Toshiba TV29C90 problem; Image fades to black...

[Mark D. Zacharias]

"Brasto" <bram.stolk@gmail.com> wrote in message
news:c2493e74-7d57-453d-a04f-d10abeafc64b@f63g2000hsf.googlegroups.com...

This DENON has a separate Powersupply board which is totally
inoperative. Yes it does charge the Big Reservoir ELCO upto 350VDC but
no further SMPS action noted,
I replaced as a shotgun approach the Q1 FET and the Optocoupler
SFH617.
Not having its schematic I have been unable to identify the FET
driving components.......
Is Mark still out there fighting the SPAM allowing me to get some
light on the most likely cause of failure?
TY
Brasto

This model is a bit old for a PDF from Denon - I looked and it's not there
on the D&M FTP server.
In my experience the cost/effectiveness repair equation doesn't work out on
these. The DVD-1000 wasn't a great player to start with, and now there
aren't even major parts available for this model.

Mark Z.

 

[Mark D. Zacharias]

"Brasto" <bram.stolk@gmail.com> wrote in message
news:822c985d-00a8-47fc-a3e2-e2d6328e0e9a@b1g2000hsg.googlegroups.com...

This Denon DRA-455 fails to turn-on when powered on.
The Red SBY-light and PanelDisplay donot illuminate.
Most likely it's SBY voltage generating circuit has developped some
problems as the kick-back diode across the MainPower Relay was found
fully shorted. Replacing the diode did not help.
The SBY voltage probably is generated and routed through the
frontpanel, but as usual I have no schematic to do any detailed
diagnosis.
Is there anybody around having more knowledge of this problem?
TY
Brasto

No PDF from the server - how old is this model?

Mark Z.

 

[Mark D. Zacharias]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:%CI_j.11506$xJ7.8701@newsfe08.ams2...

"b" <reverend_rogers@yahoo.com> wrote in message
news:d32e6aab-516d-4e11-9597-13804e2bc75b@m36g2000hse.googlegroups.com...
On 25 mayo, 13:45, Brasto <bram.st...@gmail.com> wrote:
This DENON has a separate Powersupply board which is totally
inoperative. Yes it does charge the Big Reservoir ELCO upto 350VDC but
no further SMPS action noted,
I replaced as a shotgun approach the Q1 FET and the Optocoupler
SFH617.
Not having its schematic I have been unable to identify the FET
driving components.......
Is Mark still out there fighting the SPAM allowing me to get some
light on the most likely cause of failure?
TY
Brasto

look for a small value cap in the SMPS primary or near its IC. often
these are something like 1uF or 4.7UF and go bad preventing the psu
starting.

As well as the startup supply decoupling cap detailed above, check also
the startup resistor(s). Usually either a single resistor of 100k or so,
or a couple of lower values in series. Normally connects directly from the
"+" terminal of the main filter cap, to a pin on the controller IC (the
same pin as that small value cap connects to). Very common for these
resistors to fail open. Usual symptom is that the supply works fine until
one day the unit is unplugged, or there is a power failure, after which,
it never restarts.

Arfa

I've seen the FET switcher get leaky on these, but wasn't able to find a
source for it...

Mark Z.

 

[Bob Shuman]

If they are truly on separate circuits then what you describe is happening
should not be possible. Perhaps the circuits have a common (improperly
terminated) neutral wire and the devices are floating and are seeing
transients during start up?

Bob


<kolwicz@minetfiber.com> wrote in message
news:a41ae838-f7c8-4853-9da2-53b27bd6e65f@w1g2000prd.googlegroups.com...

Sometimes my microwave trips the other circuit that has our computers
on it, even though the appliance is on a different circuit at the far
end of the house. This happens maybe 1 out of 3 starts.

I've replaced the GFCI and it still trips; moved the microwave to a
third different circuit - same problem.

The microwave has been working normally for almost 5 years, but has
recently started making a buzzing sound on start up.

 

[David Lesher]

phil-news-nospam@ipal.net writes:

| I envy EU houses. If we had regular 240V/30A+ outlets, I'd be able to
| buy a snowblower with real guts. The 120v@15A ones are wimpy.

