The 3BP1 Anderson monitor

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Re: 3BP1

Postby Harry Dalek » Fri Nov 20, 2015 9:47 am

Steve Anderson wrote:The divider will be as accurate as the meter itself, plus/minus the 10M resistor tolerances. 10% is near enough but it seems you're getting better results than that, a bit of good luck for once!


Yes pretty good results on the click ut33b i am using .i noticed some others on the net making something like this were out by a bit ...i am using metal film half watt resistors so they are petty much correct value wise on DC...tried the Ac test on 128 volts and getting 5.0 4.9 volts and 222 volts ac getting 8.4 so a bit off even when you times those numbers by 3 ...might have a different resistance on the AC side in the meter...Still happy with the DC results

A couple of other bits you'll be needing for the CRT, a Zener diode around 75V/1W or two lower voltage ones in series (for a total of at least 60V), and possibly a 5V/0.3W version too. CRTs always need all this mucking around if you're going to do it properly.

Steve A.

[/quote]

Ok i can get those jaycar have a good zener diode range i might even have one handy if i can read the case with my eyes :shock:

BTW i tested the resistor looking parts on 142volts DC its 52.4 volts out either side i think its a high megohm resistor theres one with just a blue marking is the 52.4 volts the one with black blue strip is 1.7 volts out on this voltage the yellow only marking one is 48.7 volts...interesting
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Re: 3BP1

Postby Steve Anderson » Fri Nov 20, 2015 11:59 am

Oh well, shame about the AC mode, consider it useless - anyway, it's not that often you need to measure high AC voltages.

If you needed to measure high 50/60Hz AC voltages on a regular basis then a small interface which would run off a 9V battery would be quite simple to knock up. For the likes of us it's probably not worth it.

Steve A.
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Re: 3BP1

Postby Harry Dalek » Fri Nov 20, 2015 10:57 pm

Steve Anderson wrote:Oh well, shame about the AC mode, consider it useless - anyway, it's not that often you need to measure high AC voltages.

If you needed to measure high 50/60Hz AC voltages on a regular basis then a small interface which would run off a 9V battery would be quite simple to knock up. For the likes of us it's probably not worth it.

Steve A.


I could try it on my other meter just to see ...but for me a correct or close High voltage DC reading is of more use .
AC tends to be at highest for me in the hundreds of volts what my meter could read any way .
Your help on the HV probe i had confidence to try a second resistor train to fit in that probe tube of 19 10 meg resistor with a select range switch High low at the output wire to the DVM but i have to double the number. so 140 volts is 14 on the low select and 7 volts on the high so i suppose top range 5000 volts shows up at 500 volts with the 9 resistors and 250volts on the high 19 ...10,000 volts top range now on this DVM.
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Re: 3BP1

Postby Steve Anderson » Sat Nov 21, 2015 8:07 pm

Harry, here's my suggestion for the HV CRT supplies. It may seem a bit odd grounding one of the 240v parts of the transformer, but it does give you 240v and 480v AC at the same time. I guess you'll get 1.2-1.3kV out of this once a load is applied.

The capacitors should again be a 'batch match' and preferably unused and new, this is so their leakage currents are likely to be fairly equal - this is important.

Equally important is to only apply 240v at first to the voltage doubler and quickly check that the voltages across each capacitor in the two arms are roughly equal within each arm. If they are leave the circuit energised for a few hours to 'form' the capacitors. Check no smoke or heat. Power down and wait until the capacitors discharge.

Apply the full 480v and repeat the above. Measure no-load voltage.

If it's found later that this isn't enough voltage we'll add another stage. Also because the capacitors are quite small (electrically) there may be issues with ripple, we'll cross that bridge when we get to it.

Steve A.
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Re: 3BP1

Postby Harry Dalek » Sun Nov 22, 2015 10:11 am

Steve Anderson wrote:Harry, here's my suggestion for the HV CRT supplies. It may seem a bit odd grounding one of the 240v parts of the transformer, but it does give you 240v and 480v AC at the same time. I guess you'll get 1.2-1.3kV out of this once a load is applied.


Thanks for the power supply circuit ,i have to go out today but i will look for all the parts this afternoon will not take much time to put together .

The capacitors should again be a 'batch match' and preferably unused and new, this is so their leakage currents are likely to be fairly equal - this is important.


Yes i again did buy a batch of them at once all new 450 v 10 uf have about 40 of them so i would think they were made around same time .

Equally important is to only apply 240v at first to the voltage doubler and quickly check that the voltages across each capacitor in the two arms are roughly equal within each arm. If they are leave the circuit energised for a few hours to 'form' the capacitors. Check no smoke or heat. Power down and wait until the capacitors discharge.


OK will do ,i know you have to take care making these things ,i had made lots of mistakes in the past ...power supplies show you pretty quick how well the circuit is put together ..mistakes get converted to Heat pretty fast///never liked the exploding capacitor and sizzling transformer experience.. :roll:

Apply the full 480v and repeat the above. Measure no-load voltage.

If it's found later that this isn't enough voltage we'll add another stage. Also because the capacitors are quite small (electrically) there may be issues with ripple, we'll cross that bridge when we get to it.

