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I'm trying to determine the best way to hook up to the connector shown in
the Photos section under Miscellaneous/unknown.connector.jpg.

It is a stepper motor driver board. I have searched the internet by the
board's id and found nothing. I can not find any product ids on the
connector itself.

Any suggestions?

Thanks

Bill



------------------------------------

Please trim excess when replyingYahoo! Groups Links

Steve,

Do you have a reference for that? I have never heard that before and
would like to understand the science behind it.

Thanks,

Ross

On 26/01/2011 12:53 PM, AlienRelics wrote:

Do NOT give in to the temptation to get caps with much higher

voltages. Electrolytics must run at something not to far under their rated voltage.

I'm not sure what the voltage derating is supposed to be, but I

usually try not to use caps at less than 70% of their rated voltages.

Steve Greenfield AE7HD

Steve,

Do you have a reference for that? I have never heard that before and
would like to understand the science behind it.

Thanks,

Ross

On 26/01/2011 12:53 PM, AlienRelics wrote:

Do NOT give in to the temptation to get caps with much higher voltages.

Electrolytics must run at something not to far under their rated voltage.

I'm not sure what the voltage derating is supposed to be, but I usually

try not to use caps at less than 70% of their rated voltages.

Steve Greenfield AE7HD

------------------------------------

Please trim excess when replyingYahoo! Groups Links

Do NOT give in to the temptation to get caps with much higher voltages. Electrolytics must run at something not to far under their rated voltage.

I'm not sure what the voltage derating is supposed to be, but I usually try not to use caps at less than 70% of their rated voltages.

Steve Greenfield AE7HD

Thanks. I'll remember that if the time comes.

Mark

Sent from my iPhone.

On Jan 25, 2011, at 1:44 PM, "Roland F. Harriston" <rolohar@...> wrote:

Mark T.:

Also, consider getting caps with a higher temperature rating.
Nichicon makes good caps that have higher temp. ratings
for not much more than the cost of lower temp rating devices.

Roland F. Harriston

Last year I got a Phillips PM3267 100MHz scope
(with probe) like new for $10!

Oh I hate you....

And now I hate my 15 Mhz scope (that I bought for $15).

====

And by the way... what city is this, that people trash such nice toys ? Any gold bars for $10?

Jong

Mark T.:

Also, consider getting caps with a higher temperature rating.
Nichicon makes good caps that have higher temp. ratings
for not much more than the cost of lower temp rating devices.

Roland F. Harriston


Mark Tolleson wrote:

Ah! An answer that supports my hypothesis--my favorite kind. Anyway,
I knew there must be something that explained my luck. So, if this
monitor quits I'll just upgrade the caps to a higher voltage and go on
my merry way. I've got this brick (with a box full of others) and
instead of giving it away on freecycle, I'd rather just use it.

Cheap and ill advised, perhaps, but I just won't throw something if it
works (or has any hope of working again).

Mark

--- On Mon, 1/24/11, Peter Morris <morris-peter@...
<mailto:morris-peter%40sky.com>> wrote:

From: Peter Morris <morris-peter@... <mailto:morris-peter%40sky.com>>
Subject: RE: [Electronics_101] LCD monitor power supply
To: Electronics_101@...
<mailto:Electronics_101%40yahoogroups.com>
Date: Monday, January 24, 2011, 6:15 PM



The reason that you can often get away with using the wrong "brick" is

because most of the monitor's internal circuitry requires voltages other

that 12 (usually 5 and 3.3 among others). The monitor has DC-DC converters

inside which will maintain a constant output voltage over a wide range of

input voltages. When using DC-Dc converters, the higher the input voltage,

the less current will be drawn from the supply. I'd be careful going too

high though, as there will be some devices requiring 12V (audio op-amps

spring to mind). Also, there are probably some electrolytic capacitors

across the 12V rail rated at either 16V, 25V, or 35V. If 16V - 19V "brick"

will kill them. With 25V - 19V will be close, but probably ok. If the caps

are 35V rated, then 19V won't harm them.