So put one in.

The issue is not the outlets available in my house [but I sometimes wish
for 3 phase..].

Rather, it's the ready market of consumer appliances that would take
advantage of them. That would require many houses to have them.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Daniel Who Wants to Know]

"James Sweet" <jamessweet1@trashmail.net> wrote in message
news:RYJ_j.5752$0R.3162@trndny05...

David Lesher wrote:
phil-news-nospam@ipal.net writes:

| I envy EU houses. If we had regular 240V/30A+ outlets, I'd be able to
| buy a snowblower with real guts. The 120v@15A ones are wimpy.

So put one in.

The issue is not the outlets available in my house [but I sometimes wish
for 3 phase..].

Rather, it's the ready market of consumer appliances that would take
advantage of them. That would require many houses to have them.



Get UK/commercial appliances, they're out there.

Yes like my Amana commercial RadarRange which is 4KW in 2.2KW out and has 3
HV magnetrons along with 3 each of the other necessary items (cap, diode,
etc.). It even has a current transformer that tells the control board via
current draw when the magnetrons are warmed up so that the timer doesn't
start counting down until it is actually cooking. It has a standard NEMA
6-20 plug on it now and will pop a bag of popcorn in roughly 75 seconds
without scorching it. I can tell you it sure beats the hell out of regular
microwave ovens for most things. The only thing I still use the regular one
for are items that involve liquids as the Amana tends to make them either
boil over or boils out all of the water before the food is cooked.

 

[Daniel Who Wants to Know]

"James Sweet" <jamessweet1@trashmail.net> wrote in message
news:RYJ_j.5752$0R.3162@trndny05...

David Lesher wrote:
phil-news-nospam@ipal.net writes:

| I envy EU houses. If we had regular 240V/30A+ outlets, I'd be able to
| buy a snowblower with real guts. The 120v@15A ones are wimpy.

So put one in.

The issue is not the outlets available in my house [but I sometimes wish
for 3 phase..].

Rather, it's the ready market of consumer appliances that would take
advantage of them. That would require many houses to have them.



Get UK/commercial appliances, they're out there.

Yes like my Amana commercial RadarRange which is 4KW in 2.2KW out and has 3
HV magnetrons along with 3 each of the other necessary items (cap, diode,
etc.). It even has a current transformer that tells the control board via
current draw when the magnetrons are warmed up so that the timer doesn't
start counting down until it is actually cooking. It has a standard NEMA
6-20 plug on it now and will pop a bag of popcorn in roughly 75 seconds
without scorching it. I can tell you it sure beats the hell out of regular
microwave ovens for most things. The only thing I still use the regular one
for are items that involve liquids as the Amana tends to make them either
boil over or boils out all of the water before the food is cooked.

 

[Arfa Daily]

"Mark D. Zacharias" <mzacharias@nonsense.net> wrote in message
news:S_J_j.1477$ZE5.1164@nlpi061.nbdc.sbc.com...

"Brasto" <bram.stolk@gmail.com> wrote in message
news:c2493e74-7d57-453d-a04f-d10abeafc64b@f63g2000hsf.googlegroups.com...
This DENON has a separate Powersupply board which is totally
inoperative. Yes it does charge the Big Reservoir ELCO upto 350VDC but
no further SMPS action noted,
I replaced as a shotgun approach the Q1 FET and the Optocoupler
SFH617.
Not having its schematic I have been unable to identify the FET
driving components.......
Is Mark still out there fighting the SPAM allowing me to get some
light on the most likely cause of failure?
TY
Brasto

This model is a bit old for a PDF from Denon - I looked and it's not there
on the D&M FTP server.
In my experience the cost/effectiveness repair equation doesn't work out
on these. The DVD-1000 wasn't a great player to start with, and now there
aren't even major parts available for this model.

Mark Z.

Gotta be worth just trying the 'usual suspects' first though, hasn't it ?

