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Source /Sub for SV-3a Diode

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Bob T
Guest

Mon May 12, 2008 1:23 am   



I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob

DaveM
Guest

Mon May 12, 2008 3:10 am   



..
"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:q6MVj.4188$GK4.3700_at_trndny01...
Quote:
I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob


The NTE177 is a sub for that diode, which appears to be an ordinary 200V silicon
rectifier. You can probably use any rectifier with the same case as your
original part.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some people are like Slinkies. Not really good for anything, but they bring a
smile to your face when pushed down the stairs

Bob T
Guest

Tue May 13, 2008 2:09 am   



Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look
like a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had me
wondering if there were two devices in the case or something that might
raise the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob
"DaveM" <masondg4499_at_comcast99.net> wrote in message
news:JL6dncVTQOa3OrrVnZ2dnUVZ_uCdnZ2d_at_comcast.com...
Quote:
.
"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:q6MVj.4188$GK4.3700_at_trndny01...
I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob


The NTE177 is a sub for that diode, which appears to be an ordinary 200V
silicon rectifier. You can probably use any rectifier with the same case
as your original part.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters
in the address)

Some people are like Slinkies. Not really good for anything, but they
bring a smile to your face when pushed down the stairs


Bob T
Guest

Tue May 13, 2008 2:09 am   



Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look
like a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had me
wondering if there were two devices in the case or something that might
raise the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob
"DaveM" <masondg4499_at_comcast99.net> wrote in message
news:JL6dncVTQOa3OrrVnZ2dnUVZ_uCdnZ2d_at_comcast.com...
Quote:
.
"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:q6MVj.4188$GK4.3700_at_trndny01...
I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob


The NTE177 is a sub for that diode, which appears to be an ordinary 200V
silicon rectifier. You can probably use any rectifier with the same case
as your original part.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters
in the address)

Some people are like Slinkies. Not really good for anything, but they
bring a smile to your face when pushed down the stairs


DaveM
Guest

Tue May 13, 2008 3:08 am   



"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:TS5Wj.1982$za1.1107_at_trndny07...
Quote:
Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look like
a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had me
wondering if there were two devices in the case or something that might raise
the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob
"DaveM" <masondg4499_at_comcast99.net> wrote in message
news:JL6dncVTQOa3OrrVnZ2dnUVZ_uCdnZ2d_at_comcast.com...
.
"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:q6MVj.4188$GK4.3700_at_trndny01...
I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob


The NTE177 is a sub for that diode, which appears to be an ordinary 200V
silicon rectifier. You can probably use any rectifier with the same case as
your original part.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the address)

Some people are like Slinkies. Not really good for anything, but they bring
a smile to your face when pushed down the stairs


When checking a diode (rectifier or other semiconductor junction), make sure
that you use the Diode function on your DMM. If you use a normal resistance
range, the applied voltage from the DMM isn't enough to cause the junction to
conduct. If it checks OK with a Huntron, then it's probably OK.
There are devices that have multiple PN junctions, and are usually used for
setting bias levels and temperature compensation in audio circuits, but
according to the NTE reference, the SV-3A is just an ordinary (low current) 200V
silicon rectifier. If you're concerned about a proper replacement, then you can
see the NTE177 datasheet at http://www.nteinc.com/specs/100to199/pdf/nte177.pdf.

Cheers!!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some people are like Slinkies. Not really good for anything, but they bring a
smile to your face when pushed down the stairs.

DaveM
Guest

Tue May 13, 2008 3:08 am   



"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:TS5Wj.1982$za1.1107_at_trndny07...
Quote:
Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look like
a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had me
wondering if there were two devices in the case or something that might raise
the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob
"DaveM" <masondg4499_at_comcast99.net> wrote in message
news:JL6dncVTQOa3OrrVnZ2dnUVZ_uCdnZ2d_at_comcast.com...
.
"Bob T" <boboranntrottier_at_verizon.net> wrote in message
news:q6MVj.4188$GK4.3700_at_trndny01...
I have a marantz 4230 receiver with a blown amp
looking for a SV-3a temp compensating diode (or an entire amp board)
Can I use any temp compensating diode or is there something I should be
looking for
Thanks
Bob


The NTE177 is a sub for that diode, which appears to be an ordinary 200V
silicon rectifier. You can probably use any rectifier with the same case as
your original part.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the address)

Some people are like Slinkies. Not really good for anything, but they bring
a smile to your face when pushed down the stairs


When checking a diode (rectifier or other semiconductor junction), make sure
that you use the Diode function on your DMM. If you use a normal resistance
range, the applied voltage from the DMM isn't enough to cause the junction to
conduct. If it checks OK with a Huntron, then it's probably OK.
There are devices that have multiple PN junctions, and are usually used for
setting bias levels and temperature compensation in audio circuits, but
according to the NTE reference, the SV-3A is just an ordinary (low current) 200V
silicon rectifier. If you're concerned about a proper replacement, then you can
see the NTE177 datasheet at http://www.nteinc.com/specs/100to199/pdf/nte177.pdf.

