Inferno #06 03 декабря 2004

Железо

Iron - Video GoldStar RN800AW Art vision. The history of repair.

   VCR: Home

   Repairing old Vidic, in fact,
GoldStar RN800AW Art vision. Features: RECORDING FUNCTION, HIGH 
SPEED REWIND, AUTO HEAD CLEANER, AUTO VOLTAGE, Multi System / 
Digital Auto Tracking / VHSpal, PAL-B / G, D / K, SECAM-B / G, 
D / K, NTSC PLAYBACK. Of course, a two-times Image (PLAY x2), 
fast, forward and back (to rewind when viewing), are united on 
the button STOP / EJECT, is STILL, food OPERATE (Auto power 
when inserting a cassette). C console can A. REPEAT, otherwise 
at the end of the film itself rewind and throw kassetu.Kasseta 
perfectly loaded and well-thrown (only slightly inserted to 
start up the mechanism, and further automation like clockwork 
...). Rewind very fast Gentle, soft at the beginning and end,

acceleration occurs in a few seconds after the start of 
winding, the mechanism switches to fast mode, and before the 
end of the film slows down and the wind off as must ...



   Mechanism is very reliable, gear,
transferring two friction clutches (for axes)
More central clutch friction (mobile)
two engines (not counting heads: software,
Managing with a reducer, and drive for
the tape and load the cassette), one
Passic (thick, from the driving engine), two
konechnika (to protect the records and load tapes), two 
optocouplers to determine the actual speed of rotation axes, 
two optodatchika (central LED source through lateral optic 
mechanism lift their lights). Pulse pumped power supply to any 
network (to generate the voltage - 14 V - and control - 6 - by 
Krenek, allows operation without a load (typically)), 6 through 
the key, and a diode switched to 5 V, and served, including

to drive the engine (the key is activated when
loading cassettes). Under the board soldered CPU and (probably) 
diode technology. Not All parts are (not all possible functions

implemented, other than those listed, or not
all television system ...). The board painted fragments of the 
mechanism and many of technical acronyms that facilitate 
learning. 

   Fault originally was to
button STOP (it was impossible to throw the tape had to look 
through) and then system does not become a work tape

upload, I thought that even food is not served. Required to 
make at least PLAY, t.k.knopka records (he arm) was broken

(If the lever was Wiedicke, I would have stuck together),
Hope for repair do not eat, and the repair time was not limited.

   It turned out that the food is, the indicators
shine, but loading the cassette does not occur, although the 
mechanism of spinning and jerking (Trying to function 
normally). We had things apart, although some of the screws are 
already otkruchena (even a cap is not screwed) to remove the 
mechanism, a fee - and all to examine. 

   Trouble was in the control circuit
drive motor. Among other things, was once a system is exposed 
to water, and the system was under the current (being wet) and 
electrolytic processes have done Delov ... Engine not normally 
controlled and does not load tape. Also, someone unsuccessfully 
climb (tried to repair and once repaired), something broke 
(probably the last times). In general, we had pretty tricky,

change and fix the little things as well
All clean of salt and rust. Although the
zasrat mind was not strong, "but the label" for
of breakdowns. Replaced, and two buttons (STOP and STILL). 
Mechanism of almost all been defective, something straightened, 
cleaned and oiled. Check all the mechanics of hand (oh, and 
long as it is ...), almost perfectly valid. Plug-and-tested "on 
weight" - works. We can say - ispravil.Pravda, the REC button

(Record) did not do (no levers, and invent
it once - if the itch to write, you can remove the panel and 
click directly ...). Yes and some other buttons sticky (not 
waste) due to deformation of their instruments in the panel, 
perhaps because once carelessly shot / put the panel, and 
leverage excessively deformed. I had to fix it. Makes an 
incision at the site of bending / mounting arm, he walked with 
the softer (due to the subtleties in the cut), then recorded 
the anything in right position and embedded cuts superglue. 
Fixation is needed, t.k.kley (albeit super) to complete 
solidification of a long dry (Though maybe not the cheapest 
superglue), and new provision should not stand, otherwise the 
lever will return to its former state. After 15 minutes flooded 
again, and left as much as several hours (preferably at noon). 
With a strong deformation on the cuts imposed pieces of plastic 
to fix the new position and hardening, and fill it all 
together. In eventually all worked out, the buttons worked well

clear, but much tougher. Needless to say, because
place gluing stiffer than a plastic,
but stronger ... The mistake was trying to glue on his hands, 
at once (hold in the new position, the Gulf of superglue for a 
few seconds, minutes), although this super (super!)

glue it may get ...

   All anything, but I was waiting for a big bummer ...



