Commodore Free 14/Commodore_Free_Issue_14_2007_Commodore_Computer_Club.d64/t.64 beginners

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THE Absolute Beginners guide to the
Commodore 64

WARNING
Some items in this article involve
opening up your machine & testing
electrical continuity; while this
should be a safe process ensure the
machine is Powered off & unplugged,
also earth yourself this can be done by
connecting a cable to your wrist & to a
radiator or through the purchase of a
Commercial earthling kit, computers are
susceptible to static electricity

You follow the following article at
your own risk & Commodore free & indeed
I cant be held responsible for problems
caused by following this Article as a
result of damage to yourself others &
any electrical equipment.

My New Commodore 64 Computer

Commodore 64 history in brief

Introduced at the winter Consumer
Electronics Show in January 1982
The machine is listed as the highest
selling personal computer in the
Gunniess book of records

The machine was redesigned to make a
reduced cost version
this was the Commodore 64C system
released around 1986 featuring a more
streamline designed case & surface
mounted chips to reduce costs

The C64 uses a 8-bit MOS Technology
6510 microprocessor.

The C64 had 64 kilobytes of RAM, only
38 KB is available for the Basic
programmer to access

The VIC-II, produced graphics & could
display 16 colours, also eight hardware
sprites

The sound chip, SID, had 3 channels,
each with its own ADSR envelope
generator, & with several different
waveforms, ring modulation & filter
capabilities

There are two versions of the SID chip.
The first a 6581, which is to be found
in all of the original "breadbox" C64s,
& early versions of the C64C & the
C128. It was later replaced with the
MOS Technology 8580 in 1987 they both
use different voltages & are not
interchangeable

Retro Classic

So you obtained a C64 for whatever
reason & the machine came with no
instructions or manual just the C64 &
hopefully a powerpack in the form of an
external "brick" you may be new to the
system or returning to the machine
after years of inactivity. The C64 is a
well loved machine, it does contain
some faults but most enthusiast choose
to ignore them or class them as quirks
rather than hardware & software bugs. I
still remember the day I received my
C64, mainly because it was Christmas
day, but also remembering going to a
Computer exhibition with my father in
London & seeing Geos operating system &
purchasing Geos & a 1541 floppy disk
drive, this could of course be
remembering a great childhood, I prefer
just to remember my C64 & me & dad
wowing over Goes & thinking we must buy
a printer for this system.

Question

What can I do with this machine how is
it supposed to be used & is there still
support

Fear not! Applications, games & even
new hardware is appearing all the time
for one of the best systems ever
created, but we dont want to dwell on
that for now what we want is to know
the system is working & then see what
"bits" we have

New starters

Lay all the parts out in front of you
lets see what you have hopefully you
will have at least these items

TV to connect the machine to otherwise
you wont be able to view a picture

C64 itself This may be a new designed
C64c or the older more rounded shape

Picture of original 64

Picture or the redesigned 64c

Tv/Av lead

Commodore power supply

TV Connection

While the C64 can connect to a domestic
TV via the aerial socket the picture
isnt as good as a dedicated Av
connector, (more about this later)

Plug in the power supply to the C64 the
connector should only fit one way round
& its location is on the right of the
machine with the keyboard facing you,
also here you will notice 2 joystick
ports & a power switch (on/off) ensure
the switch is off.

Now connect the Tv/av cable to your C=
machine, this will connect to the
Commodores modulator located at the
rear of the machine

The modulator converts the digital
signal produced by the machine to an
analogue format for display on a
standard domestic television via the
Arial socket.

One thing to be aware of is that
different countries have different
standards, for TV signals & for power,
so if the C64 came to you from England
& you are in the U.S. the TV signal
isnt compatible & the power require-
ments are different, England or the UK.
Use a Pal tv signal & U.S. use NTSC so
you would need a TV that can handle the
different format.

The other thing is that U.S use 110
volts of electricity from the wall
socket usually on a 2 pin plug whereas
the UK. use 240 volts on a 3 pin plug
(live, neutral & earth)

Now connect the other end of the Av
cable to the tv & select an unused
channel, tune on the C64 at the wall
socket & at the machines switch (by the
joystick port) now turn on the TV press
the unused channel & follow the TV
instructions to manually tune to a TV
signal with luck you should find the
commodore screen slowly fade into
picture as you start to tune in.

