Star Tech Journal

Issue: 1983-November - Vol 5 Issue 9

STAR*TECH JOURNAL/NOVEMBER 1983
24
Pioneer PR-7820 continued.
Please take note . .. If your unit is under warranty, I would advise that you
attempt NO disc player repairs yourself as this will void your warranty on
the entire player.
If your distributor cannot ( due to distance or whatever) repair your unit
and you're 300 miles from the nearest Pioneer service center and the player
is out of wa"anty and you &re not familiar with CMOS handling
procedures, mail the unit to the service center, Cinematronics, or your
distributor!
Only highly qualified technicians should attempt to do any repair work
whatsoever to a disc player unit.
Now, I'm not trying to sound negative or anything, but this is a very
sensitive unit and should be treated as such!
An old tech once told me that the sign of a good tech was that a good tech
could go into a unit and repair it, close the unit up, and if the work was
inspected, no one could tell what work was done! If you don't feel
comfortable with that standard, please don't attempt any repair on a laser
disc player.
Next month I will give you information on cleaning the optic system, but
I want to give you an update on cleaning the disc.
Video discs are made of a very soft plastic which cannot be cleaned with
"safe for plastic" cleaners unless they are totally free of all abrasives,
alcohol, or are aerosol-driven cleaners. The best cleaners ( and the only
recommended cleaners) are pump bottle window cleaners (alcohol-free) or
an ammonia/water mixture. For cloth, please use lint-free, 100% cotton
(baby diapers work great!).
Until next month, take care! ... "Bear"
FIGURE 5
PR-7820 DISC PLAYER
PC BOARD LOCATION
(SYPS)
ND
~
VR2
fr
VR1
TP1
r----- ------------- -------------,
I
(VDEM)
I
I
1 TOP/BOTTOM
al
0
::::,
(§)(§) :
VR1 . VR2
~
(DSPL)
i SIDE BY SIDE
(MCPR)
1
I
1... ___ - ---- - - - - ---------------- _,
~g,~ooo
~,
I
(D&CR).
0
(CARG)
(STPM)
~
A LIMITED OFFER FOR [~)
~ UNLIMITED USE...
J,t
Now, get twice the technical information you need to run your operation.
S*T J'S 2 FOR 1 BACK VOLUME OFFER
For a limited time, when you order one of our back
volumes, you can choose another back volume absolutely
free when you send payment ($42.00). Two for the price of
one.
Now's your chance to build your complete library of
Star•Tech Journals if you haven't already.
If you've hesitated in the past, now's the time to act.
With technical information in such high demand, you can
catch up and have the most complete stock of technical
material right at your disposal. Star•Tech Journal's long
shelf life for reference again and again is what makes it
valuable for successful operation and maintenance of the
I
I
I
I
I
I
I
---
-
-
□ Volume
□ Volume
□ Volume
□ Volume
-
----
-
-
------
games you service. That's how the Journal provides you
with unlimited use.
So act now. Fill out the coupon below. Tell us which 2
volumes you'd like to receive for the price of one. Each
volume has 12 issues and is self-contained in one neat,
bound book - no single issues - and has its own index to
track the articles you need.
Make your check or money order payable to Star* Tech
Journal, PO Box 1065, Merchantville, NJ 08109. Canadian
and Foreign rates differ. See page 26 for your cost and
select two for one. (US funds please.)
This offer available only to Star• Tech Journal subscribers.
Fill out and mail -
-
-
-
-
---
-
-
-
-
-
-
-
-
-
I'm taking you up on your 2 for 1 offer. Payment is enclosed. Send me the volumes I've checked.
1 (March '79-Feb. '80)
RUSH MY VOLUMES TO:
2 (March '80-Feb. '81)
Your name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
3 (March '81-Feb. '82)
Company _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
4 (Ma~ch '82-Feb. '83)
Address _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Mail to:
Star•Tech Journal
PO Box 1065, Merchantville, NJ 08109
City/ State/Zip _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
S•T J Accoun t # (i f known - mail label/top right)
-
-.
I
I
I
I
I
I
I
-----------------------------------------J
STAR*TECH JOURNAL/NOVEMBER 1983
heJ;
rus
The names of various Laser Disc Optics
