Re: 3 cd stereo


"Meat Plow" <meat@xxxxxxxxxxxxxx> wrote in message
news:11mdlj.l2i.19.1@xxxxxxxxxxxxxxx
On Mon, 25 Jun 2007 23:38:47 +0000, Arfa Daily wrote:


"Meat Plow" <meat@xxxxxxxxxxxxxx> wrote in message
news:11lvcg.kv3.19.1@xxxxxxxxxxxxxxx
On Mon, 25 Jun 2007 14:34:45 +0000, Arfa Daily wrote:


"Meat Plow" <meat@xxxxxxxxxxxxxx> wrote in message
news:11kso9.8um.17.1@xxxxxxxxxxxxxxx
On Mon, 25 Jun 2007 09:29:02 +0000, Arfa Daily wrote:


"jon" <jonny2bye4@xxxxxxxxx> wrote in message
news:1182738006.866140.69130@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
i found this 3 cd stereo and having some troubal with it. its used
but
tapes and the raideo work on it. the problem is the cd player. when
i
try to play any cd in the cd player nothing happens. its a weird
brand, i think its aiwa but am not sure. any help would be helpfull.


Aiwa is not a weird brand. It is part of the Sony group, and is very
common.
The most likely thing on one of these - assuming that it's one of the
carousel models - is that the laser lens is very dusty. In their
heyday,
I
used to do probably 4 or 5 a week. Cleaning the lens - properly ,
that
is,
not with a 'CD lens-cleaner disc' - will restore one of these in 7
out
of
10
cases. Failing that, you're probably up for a replacement laser.
There
are a
couple of other potential issues which have been known to stop one
working,
but they are very rare. The decoder / deck drive electronics are
generally
very reliable on them. If you do have to get a replacement laser,
make
sure
that you get the right one. KSS 213B is the commonest (and cheapest),
but
they have also had '213C, '213D, and '213E fitted. They don't like
having
the wrong one in them. None of them is expensive as lasers go, but I
would
warn against using the real 'cheapies' in these units, particularly
if
it's
not a '213B, as in my experience, operation can be a bit marginal
with
a
less than full spec laser fitted.


Very nice post indeed Arf, but I doubt anyone who thinks Aiwa a weird
brand has the potential to do anything but swab the laser if he/she
can
even do that :)


Hi Meat - how's it a'goin?

That did occur to me too, but I thought it was a nice example of 'one
of
those' questions relating to what is actually a very common stereo with
a
very common problem, and I thought it might serve as a useful vehicle
for
one of those magazine type "Uncle Arfa Answers ... " responses that
could
be
useful to others with a bit more experience ;~}

Arfa

LOL Uncle Arfa's Answers. I'll archive these from time to time just in
case a friend or someone asks me a question here. I basically dropped
that
line of stuff years ago and focused on vintage tube guitar amps for my
brother in law's music store. He's kind of nuts and will buy these off
the
wall tube amps from street walk ins. I worked on an Alamo Montclair 1x12
he bought from a walk in. Needed some minor things, tube, resistor,
etc...
Nice little 22watt amp, great for blues as it breaks up nicely for that
tube amp distortion before it gets too loud. Myself the smallest amp I
have is a Laney Pro Tube 50 watt that sounds like a 100 watts. The rest
of
my tube amps are all 130+ watts RMS :)


I do a lot of guitar amps as well for the music store in the village
where I
live. I have just today been doing a Studiomaster 400 mixer / amp that
had
the LED bars both illuminated and behaving very oddly, and no output from
either main output channel. I had to shell out $20 for a schematic-set
download. The two final mixdown boards, are the same, but different ...
!!
One uses opamps with a standard 8 pin DIL package, and the other uses
different opamps in 8 pin SILs. I've never managed to find anyone here
who
supplies those SIL opamps. Oddly, the same stage was faulty on both
boards,
and I suspect that something nasty must have been jacked into the insert
sockets. I replaced both chips, using a standard DIL standing on end with
wires to the other four pins, for the SIL one. That restored all the
mixer
functions, only to find that one power amp didn't work. There are 8
transistors blown, and the reason it just sits there quietly with no
blowing
fuses or flames, is that it's full of safety R's, which are all open
circuit.

