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SERVICEMAN'S LOG
Fixing the food processor that wouldn't
I’m not sure whether it is Sunspots, Murphy’s
Law or just plain bad luck, but it appears
there is a conspiracy among our household
appliances to all fail around the same time.
Sitting among those appliances that fail is one
of our food processors which is only a few years
old.
Last month it was the vacuum cleaner. Then a fan heater decided to stop
fanning and heating. Even my own
computer has been increasingly throwing up those cloying “your PC has encountered a problem so we have shut
it down” screens.
Between crashes, it often displays
weird on-screen artefacts, such as coloured blocks of pixels and very thick
black lines appearing randomly. As I
write this article, it is as if someone is
trying to redact what I am writing in
real time. Maybe the CIA really can
hack into our homes via our smart
fridges (or is it ASIO?)! Hmm, we don't
have a smart fridge...
Obviously, the computer has a problem and I suspect my graphics card’s
VRAM is faulty, though this is a wasted
diagnosis because I can’t actually do
anything about it except replace the
card anyway. I’m not about to start
stripping memory chips off the thing
and replacing them.
Considering that it cost a small fortune and was the single most expensive component in this system, I’m not
that happy it has decided to fail just
outside of warranty. I would expect
more than 16 months out of a high-end
graphics card, but that’s how it often
goes with high-performance hardware.
The irony is that I haven’t had time
to play the games I originally obtained
it for as I am too busy doing far more
mundane things, such as renovating
workshops, which is proving surprisingly difficult to do whilst actually
working out of them.
It’s a bit like changing the tyre on
your car while driving it down the
46 Silicon Chip
road; not impossible, as demonstrated
by many car-crazy middle-eastern
YouTubers, but for the rest of us it is
definitely pretty tough.
Now our brand-new dishwasher,
purchased when we renovated the
kitchen nine months ago, has started
making odd noises and during the last
few nights, the LED display has been
randomly flickering between showing
all 8's or nothing, to the time remaining and back again.
I can hurry things up with a light
tap on the door, so it looks as if something is not quite making contact somewhere in the electronics behind the
door panel.
That’ll mean a trip to the repair
agent; I have to resist the temptation
to go searching for the fault myself. For
starters, I haven’t the room to pull it to
bits in my workshop and besides, Mrs
Serviceman wouldn’t be too keen on
me voiding the warranty!
The curse takes another victim
Now to top it off, one of our food
processors has decided it wants to
stop processing. This appliance is
one of the better and most-used of
our kitchen tools so having it give up
is a bit of a curse, as it is a few years
old now and I’m reasonably sure they
don’t make them any longer, so we
can’t just go out and buy another one
(which is I’m sure what the manufacturer intended). Then I remembered;
I’m a serviceman! This shouldn’t be a
problem for the likes of me!
This particular mixer has a solid
Pyrex glass mixing bowl forming the
bottom half of the appliance. A tough
Dave Thompson*
Items Covered This Month
•
•
•
A Serviceman’s kitchen
Brownout protection for a TV
TEAC HDR PVR
*Dave Thompson runs PC Anytime
in Christchurch, NZ.
Website: www.pcanytime.co.nz
Email: dave<at>pcanytime.co.nz
plastic lid then clamps securely onto
the glass bowl and sitting on that lid
is a chrome-and-black plastic housing
which contains the motor and drive
assembly.
This spins a centrally-mounted twin
blade system down through a hole in
the lid via a splined drive shaft. This
machine is so powerful, you could
stuff the bowl full of ice cubes and
with a few short bursts of the motor,
turn them into slush.
The four curved and razor-sharp
blades make small work of anything
in the bowl, and while Mrs Serviceman and I aren’t great foodies (or cooks
for that matter), when the urge takes
us, we like to have decent tools with
which to do the job.
The problem with this thing was
that it no longer powered up. There
is no obvious on/off switch; instead,
it has an interesting push-switch
arrangement. On the very top of the
motor housing is a black plastic cap
that activates a switch when pushed
with the palm of one’s hand.