When choosing a replacement PSU (brick), the voltage is usually the most

important point of specification. If the original was 12V 4A, then the

replacement should be 12V (or close, eg. 11-14ish) and at least 4A. If the

monitor requires 4 amps, a 2 amp PSU won't be able to cope. A 12V 10A PSU

will work fine. A 20V 4A supply is not recommended.

As for repairing the old "brick", in my experience, the most common
cause of

failure of switch-mode PSUs is electrolytic capacitors 'drying out'.
This is

often because the PSUs are built to a pathetic budget, meaning the
cheapest

parts are used, not the most appropriate. Switch-mode PSUs operate at high

frequencies (usually in the region of 100KHz). With current flowing in and

out of the bulk electrolytic capacitors at these rates, ESR of the

capacitors becomes crucial in order to keep ripple on the output (and

instability as a result) low. When capacitors with high ESR are used, the

result is that the capacitors heat up while in use. This often causes the

top of the can to bulge until the weak point in the middle breaks. At this

point, the electrolyte will evaporate. As this happens, the effective

capacitance of the capacitor reduces to almost nothing. The ripple of the

PSU will increase and eventually, the PSU will no longer even start.

In short, when I am presented with a faulty piece of equipment which I

suspect may be the SMPS, I immediately visually inspect the
electrolytic for

signs of bulging. If there are any with even the slightest of bulges, I

replace them without question. 9 times out of 10, this has worked.
Just last

week, I repaired a PC which would power on and then power down straight

away. I took the cover off and there were 7 caps on the MoBo with bulging

tops. I replaced them and the PC now works fine.

Hope this is insightful for some of you. Please tell me if you think I

missed the point, or have just wasted a lot of your time reading this.

Thanks

Pipester

From: Electronics_101@...
<mailto:Electronics_101%40yahoogroups.com>

[mailto:Electronics_101@...
<mailto:Electronics_101%40yahoogroups.com>] On Behalf Of Roland F.
Harriston

Sent: 24 January 2011 15:41

To: Electronics_101@...
<mailto:Electronics_101%40yahoogroups.com>

Subject: Re: [Electronics_101] LCD monitor power supply

An excelllent source for a variety of power supplies is Marlin P. Jones

Associates, Inc., located in

Lake Park, Florida (www. mpja.com). Prices are very reasonable, and a

wide variety of linear and

switch-mode power supplies are available. MPJ is always my first choice

when I need a power

supply.

Another thought: "Wall Warts" are not (generally) NOT regulated. A

"nominal" voltage is usually

specified on the unit, but since they are not regulated, the actual

voltage delivered to the device

being powered can vary a great deal, proportionate to the V/I demand of

the device being powered.

Switch-mode power supplies are almost always regulated, and these are

they types of supplies

that are used with computer monitors, etc.

IMHO, using an unregulated "wall wart" to powrer some devices can lead

to drastic disaster

at worst, and poor and erratic operation at best.

MPJ usually has in stock, a variety of switch-mode, regulated "bricks"

that are reasonably priced.

I never attempt to repair a failed switch-mode brick..............it

just not economically worth the

effort........that is.........if you can ever actually repair the

blasted thing and get back to spec.

For example: MPJ shows several 12VDC bricks with 1 Amp, up to 4 Amp

capability at prices

around 10 to 15 bucks.

Can't beat MJP's prices, variety, and fast shipment.

Spend your time designing something that's fun and useful.

Roland F. Harriston, P.D.

****

Roland F. Harriston

Andrew Villeneuve wrote:

I've actually had this exact same problem ( 19" LCD with a 12V/4A power

brick that burnt out ), and since I had a pair of 12V/2A wall-warts

laying

around, I ganged them together in parallel. Seems to work great.

Barring that, my standard approach to these problems would just be

to hook

up a spare ATX power supply - you can usually find them for free in

old PCs

that people throw away because they're underpowered they don't know

how to

clean up their virus collection.

-Andrew

On Wed, Jan 19, 2011 at 11:27 AM, Reese <reeza@...