Cheers!!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some people are like Slinkies. Not really good for anything, but they bring a
smile to your face when pushed down the stairs.

Thomas Tornblom
Guest

Tue May 13, 2008 6:50 am   



"Michael A. Terrell" <mike.terrell_at_earthlink.net> writes:

Quote:
maarten_at_panic.xx.tudelft.nl wrote:

In sci.electronics.repair jakdedert <jakdedert_at_bellsouth.net> wrote:
I'm a little confused about a 230 volt circuit. In what part of the
world does the utility supply 230v?

Continental Europe used to have 220 volts (before that it was 127 volts in
some places), the UK used to have 240 volts. Nowadays, the common voltage
is 230 volts -10% +6%.


In other words, nothing has changed. They just wrote sloppier specs.

It has changed, the voltage is now close to 230V, at least in Sweden.

I guess the sloppiness was specified to allow a gradual switch from
220/240 to 230 and still be within spec.

Residential power in Norway is normally 230V three phase btw, instead
of 400V three phase. Their 230V outlets are two phase and ground
instead of one phase, neutral and ground. Their three phase outlets
therefore are blue instead of red and have four prongs instead of five.

DaveM
Guest

Tue May 13, 2008 1:57 pm   



"Franc Zabkar" <fzabkar_at_iinternode.on.net> wrote in message
news:e6bi24pgbdut2uk6mu1kq1k326mapnpo0t_at_4ax.com...
Quote:
On Tue, 13 May 2008 01:09:07 GMT, "Bob T"
boboranntrottier_at_verizon.net> put finger to keyboard and composed:

Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look
like a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had me
wondering if there were two devices in the case or something that might
raise the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob

See this schematic:
http://www.jmargolin.com/marantz/p750.pdf

Diodes H005 and H006 are identified as "HV0000212, SV-3A". The circuit
symbol for each diode is two diodes in series.

However, the schematic diagram for the Marantz 4240 receiver draws
them as regular single diodes.

http://www.eserviceinfo.com/downloadsm/25365/MARANTZ_4240.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Looking at the NTE177 data sheet, I see that the forward voltage drop is 1.0
volt, pretty high for a low current rectifier.

I looked up the SV-3A unit in my old RCA SK-series catalog, and also in my old
Sylvania ECG series catalog. The SK3864 is listed as the replacement for the
SV-3A. The ECG605A is the ECG replacement.
Both of those catalogs list the replacement to be a Silicon Varistor, not a
rectifier.
ECG605A characteristics:
Vf = 1.26V - 1.36V @ 3ma
Tempco = -4.6mV per degree C

SK3864 characteristics:
Vf = 1.24V - 1.34V @ 3ma
Tempco = -3.6mV per degree C

In view of the Marantz schematic and the other observations, I would have to say
that the NTE177 part is not a good replacement. Instead, I suggest that the
NTE605A part is the proper replacement part. It has the same characteristics as
the ECG part, and is a silicon varistor, not a rectifier.

Another fly in the ointment; according to the datasheet, the NTE605A has been
discontinued. I emailed NTE and described the problem, including the fact that
the NTE605A has been discontinued. Will have to wait for their solution, if
they have one. You might be able to find a dealer or distributor that still has
an NTE605A in stock. Good luck on that.

Back to the OP... the original part is probably behaving correctly on your DMM
resistance test. Even in the Diode mode, the DMM might not have enough voltage
at the probes to turn on the junction, so it will read open in both directions.
The Huntron test should be reliable. Sorry for all the confusion.

Cheers...
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some people are like Slinkies. Not really good for anything, but they bring a
smile to your face when pushed down the stairs.

daestrom
Guest

Tue May 13, 2008 9:35 pm   



"Tzortzakakis Dimitrios" <noone_at_nospam.void> wrote in message
news:g0c3sa$902$1_at_mouse.otenet.gr...
Quote:

? "daestrom" <daestrom_at_NO_SPAM_HEREtwcny.rr.com> ?????? ??? ??????
news:4828b130$0$7047$4c368faf_at_roadrunner.com...