However, for (I assume) safety reasons, there is another switch activated
when the whole assembly is pushed
against the lid of the bowl. This way,
the motor will only run when significant pressure is put on the whole
motor assembly and both switches
are pushed.
It sounds more awkward than it
really is; in use, it is quite natural to
push down to start operation. It also
makes sense because the motor part
of the appliance isn’t held down by
anything other than the operator’s
hand pressure.
siliconchip.com.au
The splined output shaft of the
motor assembly locates into a circular moulding in the thick plastic lid,
which is well-fixed to the glass bowl
underneath, but other than that hand
pressure, the motor assembly is free
to move, so it makes sense to hold it
tightly when it is running and makes
even more sense to require downwards
pressure before power is switched to
the motor.
Except for the fact that no matter how hard I pushed on it, nothing
happened.
So I had to assume that either something was wrong with the switch arrangement or the motor had burned
out. I was hoping it wasn’t a dead motor, because then we’d likely have to
bin the whole thing (although I suppose we could use the bowl for somesiliconchip.com.au
thing else). However, this is a classic
example of the way everything is going
these days. We have become a consumable, throw-away society, and this is
very apparent in the kitchen.
Start of Serviceman’s rant
By comparison, my mother still uses
a mixer she bought in the seventies.
Sure, it’s had the motor reconditioned
a few times and there are a few minor
cracked mouldings here and there,
but the point is that it was designed
to be repaired and there are still parts
available for it.
Most of the high-end appliances you
buy today don’t have anything like
the parts backup these older brands
have and in 40 years they’ll be part
of a landfill somewhere while those
like Mum’s will probably be still
going. That’s not only hugely wasteful,
it’s bordering on criminal.
People these days buy new printers
rather than buy hyper-expensive cartridges for their old one. Tablet owners
chuck a tablet with a broken digitiser
rather than repair it, even though in
most cases it costs far less than a new
one. And people chuck food processors
because a part that would cost just a
few bucks to manufacture gives out and
because the parts aren’t there to repair
them, and who can blame any of them?
Most manufacturers today are only
concerned with moving as many units
as they can and don’t give a toss what
happens to their products once they
break down; that becomes someone
else’s problem.
Increasingly, I cannot source parts
for even newer models of computers,
June 2017 47
Serr v ice
Se
ceman’s
man’s Log – continued
forcing me to look to the second-hand
or refurbished market. Most punters
these days accept that having to buy a
whole new anything is inevitable, the
collateral damage of technological progression. And maybe you can’t really
blame manufacturers for not wanting
to have capital tied up in parts sitting
around gathering dust on a warehouse
shelf somewhere. It’s easier to just sell
more computers and let someone else
create a second-hand or refurbished
market.
And that’s exactly what has happened; these days many companies are
buying up old appliances – whether
computers, food processors or washing machines – just to strip them down
for spare parts. They know what car
wreckers have known for decades; that
they can make good money from selling parts rather than selling complete
appliances.
This is exactly why I am so keen to
get stuck into trying to repair anything
that breaks down. I consider it a challenge to buck that wasteful philosophy
and try to keep things going for at least
a reasonable lifespan. If something
wears out to the extent it cannot function any longer, then that’s fair enough,
but when an entire printer is junked
simply because a 20-cent proprietary
part is not made available, that is not
OK in my book.
Normal service(man) resumes
Getting into this blender motor
looked like it could be a challenge.
48 Silicon Chip
From the outside, there wasn’t anything much to suggest how it was held
together. There was a hole where the
power cable entered the case but that
was about it.
After having a closer look at the
bottom of the motor assembly, I could
see a black plug about 5mm in diameter that could be hiding something.
I used one of my favourite tools, an
old dentist’s pick, to pry the bung out
and sure enough, it was covering one
of those annoying safety-type screws.
I found the right bit for my driver and
removed the screw.
After a few attempts to pull the
cover off, I concluded that something
else must be holding it on. However,
I couldn’t find anything, and so after
sitting and contemplating it for a few
minutes, I decided to give it a gentle twist.