<mailto:reeza%40reeza.com>

<mailto:reeza%40reeza.com>

<mailto:reeza%40reeza.com>> wrote:

I have a bad news story. The 100-240 v input, 12v 4A output power

brick

that sends power to my 19" LCD monitor apparently took a dump

overnight.

An LED on the brick does not light up properly, I can't measure

anything

on the output side. I've already looked in my spare parts piles, I do

not have any power bricks or wallwarts that come close enough.

I'm in the process of opening the plastic case, to see if anything is

obviously wrong and can easily be fixed. It's glued (no screws) so it

is slow going with a hobbyist slitting saw:

<

600-h/413S586EGEL__SL500_AA280_.jpg

On the chance that the brick is properly toasted and cannot be fixed,

what are some other options for 12vdc @ 4a to power the monitor?

Yes, I can Google for something, but I thought I'd ask here first. If

something quick and easy makes for a good project build, why not do

that instead of rushing of to purchase a turnkey item?

Reese

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That was in Concord, NH. At other times, I've gotten a stereo zoom
microscope for $25, a 110MHz RF generator for $1, and other amazing
bargains. Also got a lot of junk that couldn't be repaired. The
problem is, you never know what you are going to find, or what kind of
shape it's in. It's not a good way to furnish a lab, but it is an
amusing hobby.

Kerry

Last year I got a Phillips PM3267 100MHz scope
(with probe) like new for $10!

Oh I hate you....

And now I hate my 15 Mhz scope (that I bought for $15).

====

And by the way... what city is this, that people trash such nice toys ? Any gold bars for $10?

Jong

Ah! An answer that supports my hypothesis--my favorite kind. Anyway, I knew there must be something that explained my luck. So, if this monitor quits I'll just upgrade the caps to a higher voltage and go on my merry way. I've got this brick (with a box full of others) and instead of giving it away on freecycle, I'd rather just use it.

Cheap and ill advised, perhaps, but I just won't throw something if it works (or has any hope of working again).

Mark

--- On Mon, 1/24/11, Peter Morris <morris-peter@... <mailto:morris-peter%40sky.com>> wrote:

From: Peter Morris <morris-peter@... <mailto:morris-peter%40sky.com>>
Subject: RE: [Electronics_101] LCD monitor power supply
To: Electronics_101@... <mailto:Electronics_101%40yahoogroups.com>
Date: Monday, January 24, 2011, 6:15 PM


The reason that you can often get away with using the wrong "brick" is

because most of the monitor's internal circuitry requires voltages other

that 12 (usually 5 and 3.3 among others). The monitor has DC-DC converters

inside which will maintain a constant output voltage over a wide range of

input voltages. When using DC-Dc converters, the higher the input voltage,

the less current will be drawn from the supply. I'd be careful going too

high though, as there will be some devices requiring 12V (audio op-amps

spring to mind). Also, there are probably some electrolytic capacitors

across the 12V rail rated at either 16V, 25V, or 35V. If 16V - 19V "brick"

will kill them. With 25V - 19V will be close, but probably ok. If the caps

are 35V rated, then 19V won't harm them.

When choosing a replacement PSU (brick), the voltage is usually the most

important point of specification. If the original was 12V 4A, then the

replacement should be 12V (or close, eg. 11-14ish) and at least 4A. If the

monitor requires 4 amps, a 2 amp PSU won't be able to cope. A 12V 10A PSU

will work fine. A 20V 4A supply is not recommended.

As for repairing the old "brick", in my experience, the most common cause of

failure of switch-mode PSUs is electrolytic capacitors 'drying out'. This is

often because the PSUs are built to a pathetic budget, meaning the cheapest

parts are used, not the most appropriate. Switch-mode PSUs operate at high

frequencies (usually in the region of 100KHz). With current flowing in and

out of the bulk electrolytic capacitors at these rates, ESR of the

capacitors becomes crucial in order to keep ripple on the output (and

instability as a result) low. When capacitors with high ESR are used, the

result is that the capacitors heat up while in use. This often causes the

top of the can to bulge until the weak point in the middle breaks. At this

point, the electrolyte will evaporate. As this happens, the effective

capacitance of the capacitor reduces to almost nothing. The ripple of the

PSU will increase and eventually, the PSU will no longer even start.