Steve A.


I will leave room if another stage is needed .before i go out i will go looking for those resistors.....Thanks again and let you know how it gos Steve .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: 3BP1

Postby Steve Anderson » Sun Nov 22, 2015 2:33 pm

Below is my initial suggestion for the CRT circuit. Depending on the results we may have to alter some items that are in red and the voltages may vary. I've assumed -1250V as a starting point.

To check out the voltages once built, run the CRT cold, disconnect the heater (pin 14) to check the voltages are sensibly correct.

At this stage it's best not to run the CRT until the deflection amplifiers, the ramp generators and the modulation for the opto-coupler are built and tested.

There is no brilliance control as this is done on the low-voltage side of the opto-coupler.

Next will be the final version of the deflection amps. You need to fire up the ramp generators and measure the top and bottom of each ramp (vert and horiz) referenced to ground with a valid NBTV signal on the input.

Steve A.
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Re: 3BP1

Postby Harry Dalek » Sun Nov 22, 2015 5:25 pm

Steve i got home early enough today to make the power supply circuit ,i still have to test it...Thank you for the next stage i will get the parts together for that build ...i will report back on the voltages and i hope no heating blue smoke or bangs !

OK a bit later and i have tested the circuit .
ON 247 volts AC i am getting + 368 volts
ON 270 volts AC i am getting negative 800 volts spot on

So a little high on the positive and a few hundred down on the negative ...seemed pretty steady i have not done your long run test for the caps yet .
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Re: 3BP1

Postby Steve Anderson » Sun Nov 22, 2015 7:26 pm

Harry, is the 800V DC result with the 240V AC into the doubler - I really hope so! If it is, good. If it's with the 480V AC into the doubler something is very wrong! Switch it off and trace everything.

If it is 800V DC derived from the 240V AC you need to add one more 10uF and one more 1M/1W into the string between C106 +ve and ground making a C107 and R106 as per below, otherwise the caps in that chain will be over-voltaged.

The 240/480V must be slightly higher than advertised with no load - expected, but not quite this high. It's a good result anyway.

Steve A.

A few minutes later...also the same idea in the C102/103 chain, a third cap needed. I've modified the diagram and added C103A and R102A...when you've added the additional caps repeat the same exercise at 240V so the new caps will 'form' too.

I'm now thinking you may have to increase the value of C104-107 as ripple will possibly be a problem. Four 10uF in series = 2.5uF only.

When you've added the extra Cs & Rs and they've 'formed' for a while, increase the input volts to the doubler to the nominal 480V and measure the no-load voltages again. After a while make sure each cap has approximately the same voltage across it as the others in the same chain. Let that run for quite some time if all is well.

Then add the test loads as indicated below in blue, this simulates the loads of the final circuits. Let me know what these final voltages are, I may need to adjust some of the CRT circuit as a result. This test only needs to be as long as it takes you to measure the voltages, but do both at the same time, both loads, a couple of minutes should be enough. Remove the test loads when you have the figures.
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Re: 3BP1

Postby Harry Dalek » Sun Nov 22, 2015 9:06 pm

Steve Anderson wrote:Harry, is the 800V DC result with the 240V AC into the doubler - I really hope so! If it is, good. If it's with the 480V AC into the doubler something is very wrong! Switch it off and trace everything.


The transformer gives 247 volts and 270 volts .......247 is feeding the positive voltage in your circuit and 270 the negative, the voltages are steady no signs of a mistake thank goodness i was very careful testing ...

If it is 800V DC derived from the 240V AC you need to add one more 10uF and one more 1M/1W into the string between C106 +ve and ground making a C107 and R106 as per below, otherwise the caps in that chain will be over-voltaged.


it was the 270 volts ac to try and get a 1000 negative but its dead on negative 800 volts .

The 240/480V must be slightly higher than advertised with no load - expected, but not quite this high. It's a good result anyway.


Yes the positive is a bit higher for that extra 7 volts AC

Steve A.

A few minutes later...also the same idea in the C102/103 chain, a third cap needed. I've modified the diagram and added C103A and R102A...when you've added the additional caps repeat the same exercise at 240V so the new caps will 'form' too.


OK i will have a look i think i can fit another on the board no problems.

I'm now thinking you may have to increase the value of C104-107 as ripple will possibly be a problem. Four 10uF in series = 2.5uF only.


I will build in the extra resistor cap i have another 1 meg and cap handy

When you've added the extra Cs & Rs and they've 'formed' for a while, increase the input volts to the doubler to the nominal 480V and measure the no-load voltages again. After a while make sure each cap has approximately the same voltage across it as the others in the same chain. Let that run for quite some time if all is well.


OK i will run it a bit lower for a start half voltage ....Ok understood will test those caps

Then add the test loads as indicated below in blue, this simulates the loads of the final circuits. Let me know what these final voltages are, I may need to adjust some of the CRT circuit as a result. This test only needs to be as long as it takes you to measure the voltages, but do both at the same time, both loads, a couple of minutes should be enough. Remove the test loads when you have the figures.


