Shopping cart is empty
English Polski Spanish 
Search For a Manual

(e.g. AA-V20EG JVC, ZX-7 Sony )
PayPal 1000+ rating Secure, Encrypted Checkout.
Who's Online
There currently are 411 guests and 
2 members online.
Featured Product
Home >> JVC >> GRAX770U Service Manual
 0 item(s) in your cart 

Service Manual

Tweet about this product and get $1.00 of store credit for instant use!
  • Contains Circuit Diagrams
  • Download
  • PDF Format
  • Complete manual
  • Language: English
Price: $4.99

Description of JVC GRAX770U Service Manual

Complete service manual in digital format (PDF File). Service manuals usually contains circuit diagrams, printed circuit boards, repair tips, wiring diagrams, block diagrams and parts list. Service Manual ( sometimes called Repair Manual ) is used mainly by technicians.

If You just want to know how to use Your tv, video, mp3 player etc. You should look for Owner's Manual. After placing order we'll send You download instructions on Your email address.

The manual is available in languages:

Not yet ready
You must purchase it first

Customer Reviews
There are currently no product reviews.
Other Reviews
 TXDS575 ONKYO Service Manual by Vito Platessa;
Simple and fast... The diagrams are clear and legible; i have been a great help. The site is very reliable and precise thanks.
 SX-PX103M TECHNICS Service Manual by Joop van de Kaa;
Very easy site. Great service and quick release for download. Manuals are of good quality. Joop - The Netherlands
 KM-D600 JVC Service Manual by Ryan Wells;
Very good manual, in depth and complete. Only criticism is that some of the circuit diagrams are slightly blurry and hard to follow for long periods of time, but this is to be expected. Perfect for any maintenance required. Also contains the wiring diagrams of the control cable for constructing extensions.
 MD9DL1 TOSHIBA Service Manual by mark joachimiak;
Received a quick response, material was exactly what it was supposed to be. The service did everything I expected it to do. would use service again.
 CFD980 SONY Service Manual by Todd Danielson;
Detailed SONY CFD980 Service Manual at an easy to find one stop shopping. Make my radio hobby technically interesting. Thanks.

Text excerpt from page 25 (click to view)
2.4 TAPE TRANSPORT ADJUSTMENT In most cases the deck section is in need electrical adjustment, it results from replacement of worm mechanical parts or video heads. In the event of malfunction with electrical circuits, troubleshouting with the aid of proper test instruments most be done first, and then commence necessary repair, replacement and adjustment, etc. 2.4.1 Back tension 1. Set a cassette torque meter onto the deck and measure the back tension in standard REC mode to confirm that the back tension is 0.7x10-3 – 1.37x10-3 N•m. 2. If not, replace the tension band. When the value widely fluctuates in the measurement, replace the supply reel disk. 3. With the cassette torque meter, confirm that the play torque is 1.47x10-3 – 2.45x10-3 N•m. If necessary, replace the center pulley unit.

8. When the FM waveform breaks in the level varying process, subtly adjust the height of guide rollers at every breaking point so that the waveform varies as flat as possible. Repeat the above steps 6. and 7. several times to confirm that the waveform is flat as a whole. 9. Playback the SP stairstep signal of alighment tape and adjust the tracking control to maximize the FM waveform, confirm that FM waveform variation is always flat. 10. Record the signal and play it back in both of the SP and EP modes, and confirm that the FM waveform is flat in both modes. Note: Among the above-mentioned adjustment steps, the items of No.9 and No.10 are needed for the EP model only.

CH-2 1 field

Back tension 0.7x10-3 - 1.37x10-3 N•m (7-14gf·cm)

Play torque 1.47x10-3 - 2.45x10-3 N·m (15-25gf·cm)
Causer by wrong height of supply guide roller

Flatten waveform.

Caused by wrong height of take-up guide roller

Fig. 2-4-2 FM waveform-1

Fig. 2-4-1 Cassette torque meter 2.4.2 Tape pattern 1. Remove the Cover (JIG) shwon on Fig. 2-6-1 (Page 210). 2. Connect the jig connector cable to CN25 on the MAIN board as shwon on Fig. 2-6-1 (Page 2-10). 3. Observe signal at V. TP FM with external trigger from V. FF on the jig connector cable. 4. Playback the SP stairstep signal of the alignment tape and maximize the FM waveform by the tracking button. 5. Set the tracking control to the center position by simultaneously pressing the tracking (-) and (+) buttons and maximize the FM waveform by the tracking button. 6. If the observed FM waveform is not flat, adjust the height of the supply of take-up guide roller with the roller driver. Note: To prevent the tape from damage, turn the guide rollers slowly. 7. By operating the tracking button (both in + and – directions) in the manual tracking mode, vary the output level of the FM waveform from maximum to minimum and vice versa to confirm that the waveform varies nearly in a flat shape.

Correct variation of waveform

Bad variation of waveform

Fig. 2-4-3 FM waveform-2 (U)


You might also want to buy


Owner's Manual

Complete owner's manual in digital format. The manual will be available for download as PDF file aft…
Parse Time: 0.188 - Number of Queries: 112 - Query Time: 0.034