In short, when I am presented with a faulty piece of equipment which I

suspect may be the SMPS, I immediately visually inspect the electrolytic for

signs of bulging. If there are any with even the slightest of bulges, I

replace them without question. 9 times out of 10, this has worked. Just last

week, I repaired a PC which would power on and then power down straight

away. I took the cover off and there were 7 caps on the MoBo with bulging

tops. I replaced them and the PC now works fine.

Hope this is insightful for some of you. Please tell me if you think I

missed the point, or have just wasted a lot of your time reading this.

Thanks

Pipester

From: Electronics_101@... <mailto:Electronics_101%40yahoogroups.com>

[mailto:Electronics_101@... <mailto:Electronics_101%40yahoogroups.com>] On Behalf Of Roland F. Harriston

Sent: 24 January 2011 15:41

To: Electronics_101@... <mailto:Electronics_101%40yahoogroups.com>

Subject: Re: [Electronics_101] LCD monitor power supply

An excelllent source for a variety of power supplies is Marlin P. Jones

Associates, Inc., located in

Lake Park, Florida (www. mpja.com). Prices are very reasonable, and a

wide variety of linear and

switch-mode power supplies are available. MPJ is always my first choice

when I need a power

supply.

Another thought: "Wall Warts" are not (generally) NOT regulated. A

"nominal" voltage is usually

specified on the unit, but since they are not regulated, the actual

voltage delivered to the device

being powered can vary a great deal, proportionate to the V/I demand of

the device being powered.

Switch-mode power supplies are almost always regulated, and these are

they types of supplies

that are used with computer monitors, etc.

IMHO, using an unregulated "wall wart" to powrer some devices can lead

to drastic disaster

at worst, and poor and erratic operation at best.

MPJ usually has in stock, a variety of switch-mode, regulated "bricks"

that are reasonably priced.

I never attempt to repair a failed switch-mode brick..............it

just not economically worth the

effort........that is.........if you can ever actually repair the

blasted thing and get back to spec.

For example: MPJ shows several 12VDC bricks with 1 Amp, up to 4 Amp

capability at prices

around 10 to 15 bucks.

Can't beat MJP's prices, variety, and fast shipment.

Spend your time designing something that's fun and useful.

Roland F. Harriston, P.D.

****

Roland F. Harriston

Andrew Villeneuve wrote:

I've actually had this exact same problem ( 19" LCD with a 12V/4A power

brick that burnt out ), and since I had a pair of 12V/2A wall-warts

laying

around, I ganged them together in parallel. Seems to work great.

Barring that, my standard approach to these problems would just be

to hook

up a spare ATX power supply - you can usually find them for free in

old PCs

that people throw away because they're underpowered they don't know

how to

clean up their virus collection.

-Andrew

On Wed, Jan 19, 2011 at 11:27 AM, Reese <reeza@...

<mailto:reeza%40reeza.com>

<mailto:reeza%40reeza.com>

<mailto:reeza%40reeza.com>> wrote:

I have a bad news story. The 100-240 v input, 12v 4A output power

brick

that sends power to my 19" LCD monitor apparently took a dump

overnight.

An LED on the brick does not light up properly, I can't measure

anything

on the output side. I've already looked in my spare parts piles, I do

not have any power bricks or wallwarts that come close enough.

I'm in the process of opening the plastic case, to see if anything is

obviously wrong and can easily be fixed. It's glued (no screws) so it

is slow going with a hobbyist slitting saw:

<

600-h/413S586EGEL__SL500_AA280_.jpg

On the chance that the brick is properly toasted and cannot be fixed,

what are some other options for 12vdc @ 4a to power the monitor?

Yes, I can Google for something, but I thought I'd ask here first. If

something quick and easy makes for a good project build, why not do

that instead of rushing of to purchase a turnkey item?

