Hey everyone and welcome back to the Sawickipedia. Now last week we looked at the
Commodore 64 power supply, or brick of death as its affectionately known, to see
if there were any issues with that before we plugged it into a Commodore 64.
This week we're going to look at the dead test and diagnostic cartridge. Now
this particular one basically has both cartridges in one. There's a little
jumper here to switch between the dead test or diagnostic test and I also opted
to get the full wiring harness for the dead test cartridge. These are basically
little connectors that go into the USB, USB dream on, the user port, cartridge
port, serial port, control ports, and the keyboard port. They're basically just
little loopback connectors, so signal will come out through one pin and it
basically just gets looped back into another pin so the Commodore can tell
that the data going out is the same as the data coming back in. So we'll hook
that up and see how it goes. I've got a TV here so we can see how it all looks. A
funny thing I guess back in the 80s it was hard to get a TV that was over 20
inches, now I struggle to get a TV that's under 40 inches so go figure. This
will have to do for now until I get a better set up. Let's just see what
happens with out the dead test cart, see if we get a start-up screen. It looks
like it's trying to give us a signal but we're just getting a blank screen, okay
so that took about four or five goes to actually get to the startup screen, so
I'll switch it off plug the dead test cart in, actually we might start with a
diagnostic test first.
Let's just see what the diagnostic test gives us, I won't plug in the wiring
harnesses yet we'll just go for a basic test and I'll explain why I opted for
the harnesses in a sec. It looks like it's really struggling to boot up, there
is a little light on the cartridge, it has just come on. There we go seems that
U1 and U2 are labelled as bad, they're the CIA chips and they'll always be
labeled as bad without the wiring harness, same with the cassette, control
port, serial port, user port. Everything else seems to function the SID sounds
okay, and then if the camera can pick this up, it's right here on the bottom of
the the two times seem to match up, so that's always a good sign. But yeah it
does take a little bit to actually boot this up so I'm not sure what's going on
there. Let's hook up the full wiring harness and see what results we get. Just
something to note when you hook this up it is labeled on these ones
which side is supposed to face up. These particular ones are done by a company
called Melbourne console repros, based in Melbourne Australia. I think they do
also ship internationally, I'm not affiliated with them but it was pretty
much the the cheapest and most convenient option at the time, so that's
what I went with. So yeah all of our wiring harness and
loop back connectors are all plugged in so let's let's try the diagnostic again.
So I'll boot it up first time, it's interesting it's still showing U1
and U2 as bad, the cassette port, and serial port, user port, is bad as well.
The keyboard is okay, apparently clocks still seem to be accurate, so I'll power
this off and just unplug everything, and what I'm gonna do here which I probably
should have done before even trying this out is just cleaning out all the ports.
I've got mass airflow sensor cleaner, basically just contact cleaner so it
it'll clean up any contacts and it dries without leaving any residue, so we'll
just spray that into the port's and over the connectors just give that a couple
of minutes to dry but you don't have to wait.
Okay so we've just cleaned out all the ports and contacts and just run another test.
Now what I was going to say was the reason I went for the full wiring
harness is exactly for this because without the full wiring harness it's
easy to just assume that because you don't have it connected these ports are
automatically going to show up as bad, but even with the harness connected some
of them are still showing as bad. So let's see what happens this time once
we've cleaned up all the contacts and all the ports. So we're still getting
bad here, and same with these ports over here, so next thing I'm gonna go into,
shut that up, is replacing the capacitors in the board mainly just the
electrolytic. So I did speak of this last week because they generally have a
service life of about thirty years if that, so definitely a good time to
replace them. So for this you will need a soldering iron and a preferably
desoldering station as well, and also the replacement capacitors for your particular
model, and now this one here which is the one we're playing around with last week
is a
assembly number 250425. So you can find online basically a
list out of the of the capacitors for your particular board. I think there's a
good one on which retroleum.co.uk They also do seel replacement kits so
it's easy just to pick up a kit from them and then you're pretty much ready
to go. You don't have to go trying to source all the capacitors yourself but
yeah I'm not affiliated with them so I have no idea what their capacitors are
like, they do claim to use quality ones but yeah I've bought the capacitors
elsewhere so I can't comment on the quality of those. But yeah without
further ado let's remove these capacitors and replace them
with some fresh ones. All right now as you can probably hear there's a buzzing
of fans everywhere, one of them is the desoldering station which is just over
there, and the other one is a little exhaust extractor fan / fume extractor fan
which is over here. It's basically just a computer fan that I hooked up to a
little power brick, or wall wart as the Americans would say. All right so
let's take a look. I am gonna get rid of this shielding it doesn't actually
perform any useful function it was just put in there to keep the FCC happy. I'm
gonna just take out my keyboard loop back that we had in earlier. So yeah we will
pull the board out and yeah replace some of these capacitors, and power it up
again. You might notice that this is the same one that I had in last week's video,
so that is the reset switch here which I might actually just disconnect for now
because it's just gonna get in the way, and it's just one more thing that could
possibly go wrong.
