Troubleshooting - Sharp MS722 - MiniDisc Recorder - Metallic Service Manual

It is advisable to use the TEST mode (refer to Error Data Display Mode, P13) indicating the causes of troubles before
starting repair. Causes of operation errors (up to 10 errors) are recorded as error codes. This information is useful
for repair.
When does not function
When the CD section does not operate When the objective lens of the optical pickup is dirty,this section may not operate.Clean
the objective lens,and check the playback operation.When this section does not operate even after the above step is taken,check
the following items.
Remove the cabinet and follow the troubleshooting instructions.
"Track skipping and/or no TOC(Table Of Contents) may be caused by build up of dust other foreign matter on the laser pickup lens.
Before attempting any adjustment make certain that the lens is clean. If not, clean it as mentioned below."
Turn the power off.
Gently clean the lens with a lens cleaning tissue and a small amount of isopropyl alcohol.
Do not touch the lens with the bare hand.
Is the power supply turned on when the remote control
button or main unit button is pressed?
Does the display operate normally?
Is playback state set?
Is audio output normal?
Is recording/playback operation normal?
• Power is not turned on when the
is pressed.
Is power turned on when the remote control
pressed?
Is operation normal when the main body button is pressed?
Is the pin 55 of IC401 in H state?
Are IC401 pin 3 set to "L"?
Does the pin 66 of IC401 oscillate?

TROUBLESHOOTING

Yes
Yes
Yes
Yes
/ button
button is
No
No
Yes
Yes
Perform the check stated in item "Power is not turned on
No
when the PLAY button is pressed".
Perform the check stated in item "Abnormal display".
No
Perform the check stated in item "Playback state connot be
No
set".
Perform the check stated in item "Audio playback circuit".
No
Perform the check stated in item "Recording/playback
No
operation".
Check the periphery of remote controller and main unit
Yes
headphone terminal (J703) and IC401.
Check the position of Hold switch.
No
Check the DISC IN (SW901) switch of mechanism PWB.
No
Replace XL401.
No
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MD-MS722/C/W/MS721W