Yes need to get the voltages right here to move on ............. bit late tonight but i will try and do this tomorrow after work ...have to track down those load resistors for this last test as well .. i suppose it does just need a little tweaking here and there getting close to the high negative voltage needed ...
On the other post about the next stage the opto coupler to test the brightness i would need to light the led in the coupler to see if the CRT spot and adjust focus and such ? or do you do it another way jumping ahead just wondering .
Still aways to go yet but like the new circuits for my crt you have put up .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: 3BP1

Postby Harry Dalek » Mon Nov 23, 2015 3:10 pm

Hi Steve so far it have added the extra cap and resistor.

let it run for half an hour on half voltage to the circuit and showing 540 volts i have now switched back to its normal running voltage and its showing negative 840 volts.

BTW the positive is now 390 volts ...no problems with parts heating up at all nice and cold

i will see if i can do the load resistor tests ...

and post back here in an update

OK did the load resistor test
its negative 800 volts
and positive 360 volts with both those load resistors on at the same time on the negative and positive as in your circuit.
To get to -1300 i would need another 4 or 5 stages ?
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Re: 3BP1

Postby Steve Anderson » Mon Nov 23, 2015 4:55 pm

Something isn't right here. With 270V AC into the negative voltage doubler you should get around 270x2x1.414=763V DC (no load). Now 800V DC out (no load) probably means your meter needs calibrating, the error is 4.7%. Either the AC range is reading a bit low or the DC range is reading high - or a bit of both...entirely possible.

With the (nominal) 480V AC into the doubler (but not for the positive supply) no load I would expect around -1500V DC.

Have you wired the secondary as per my drawing? - the centre-tap is not connected to ground, look at it carefully.

As for the difference between no-load and loaded conditions, as I suspected the capacitors are too small (electrically).

Steve A.
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Postby Harry Dalek » Mon Nov 23, 2015 6:52 pm

Steve Anderson wrote:Something isn't right here. With 270V AC into the negative voltage doubler you should get around 270x2x1.414=763V DC (no load). Now 800V DC out (no load) probably means your meter needs calibrating, the error is 4.7%. Either the AC range is reading a bit low or the DC range is reading high - or a bit of both...entirely possible.


NO i didn't short the positive circuit diode to ground even i could see that would be a no no /

With the (nominal) 480V AC into the doubler (but not for the positive supply) no load I would expect around -1500V DC.


It could be the transformer Steve it has 3 leads what would normally be the primary ,i think they are meant for 240 and some other countries mains voltage ,i used this to do away with 2 transformers i would need as the primary would have just 2 connection leads for 240 volts perhaps this is the problem ? i will check by measuring the voltage across the 240 270 volt leads should be over 500 if not ...as mythbusters would say theres your problem .....not your circuit but mine again i will check .

Have you wired the secondary as per my drawing? - the centre-tap is not connected to ground, look at it carefully.

As for the difference between no-load and loaded conditions, as I suspected the capacitors are too small (electrically).

Steve A.
[/quote]

As above i will check if i am having a double voltage via the 2 voltage connections ...its some thing i didn't think about till now as i am getting 240 270 i will report back ! in a sec
Last edited by Harry Dalek on Mon Nov 23, 2015 7:37 pm, edited 1 time in total.
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Re: 3BP1

Postby Steve Anderson » Mon Nov 23, 2015 7:08 pm

Ah! Maybe as it's a primary used in reverse it's actually 0-240-270V to allow for mains voltage adjustment, though 270V is really quite high for any mains. In other words the 0V is not a centre-tap at all.

I guess you (and I) have been thinking of it as 240-0-270...unlikely. Damn!

I guess the DC resistance between the 270-240V wires will be a lot less than the 0-240V winding - a lot less, like only 10% or so.

Steve A.
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Re: 3BP1

Postby Harry Dalek » Mon Nov 23, 2015 7:25 pm

Steve checked i am to blame !
I tried to cheat using one transformer with a primary with 3 wires ,i can see now its not center tapped ....its wired so its wired like this I..........I...I 0 240 270

NOt i.......i.......i 240 0 270 so testing between the 240 and 270 volt connections 22 volts only makes sense now .

OK i have room in my ac power supply case ,what i will do is put another transformer in retest //

arrrrrrrrrrrrrrrrrrr :roll:
Last edited by Harry Dalek on Fri Jul 29, 2016 7:40 pm, edited 1 time in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: 3BP1

Postby Harry Dalek » Mon Nov 23, 2015 7:32 pm

Steve Anderson wrote:Ah! Maybe as it's a primary used in reverse it's actually 0-240-270V to allow for mains voltage adjustment, though 270V is really quite high for any mains. In other words the 0V is not a centre-tap at all.

I guess you (and I) have been thinking of it as 240-0-270...unlikely. Damn!

I guess the DC resistance between the 270-240V wires will be a lot less than the 0-240V winding - a lot less, like only 10% or so.

Steve A.


Sorry for my muck up i just never thought of testing across the 2 high voltages ...

yep and only 22 volts shows this is the problem OH well another life electronic wiring lesson i shall not repeat .

I have another transformer to try with it tomorrow ,its annoying but least an easy fix...
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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