After that, I would agree that unless it's a labour of love for some reason,
it's not worth it. I had a Denon a few weeks ago (can't remember the model),
which like you, I couldn't get the switching FET for. The spares agents had
one with a similar number, but couldn't supply the exact one, and we
couldn't find data on either, so like you, I didn't proceed, as some
supplies can be very twitchy and sensitive about only having the correct
device in them ...

Arfa

 

In alt.engineering.electrical Daniel Who Wants to Know <danielthechskid@merrychristmasi.com> wrote:

| Yes like my Amana commercial RadarRange which is 4KW in 2.2KW out and has 3
| HV magnetrons along with 3 each of the other necessary items (cap, diode,
| etc.). It even has a current transformer that tells the control board via
| current draw when the magnetrons are warmed up so that the timer doesn't
| start counting down until it is actually cooking. It has a standard NEMA
| 6-20 plug on it now and will pop a bag of popcorn in roughly 75 seconds
| without scorching it. I can tell you it sure beats the hell out of regular
| microwave ovens for most things. The only thing I still use the regular one
| for are items that involve liquids as the Amana tends to make them either
| boil over or boils out all of the water before the food is cooked.

Will it operate on single phase power, like I have in my home?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

 

In alt.engineering.electrical Daniel Who Wants to Know <danielthechskid@merrychristmasi.com> wrote:

| Yes like my Amana commercial RadarRange which is 4KW in 2.2KW out and has 3
| HV magnetrons along with 3 each of the other necessary items (cap, diode,
| etc.). It even has a current transformer that tells the control board via
| current draw when the magnetrons are warmed up so that the timer doesn't
| start counting down until it is actually cooking. It has a standard NEMA
| 6-20 plug on it now and will pop a bag of popcorn in roughly 75 seconds
| without scorching it. I can tell you it sure beats the hell out of regular
| microwave ovens for most things. The only thing I still use the regular one
| for are items that involve liquids as the Amana tends to make them either
| boil over or boils out all of the water before the food is cooked.

Will it operate on single phase power, like I have in my home?

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

 

[bz]

Paul <paulguy@eastlink.ca> wrote in
news:vq5m34pd3a7jqmg5q4jiopkmkno7k34umm@4ax.com:

On Mon, 26 May 2008 01:30:42 +0000 (UTC), bz
bz+spr@ch100-5.chem.lsu.edu> wrote:

....snip!........


Nothing in ANY document I have seen so far says anything about a hazard
due to shorting the leads of an IC TOGETHER.

There is mention of discharging an INDUCED charge, via a leg during some
of the testing. The charge being induced in the assembly equipment by
the motion of the chips through the storage and assembly equipment.

One of the surprising 'reminders' [I should have remembered it from
physics] is that simply separating two conductors physically can induce
a charge. In other words, picking up a chip that has been laying on a
conductor or an insulator and lifting it vertically away from that
surface can create an electrical potential between the two objects
unless they both are grounded to a common point.


To get an idea of these voltages, you can make a crude electrometer
by using a digital voltmeter that has 10M ohms input resistance, and a
1 volt sensitivity. Connect the "common" terminal to a ground
(earthed). Connect a plate (say 3 in X 3 in.) through 10,000 Megohms
to the 1 volt input. You now have a 1000-1 voltage divider, whose
input is 10KM. If you scuff your feet on the floor, and touch the
plate you should be able to read up to several hundred volts (taking
the 1000-1 into account) as a result. You can get better results using
a more sensitive voltage range, and using 100,000Megohms or 1 million
megohms. The more sensitive of these devices can be used to pick up
the voltage potentials on insulators. (small surfaces to be measured
will require a smaller sense plate.) You have to be careful of the
insulation resistance of any components or "insulators" with this
device. These aren't your garden variety of resistors!

Nice idea on the 'electroscope'. Will play with the idea.
I have a very high impedance tube type 'electrometer' from the 50's that
was surplussed in the 70's.
I remember looking at some of these effects back then.

I use the 1000-1 circuit to demonstrate to students the degree of
voltages picked up during ordinary motions, and how well they are
controlled by use of a grounding strap. To really show ESD, you need a
charge measuring device that is calibrated, then it becomes real clear
just how bad things can get.