Sure enough, the cover slowly gave
way to the sideways pressure and after
turning ninety degrees, the whole motor mechanism began to pull out from
the plastic case. It only came out part
way as the power cable held everything in, so I forced the cable through
the stress-relieving sleeve bit by bit
and pulled the motor far enough out
until I could see the power switching
arrangement.
The series-wound universal
(brushed) motor was switched by
a large two-stage microswitch that
was actuated by two formed, plasticcapped copper-coloured springs. One
of these springs was actuated by press-
ing down on the plastic cap by way of
a captive plastic rod. When the cap was
pressed, the rod was forced down onto
the spring and that flexed and pressed
onto one toggle of the power switch.
The bottom spring actuated the second pole of the switch via a clever little
plunger arrangement; when the motor
body was pressed down onto the lid of
the bowl, a corresponding solid piece
of plastic in the lid pressed onto the
plunger, forcing it upwards into the
second spring and causing that to push
the switch’s second toggle. Only when
the two toggles were actuated would
power flow to the motor.
This was actually quite a clever
“manual” safety system, as it meant
the motor could neither be run without the load of the blades to govern
its speed nor without holding it down
quite tightly. Pressing down also engaged the blade assembly down in the
bowl and unless this was all connected
properly, the bottom plastic plunger
would not be actuated. Simple and
effective; and broken.
The motor wouldn’t power on
because the bottom spring had somehow broken away from its mount,
meaning that it simply flexed out of
the way when the plunger touched it,
instead of transferring that pressure
to the switch.
I hadn’t noticed any plastic shrapnel floating around in the case but
then again, any fragments might have
been small enough to work their way
through the small gap for the blade
shaft in the lid and fall down into the
bowl below. I suppose we’ll find them
when we defrost and eat the Ćevapi
my wife made when she last used the
blender!
Now though, I would have to rebuild
the support for the bottom spring so I
made a rough-and-ready former using
strips of gaffer tape stuck to the remainder of the plastic mount. It was originally a rectangular shape and thus easy
to recreate. To build it up, I utilised a
two-part compound that comes in a
tube and one simply slices off a small
amount and rolls it to mix it.
It sets rock-hard in about five to 10
minutes, depending on the ambient
temperature, so you can’t faff about
once mixed. Another smaller piece of
tape held the contact in place while
the pressed-in compound set and I
siliconchip.com.au
left it overnight to be certain it was
properly cured.
The next afternoon, I removed the
tape and tested the contact’s travel,
making sure it reached and actuated
the microswitch. It did, so I reassembled the motor back into the case and
with power applied, tried it a few times
to ensure it started consistently with
the usual amount of pressure. Hopefully, that fix will last and we’ll get a
bit more use before we have to consider chucking it away.
DIY circular saw
upgrade goes awry
And in one of the funnier service
moments this month, a customer (and
neighbour) brought in one of those
bright green, plastic-bodied benchtop
table saws that he’d stripped down in
order to mount the guts into another
more solid benchtop. He’d made a
nice job of swapping everything over
but had needed to remove the power
switch connections and associated
wiring in order to get it out of the original housing.
After throwing away all the old
parts, he’d fixed the saw and motor
assembly into a recessed pocket in
a sheet of 32mm custom-wood. That
would certainly make a far sturdier
base for it than the original flimsy
plastic body and thin, cast aluminium
table top.
The problem was that he’d chucked
away the diagram he’d made of the
wiring and was too smart (or afraid)
to mess about with mains wiring. Fair
enough; sometimes power tools can
be wired up in weird ways and just
randomly re-connecting spade connectors and plugging it in isn’t the best
way forward.
The first thing I did was look for a
circuit diagram for the saw. I found
plenty, all American and not much
use for our configuration. I Googled
the paddle-style safety switch’s part
number and found a suitable usage
diagram in the datasheet, and with
it all wired up correctly, I plugged it
into my Variac and wound on 50VAC
before pushing the green button. The
motor spooled up but there wasn’t
enough juice to hold the button in.
