DVD player unresponsive

[Mike Halmarack]

A neighbor even more ancient than myself has asked me to look at his
DVD player which despite the replacement of the plug fuse remains
unswitchonable. It's a Toshiba Model # SD2010KB.
Is it likely that there is another blown fuse inside the player itself
that could be replaced to bring it back to life?
--

Mike

[Jack Harry Teesdale]

It could be a 'blown'capacitor, sometimes accessible from the rear panel.

[Tricky Dicky]

Could just be a faulty switch

Richard

[The Natural Philosopher]

Indeed. When described smoke, a nasty smell and a unresponsive bit of
1970s kit my friend who fixes such simply said 'blown mains filter cap,
probably a [such and such] brand' , and indeed it was. It wasn't after
careful probing all that was wrong but it was most of it...

DVD players are however ten a penny on ebay.

--
“it should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalin’s Communist era, nor in the Orwellian
utopia of 1984.”

Vaclav Klaus

[Mike Halmarack]

On Fri, 11 Aug 2023 16:28:19 +0100, The Natural Philosopher
<t...@invalid.invalid> wrote:

>On 11/08/2023 16:05, Jack Harry Teesdale wrote:
>> On 11/08/2023 15:42, Mike Halmarack wrote:
>>> A neighbor even more ancient than myself has asked me to look at his
>>> DVD player which despite the replacement of the plug fuse remains
>>> unswitchonable. It's a Toshiba Model # SD2010KB.
>>> Is it likely that there is another blown fuse inside the player itself
>>> that could be replaced to bring it back to life?
>>
>> It could be a 'blown'capacitor, sometimes accessible from the rear panel.
>
>Indeed. When described smoke, a nasty smell and a unresponsive bit of
>1970s kit my friend who fixes such simply said 'blown mains filter cap,
>probably a [such and such] brand' , and indeed it was. It wasn't after
>careful probing all that was wrong but it was most of it...
>
>DVD players are however ten a penny on ebay.

A gross exaggeration as usual.
--

Mike

[Jack Harry Teesdale]

The quip apart the mains filter cap is the most likely culprit if you
are sure power is passing through the ON/OFF switch.

There are some helpful Toshiba manuals here;
https://www.manualslib.com/manual/321177/Toshiba-Sd2010kb.html

[Paul]

Perhaps you could do a brain transplant.

https://www.ebay.co.uk/p/135633765

A disassembly. SMPS on the right.

https://www.youtube.com/watch?app=desktop&v=DP8qU4aJlWo

[Picture]

https://i.postimg.cc/d3qQ9FQk/toshiba-dvd-player-SD2010-KB.jpg

If an SMPS is "weak", due to failing circuitry, it can
enter current limit state, with almost no external load.

You could try disconnecting the decoder from the SMPS and
measuring the SMPS output, no load. Assuming it is open-circuit-stable.
Modern supplies are open circuit stable, some old wretched designs,
needed 25% of DC output load to ensure stability (that's the worst
I've seen, printed right on the label of the thing).

Hard to say what voltages it might need. It may be a desktop drive,
rather than a laptop drive, so it needs at least 12V @ 1.5A (for
spinup) and 5V @ 1A just for the DVD controller board. The decoder might
be another 5V @ 1A as well. Laptop drives use 5V power only, which could
save making one rail on the SMPS. The thickness of the drive mechanism,
hints at the type (thin is 5V only). The drive will be rip-lock, so
it does not need to spin much faster than 1X and make a lot of noise.

SMPS don't have just GO/NOGO states. They can current limit with hardly
any output loading at all, when they become "weak". So "weakness" is a
state for an SMPS. The circuit may be visually perfect (no burned
transistor or inductor to hint at a total failure), yet, the SMPS is
incapable of producing the rated output. Draw half an amp and the 12V
output could drop to 6V. Older supplies don't bother to provide voltage
protection and may not care that their 12V output is now only 6V.

When you see three wires on a power cable, it *could* be two +5V wires
and one GND wire. Rather than being a +5V/+12V one. Some four wire assemblies
are like that too, two +5V, two GND, to get past the connector current flow
limits. A lot of times, when some dick tries to cheap out by using the
wrong connector, that's precisely where you find burn marks and ohmic
contacts. Right where the cheapness is. You can look at some of
these "jobs" and predict precisely where it's going to fail at some point.