There are some cases of chips being slid out of their antistatic
tubes, the sliding action charged up the chips, (we assume the whole
chip charged up). As the chips dropped onto a low resistance bench,
they discharged through the pin that first touched the bench, and
damaged the chip.

That I believe. What I didn't believe was Eeyore's explanation that
shorting the chips leads together caused damage due to the current flow
caused by the stored charge flowing from one lead to the other.

Mechanical movement can induce a charged surface. One of the worst
offenders is sticky tape.... Components are often delivered as
"ammo-paks", or parts that are held in position by tape (like the
belts of ammunition), so that they can be fed into a machine that
removes them from the belt, and inserts the part into the circuit
board or assembly. If you stick down a piece of masking tape onto some
plastic, then tear it off, both the tape and the plastic will generate
a high voltage. In a lot of cases, if it's dark, you can see sparks!
That's a pretty nasty voltage!

Yes!

A lot of plastics and insulators generate significant voltage when
they are flexed or rubbed. They can induce voltages in conductive
surfaces nearby, because they set up a potential field around
themselves. Just passing by one of these charged surfaces can induce
voltages on components.

I have a chair that generates a charge when I stand up after sitting on it
for a while.

that's why the much better static bags have both "dissipative"
surfaces (on direct contact with the shipped chip) to allow gentle
discharge currents, AND one or two layers of shielding surfaces to
reduce the effect of induced voltages from nearby charged objects. For
those reasons JPL prohibits the pink bags, and uses 3M #3370 bags,
which have shielding, dissipative layers, low "outgassing", low
contamination, and a good moisture resistance.
The bags are just a small part of the overall program.... you need
to have a very disciplined and comprehensive program in order to
control ESD.
That's where the ANSI/ESD S20.20-2007 comes into play, it ties
together all the recommendations, standards, mil-specs, and practices
into a standard that isn't scattered all over the place. This standard
then refers to many other ANSI/ESD standards, each one specific to
things like packaging, measuring, charge modelling, furniture,
machinery, etc.

I agree with what you are saying and appreciate the hazards of motion
induced charges.

If I were working with very ESD sensitive chips on a daily basis, I would
want a good work station, properly set up.

If I just need to put memory into a computer or build a device like the one
I built recently, I will continue to use, with caution, the techniques I
have used successfully in the past.

I will be a bit more cautious when moving things around, taking more time
and steps to discharge 'induced charges'.

Thanks again.


--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+nanae@ch100-5.chem.lsu.edu

 

[bz]

Paul <paulguy@eastlink.ca> wrote in
news:vq5m34pd3a7jqmg5q4jiopkmkno7k34umm@4ax.com:

On Mon, 26 May 2008 01:30:42 +0000 (UTC), bz
bz+spr@ch100-5.chem.lsu.edu> wrote:

....snip!........


Nothing in ANY document I have seen so far says anything about a hazard
due to shorting the leads of an IC TOGETHER.

There is mention of discharging an INDUCED charge, via a leg during some
of the testing. The charge being induced in the assembly equipment by
the motion of the chips through the storage and assembly equipment.

One of the surprising 'reminders' [I should have remembered it from
physics] is that simply separating two conductors physically can induce
a charge. In other words, picking up a chip that has been laying on a
conductor or an insulator and lifting it vertically away from that
surface can create an electrical potential between the two objects
unless they both are grounded to a common point.


To get an idea of these voltages, you can make a crude electrometer
by using a digital voltmeter that has 10M ohms input resistance, and a
1 volt sensitivity. Connect the "common" terminal to a ground
(earthed). Connect a plate (say 3 in X 3 in.) through 10,000 Megohms
to the 1 volt input. You now have a 1000-1 voltage divider, whose
input is 10KM. If you scuff your feet on the floor, and touch the
plate you should be able to read up to several hundred volts (taking
the 1000-1 into account) as a result. You can get better results using
a more sensitive voltage range, and using 100,000Megohms or 1 million
megohms. The more sensitive of these devices can be used to pick up
the voltage potentials on insulators. (small surfaces to be measured
will require a smaller sense plate.) You have to be careful of the
insulation resistance of any components or "insulators" with this
device. These aren't your garden variety of resistors!

