Description Of Service Modes; Error Rate - Canon ZR70 MC A Service Manual

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
<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
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)
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>
ST EP PROCEDURE
1 1) Make setting shown at right.
2) Execute ST ORE. (Press PAUSE.)
Remarks) Selecting DT back to "0"makes a return to Audio + Video error rate.
-5
CS Function ADDR MODE
0 10
↑ ↑
3-7
CHAPTER 3. INFORMATION FOR REPAIR · SERVICE HINTS
Low ch.
E O 2 5
2 × 1 0
Fig. 3-8
Low ch. High ch.
AO 2 3 A1
2 3
(hexadecimal)
(2 ×16)+ 3 = 35
Fig. 3-9
MONIT OR
Microcomputer operation
DT
001D ST 00 → 03 Product setting
↑
RD 03 Audio error rate indication
ZR70 MC A, ZR65 MC A, ZR60 A
High ch.
E 1
- 5
(decimal)