THe last mixing console I worked on was a few years back and as a favor
repaid. It was a 24 channel Mackie that needed new faders(sliders)after
beer was spilled in it. In order to get to them I had to remove all the
knobs for each channel, must have been 200 of them, about a 100 screws and
that allowed me to pull the top off enough to get at the 4 banks of 6
faders that were soldered onto 2 peripheral boards. Luckily all the trim
pots for each channel did not have a nut and washer. I think I spent more
than 2 hours just dissembling it. Total time from start to finish was
probably 6 hours.

Last week I did a Marshall with both output IC's blown to pieces. They
are the size of something in a car radio, and have 96v across them !!! I
also had another Marshall that had three 5.3 ohm speakers in series in
the cab - very odd arrangement to make up 16 ohms. One of the speakers
was short circuit, and someone had screwed about with the wiring to try
to compensate. The new speaker sent by Marshall was an 8 ohm - so much
for their clever impedance calculations. When all fitted, the amp output
seemed low, and lacking in 'zing'. Turned out a screen feed R on one of
the output tubes was open. Sounded a treat when it had been replaced.

LOL I've seen all kinds of idiots bring in 4x12 cabs with some really
whacked out things inside. BTW my Waller DSP 100 2x12 combo amp has a TDA
something or another for it's power output. It sits on 90 volt rails and
is the size of a car stereo amp chip. It had a digital hum problem shortly
after I purchased it. The said send the chassis back to them so they could
do some ground lift mod. I gave them my credentials and they emailed me
the procedure complete with illustrated pics and allowed me to do the
warranty :)


I don't know about you, but I find this interesting and varied work, and
there doesn't seem to be too many of us about still doing it -
particularly on tube equipment. All of the young engineers and fellow
radio hams that I know, are terrified of tubes and the high voltages
involved, and won't go near them. I make up the rest of my work with
hifi equipment - some of it very high end from the nearby town's last
remaining 'proper' specialist hifi store, and some of it basically junk,
that comes to me through the last few independant retailers in the area.
I only do trade work, as I can't be bothered with whining customers. I
also have a 'commercial' contract to repair pcb's from drinks vending
machines. No service info, but I rev-eng'd one a long time ago, and
built a jig to test every function very rapidly. Takes me about 10
seconds to test and diagnose each board. VERY boring and repetitive
work, but good bread and butter money for the business.

I love high voltages and tubes. The smell of rarefied air and ozone.
The knowledge that you could die instantly if you grab the wrong thing in
say an Ameritron legal limit amp with a 3CX1500A inside. If you have the
time Arfa, have a look here

http://hawkins.pair.com/wlw.shtml

If you like power and volts and tubes, this is WLW in Ohio formerly 500
thousand watts :)

That's a very good site. The tubes in the high power tx seem smaller than
the ones we had here. I live not far from the famous Borough Hill BBC
transmission site at Daventry, and went there several times on college field
trips. The Third Programme transmitter that used to be located there,
radiated 200kW during the daylight hours, and 470kW at night. The antenna
was a lattice vertical dipole, located about a mile or so across fields from
the transmitter house. It used an 'open wire' feeder made from 3/4" copper
water pipe on 11 foot wooden telephone poles. I remember commenting to one
of the transmitter engineers that was showing us round, that the feeder
losses must be colossal. Not really, he said, only about 10kW ! Each half of
the mast was fed by a separate final cabinet. I remember asking the same
guy, naiive as I was, what would be the effect of one of the halves of the
tx failing. He asked if they taught us nothing at college and said to just
think about it. He said that one half of the tx stopping would represent
only a 3dB drop in output power, and it would only be noticed at the fringes
!!

The tank coils for the finals, were mounted on trolleys that ran on rails,
so could be moved from cab to cab for frequency changes. The coupling was
achieved courtesy of brass yardsticks set in the floor, and hand-written
charts of measurements for different frequencies. I can also remember seeing
those big old brown bakalite cased silver mica caps, strung across the
insides of the cabs on long wires, apparently to kill internal resonances.
This is all long wave stuff of course, but there were also many short wave
transmitters on the site, sadly all gone now.

The finals, as I recall, were steam cooled, and the steam used to heat the
buildings. As I say, the PA tubes were big things, also trolley mounted I
seem to remember, predominantly glass, and with big nuts and bolts inside.
The warranty started from the time they were delivered, so new or rebuilt
ones were always put into service immediately to get the warranty period out
of them, before being removed again, and put into stock. Happy days. I tried
to find some pictures on the net to show you, but there seems to be very few
surviving, which is odd as it was a very famous transmitter site, and also
had a very active ham radio club located there.

Arfa


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