comprise this issue's word puzzle. Find and
encircle these words as they appear below.
They run vertically, horizontally, diagonally
and sometimes backwards.
25
66. The distinguishing feature and principal advantage of thyristors is that
a. they are the only high-power semiconductor switching devices available.
b. their switching speed is faster than that of most transistors.
c. they are typically less expensive than transistors.
d they are easy to tum off by means of control current at the gate.
e. only a quick, momentary pulse of gate current is required to tum them on all
the way ( so that less power is wasted in the control circuit than with a
transistor).
67. Which of the schematic symbols shown is that of the SCR ( silicon controlled
rectifier, also called "reverse-blocking triode thyristor")?
MT 2
a.
LASER DISC OPTICS
GATE
M E Q B O N C D Q R
I Q O N W I V O U U
RXPSDFZIWT
R N V E A P Z
Q
E Z
0 B Y H B F M U V G
R S X V E A N R A C
G I N X F P R I W F
T R I E A S W I R U
0 R A J L X F Z E E
N B A T C C K L T 0
B Y J N I X Q I R D
Q G A E S N Y V A V
T T N H C D G J U F
K R J I O T U A Q C
R
X
F
P
U
P
N
D
A
F
R
T
Y
C
Y
I
G
N
K
U
O
R
Z
I
I C L D
V V E G
E R E R
J V E T
0 Q J P S M N A I S
Z J C W A M H G N D
LENS
GRATING
TRANSDUCER
PRISM
TRACKING
QUARTERWAVE
SERVO
DIVERGING
MIRROR
OBJECTIVE
Here is the answer key
to October's puzzle:
S•TJ ADVERTISERS
s
R
H
0
C
I B
R I
F O P
s
B F Y P 0
L
L M W Y
N A
N
A
R N
B
O C
T
S R
R O
C
E
N I N
P
E A N
S
WP 0
T E C
A
O R 0
C
N
E
R
A M A Z
N
u
M
F
s
.1-
_rr-
MT 1
*
ANODE
b. ::::
c. :::::
(Q
CATHODE
*
ANODE
d.
*~
ANODE
e.
GATEfi
CATHODE
CATHODE
68. What is the main difference between the function of the SCR and that of the
triac?
a. The SCR performs better than the triac.
b. The SCR is a switching device, while the triac is an amplifying device.
c. The SCR can be triggered into conduction in only one direction, while the
triac can be switched on for current in either direction.
d The SCR is made of silicon but the triac is not.
e. Inside every triac package are two little SCR packages.
69. Photodiodes and phototransistors are used:
a. to sense light by permitting current from some power source to pass in rough
proportion to the intensity of light falling on the device.
b. to generate light for transmitting information or providing useful illumination.
c. to block current when light strikes them, and pass current when dark.
d in the "act" section of systems.
e. for the same purposes as standard diodes and transistors.
lnQuizitive Answers (October)
61) b
62) c
63) d
64) e
65) e /
Star*Tech Journal Technical Seminars
-----------------------------
The most recent Star*Tech Journal Seminar & Workshop was held at
Betson Enterprises, Moonachie, NJ on September 12-16.
The students each received a certificate of completion having
successfully finished the 5-day course.
Betson Enterprises sponsored the seminar which covered Basic
Electronics (Electron theory & semiconductors), Video Game
Systems (Power supplies, control panel interfaces, rasterscan and
X-Y monitors), Electronic Pinball Systems (Electronic digital
systems), Troubleshooting Techniques, Test Equipment (Digital
multimeters and logic probes), Proper Soldering Techniques, How to
Read Electronic Schematics and other essential skills.
Future Star*Tech Journal Seminars will include Laser Disc
Operation and Maintenance.
Distributor-sponsored S*TJ Technical Seminars are available to
any distributor interested in assisting their clients to understand
operation and maintenance of videos, pins and lasers.
Star* Tech Journal hosts these seminars at no cost to the
distributor.
If you'd like to sponsor this 5-day course, contact Star* Tech
Journal at 609/662-3432 and ask for our information package. This
package helps you plan your promotion for a successful seminar.
MURPHY'S LAW #509
The most vital dimension on any plan or drawing
stands the greatest chance of being omitted.

Download Page 24: PDF File | Image

Download Page 25 PDF File | Image

Future scanning projects are planned by the International Arcade Museum Library (IAML).

Pro Tip: You can flip pages on the issue easily by using the left and right arrow keys on your keyboard.