Make sure the TV show or movie you are watching is recorded in Dolby Surround.
If there is no sound from the center speaker, check the following:
• Make sure that the processor is in the Pro Logic mode. If it is in Phantom or Stereo mode, the center speaker will not play.
• Check the connections between the subwoofer and the center speaker.
If you have low bass output, check the following:
• Experiment with placement of the subwoofer. Remember, place the subwoofer in a corner to get maximum bass output from the system.
• Increase the level of bass, using the remote control.
• Adjust the level control on the rear of the subwoofer.
If you are having trouble picking up radio stations, check the following:
• Make sure the antenna is hooked up properly.
• Depending on your distance from the station’s transmitter, you may need to install an FM antenna on the roof or in the attic.
Sub exploded view
                              Exploded view
                             Schematic