Reese

I think they have gotten good at designing things so they are barely capable of performing the task.

Over the years, I noticed that CRT TVs and monitors are very sensitive to having the airflow impeded. Even just setting a TV in an entertainment center that has only a few inches around and above, or setting a doily on the TV that partly blocks the air slots are enough to cause lots of signs of overheating.

Sony TVs, while otherwise great TVs, seemed to be especially sensitive to cooking capacitors, although all were subject to this problem. Shrinking vertical? Bad caps. Whining audio? Bad caps. I fixed quite a few Sony Multisync monitors where the only real problem was bad solder and a few bad capacitors.

For quite a few years as things were in process of switching to mixed DIP and SMD, bad solder was a real problem. I think it was RCA that we saw a -lot- of TVs never make it out of the showroom. As soon as they'd been in for three warrantee repairs, they got replaced by RCA. We got quite a few sets right from the local distributor. The other techs would try very hard to find the one solder joint that would make it work, so of course they'd come back in a short time and they could bill for another warrantee repair.

That's not me - I'd resolder 100 or more solder joints and mine would not come back.

Steve Greenfield AE7HD

--- In Electronics_101@... <mailto:Electronics_101%40yahoogroups.com>, "vaclav_sal" <vaclav_sal@...> wrote:

To Reese and others who were after the capacitors (me included).
Please keep the subject handy. There must be something wrong with

design or manufacturing them if so many of them fail.

Vaclav

PS Last question - did your failure occured while monitor was

running or you noticed (!) it when you turned it on next time?

All,

I am throwing in the towel on the LCD monitor itself. Please

cease and desist all discussions of the LCD Monitor circuit

board under this thread. Or elsewhere.

I have purchased a replacement LCD monitor and will be shitcanning

the old LCD monitor at the recycle place. I'd like to keep it on

hand for spare parts but "on hand" is a space with limited room.

So, it must go.

Meanwhile, the brick is still on my desk and it's malfunction,

still a curiosity. It's also potentially useful for other

projects if it can be made to work again. And unlike the

monitor, it doesn't have quite so many SMT components. So.

I'll bring the brick up again when some time has passed

(read, when I get the caps replaced). Or not, if like too

many other projects, this one gets pushed aside. It's not

my fault, the 73 Camino needs quarter panel replacements...

Reese

------------------------------------

Please trim excess when replyingYahoo! Groups Links

I've actually had this exact same problem ( 19" LCD with a 12V/4A power

brick that burnt out ), and since I had a pair of 12V/2A wall-warts laying

around, I ganged them together in parallel. Seems to work great.

Barring that, my standard approach to these problems would just be to hook

up a spare ATX power supply - you can usually find them for free in

old PCs

that people throw away because they're underpowered they don't know how to

clean up their virus collection.

-Andrew

On Wed, Jan 19, 2011 at 11:27 AM, Reese <reeza@...

<mailto:reeza%40reeza.com>> wrote:

I have a bad news story. The 100-240 v input, 12v 4A output power brick

that sends power to my 19" LCD monitor apparently took a dump overnight.

An LED on the brick does not light up properly, I can't measure anything

on the output side. I've already looked in my spare parts piles, I do

not have any power bricks or wallwarts that come close enough.

I'm in the process of opening the plastic case, to see if anything is

obviously wrong and can easily be fixed. It's glued (no screws) so it

is slow going with a hobbyist slitting saw:

<

On the chance that the brick is properly toasted and cannot be fixed,

what are some other options for 12vdc @ 4a to power the monitor?

Yes, I can Google for something, but I thought I'd ask here first. If

something quick and easy makes for a good project build, why not do

that instead of rushing of to purchase a turnkey item?

Reese

[Non-text portions of this message have been removed]

To Reese and others who were after the capacitors (me included).
Please keep the subject handy. There must be something wrong with design or manufacturing them if so many of them fail.
Vaclav

PS Last question - did your failure occured while monitor was running or you noticed (!) it when you turned it on next time?