Nothing is working

Ok dont panic if this isnt working 1st
we need to check the C64 is receiving
power, in the u.k. the plug that goes
to the mains has a fuse this need
checking to ensure its working, then
look at the C64 there will be a POWER
light this should be glowing red, if
not then you could try a friend & swap
power supplies but also be aware the
C64 has a fuse inside this could be
blown & I have been given 3 or 4
machines where this was the only fault,
its a clear glass fuse similar to the
picture below, test it with a multi-
meter or take it to an electrical
specialist for a replacement they
should be only a few U.K. pence, I was
charged 10 pence for a replacement, &
the guy in the shop even kindly tested
it for me. See the how to use  a multi-
meter for continuity testing section.

Still dead?

Depending on the model, the old brown
Bread box machines used socket mounted
chips, look for the SID chip it should
be as shown in the picture below. This
could have blown & while the machine
will work without the SID chip albeit
without sound it wont work with a blown
one, so carefully remove it with a chip
extractor or with 2 flat bladed screw-
drivers remove the SID chip & then
screw the case back together now try
powering on & tuning the picture if you
have a picture now you have a dead SID
chip, try eBay for a replacement ensure
its the exact same model of SID
remember there are two versions 6581 &
6580 they are NOT interchangeable

TV/Monitor

As described at the start of this
article, using the aerial socket on a
TV isnt the best picture quality the
Commodore can produce, on the rear of
the machine is a AV??? Socket. Various
cables have been made allowing the
Commodore to connect to modern TV & Av
equipment, for example your 32" plasma
TV that may not have an internal tuner,
only Scart & Composite connections try
looking on Protovisions website as they
sell various cables, also eBay sellers
have C64 to scart cables as well as
svideo & composite

Picture of Commodore to Av cable

Variants available for a few pounds, If
soldering is a skill you possess you
could even produce your own try looking
here:

http://pinouts.ru/Video/C128C64CV
 ideo_pinout.shtml

and here

http://pinouts.ru/VideoCables/C128
 toScartSVideo_pinout.shtml

for some ideas how to produce various
cables.

Picture of a Commodore to Scart cable

As shown in older versions of Commodore
free various boxes exist that will take
a composite signal & create a picture
viewable on a TFT PC screen or an old
CRT screen, the CRT screens are the big
TVs the TFT are the slim sexy models,
looking on eBay. The Commodore 1084S
monitors that were one favourite with
Commodore users seem to be going for
around 20

U.K. pounds really its better to use
the money to purchase a cable, I
purchased a cheap TV with Av sockets on
the front & plug the Commodore into
this, the picture is excellent the
cable cost me 5 UK. from eBay & the TV
cost me 89 new

How to use a multimeter for continuity
testing.

A mulimeter can be obtained for a few
pounds. The one I use cost me 3 U.K.
pounds I am not an electrician so we
are not going to be doing anything
fancy like testing circuits for basic
fault finding a continuity test can
save time & money

Set the multimeter to the Ohm setting.
Now touch the two probes together & you
should hear a noise & the display will
change, this confirms that continuity
or electrical current is flowing round
the device, open the two probe contacts
& the display will drop back to zero,
showing us there is no continuity.
This can now be used on fuses. Touch 1
probe to one end of the fuse & the
other probe to the other end of the
fuse if the multimeter makes a noise or
the display changes we have continuity
or current flowing through the fuse if
the display doesnt change then the fuse
is dead. You can use this to check the
fuse in the plug of the C64 & the
internal glass fuse (I am sure there is
a technical name for this fuse but I
dont know what it is)

Opening up the C64

This depends on the model but the
basics are really the same. Ensure
nothing is plugged into the machine.
Turn the machine over on your lap so
the keys are facing down & the under-
side is now facing up.

You will need a small cross head screw-
driver to remove the screws from the
base of the machine, Locate the screws
as shown they should come out quite
easily. Turn the machine over carefully
noting where the screws fall out Also
worth checking is that all the chips
are secure by gently pressing them into
there sockets (if they are socketed)