I added another 100 volts and away
it went.
Pushing the red “Stop” button
switched it off as expected so I called
my neighbour to tell him it was ready.
The next day, he brought it back, claiming the motor was running backwards.
Puzzled, I drew a quick wiring diagram
and looked at how changing the connections on the switch would make
the motor run in reverse.
There wasn’t any configuration
that would do that; to swap rotation,
I’d have to change either the armature polarity or the field polarity with
respect to each other and as it had run
properly before, I couldn’t see how that
was all necessary.
After pondering it for a while, it hit
me; he’d put the blade on backwards,
which of course made it look as if the
motor was running the wrong way.
After flipping it, all was well. At least
it was an easy fix!
Browned off by brownout protection
G. M., from Pukekohe in New
Zealand, recently had a call-out to a
remote location to a malfunction in a
new TV installation which proved to
be a case of “too much protection is
too much”.
I am the local service agent for a
well-known and popular range of
home entertainment products. I normally restrict my call-out radius to
about twenty-five kilometers from
base but this was one of those occasions when Murphy's Law kicked in,
and a faulty TV as far away from base
as I could be enticed to go became a
siliconchip.com.au
real head scratcher. This law is closely
related to the one which decrees that
when a screw is dropped, it will always roll to the darkest, dustiest, most
inaccessible corner of the workshop!
A local retailer phoned me with an
appeal to talk with one of their customers who had purchased a 55-inch
TV three months earlier and he was
now convinced the TV was faulty.
The farming owner lived near the
end of a long peninsula, a 60km onehour drive over reasonable but quite
twisty roads.
I was very busy with other work so
I was not keen to waste half a day unproductively driving back and forth all
that way, despite the very scenic vistas I would enjoy on the journey. So I
was eager to solve the problem by any
other means, hoping for an installation
or operation issue which I could talk
the owner through.
I phoned the owner and he explained his problem. The TV would
completely cut out for two to three
minutes and then come on again with
no sound or picture. It would repeat
this several times an evening and it
was happening virtually every night.
Soon after cutting out, the screen
would show the word “SAT” in the
top left corner. When the picture and
sound eventually came back on everything worked normally until the next
time. He had only experienced these
problems since purchasing the new
TV. The old plasma TV had worked
just fine.
I asked some obvious questions
such as whether the problem was occurring on all sources which was responded to with a considerable pause.
So I clarified my question by asking if
there was anything else connected to
the TV such as a set-top box or DVD
player. Yes, there was a Sky box (pause
again); not sure about a DVD player.
Now we're getting somewhere – or are
we? I gained the impression that he
was not sure what a DVD player was.
He only watched Sky broadcasts.
The owner explained that he had
had the Sky people out twice attempting to solve the issue and they had
eventually replaced the decoder, to
no avail. Having eliminated that as a
cause, he surmised that the problem
now had to be with the TV. He even
took a photo of the malfunctioning TV
June 2017 49
Serr v ice
Se
ceman’s
man’s Log – continued
with his phone and sent it to me so he
was obviously not completely technophobic! I talked the owner through
the procedure to reset the TV to factory condition and left him to test it
that night.
The next morning, I phoned a couple of satellite installers whom I knew
and discussed the possibility of there
still being a decoder or satellite signal issue since this was not my area
of expertise, but neither of them were
convinced that the problems were Sky
related. However, since they had both
been in the trade nearly as long as me,
neither was prepared to lay odds that
it was not a Sky reception fault.
Meanwhile, I forwarded the photo to
the TV brand’s technical manager and
had several discussions with him by
email and phone regarding the fault.
He seemed to be quite certain that the
"SAT" logo appearing on the screen was
not something being generated by the
TV so the problem had to be elsewhere.
We were running out of elsewheres.
The last straw caused the frustrated
owner to send a curt text to my phone
a couple of days later that 'Now everything had cut out, nothing was working – I'll pay for you to call'. I phoned
him and waited while he fetched an
electric drill to plug into the wall to
test that the power was on. The drill
whirred into life so I said I'd think
on it and let him know. He was slowly convincing me that the TV was to
blame and had somehow now caused
everything to fail.