When a connector fails, both the male and the female part must be replaced.
You cannot "half-fix" a burned connector situation, or the un-repaired
part will burn the repaired part.

Paul

[Mike Halmarack]

Thanks for the advice and links JHT, much appreciated.
--

Mike

[Mike Halmarack]

On Fri, 11 Aug 2023 14:37:05 -0400, Paul <nos...@needed.invalid>
wrote:

Incredibly inspiring Paul, thanks.
I've managed to take the first step and acquired a screwdriver.
--

Mike

[Brian Gaff]

Most of these, assumedly cheapish ones have a switch mode psu inside of them
which runs all the time. Eventually, for reasons unknown they just stop
working. It could be as simple as dodgy capacitors, a Semiconductor or that
little chip they all use, even the tiny transformer or diodes in it. Either
way, it would not hurt to open it up and see if there are any supplies on
the main board, but in these surface mount unrepairable days, one normally
visits the tip and buys something new from Amazon as I did. It obviously
needs to have the sockets you need and its becoming harder to find analogue
connectors other than basic stereo these days, most of the clever stuff
comes out via a fibre optic cable. Might be time to move a bit more up
market, as there are a lot to choose from, and most blue ray, so if he is
into surround or Dolby Atmos sound, he could buy the new remixed versions of
the Beatles albums in Dolby Atmos.
grin.
Brian

--

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[Brian Gaff]

Besides if the fuse was blown, they blow for a reason usually. That reason
could be a capacitor, certainly, but is most often the switch mode supply.
Indeed most supplies as mentioned previously, run all the time and die by
just stopping working.

Brian

--

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[SteveW]

On 13/08/2023 11:00, Brian Gaff wrote:
> Besides if the fuse was blown, they blow for a reason usually. That reason
> could be a capacitor, certainly, but is most often the switch mode supply.
> Indeed most supplies as mentioned previously, run all the time and die by
> just stopping working.

Fuses can just age and fail. You can (with glass fuses) sometimes see
that the fuse wire has simply failed at one spot and the wire is still
there, rather than blown and the wire has mainly disappeared.

[Paul]

There's a pattern to it.

The speed of the fuse, predicts application stability.

Slow blow fuses are really the champs at "proper" behavior.
However, if one fails to blow, you may end up wishing it
was more loosey-goosey like the faster blowing fuses.

The faster the fusing speed, the less predictable it becomes.
It's like putting "flash paper" in a circuit :-) We had one fuse
in the lab, that was so fast, we had to re-rate them 5x.
(Use a 10 ampere fuse in a 2 ampere circuit, to stop nuisance trips.)
With that high a re-rating, you're then asking yourself "what is
the point of these things". These were only used in lab prototypes
at the time, they were never used in production.

You can find articles with some of the technical details, but
these style articles aren't anecdotal enough to be useful to
end-users. A good search term is "fuse I-squared-T".

https://forum.digikey.com/t/fuse-i2t-rating-melting-point-and-interrupt-rating/1271

If the ambient temperature around a fuse is way too high, this can
lead to the fuse opening at less than the rated current.

Paul

[Mike Halmarack]

On Sun, 13 Aug 2023 10:55:32 +0100, "Brian Gaff"
<brian...@gmail.com> wrote:

>Most of these, assumedly cheapish ones have a switch mode psu inside of them
>which runs all the time. Eventually, for reasons unknown they just stop
>working. It could be as simple as dodgy capacitors, a Semiconductor or that
>little chip they all use, even the tiny transformer or diodes in it. Either
>way, it would not hurt to open it up and see if there are any supplies on
>the main board, but in these surface mount unrepairable days, one normally
>visits the tip and buys something new from Amazon as I did. It obviously
>needs to have the sockets you need and its becoming harder to find analogue
>connectors other than basic stereo these days, most of the clever stuff
>comes out via a fibre optic cable. Might be time to move a bit more up
>market, as there are a lot to choose from, and most blue ray, so if he is
>into surround or Dolby Atmos sound, he could buy the new remixed versions of
>the Beatles albums in Dolby Atmos.
> grin.
> Brian

I think you're right there. A new player and a new TV is the way to
go.
--

Mike