REPAIRING AND NOT THROWING AWAY

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, 13 March 2019

JBL PSW-D112 - DPS-12 POWERED SUB WOOFER SCHEMATIC

JBL PSW-D112 - DPS-12 POWERED SUB WOOFER SCHEMATIC

A. Power Amp Section
1. Resistance Check Resistance from O/P of the module to GND should be >1M (NO LOAD)
Resistance from V+ of the module to V- of the module should read >5k
Resistance from V+ of the module to O/P of the module should read >1M
Resistance from V- of the module to O/P of the module should read >1M
2. Power Up LED RED
- With a 35mV signal to Low level input, LED should change to GREEN
3. D.C. Operation
-Voltage measurements (DVM).

Between
And
Should be Reading
+6V
V-
+6.2V
V+
GND
+90.1V
O/P
GND
0V
 V-
GND
-90.1V
+15V
GND
 +15.5V
S/D
V-
 +5.75V
 FR
GND
0V
I/P
GND
0V
GND
GND
0V
 -15V
GND
-15.5V

4. Check Switching Frequency
-Use scope (EITHER USES AN ISOLATION TRANSFORMER OR ATTACHES THE PROBE TIP TO SPK- and REFERENCE LEAD TO SPK+)
-Reading 100kHz +/-10%,500mVpp.
B. Pre Amp Section
1. Low Level Input Sensitivity -Set up Turn level and Low-Pass Pot Fully CW Generator set at 100mV@39Hz Signal to Low level input
-Voltage measurements.
OPAMP
U1(14)
271mV
U1(7)
409mV
U1(1)
486mV
U2(8)
471mV
U2(14)
456mV
U2(1)
460mV
U4(1)
2.94V
U4(7)
2.67V
SPEAKER
OUTPUT
17.4V


2. High Level Input Sensitivity
-Set up Turn level and Lo Pass Pot Fully CW Set Generatorat 3.6v@39Hz Signal to High level input
-Voltage measurements 17.4V at speaker out
3. Low-Pass
-Set up Set Generator at 100mV@100Hz Signal to Low level input Measure voltage at speaker output
-Voltage measurement
Low-Pass Pot Setting
Output
CW
12.2V
CCW
1.2V
4. High-Pass
-Set up Set Generator at 100mV@100Hz Signal to Low level input Measure voltage at high-pass output
-Voltage measurement
High-Pass Pot Setting
Output
CW
24mV
CCW
55mV
5. Direct out
-Set up Set Generator at 100mV@100Hz Signal to Low level input
-Voltage measurement 100mV at direct out.
SCHEMATIC DIAGRAM 
CLICK ON THE IMAGES TO ZOOM IN
Posted By: FRANK at 03:12
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