"Michael Moroney" <moroney_at_world.std.spaamtrap.com> wrote in message
news:g0a1o5$bcq$1_at_pcls6.std.com...
"daestrom" <daestrom_at_NO_SPAM_HEREtwcny.rr.com> writes:


P.S. In the US, a 'tap-changer' may be built for either for unloaded or
loaded operation. The 'unloaded' type can not be stepped to another tap
while there is load on the unit (although it can still be energized).
It's
switch contacts cannot interrupt load though, so if you try to move it
while
loaded, you can burn up the tap-changer. The classic 'load-tap-changer'
is
actually several switches that are controlled in a precise sequence to
shift
the load from one tap of the transformer to another while not
interrupting
the load current.

P.P.S. Load tap changers typically have a significant time-delay built
into
the controls so they do not 'hunt' or respond to short drops in voltage
such
as starting a large load. 15 seconds to several minutes is typical. So
even with load-tap-changers, starting a single load that is a high
percentage of the system capacity will *still* result in a voltage dip.

Are the load tap generators configured make-before-break?
Break-before-make would mean a (very short) power outage every
activation
but make-before-break would mean a momentarily short-circuited winding
and
the break would involve interrupting a large short circuit current.

Certainly modern ones likely use thyristors and zero crossing detectors.


I figured someone would 'bite' :-)

Typical large power load-tap-changers have a primary winding and two
secondaries.
You mean a secondary and a tetriary? The transformer for the hotel load of
a 300 MW unit is powered directly from the turbo alternator (21 kV) and
has a secondary of 6.6 kV and a tetriary of again 6.6 kV. This is done
because it has wye-wye-wye connection (IIRC). The hotel load of such a
unit is 10%, also 30 MW, including 7 brown coal mills. Typical size of a
6.6 kV motor is 1 MW.
One secondary produces about 100% of 'rated' secondary voltage. The
second secondary produces about 15% to 20% of the rated voltage, but has
numerous taps from end to end, about 2.5% 'steps'. (for a total of about
eight taps). The cental tap of the boost/buck winding is tied to one end
of the main secondary. The boost/buck can be used to step from 90% to
110% of the 'design' output. I suppose some can step over a wider range,
but I haven't run across them.

*TWO* rotary switches have each tap tied to one of the positions of each
rotory switch, and each 'wiper' is tied to single heavier contacts that
are opened in the operating sequence. The output side of these two
interrupting contacts are tied to each end of a large center-tapped
inductor.

So, normally both rotary switches are aligned to the same transformer
tap, both interrupting contacts are shut, and load current flows from the
boost/buck winding tap, splits and flows through both rotary switches,
both interrupting contacts, enters both ends of the inductor and out the
inductor center tap. Because the current flows into both ends of the
inductor and the mutual inductance of the two parts cancel, there is
little voltage drop in the inductor.

Begin step sequence:
1) Open one interrupting contactor. Now load current doubles through
half the inductor and is zero in the other half, so the voltage drop
across the inductor actually makes output voltage drop, even if trying to
step 'up'.
2) Move associated rotary switch to next step of transformer bank.
3) Close interrupting contactor. Now, the two rotary switches are across
different taps. The inductor prevents a excessive current, otherwise you
have a direct short of the two winding taps. Some tap changers can stop
at this point and are called 'half-step' units. Obviously, the inductor
has to be rated for sustained operation across a step of the boost/buck
winding plus load current in order to survive sustained 'half step'
operation.
4) But for tap changers that can't operate 'half-step', the sequence
continues. And opens the other interrupting contactor. Now the other
half of the inductor has full load current.
5) Move second rotary switch to next step (now both switches are on the
new step)
6) Close the second interrupting contactor. You're back in the initial
configuration, but with both rotary switches on a new transformer tap.
Quite the same principle is done with diesel locomotives and is called
diesel-electric transmission, and also in pure electric locomotives (E-Lok
in german, for Elektrische Lokomotive). The diesel engine, 2-stroke and
usually 600 to 900 rpm at full throttle, is coupled to a generator. The
generator has small windings, connected in series for the last notch,
higher voltage and relatively smaller current, and in parallel for start,
higher amperage and smaller voltage. The traction motors are directly
coupled on the wheel shaft, and are air cooled. An E-Lok has a trasformer,
with the primary directly supplied by the cetenary, 15 kV 16 2/3 Hz in
Germany, and 25 kV 50 Hz in Greece, The secondary uses the same principle.
The typical size of a traction motor is 1 MW, 4 (one each shaft) and
maximum voltage 700 volts, and are series wound motors with special
construction to operate at 16 2/3 Hz (or 50 Hz with today's technology).
Typical power of a diesel locomotive is 2850 HP, while an electric is 6000
HP. with 1500 HP at each shaft, also ~1MW. There is a heavy duty 12,000 HP
diesel engine in USA(with 6 shafts, also 2000 HP at each shaft). The high
speed ICE train (InterCityExpress) in germany is 13,000 HP, has a normal
travelling speed of 200 km/h, 2 locomotives, 3-phase induction motors,
electronic drive.

