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 !

Thursday, 7 February 2019

YAMAHA YST SW320 – SUBWOOFER - CIRCUIT DIAGRAM - ADJUSTMENTS

Yamaha YST SW320 – Subwoofer - Circuit diagram - adjustments

Amplifier Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250W/5
Frequency Response . . . . . . . 20 Hz to 160 Hz (-24 dB/oct.)
Power Supply
U, C models . . . . . . . . . . . . . . . . . . . . . . . . . AC120V, 60 Hz
A model . . . . . . . . . . . . . . . . . . . . . . . . . . . . AC240V, 50 Hz
B, G models . . . . . . . . . . . . . . . . . . . . . . . . . AC230V, 50 Hz
R, T models . . . . . . . . . . . . AC110/120/220/240V, 50/60 Hz
Power Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60W
Dimensions (W x H x D) - 340 x 432 x 370 mm (13-3/8" x 17" x 14-9/16")
Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 kg (37 lbs. 7 oz)

Disassembly
Removal of Front Panel Ass'y
Remove 4 screws (1) and then remove the Front Panel Ass'y in Fig. 1.
Use an Allen wrench (3mm) to unscrew the Front Panel Ass'y
Remove 8 screws (2) and then remove the Base Ass'y in Fig. 2.
Remove 4 screws (3) and then remove the Loud Speaker in Fig. 2.
Remove 12 screws (4) in Fig. 3.
Arrow marks (<=) are printed to identify the screws to be removed.
When assembling the Rear Panel, check to ensure that the gasket is not damaged so as to prevent air leakage from occurring.
Installation of emblem
1. Put the emblem into the cabinet at the specified position.
2. Place a piece of cloth/wood on top of the emblem.
3. Using a mallet, hammer the emblem in place through the cloth/wood.
Use special care not to cause damage to the emblem or cabinet while hammering the emblem.
Installation of power switch
Rapid cures bond (such as 5 minute epoxy) is required to fix the power switch.
Apply rapid cures bond (such as 5 minute epoxy) to the power switch (the area which contacts the rear panel), insert it in the rear panel and make sure it is fixed.
(Inserting the power switch in the rear panel only would not be sufficient for its secure installation.)
Circuit diagram
PWB - Foil side
For the power amplifier which has been repaired, it is absolutely necessary to confirm that a correct waveform is obtained at points indicated by A and B in the schematic diagram according to the following procedure.
Idling Adjustment
To stabilize operation of the amplifier, turn ON the power with no input signal and wait for 1 or 2 minutes in non loaded condition before the adjustment.  Adjust VR1 so that the voltage between terminals TP11 and TP12 is DC 50mV to 250mV.