"The Brute" takes form.

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Postby Steve Anderson » Thu Jan 01, 2009 9:32 pm

Dear All,

As I now have some free time the timebases for 'The Brute' are done. The attached waveform is of it in 72-line non-interlaced mode. Interlacing should hopefully come soon.

I'm trying to clear all the low-voltage stuff away before I get onto the Ozone generating stuff.

Happy New Year everyone!

Steve A.
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Postby Steve Anderson » Mon Jan 12, 2009 2:57 pm

Viewmaster wrote:It might become, Feb or March. Albert.


err...it's increasingly looking that way, no further work on "The Brute" recently...but I'm really hoping to make a real re-start on it within a week or so. The project (real work) I've been working on just won't lay down and die.

Steve A.
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Postby Viewmaster » Mon Jan 12, 2009 7:28 pm

Steve Anderson wrote:
Viewmaster wrote:It might become, Feb or March. Albert.


err...it's increasingly looking that way, no further work on "The Brute" recently...but I'm really hoping to make a real re-start on it within a week or so. The project (real work) I've been working on just won't lay down and die.
Steve A.


You're obviously not an undertaker, Steve. :wink:
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Postby Steve Anderson » Sat Jan 17, 2009 9:23 pm

OK, now I have a little more time, 'The Brute' moves forward...

Timebases done, next is the PWM grid modulation....very temporary as all can see...

Steve A.

Also with the audio tubes alight....
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Last edited by Steve Anderson on Sun Jan 18, 2009 12:16 am, edited 3 times in total.
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Postby dominicbeesley » Sat Jan 17, 2009 11:53 pm

That's looking great!

Out of interest what frequency are you using for the PWM - I'll be very interested to see the results....

What are the advantages of PWM for CRTs? Is it just to get a linear light response rather than the usual 2.2 gamma?



Dom
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Postby Steve Anderson » Sun Jan 18, 2009 1:07 am

dominicbeesley wrote:That's looking great!


Thanks, little by little....

dominicbeesley wrote:Out of interest what frequency are you using for the PWM - I'll be very interested to see the results....What are the advantages of PWM for CRTs? Is it just to get a linear light response rather than the usual 2.2 gamma?


It started with the 'requirement' of Steve O's Luxeons in his monitor that (as the datasheets specified) required PWM for dimming/modulation. As it turns out many have used Luxeons in a standard linear fashion with no problem. But as always it's not guaranteed. The PWM frequency is currently at approximately 100kHz, but given suitable output transistors there is no reason that this could be raised.

As for the linearity of CRTs driven by a similar waveform, it seems intuitive that it should be linear, negating the the requirement for non-linear drive to the cathode or grid. which I have done in the 3" monitor as published, and plan to use within 'The Brute". Resuts will prove or otherwise if I'm headed in the right direction.

Updates as and when even if turn out to be proved totally wrong...

Steve A.
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Postby Steve Anderson » Mon Jan 26, 2009 3:21 pm

This is a bit off-topic for this thread but couldn't think of anywhere else to post it until I create a thread when I make a start on a camera.

Below is the lathe I intend to use to turn the drum for the camera, it will be a drum camera called "The Beast" to compliment "The Brute". This lathe can easily take a drum of 1.5m (say 5ft) in diameter.

The oranges are due to Chinese New Year, the year of the Ox.

Steve A.
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Postby Viewmaster » Mon Jan 26, 2009 7:34 pm

You must be in a large workshop there, Steve.....put some steel capped shoes on just in case something falls onto those NBTV toes!

Wearing sandals in a workshop?...NO NO NO!
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Postby Steve Anderson » Mon Jan 26, 2009 7:55 pm

Viewmaster wrote:Wearing sandals in a workshop?...NO NO NO! Albert.


Thanks for the concern Albert, but two things. Firstly as it is/was Chinese New Year so the place was closed and inactive, secondly this is Thailand....Health and Safety? Forget it!!