I talked with the brand's head technician again and he agreed to cover
the considerable cost of a call out if it
proved to be a TV fault. I phoned the
owner and he was happy for me to call
on the basis that if it was not the TV at
fault then he had to bear the cost. He
was quite convinced that the TV was
faulty, so was confident that he would
not be writing a cheque.
I called the next day armed with a
small loan TV of the same brand with
a twofold job for it – first, to pacify
the owner by leaving him something
to watch and second, to act as a test
unit while I checked his new TV at
my shop.
The first thing I noticed when I arrived at his home was that there was
indeed no power. The TV, decoder and
sound bar/sub-woofer were all dead.
50 Silicon Chip
Up until this point I had not known
there was a sound bar. It was now I
also learned that the TV and sound
bar had been delivered and installed
by the retailer at the time of purchase.
I knew there was power to the wall
so I peered over the back of the TV
and saw a nice new multi-outlet power box there, no doubt sold by the retailer as an add-on to give protection
to the new equipment in the event of
a power surge. In my opinion this is
a duplication of the sort of protection
which is now already built into most
equipment, but having been a retailer
myself in a past life, I was not about
to cast aspersions on the practice of
up-selling.
The box had an on/off switch on the
top so I reached for it and toggled it to
the other position at which point I was
greeted by an encouraging green glow
from beneath the switch button and
now everything was working.
I quizzed the elderly couple about
how the switch could have been
bumped off since there were obviously
no children around at which point the
lady admitted that one of her cats had
chased a mouse behind the TV the previous day and must have jumped on
the switch. This seemed quite plausible since the switch button was quite
large and the switch took little effort
to operate.
So, the immediate no-power problem was solved but I was fairly sure
this had no connection (pun intended)
with the original complaint so I carried
on with swapping the TVs and after the
loan TV was connected and working,
I checked some of the menu settings
on the decoder and sound bar. These
were both connected with HDMI cables to the TV.
I’ve experienced some odd behaviour in the past by allowing such appliances to talk to each other. I went into
the menu of each device and switched
off this interactive feature to eliminate
arguments between them as a possi-
ble cause of the original complaint.
If the owner wants this feature, it can
be readily restored, once our present
issues were behind us.
Back at base I connected the new TV
to an HDMI source and left it running.
It didn't miss a beat. That evening I
received a text from the exasperated
owner to say the same thing was happening with the loan TV except that
this TV displayed the "HDMI1" in the
top left corner, not “SAT” which the
new TV had displayed.
It was now that he offered a little
more information which in hindsight,
I probably should have asked about
earlier. The problem only seemed to
occur at around dinner time each evening and it did not happen so often later
in the evening.
Now armed with another clue in the
timing of the fault occurring, I wondered whether this could be a power
supply problem after all, but the owner
wasn't convinced of this since despite
living at the end of the road at the tip
of a long peninsula, it couldn't be a
power voltage drop because the lights
remained bright.
Now clutching for straws and wanting to resolve the problem before I
headed away for a brief break in a few
days, I connected the new TV in my
shop to a variable transformer just to
eliminate that from the mix of possibilities. I slowly reduced the voltage
from the normal 230VAC and I was
surprised that the TV worked perfectly
down to 80VAC, at which point it cut
out. As soon as the voltage came up a
bit, the set burst back to life without
so much as a hiccup. I reset the TV a
second time and adjusted some of the
menu settings.
The next day was a public holiday.
Despite that and being so keen to get
on top of the problem, I loaded the
owner's TV into the van. I included
the variable transformer and set off
with some trepidation, knowing that
if I did not solve the problem this time
Servicing Stories Wanted
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column? If so, why not send those stories in to us?
We pay for all contributions published but please note that your material must
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around, I would have to admit defeat.
Who would want to pay me for the
many hours I had already invested in
this job if I couldn't provide a solution?