Nice idea on the 'electroscope'. Will play with the idea.
I have a very high impedance tube type 'electrometer' from the 50's that
was surplussed in the 70's.
I remember looking at some of these effects back then.

I use the 1000-1 circuit to demonstrate to students the degree of
voltages picked up during ordinary motions, and how well they are
controlled by use of a grounding strap. To really show ESD, you need a
charge measuring device that is calibrated, then it becomes real clear
just how bad things can get.

There are some cases of chips being slid out of their antistatic
tubes, the sliding action charged up the chips, (we assume the whole
chip charged up). As the chips dropped onto a low resistance bench,
they discharged through the pin that first touched the bench, and
damaged the chip.

That I believe. What I didn't believe was Eeyore's explanation that
shorting the chips leads together caused damage due to the current flow
caused by the stored charge flowing from one lead to the other.

Mechanical movement can induce a charged surface. One of the worst
offenders is sticky tape.... Components are often delivered as
"ammo-paks", or parts that are held in position by tape (like the
belts of ammunition), so that they can be fed into a machine that
removes them from the belt, and inserts the part into the circuit
board or assembly. If you stick down a piece of masking tape onto some
plastic, then tear it off, both the tape and the plastic will generate
a high voltage. In a lot of cases, if it's dark, you can see sparks!
That's a pretty nasty voltage!

Yes!

A lot of plastics and insulators generate significant voltage when
they are flexed or rubbed. They can induce voltages in conductive
surfaces nearby, because they set up a potential field around
themselves. Just passing by one of these charged surfaces can induce
voltages on components.

I have a chair that generates a charge when I stand up after sitting on it
for a while.

that's why the much better static bags have both "dissipative"
surfaces (on direct contact with the shipped chip) to allow gentle
discharge currents, AND one or two layers of shielding surfaces to
reduce the effect of induced voltages from nearby charged objects. For
those reasons JPL prohibits the pink bags, and uses 3M #3370 bags,
which have shielding, dissipative layers, low "outgassing", low
contamination, and a good moisture resistance.
The bags are just a small part of the overall program.... you need
to have a very disciplined and comprehensive program in order to
control ESD.
That's where the ANSI/ESD S20.20-2007 comes into play, it ties
together all the recommendations, standards, mil-specs, and practices
into a standard that isn't scattered all over the place. This standard
then refers to many other ANSI/ESD standards, each one specific to
things like packaging, measuring, charge modelling, furniture,
machinery, etc.

I agree with what you are saying and appreciate the hazards of motion
induced charges.

If I were working with very ESD sensitive chips on a daily basis, I would
want a good work station, properly set up.

If I just need to put memory into a computer or build a device like the one
I built recently, I will continue to use, with caution, the techniques I
have used successfully in the past.

I will be a bit more cautious when moving things around, taking more time
and steps to discharge 'induced charges'.

Thanks again.


--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+nanae@ch100-5.chem.lsu.edu

 

[bz]

kolwicz@minetfiber.com wrote in news:a41ae838-f7c8-4853-9da2-
53b27bd6e65f@w1g2000prd.googlegroups.com:

Sometimes my microwave trips the other circuit that has our computers
on it, even though the appliance is on a different circuit at the far
end of the house. This happens maybe 1 out of 3 starts.

I've replaced the GFCI and it still trips; moved the microwave to a
third different circuit - same problem.

A GFCI trips when it senses that the current on the hot and return lines
are not the same [implying leakage to earth somewhere] or when there is a
significant voltage sensed on the safety ground.

Look for any way that currents flowing in the microwave's power circuit
could be getting to the GFCI for your computers.

The microwave has been working normally for almost 5 years, but has
recently started making a buzzing sound on start up.

Probably unrelated to your GFCI problem.





--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

 

[bz]

kolwicz@minetfiber.com wrote in news:a41ae838-f7c8-4853-9da2-
53b27bd6e65f@w1g2000prd.googlegroups.com:

Sometimes my microwave trips the other circuit that has our computers
on it, even though the appliance is on a different circuit at the far
end of the house. This happens maybe 1 out of 3 starts.