I won't actually be 'driving' the lathe but I'll probably be present when the work is done. I'll wear whatever I have to hand but the guy operating certainly will be wearing sandals, as they all do. No-one wears 'real' shoes except for business people in safe offices. I doubt very much you could even buy a pair of 'Toe-Tectors' here.

Now however much legislation is put in place there is no way you can protect people from their own stupidity....here's this years Darwin Awards...

Sometimes the Fact is scarier than Fiction!


The Darwin Awards (New list folks)..It's that time again... The Darwin Awards are finally out, the annual honour given to the persons who did the gene pool the biggest service by killing themselves in the most extraordinarily stupid way.


Last year's winner was the fellow who was killed by a Coke machine, which toppled over on top of him as he was attempting to tip a free soda out. This year's winner was a real rocket scientist.... HONEST! Read on...And remember that each and every one of these is a TRUE STORY. And the nominees were;

Semifinalist #1

A young Canadian man, searching for a way of getting drunk cheaply, because he had no money with which to buy alcohol, mixed gasoline with milk. Not surprisingly, this concoction made him ill, and he vomited into the fireplace in his house. This resulting explosion and fire burned his house down, killing both him and his sister.

Semifinalist #2

Three Brazilian men were flying in a light aircraft at low altitude when another plane approached. It appears that they decided to moon the occupants of the other plane, but lost control of their own aircraft and crashed. They were all found dead in the wreckage with their pants around their ankles.

Semifinalist #3

A 22-year-old Reston, VA, man was found dead after he tried to use octopus straps to bungee jump off a 70-foot railroad trestle. Fairfax County police said Eric Barcia, a fast food worker, taped a bunch of these straps together, wrapped an end around one foot, anchored the other end to the trestle at Lake Accotink Park , jumped and hit the pavement. Warren Carmichael, a police spokesman, said investigators think Barcia was alone because his car was found nearby. 'The length of the cord that he had assembled was greater than the distance between the trestle and the ground,' Carmichael said. Police say the apparent cause of death was 'Major trauma.'

Semifinalist #4

A man in Alabama died from rattlesnake bites. It seems that he and a friend were playing a game of catch, using the rattlesnake as a ball. The friend -- no doubt a future Darwin Awards candidate -- was hospitalized.

Semifinalist #5

Employees in a medium-sized warehouse in west Texas noticed the smell of a gas leak. Sensibly, management evacuated the building extinguishing all potential sources of ignition; lights, power, etc.


After the building had been evacuated, two technicians from the gas company were dispatched. Upon entering the building, they found they had difficulty navigating in the dark. To their frustration, none of the lights worked. Witnesses later described the sight of one of the technicians reaching into his pocket and retrieving an object that resembled a cigarette lighter.


Upon operation of the lighter-like object, the gas in the warehouse exploded, sending pieces of it up to three miles away. Nothing was found of the technicians, but the lighter was virtually untouched by the explosion. The technician suspected of causing the blast had never been thought of as ''bright'' by his peers.

Now, the winner of this year's Darwin Award (awarded, as always, posthumously):


The Arizona Highway Patrol came upon a pile of smoldering metal embedded in the side of a cliff rising above the road at the apex of a curve. The wreckage resembled the site of an airplane crash, but it was a car. The type of car was unidentifiable at the scene. Police investigators finally pieced together the mystery. An amateur rocket scientist ... had somehow gotten hold of a JATO unit (Jet Assisted Take Off, actually a solid fuel rocket) that is used to give heavy military transport planes an extra 'push' for taking off from short airfields. He had driven his Chevy Impala out into the desert and found a long, straight stretch of road. He attached the JATO unit to the car, jumped in, got up some speed, and fired off the JATO!


The facts as best as could be determined are that the operator of the 1967 Impala hit the JATO ignition at a distance of approximately 3.0 miles from the crash site. This was established by the scorched and melted asphalt at that location.
The JATO, if operating properly, would have reached maximum thrust within 5 seconds, causing the Chevy to reach speeds well in excess of 350 mph and continuing at full power for an additional 20-25 seconds.


