445027 25.05.2000
Hello, dear (c) Nemo!
1. I received your letter dated 20/04/2000.
2. Judging by the description BP9022 - a self-excited
blocking oscillator (as well as else?), similar to television
MP-3 (Journal of the radio amateurs "№ 1 for 1997 I
never found).
And MP-3, in my opinion, there are two drawbacks: 1) often
leave their damaged electrolytic capacitors in the feedback
loop Communication (14C in MP-3-3). Perhaps the reason
This is a pulse mode, and
can me such a source of random row
suck, 2) measuring the voltage
not removed from the power outlet (such as the power supply IBM
PC, via the opto-coupler), and additional. A this is, after
all, reduces the stability of the output voltage (5 V).
The most suitable power supply for
Spectrum'a, in my opinion, is as follows:
1). The integrated PWM controller type
TL494 (our analog 1114EU4 worth a total of 12
p. when sold at retail) - good "run-in PSU IBM PC, and can work
in one-and two-stroke mode
2). The power stage can be anything -
push-pull, flyback, just screwed, although preferable flyback
because of the natural defense power transistor. The switching
frequency should be designed for domestic use
transistors, the same KT872A.
3). Voltage on power "+5 V" output from the opto-coupler;
+12 - after KR142EN8B (7812-CPU) - or vice versa EN8B analog
7812.
4). To protect the hard drive, sensitive to rejection power
can be should organize a separate regulator
on the +5 V linear type, for example,
KR142EN5A. This will limit the current consumption
and possibly improve the transient response. Zasinhronizirovat
work of all the channels no problem. The cost of BP course
increase, but better than 1 time to pay for BP than 5 times the
hard drive. By the way, thank you for warning about the danger
of burn Winchester. Efficiency, of course, will decrease, but
with This can also be reconciled.
5). Desirable channels at -12
V and -5 V with stabilizers, respectively, 7912 and 7905. The
presence of these channels encourages the purchase of
HAYESmodemov, but with On the other hand for the installation
HAYES'a usually buy PSU IBM PC, and not another.
Produce such a PSU you can try
and handicraft, but the prefabrication
preferable.
3. You write that between MS146818 and
512VI1 likely to have differences, which
unimportant. I can say the following:
IC KS82C6818, which was bought as an analog MS146818, work did
not, although earned a master oscillator, and 512VI1 worked
under the program in the same scheme.
Download counterfeit software with technical. Doc. I'm not
on MS146818 going to, had no idea what
possible. Tech. Doc. MS146818 on me yet
is not needed.
If you came to my translation of 54 p.
for technical. Doc. at MS146818, then send
instead
ZX-Format № 8.
Op. let., which I have, amended on 2/24/2000, so if the
latter edition has a significant (at your
view) update, send it. If
not, then something from the archive.
P.S. Will ZX-Format № 9?
05.05.2000
Dear N!
2. First, some general comments
character.
2.1. Discuss power supply circuitry
in "Op. let." hardly appropriate. Especially in
such an extent. Hardly anyone would be interested. Well,
consult a private not see the point. This is already
other prices. For information: h tutor
in SP-B costs around $ 2 -5 per hour.
2.2. You seem essential means
not the issues that really matter.
Circuitry of course important, but as an abstract
self-contained theme it is vacuous, ie, makes no sense. Variety
demomeykerstva.
2.3. Operational and производственнотехнологические
approaches to addressing PD vary widely. Therefore, I always
amuse users talk about
production - it is very difficult to explain that their
arguments are inadequate. I think when reading further you will
have the feeling that it's just the birds are singing.
Hereinafter, purely concisely:
- "Self-excited blocking oscillator - how else?" This
terminological subtlety, though perhaps "self-excited" - not
quite specific. Just is, for example, waiting blokinggeneratory,
and they too can do PD.
-"... Fail electrolytic capacitors ... " This is a common
problem for all BP, including the RS-shnyh. Electrolytic
capacitors - is generally the most unreliable elements. With
regard to C14, then under the scheme, he is working at the
reactive power. And the nominal value typically 63 V, although
actually the capacitor DC voltage of several volts. Too "smart"
technologies (In some plants), put back
35 V or even 16 V. This works for the time being,
to time. In addition, the capacitors
C50-35 and there are Armenian "spill." This
altogether separate issue.