I've replaced the GFCI and it still trips; moved the microwave to a
third different circuit - same problem.

A GFCI trips when it senses that the current on the hot and return lines
are not the same [implying leakage to earth somewhere] or when there is a
significant voltage sensed on the safety ground.

Look for any way that currents flowing in the microwave's power circuit
could be getting to the GFCI for your computers.

The microwave has been working normally for almost 5 years, but has
recently started making a buzzing sound on start up.

Probably unrelated to your GFCI problem.





--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

 

[bz]

CharlesBlackstone <charlesblackstone1@hotmail.com> wrote in
news:f464e097-97ab-4366-87ab-a8dc42e1b594@i76g2000hsf.googlegroups.com:

On May 19, 10:07 am, bz <bz+...@ch100-5.chem.lsu.edu> wrote:
"Dave Plowman (News)" <d...@davenoise.co.uk> wrote
innews:4fa14a16d7dave@d
avenoise.co.uk:

In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.139>,
   bz <bz+...@ch100-5.chem.lsu.edu> wrote:
This means that you can regulate the 'open circuit voltage'. You
would want to make sure that never exceeds your battery voltage by
more than a few percent.

IMHO the charge voltage is pretty irrelevant. It's the current that
matters.

Here is a current regulator that can be used for 0-2A with supplies
that don't have current regulation built
in.http://kd1jv.qrpradio.com/vps/voclp
s.HTM


Hey thanks everyone for all the great answers. I have been busy and
not returned (and I thought the thread had sort of faded away).

bz, what is the purpose of regulating the current, when the power
supply can supply current from 0 to 10 amps (or if I parallel the two
PS in it, 20 amps)?

I was assuming directly charging batteries from a DC power supply.

If you have a supply that has an adjustable current regulator built in,
the cicuit I showed is not needed. I didn't look at the specs on YOUR
supply so I was just giving a link to a nice current regulator I had seen.
If you were charging batteries directly from a voltage regulated supply,
without any current regulation or limiting, you can damage your batteries.

.....

Thanks to your help I set the voltage at a little over 12 (since I
dont' have a diode between charger and PS), put the amps at max,

Check the specs for the batteries you are charging and be sure that you
never exceed the 'maximum charging current' ratings. Otherwise you will
damage your batteries and shorten their life.

I had a small battery blow up when I tried to recharge it.

turned the PS on, connected it to the charger which was already
connected to the battery, and the charger nicely started pulse
charging the nimh transmitter pack.

You have a charger that is [I assume] designed for the batteries you are
using. Its job is to regulate the current flow so as to charge as fast as
possible without damage to the battery.

I'm so new to this stuff I was
afraid to turn the Mastech on which I just got. All is good now.

Wow, this is a great group and lot's of nice folks, I'll come back for
help and let you know how my learning curve goes.

Good luck and be careful.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

 

[bz]

CharlesBlackstone <charlesblackstone1@hotmail.com> wrote in
news:f464e097-97ab-4366-87ab-a8dc42e1b594@i76g2000hsf.googlegroups.com:

On May 19, 10:07 am, bz <bz+...@ch100-5.chem.lsu.edu> wrote:
"Dave Plowman (News)" <d...@davenoise.co.uk> wrote
innews:4fa14a16d7dave@d
avenoise.co.uk:

In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.139>,
   bz <bz+...@ch100-5.chem.lsu.edu> wrote:
This means that you can regulate the 'open circuit voltage'. You
would want to make sure that never exceeds your battery voltage by
more than a few percent.

IMHO the charge voltage is pretty irrelevant. It's the current that
matters.

Here is a current regulator that can be used for 0-2A with supplies
that don't have current regulation built
in.http://kd1jv.qrpradio.com/vps/voclp
s.HTM


Hey thanks everyone for all the great answers. I have been busy and
not returned (and I thought the thread had sort of faded away).

bz, what is the purpose of regulating the current, when the power
supply can supply current from 0 to 10 amps (or if I parallel the two
PS in it, 20 amps)?

I was assuming directly charging batteries from a DC power supply.