On arrival, I connected the variable transformer to the wall socket
and the multi-outlet box in turn to
the transformer and turned everything on. As I slowly reduced the
voltage from 230VAC to just above
200VAC there was a click and everything died. Turning the voltage back
up a little produced another click
and everything except the sound bar
powered up again.
The clicking noise was coming from
the power multi-box and it was now
obvious to me that this was a feature
of the device to protect connected
appliances against brown-out damage
due to prolonged low voltage supply.
A press of the power button on the
sound bar remote control turned that
on again.
When I repeated the exercise, I
noticed the TV came back on almost
immediately after the voltage was
restored but the Sky decoder took
several minutes to reboot itself. In
the meantime, the TV patiently displayed a blank screen with “HDMI1”
showing in the top left corner, until it
once again received a signal from the
decoder and then displayed a perfectly
normal picture.
These were exactly the symptoms
the owner had described. Eureka! After
substituting the power multi-box with
a cheap discount store version, without the brown-out protection feature,
he has had no further problems – so far.
Epilogue
So I had been hoodwinked by a tech-
nological feature of the power outlet
multi-box which I did not realise it
had. In any other location, the protection would most likely not have
tripped until a real and rare brownout event happened and I would have
remained blissfully unaware of the
feature.
After the power was restored and
the protection reset, the viewer would
continue to enjoy uninterrupted television for many more months or even
years, before such an event might happen again to trip the protection.
Since I was never present in the
owner's home when the unprompted
fault happened, I can only suspect his
mains voltage is regularly dropping
below 200VAC. I was not planning to
spend an evening there monitoring the
mains voltage to find out. I suggested
to him that he purchase a $30 plug-in
power monitor available from Jaycar
to check for himself; it is not uncommon for there to be power fluctuations
in rural locations.
The owner was hoodwinked into
believing he did not have a power
problem by a different technology
– CFL lights which maintain their
brightness despite the voltage drop.
Unlike incandescent lamps which give
a visual indicator of the voltage of your
power supply; flickering or obviously
dimming when the voltage dropped.
Yet another hidden and overlooked
clue was that the Sky decoder was
housed in a cabinet with a tinted glass
door, so it was not obvious to the owner that the decoder was going through
its reboot sequence after the power interruption. All he saw was the blank
TV screen which came back to normal
by itself after a few minutes.
I suggested the owner have an electrician check his power supply as
such a severe voltage drop could suggest a high resistance in one of the
three phases supplied to the property,
which in turn could pose a fire risk.
All of this happened in late summer
so it was destined to be much more of
an issue come mid-winter when heaters, hot water and ovens are all working harder.
The “SAT” word which sidetracked me briefly must have been
programmed into the new TV when it
was installed by the retailer. I was surprised he had gone to this much trouble. It is a feature within the menu of
some TVs which allows you to enter
your preferred label for the various
inputs. Resetting the TV the first time
erased this entry and it defaulted back
to the HDMI1 label.
Another little twist was that despite
purchasing a nice sound bar and subwoofer, again maybe an upsell by a
keen salesman, the new owner was
missing out completely on the muchimproved sound these systems offer
over the standard TV speakers.
From the very first time the power
dropout happened, the speaker system
had not automatically restarted. It was
the only device not to do so and despite a scan through its menu, I could
not find any reference to power settings which would allow me to select
auto power on. It probably relies on
the HDMI interaction feature which I
mentioned earlier, switching itself on
or off in sync with the TV.
The owner had been using the TV
speakers only and I know this because
he complained that he had to hold
the TV remote control high in the air
ualiEco
Circuits Pty Ltd.
siliconchip.com.au
June 2017 51
to adjust the volume. The sound bar
was blocking the infrared signal to the
TV, unless the remote was raised sufficiently above it.
When I explained to the owner
that he needed to deliberately power
the sound bar back on after a power
interruption, I could tell he had not
been doing so. In fact, he was completely unaware that it had not been
working and that he had been missing
out on much improved sound fidelity
from his entertainment system.