   Informed about the possibility to take Vidic in the evening, 
I at noon the same day had it on his old three-hour tape, and

Half an hour later, he broke ... And quite
differently, not like before!


   Plays accelerated sharply (judging
the sound of the engine), and the image disappeared from the
screen. Since I have long ceased to be looked
cassette, but it is already very old, I assumed that was erased 
sync, even though the film speed, seizing her spikes (in my 
assumption), it was not quite right logically ... 

   I stopped the cassette (STOP) and again clicked PLAY, but it 
quickly accelerated, although in one of several attempts on the 
screen glimpse of something similar, it is confirmed

serviceability zapisi.Uskorenie was not always instantaneous, 
and when the rate coincided with normal, sometimes appears a 
picture ... After trying to fast forward, I realized (at

engine noise) that it almost does not differ in
speed of play. Further more interesting ... Domotavshis (3 
minutes hours of video!) until the end, the film with a bump 
stop (yes, it was not the super orderly completion of winding 
in the test of gentleness and caution which I was blown away) 
and then began to rewind ago, is just as crazy and quickly 
ended. Vidic then tried to throw cassette (and it is thrown, 
but not fluently, softly, as usual, opened the lid and put 
forward, and emissions, not just outside, of course, but

sharply), and this was preceded by a loud and shrill screams 
gear that I almost managed to pull the plug when he

ended ...

   This is me zaputalo.Ya thought that broken
mechanic, opened Vidic, took the elevator and looked
- Works, the mechanism and hand spinning. But
when I tried to load the tape, heard the same scream, and the 
cassette is not loaded. I turned off the network, took the 
elevator, but he not jammed, even with the cassette, although 
the effort increased ... I have included no elevator and 
pressed the load sensor, the system has shifted the mechanism

in IP [Original position], and the engine
furiously unwound, and the gear, the transmission
rotation of the elevator, pre-scream,
but untwisted tozhe.Dalee system has entered
to check the availability of tape, turning the nodes
and testing their speed, but a few
futile cycles, cut off the power ... I
perevklyuchil her and repeated the test (by pressing the
sensor), the same thing happened ... In the future I
found that if you re at the right time
click on the sensor, the system will settle down and
understand that the tape was removed, and it can again
"Embed."

   Carefully analyzing the behavior of I
understood that the system is trying to load the cassette, the 
engine spins so fast that the mechanical connection with the 
cog does not have time install, and cloves clutch vereschat of 
teeth of gear, with great speed rub about them, without having 
them go. Idle go gears for a shitty connection

Still a little spin up, and speed
aligned, and the teeth eventually joined
normally (and therefore intermittent squeal), and under load 
(with lift and cassette) Gear weak coupling does not spin up, 
and the teeth are constantly screaming, not getting as 
necessary. 

   Noticing that the engine starts to unwind with a transition 
mechanism in IP, I stood in front of this issue: either the 
engine too rapidly accelerated (in favor of this

- Unacceptably high rate of viewing),
or the system too early it unwinds
(Faulty operation or position sensor, t.e.vozmozhno anything). 
Because of the uncontrolled acceleration and had a strong 
squeal when you try to throw me a cassette, which still fails, 
the elevator is t.k.u idling in the final (for the initial 
release) position and the gear is still grappling. 

   I had to disassemble everything again. Check
mechanism - it is in order and pattern. Given
large number of options position sensor mechanism and the lack 
of precise data its signal combinations, I still left a theory 
about his fault. A decided check the engine control circuit 
(after once they were out of order, although it was not about 
speed ...). 

   Experimented, Popayán, found the source of speed. But you 
can not say that mikruha died just like that, then there is the 
feedback, and perhaps it is faulty, or receives a signal to 
activate the rewind (Although the parallel circuit, I have 
already ruled out). 

   All tracks and circuits are functioning properly, and I
decided to check himself engine, took it, soldered the three 
wires supply (+5, +12, GND), rezyuk 1 kOhm wire and direction 
control. Connected to the Speccy and the beginning of the test. 
12 filed through the bulb, and it lowers the voltage under 
load, but it is not important because Main Office - 5 V).


   The engine is working properly, spins in both directions and
regulated, although above the threshold, and quite 
dramatically, but really - it is their properties. There still 
remains the rotation sensor ... With the appropriate connector 
pins do not rate! And this there is a fault, t.k.sistema 
without receiving desired speed, the control voltage increases 
up to a maximum, so he spun like crazy in any mode. It remains 
to determine what actually malfunctioning: a sensor, from which 
the signal is removed, mikruha motor control via he amplified, 
or fines, which Set operation.