The driver, and soon to be pilot, would have experienced G-forces usually reserved for dog fighting F-14 jocks under full afterburners, causing him to become irrelevant for the remainder of the event. However, the automobile remained on the straight highway for about 2.5 miles (15-20 seconds) before the driver applied and completely melted the brakes, blowing the tires and leaving thick rubber marks on the road surface, then becoming airborne for an additional 1.4 miles and impacting the cliff face at a height of 125 feet leaving a blackened crater 3 feet deep in the rock. Most of the driver's remains were not recoverable. However, small fragments of bone, teeth, and hair were extracted from the crater, and fingernail and bone shards were removed from a piece of debris believed to be a portion of the steering wheel.


Epilogue: It has been calculated that this moron attained a ground speed of approximately 420-mph, though much of his voyage was not actually on the ground.


You couldn't make this stuff up, could you?


Steve A.
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Postby Panrock » Mon Jan 26, 2009 9:42 pm

Equally OT but I'm longing to ask... will you be transporting the legendary 'Brute' from Thailand to the convention Steve? How will it be declared at Customs? :D

Steve O
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Postby Steve Anderson » Tue Jan 27, 2009 3:19 pm

Panrock wrote:...will you be transporting the legendary 'Brute' from Thailand to the convention Steve? How will it be declared at Customs? Steve O


Sorry to disappoint, (I hope) but I'll not be ready for this years convention. Although "The Brute" should be completed I'm aiming to get a complete signal chain done like yourself from camera to monitor. That will not happen before April for sure. So I'll have to defer until the 2010 convention.

As for customs, "A prototype and demonstration unit of no commercial value and due for re-export on (date)". In other words a Temporary Import License. I've always found the staff in the 'Red Channel" to be helpful and never had to pay duties etc.. Even things like brand-new camcorders and the like, I start to get my cheque book out and they wave you through, too much paperwork for them.

In my case it helps to prove that you are resident outside the EU, Thai driving license, residents permit and appropriate visas for Thailand in the passport all 'grease the wheels'.

Steve A.
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Postby Steve Anderson » Fri Jan 30, 2009 2:58 pm

OK, moving on...progress is being made, now it's the turn of the Waveform Monitor which I am just about to start on. Below shows it 'naked' with a better view of the DH3-91 CRT and the three EF91s for deflection. The very 'open' nature of the EF91 can be seen in the right-hand tube, there appears to be little inside. There's a large void between the grid structure and the very small anode consisting of two thin strips of metal (just visible in the left-hand tube) . One way of keeping capacitance down for what is an RF pentode.

What appears to be a blemish to the left of the CRT face is actually a bit of fag-ash, since removed.

Steve A.
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Postby dominicbeesley » Fri Jan 30, 2009 11:25 pm

Those little tubes really are sweet. I've got a few of them and keep meaning to do something with them....I feel a mini-nbtv-scope coming on!

Are you running that with its own deflection-X drive or are you stealing that from the main tube?

Dom
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Postby AncientBrit » Fri Jan 30, 2009 11:38 pm

Dominic,

re Mini NBTV scope using ICP1.

"Here's one I made earlier"

Circuit schematic is not up to Steve's drawing standard though.

Regards,

Graham
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Postby Steve Anderson » Sat Jan 31, 2009 12:05 am

dominicbeesley wrote:Are you running that with its own deflection-X drive or are you stealing that from the main tube? Dom


Stolen in a way for horizontal/line monitoring but switchable to frame/field rate therefore it has its own set of deflection tubes as in the photo. The main CRT has its own complement of four EF91s for deflection. In a way I wish I had opted for using the ECC91 I mentioned earlier just to reduce the amount of soldering required and I have those in stock too...oh well, next time.

Graham, nothing wrong with that drawing, perfectly good enough. I only wish some equipment manufacturers would produce drawings to the same standard. Some are simply undecipherable. With all due respect those from 'across the pond' are usually the worst.

Steve A.
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