-"... Measuring voltage ... " in
BP9022 is removed from the output of +5 V, - so he
and differs from the MP-3, and further, through the comparator
/ reference voltage KREN1 through optocoupler operates moment
switching thyristor VS1 KU112A. As for the MP-3, it is the
stabilizer of the magnetic flux in the core, and has already so
far - because the actual voltage stabilizer. To this
circumstance is not so much influenced stabilizing properties
of the scheme for voltage, it employs a special partitioned
"layout" of the windings in the window. Instability of the
output voltage -1% BUT IT IS GUARANTEED ONLY TO EXIT
135 V, - on the other stresses we are not
goes. Because in the TV small multiplicity
load current (as opposed to computer) -
this is permissible.
-"... Integrated PWM controller type
TL494 ...- respectively. The power supply the most
sophisticated sites are responsible motochnye [???] products.
They are, incidentally, is the most expensive. A question cool
the chip should be discussed in networks - there is the
contingent and appropriate level. Notify you by
confidence that power high-frequency
transformer in the party from the hundreds of pieces will cost
about the same number as Used PSU from PC-ka in working
condition, bought kakomnibud cellar. In fact, the cost of the
PC-power supply in the production of is about 5 - 10% of the
price of computer (ie, approximately 100 - $ 200).
Everything that you see MS-Shnogh - it is garbage to the
European / American garbage dumps. And to make any conclusions
on cost production based on these post-industrial landscape, at
least stupid. This creates certain problems,
as there is such a thing as price expectations. This is when
the sheep begin to judge production cost. To do something
impossible. I will not hide we also have a high-tech. In
Sobchak's reign (he was a governor in the SP-B to Yakovlev) was
constructed Only two high-tech factory with the active
support of the international community. Both plants
- Garbage. When something
leaves, for example, Western
garbage dumps of electronics, the authorities pay more
"traders" for garbage. Then same goes for illiquid - "morally
obsolete "models. It is clear, where are the prices?
-"... Well run-in PSU IBM PC ... " On
really good run-in process vparivaniya debris population. As for
technology, production, she obkatat
THERE, not here. And the technology - it is know
how, praxis - it is not removed from the debris.
-"... Because of the natural defense power transistor ... "
(It should be stipulated that the entire letter deserves a
detailed comments, ie, should not think that
the rest corresponds to something, somehow
meanings. It's just a frame [???]. For lack of time and place
chosen by the most fat "pearl"). Flyback circuitry sources
prevailed recent years on the grounds that they
the most simple. Meanwhile transistors
work for, in worse conditions than
in other types of circuits. The utilization ratio of
transistors in the current, for example, worse than a 4 times
higher than in the corresponding push-pull configuration.
Moreover, the current maximum achieved in the most adverse
time - namely at the time of shutdown.
Therefore, the transistors must be used on the verge of
admissible modes and VERY POWERFUL (compared with the power of
the source). The working point of the transistor
"Flies" in the most dangerous area, and
it is in the upper right corner of the CMR (secret acronym -
the region of maximal regimes). With regard to short-circuit
load, so, in the flyback
sources, it is less dangerous. But it is in
flyback sources, there is another problem associated with very
poor using the transistor current - and
Namely, an underestimated the input voltage. In
TV source MPD IS SPECIAL CASCADE,
disconnect the power at an undervalued input voltage. And the
situation between it is likely - for example, poor contact in
the socket, or breakage of the connecting cord with a "cold"
ohmic contact.
-"... Switching frequency ... " not so
obviously related to the type of transistor. AND
in general, the initial assumptions for the design PD are
required power (which, incidentally, is limited by the type and
size of the body - that is, BS in design, as well as fee,
"under the body." In "Korvetovskom" housing, for example, the
maximum power PSU - 100 W or less, or body of the melt).
Frequency - this is a compromise to be achieved in a number of
contradictory requirements. Usually chosen frequency
just above 20 kHz to avoid acoustic noise.
-"...+ 12 V - via KR142EN8B ... " - So
done in BP9022. By the way, not the best solution in the sense
that the maximum current - 2A. Include parallel rolls can not be
a pass transistor reduces efficiency, and current protection -
only from flyback circuit and its properties. Ie if you need
more 2A - continuous problems with the rolls.
-"... KR142EN5A to the hard drive. " Wonderful ...
-"... 7912, 7905 by HAYES modem. Try, at least mentally put
it all in one pile, and evaluate the resulting shed. It is also
useful to remember that each ROLL - is a separate winding
transformer with an appropriate contribution to the price tag.
Not to get a stove.