   So, go mikruhi 0.78 V, and
full speed is obtained in 0.8, permanently, without the 
frequency and pulsatsiy.V system needed variable component 
(Conder at the entrance) but its not! Since the sensor is a 
displacement of - 30 mV, it floats, but the vector stores, and 
polarity menyaetsya.Vektor retained when removed the rotor, 
although the Hall sensors of the motor issue 0V differential 
(sometimes, and 2 mV residual magnetism), and when the rotor 
symmetrically me the difference + - 38 mV, depending on the 
position of the rotor. However, the difference Sensor motor 
directly (without correction) are the inputs of the 
differential amps, and One of the inputs of the sensor rotation 
comes rezyuk OS [feedback] from the output frequency 
vrascheniya.Rezyuk fix it, and remains two versions - the 
sensor, permitting unipolar offset, or mikruha with leakage 
input. 

   Disable the sensor, and output voltage
mikruhi soars to 3.8 V. I was a little
baffled - because the OS is the inverting input, direct input 
nameryaetsya about 1.6 V, and flew out ... Rezyuki attaching to 
the inverting input, has left doubts as to their confusion, but 
if both inputs are shorted, the yield drops to 0.78 V, despite 
the fact that initially it was 3.8, as if to throw rezyuk

direct and negative, the output becomes too 0.78
B, as a plus - does not change.

   The point was to prioritize the implementation of 
operatsionnika in scatter transistor input stage, and that the 
inputs - unipolar base pnp (presumably)

tranzistorov.Kak just threw rezyuk with direct input by the 
divisor (it is always on board motor), obtained at the output 
of half Power, in short, convinced that mikruha

is working and not working sensor. Rather, it
punched, or "burst", and the output difference
shifted from 0. And being cut off from
amp, it gave an even greater difference in
outputs, as many as 130 mV without rotor, but rotor
This value is shifted by a few dozen in the + and -. When 
checking mechanism may be occasions when the motor rotates, 
barely noticeable touches the sensor. In other cases, this does 
not happen, and it is not clear how it turns - And the 
clearance gap is, how can he reduced if the rotor is firmly 
seated in the bearings? Response to the savagery is simple: the 
mud! A It is a combination ... the edge of the rotor - is

magnet, and a very powerful, it pulls any crumbs that came to 
the paramagnetic, which begins at touch sensor, while at high 
speed could damage it. Enough to run your hand along the edge 
of the rotor, and he ceases to affect a sensor - baby flies. Of 
course, the mechanism of wear, and the particles can no longer 
stick to the dried grease ... In my case, flowing water, and 
was rust, which is known to be excellent magnet, and although I 
carefully cleaned all, who knows where the baby could hide what 
... 

   As a result, I shifted the voltage on the direct
entrance, parallel to the solder pins 1
(+5) And 2 (+ oy, 3 GND, 4-w) rezyuk 8.2
ohms and the resistance increased OS (instead of 6.2
ohms, which is soldered to the exit point to
poteyat not soldered 24 ohms), since the amplitude output from 
the sensor is dropped - in part flowing out through the 
suspended rezyuk. 

   Of course, I came to these values ​​is not
immediately, but from experience. But the fact is that the 
faulty sensor is unreliable, and the next Day shift is markedly 
different - it floats, and the sensor must be replaced. Until

works, the tape a couple of times watching - speed keeps clear 
(even strange ...). By the way, the sensor surface was smooth, 
although asymmetrical pattern, and not on the outside

mean to say that it is faulty, only a test! Theoretically, you 
can use a floating probe, given that it

shift (due to a malfunction) varies
very slowly, and work shift quickly -
this frequency.

   Later, I unsolder those rezyuki and changed
scheme, using three resistors of 100 ohms and
3 capacitors of 1 uF (non-polar). I
Connect the positive input through the amp
RCR circuit (filter, C at GND) to the splitter and
replaced rezyuk OS (old and hanging on
exit point not to lose), and outputs
sensor let kondery.V eventually got through to the output of FG 
stable half-supply (dc), although the voltage changes slightly 
under load and the test was 2.55 + -0.15 in all modes. And on 
the break frequency was rotation, and with a good amplitude, 
although swamped at work. If we consider that

displacement from the sensor comes in sync, but
still slightly unbalanced (due to its
failure and non-uniform sensitivity to the magnetic field), we 
can assume the presence of short high-frequency emissions at 
some point in time, but because is dominated by the working 
component, Such emissions are very short, and their amplitude

small. And on the main board there is a filter
which extinguishes them.



   Of course, in this case, with a failure
sensor can be surprises, but short-lived ... You can make your 
sensor - katushechku reel, someday, maybe, and try (perhaps 
with this Vidic). 

KSA-7G