Canon ZR60 A, Service Manual

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ZR70 MC A, ZR65 MC A, ZR60 A
CHAPTER 3. INFORMATION FOR REPAIR · SERVICE HINTS
3-7
4. Description of Service Modes
4-1 Error Rate
<Generals>
(1) A VIDEO error rate (VIDEO + AUDIO) and an AUDIO error rate can be checked.
(2) Note that the error rate is worsened on occurrence of failure in tape running, deterioration of tape, decreased in head output, failure
in head amplifier, improper drum shield, etc.
<How to read a VIDEO error rate>
An average error rate on 64-track AUDIO+VIDEO sector is indi-
cated in exponential representation.
Example) ‘25’ is indicated:
Error rate = 2
×
10 -5
<How to read an AUDIO error rate>
To read error rate of AUDIO track, follow the procedures in the
table below.
The number of erroneous sync block of 64-track AUDIO sync
blocks is indicated in two hexadecimal digits.
(FF limitation is imposed on a value exceeding 255.)
Example) ‘23’is indicated:
Number of erroneous sync blocks = 35
Important
After the adjustment, set the DT to the product setting . (press STORE key at 1 of STEP 1 state.)
<Change to an AUDIO error rate>
In the product specifications, the error rate on both chan-
nels in self -recording LP playback is as follows :
Error rate =28H or less
(Number of erroneous sync blocks = 40 or less)
Fig. 3-8
Low ch. High ch.
E O 2 5 E 1
2
×
1 0
- 5
Fig. 3-9
Low ch. High ch.
(hexadecimal)
(decimal)
A O 2 3 A 1
2
( 2
×
1 6 ) + 3 = 3 5
3
ST EP PROCEDURE Microcomputer operation
CS Function ADDR MODE DT
1 1) Make setting shown at right. 0 10 001D ST 00 → 03 Product setting
2) Execute ST ORE. (Press PAUSE.) ↑ ↑ ↑ RD 03 Audio error rate indication
Remarks) Selecting DT back to "0"makes a return to Audio + Video error rate.
MONIT OR