I had another job recently with
a near new TV which came in for
service with both speakers blown; this
despite the owner having a sound bar.
I wonder if this was another case of
the sound bar not being able to come
back on automatically after a power
interruption?
Faulty capacitors don’t
need to be bulging
L. W., of Logan, Qld, replaced bulging capacitors on the main board of his
malfunctioning PVR and thought that
would fix it. But it wasn’t that simple
and it took a lot more detective work
to complete the repair.
About 12 months ago, my TEAC
HDR 1600T Personal Video Recorder
began to exhibit erratic operation until
it finally failed and would not complete
its start up boot process, hanging approximately half-way through.
I had experienced problems before
with the unit which had turned out
to be a bulging electro in the power
supply circuit, so it was with some
hope that I removed the cover to take
a look inside.
After spending some time examining the power supply and finding no
signs of distress, I turned my attention
to the main board. Only part of this
board was visible as the hard drive is
mounted above it. There was nothing
obvious here either so I decided to
switch on and measure the outputs
from the power supply.
I waited for it to complete as much
of the boot process as it could and
then took some measurements. There
was no joy here as all appeared to
be well within tolerance. At this
point I started to lose interest as the
machine was now getting a little long
in the tooth and much better machines
with larger hard drives are available
on the market.
However, there were a couple of
weekly shows that I had recorded and
52 Silicon Chip
I really did want to view them. I decided to remove the hard drive for a
better look of the main board. And it
was here that I struck pay dirt or so I
thought. Under where the hard drive
had been sitting I could clearly see
three electrolytic capacitors with their
tops bulging.
I didn’t have any of the correct values (all three were 220µF 16V types)
so after a quick visit to the local electronics store, I wasted no time fitting
the capacitors and replacing the main
board. The HDD was reinstalled, power supply connected and switched on.
Well, you can imagine how I felt
when this time there was even less
response from the unit than before I
had started. In disgust, I switched off,
pushed it to the rear of the bench and
that’s where it sat for 12 months.
During that time it got in my way on
several occasions but I just ignored it
as best I could. I did make an attempt
to boot the HDD from my PC in an
effort to retrieve the information from
it but even with the assistance of the
internet I wasn’t able to achieve an
end result.
Having recently purchased a
replacement machine, the time came
to decide whether to have another go
at fixing it or consign it to the wheelie
bin. It was still in a dismantled state
and picking up the main board, I
noticed that there were several other
similar capacitors in the same area as
the ones I had previously changed.
All were black with blue labelling while most of the other electros
on the board were black with white
labelling. So for no other reason I
decided to change those too, as I felt
the symptoms dictated a faulty electro somewhere.
I didn’t have the correct values but
decided to use what I had at hand
rather than waste any more money
buying new ones. In all I ended up
changing CE2, 3, 11, 15, 16, 24, 29
and CE223.
Some of the capacitors I used were
physically bigger, so I had to leave
their legs fairly long and bend them
over into what space I could find so
as to reinstall the HDD which, as
stated, fitted over the whole lot. The
photo shows some of the replacement
capacitors.
I didn’t hold much hope of success,
so it was a surprise when the machine
booted up and all appeared well. That
was several months ago now and I am
gradually catching up on episodes of
the weekly shows I had recorded some
12 months ago.
However, it did bug me in not knowing which capacitor was actually the
culprit. So one night I fired up the
scope and oscillator and measured
the ESR of the capacitors that I had
replaced the second time around.
Again to my surprise, while it was a
220µF capacitor like the bulging ones
I had originally replaced that was obviously faulty, all the others were at
various stages of deterioration, with
much higher ESR than they should
have exhibited.
So there you go; another piece of
electronic equipment saved from the
tip for just the price of a few electrolytic capacitors. You can be lucky
SC
sometimes.
Bulging 220µF 16V electrolytics weren't the only issue in this video recorder as it
wasn't until some of the larger capacitors were changed due to high ESR values
that the set came back to life. This photo shows the new capacitors installed.
siliconchip.com.au
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