-"... Stimulates purchase HAYES-modems ... " And it needs to
be stimulated? Understand modems are all different - solid,
liquid and gas - even if imported.
Support and promote such a motley hodgepodge IMPOSSIBLE. And who
will be repaired? Who will give a guarantee? This, of course,
great that it costs 200 rubles. But How much is the connection?
At least 300 p. because required kulibinstvo particularly
perverted form. Probably, for 300 rubles.
no one will undertake. Therefore, "podpihivat"
users to PC-shnomu garbage tank
it hardly makes sense. HAYES needed
only in one place - namely the Gateway -
Hub to enter the transport
Level I-net. Ie at BBS, - yes, and
then, only one of the city. Much
easier to organize (or rather, less difficult)
production HORIZONTAL modems under the standard joint (bus or,
better yet, Centronics) and ALL HURT their support / promote.
It is curious that Kondratiev thinks, for example, on the
contrary. But that is because that he never dealt with it
professionally, ie, for the money - regularly and respectively.
If he tried this foolishness instantly to erode from his
head. Ie This can be done and the level of
kulibinstva, but can not be done -
ie create a network HAYES'ah.
-"... Can try and homemade ... "
Price of power obtained at least 500
p.
-"... Prefabrication ... " - Unrealistic, too small amounts,
too low price expectations, too little custom content
Spectrum'a. As for the existing power supply - it is
unmarketable products ... Because the price was.
3. "KS82C6818A". No doubt
that we can invent such a scheme in which analogs will not
work. Moreover, we can devise a scheme where half similar
crystals will refuse to work. Catching these glitches may even
completely take possession of man. The technology exists such a
thing as reproducibility. Good design (note, NOT
LAYOUT! - Because the concept of development is
and technology implementation) works on any garbage.
4. ZX-F № 8 sending, about the ZX-F № 9
uncertainty.
5. Sending the first issues of "Op. Let", and
is number 1 and number 2. May find something
interesting.
(C) Nemo.
P.S. Likely to read such responses are not
very nice, but I see no other way to "filter" in "Op. let."
frame. Idle Manilov argument best left to themselves, or
discuss it in networks. However, if the question was
and in the case, it is always ready to explain the most
detailed manner.
When they say "well run-in production" means the technology,
and circuitry, so the last thing. Take, for example, the same
MPD. There Some molds and dies are millions
Rubles. But due to the volume, as befits a high-tech, the price
of parts - a cheap. That is why the production of television
sets in the USSR was the most Tech, - ie this is
HIGH TECHNOLOGY. But not any there megahertz and megabytes -
this is the Corollary. Building "Corvette" MORE high-tech than
the RS-shnye Corps. It is clear that it is not obvious,
especially if the TV and see a lot read a lot of PC-shnyh
magazines.
617170 24.04.2000
Hello, Nemo!
First I want to thank you for
performance (or rather, a re-execution) of my previous order.
With this drive all the disks that I have,
are working normally. Apparently, as you pointed out in his
response to my questions, there is some incompatibility with
720 Kb drives and floppy disks - not all of them work. Also, a
diskette with the ZX-Format № 8 was normal. I sincerely thank
You for this additional work.
Now my new order:
1.Diskety "Isot" 5.25 ", DS / DD - 20
cu
2.Spravochnik "Digital devices."
Textbook for higher technical schools. Pukhal'skii
GI, Novoseltseva TY
Total to pay 20 +45 = 65 * 3.4 = 221 rubles.
I sent money by postal order
Today, April 24.
Also sending you stamps for 15 rubles. -
As I understood from your price list, so
required to obtain an order from a floppy disk
"Open letters".
C Yours sincerely, N.
P.S. Totally forgot to ask you about the service: in his time
(08/23/1999) I spoke with order catalog "LOGROS" a to Akimov
Michael Anatol'evichu. Then again wrote
it (somewhere in December 1999) with a reminder about the
order. But so far not received neither ordered nor simple
answer. Could you somehow connect with Akimov and find out how
things are going with my order (or am I wrong to do anything).
I would be very grateful if you would help me with this.
06.05.2000
Dear N!
Of your claims to Logros'u not clear
Do you pay the money or not.
Logros no longer works for Spectrum'u.
If money were not paid, then just need to take note of that
Logros no longer works.
If you pay, you must provide:
- Date of sending money
- The amount
- A list of the order.
Firm (s) Nemo is not liable for the obligations of Logros'a,
and yet However, if you can do something,
it will be done.
(C) Nemo.
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