If you have a supply that has an adjustable current regulator built in,
the cicuit I showed is not needed. I didn't look at the specs on YOUR
supply so I was just giving a link to a nice current regulator I had seen.
If you were charging batteries directly from a voltage regulated supply,
without any current regulation or limiting, you can damage your batteries.

.....

Thanks to your help I set the voltage at a little over 12 (since I
dont' have a diode between charger and PS), put the amps at max,

Check the specs for the batteries you are charging and be sure that you
never exceed the 'maximum charging current' ratings. Otherwise you will
damage your batteries and shorten their life.

I had a small battery blow up when I tried to recharge it.

turned the PS on, connected it to the charger which was already
connected to the battery, and the charger nicely started pulse
charging the nimh transmitter pack.

You have a charger that is [I assume] designed for the batteries you are
using. Its job is to regulate the current flow so as to charge as fast as
possible without damage to the battery.

I'm so new to this stuff I was
afraid to turn the Mastech on which I just got. All is good now.

Wow, this is a great group and lot's of nice folks, I'll come back for
help and let you know how my learning curve goes.

Good luck and be careful.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

 

[danny burstein]

In <g1h7ie$bap$1@reader2.panix.com> David Lesher <wb8foz@panix.com> writes:

Get UK/commercial appliances, they're out there.

A Lucas snowblower? It would leak oil, not work when damp,
and plow down the wrong side of the driveway...

Still thinking of the British Rail trains that
wouldn't work because (to quote their PIO)
"It was the wrong kind of snow"?

And want 50Hz...

They'd be drooling over 60 Hz.


--
_____________________________________________________
Knowledge may be power, but communications is the key
dannyb@panix.com
[to foil spammers, my address has been double rot-13 encoded]

 

[David Lesher]

James Sweet <jamessweet1@trashmail.net> writes:

Rather, it's the ready market of consumer appliances that would take
advantage of them. That would require many houses to have them.

Get UK/commercial appliances, they're out there.

A Lucas snowblower? It would leak oil, not work when damp,
and plow down the wrong side of the driveway...

And want 50Hz...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[N_Cook]

dodger741 <dodger741@gmail.com> wrote in message
news:34e36bd2-eb48-4272-9dd2-49dae0862d01@x1g2000prh.googlegroups.com...

I have an HP 8568B spectrum analyzer which went through shipping
recently. The display unit no longer works and it appears that the
CRT section is the culprit. I checked the HV and signals and on the
surface they appear OK. I did find some glass chips in the case
which leads me to believe the tube is damaged/broken. Taking the CRT
out is a pain. I can measure the filament resistance at about 4 ohms.
If the tube is cracked or broken, wouldn't the filament burn-up with
an infinite resistance??

On the 2 occassions I've come across scopes that have been dropped and the
CRT has failed then I've heard bits of glass pillars loose inside the tube
if you slowly turn the whole case around every whichway. Any smallbits of
external glass is likely to have come away from the socket area which you
may get away with.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[Geoffrey S. Mendelson]

Major Debacle wrote:

I need an FSL-520-D Japanese style fluorescent lamp. It is unlike an
American style lamp in that it only has one electrode at each end. An
American style lamp flickers and overheats when plugged into this
Japanese style fixture. Does anyone know where I might be able to
procure these FSL-520-D Japanese style fluorescent lamps?

The AC voltage across this Japanese fluorescent fixture when plugged
into a 110-120 American socket is about 600 volts measured with a
standard American multimeter. Just for my own edification, does anyone
know how this kind of fixture differs in its operation from an American
style fluorescent fixture?

It's called an "Instant Start" bulb.

http://en.wikipedia.org/wiki/Fluorescent_lamp

Page down to the starting section or search the page for "instant start".

Here's an example of one, found with a quick web search:

http://www.kwhlighting.com/Merchant2/merchant.mv?Screen=PROD
&Store_Code=kwh&Product_Code=SYL-22403

(sorry for the split link).

You could call them and ask.

Or just take the bulb to any lighting supply company and ask for
an "instant start bulb" that fits.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson.com N3OWJ/4X1GM