In US, diesel-electric used to always be DC machines, but modern ones are
now AC generators with thyristers to regulate the power flow to the traction
motors. Traction motors are still DC however to allow for their use in
dynamic braking.

I suppose in Europe the better way to go would be regenerative braking,
putting the braking power back into the overhead line, but that would need a
static inverter. Probably the transformer secondary has a four-quadrant
converter to allow reversal of power flow ??

Nice thing about the newer solid-state control systems (AC-Generator/
DC-Traction) is the ability to control wheel-slip. In the old days it took
a skilled engineer (the train-driving kind) to get maximum power without
slipping a lot (and wasting a lot of sand). Now modern units have speed
sensors on each individual wheel set and control the power flow to
individual traction motors. As soon as a wheel set starts to slip it can
redirect power flow to other traction motors to prevent the slipping set
from 'polishing the rail'. This prolongs life of the wheels and rail and
actually improves the maximum tractive effort a locomotive can deliver. And
when hauling 100+ cars of coal in a unit train up grade, tractive effort is
what keeps you moving.

You forgot to mention that traction motors often have separately powered
blower motors for air-cooling. This is because the motor may spend hours
operating at low speeds and shaft-mounted cooling fans are not enough. The
motor blower is usually mounted up inside the engine house and connects to
the traction motor via a large flexible duct.

Some diesel-electric unitl have six axles and six traction motors. The
trade-off is between how much power you can get to the traction motors and
how much weight you can keep on the wheels to keep them from slipping. Sand
is okay for starting and some special situations, but you can't carry enough
to use it for an entire run. But of course too much weight and you need
more axles to protect the rail from damage (depending on the size of the
rail being used).

daestrom
P.S. As you can see, I've seen a few railroad locomotives as well. Mostly
just the older EMD's though, not GE's newer 'green' units.

Bob T
Guest

Wed May 14, 2008 2:13 am   



Thanks that's it I found a spec for the replacement and it had a forward
voltage drop of 1.2V
I put a pair of series connected 1n2002's and it seems to be running fine
Bob
"Franc Zabkar" <fzabkar_at_iinternode.on.net> wrote in message
news:e6bi24pgbdut2uk6mu1kq1k326mapnpo0t_at_4ax.com...
Quote:
On Tue, 13 May 2008 01:09:07 GMT, "Bob T"
boboranntrottier_at_verizon.net> put finger to keyboard and composed:

Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look
like a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had
me
wondering if there were two devices in the case or something that might
raise the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob

See this schematic:
http://www.jmargolin.com/marantz/p750.pdf

Diodes H005 and H006 are identified as "HV0000212, SV-3A". The circuit
symbol for each diode is two diodes in series.

However, the schematic diagram for the Marantz 4240 receiver draws
them as regular single diodes.

http://www.eserviceinfo.com/downloadsm/25365/MARANTZ_4240.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.


Bob T
Guest

Wed May 14, 2008 2:13 am   



Thanks that's it I found a spec for the replacement and it had a forward
voltage drop of 1.2V
I put a pair of series connected 1n2002's and it seems to be running fine
Bob
"Franc Zabkar" <fzabkar_at_iinternode.on.net> wrote in message
news:e6bi24pgbdut2uk6mu1kq1k326mapnpo0t_at_4ax.com...
Quote:
On Tue, 13 May 2008 01:09:07 GMT, "Bob T"
boboranntrottier_at_verizon.net> put finger to keyboard and composed:

Dave
thanks the only thing odd I noticed is that the SV-3a diode doesn't look
like a diode using a dvm. i.e. looks open in either direction
They do look like diodes when I put them on my huntron tracker which had
me
wondering if there were two devices in the case or something that might
raise the forward voltage drop
I have a few diodes from a old scott receiver that I'll try and see what
happens

Bob

See this schematic:
http://www.jmargolin.com/marantz/p750.pdf

Diodes H005 and H006 are identified as "HV0000212, SV-3A". The circuit
symbol for each diode is two diodes in series.

However, the schematic diagram for the Marantz 4240 receiver draws
them as regular single diodes.

http://www.eserviceinfo.com/downloadsm/25365/MARANTZ_4240.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.


elektroda.net NewsGroups Forum Index - Repair Electronics - Source /Sub for SV-3a Diode

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