DECK MECHANISM ADJUSTMENT
7. Adjustment after Replacing Drum Assembly (Video Heads)
Purpose: To correct for shift in the Roller Guide and X value after replacing the Drum.
Test Conditions
Test Equipment/ FixtureConnection Point(Mechanism Condition)Adjustment Points
Y OscilloscopeY CH-1: PB RF EnvelopeY Play the blank tapeY Guide Roller Precise
Y Alignment tapesY CH-2: NTSC: SW 30HzY Play an alignment tapeAdjustment
Y Blank TapePAL: SW 25HzY Switching Point
Y Post Height Adjusting DriverY Head Switching OutputY Tracking Preset
Y Screw Driver(+) Type 5mmTest PointY X-Value
Y RF Envelope Output Test Point
Checking/Adjustment ProcedureConnection DiagramOSCILLOSCOPE
Play a blank tape and check for tape curling or creasing around
the roller guide. If there is a problem then follow the procedure
RF ENVELOPE OUTPUT TEST POINT
4. "Guide Roller Height" and 5. "Audio Control(A/C) HeadCH1 CH2
Adjustment".HEAD SWITCHING OUTPUT TEST
POINT
Waveform
V1/V MAX EE 0.7V1VV2
V2/V MAX EE 0.8
RF ENVELOPE OUTPUT
Fig. C-7
8. Check the Tape Travel after Reassembling Deck Assembly.
8-1.Checking Audio and RF Locking Time during playback and after CUE or REV (FF/REW)
Test EquipmentTest Conditions
Test Equipment/ FixtureSpecificationConnection Points(Mechanism Condition)Connection Points
Y OscilloscopeY RF Locking Time: Less than 5Y CH-1: PB RF EnvelopeY Play an alignment tape
Y Alignment tapes(with 6Hsec.Y CH-2: Audio Output(with 6H 3kHz Color Bar
3kHz Color Bar Signal)Y Audio Locking Time:Less than Y RF Envelope Output PointSignal)
Y Stop Watch10secY Audio Output Jack
Checking ProcedureNOTES:
Play an alignment tape then change the operating mode to1) CUE is fast forward mode (FF)
CUE or REV and confirm if the unit meets the above listed
specifications.2) REV is the rewind mode (REW)
3) Referenced to the Play mode
8-2. Checking for tape curling or jamming
Test Equipment/ FixtureSpecificationTest Conditions (Mechanism Condition)VCR(VCP) State
Y T-160 TapeY Be sure there is no tape jamming or curling atY Run the CUE, REV play mode at the
Y T-120 Tapethe begining, middle or end of the tape.beginning and the end of the tape.
Checking Procedure
1) Confirm that the tape runs smoothly around the roller2) Confirm that the tape passes over the A/C head assem-
guides, drum and A/C head assemblies while abruptlybly as indicated by proper audio reproduction and prop-
changing operating modes from Play to CUE or REV.er tape counter performance.
This is to be checked at the begining, middle and end
sections of the cassette.
4-18 |
ACEC