Okay so yeah, this thing in the bin, it sort of just traps heat within that
shield anyway so we don't want to cook our chips. All right let's start with
desoldering, okay this is our desoldering gun and we're just gonna start with
this little capacitor down the end here.
That came out surprisingly easy, so first one out, 25 volt 22 micro farad. This is the
original cap which is a unicon branded cap, the one I'm replacing with is a
Nichicon, which apparently is a decent capacitor brand. So I recommend finding out
which brands are you know are at least half-decent
and only using those. If you use a cheap capacitor brand chances are you're just
gonna end up with more problems. I just have to have a look at which side, so the
capacitors on the board actually mark where the positive
lead goes, and in this case it's on the right. So positive,
and negative leads are generally the shorter of the two,
and I just like to sort of just bend them in opposite directions just so they
get held in the board and then apply some fresh solder.
Trim the excess of the leads off and then move on to the rest. Okay so I
finished recapping the board except for this one because I'm still waiting on
that to arrive. Most of these are pretty easy, the biggest challenge was the
capacitors inside the RF modulator because you need to desolder the lid
and also in the RF box and then desolder the bottom of the box as well. So there
is a lot of desoldering going on, and it's quite tricky to get out but I was
sort of aware of that going in. So yeah hopefully that should clean up the
video, and this should arrive in the next couple of days to replace that one, so
I'll get that done. But yeah for now let's just power it back
on and see if it's working. So before I do power it back on I'll just pull out
these socketed chips. So this is the VIC-II chip, this little guy's quite handy, you
can make up your own mind as to what it looks like. Yeah it's got a nice little
grabber to pull any IC's. So it will just fit around the VIC-II chip, now what I
want to do here is just remove any of these socketed chips just so I can clean
out the actual sockets, clean off the legs on the chips themselves, just to
sort of ensure everything's making good contact when we put it all back together.
God that SID chip looks like it's seen better days. Alright now remember when you do put
these back in to line up a little notch on the end with the notch
on the socket. All right let's put it back in her and see if it works. Okay so
I've got the diagnostic cartridge plugged back in, and also the full wiring
harness so let's power it up and see what we get. Interesting I'm still
getting U1 and U2 is bad, Cassette port, control port seems okay
serial and user port are also coming up as bad, and the interrupts
are still coming up is bad. So don't know what's gone on there, that's gonna
require further investigation. So on that slightly disappointing note we'll have
to leave here for this week, but join us next week we'll look further into those
issues and also fix up a couple that the other Commodore 64's,
so we'll get into pulling out some chips putting some sockets in and that kind of
thing, and see how we go from there, and obviously I'm gonna replace this one
capacitor here which hasn't been done yet, at least we got the rest of the caps
replaced for today which is always a good thing to prolong the life
of your c64. So we're off to a fairly decent start, we've tested out our power
supplies and recapped our board, so yeah look out for us next week where we'll
do some more tests and hopefully get all the okay's on the diagnostic cart, and
then we'll follow that up with cleaning up the video output. So until next week
thanks for watching the Sawickipedia, be sure to leave me a comment down below,
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haven't already, and we'll see you next week thanks for watching!