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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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Link Posted: Wed Sep 02, 2009 2:16 am Post subject: |
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WTS wrote: | Odd that the regulator puts out that much noise. |
Walt, I think its not really the regulator and more the power lines proximity to the 390 VDC line that feeds the HVPS, and that is super noisy from what others who have scoped it told me, like Jarmo and Steve. In the LVPS the lines run parallel to each other on the PCB board, a bad design from the manufacturer i bet and Electrohome probably never caught it.
Athanasios
_________________ Don't blame your underwear for your crooked ass~ unknown Greek philosopher
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WTS
Joined: 08 Mar 2006 Posts: 1276 Location: Calgary
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Link Posted: Wed Sep 02, 2009 1:24 pm Post subject: |
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Okay that could be the case for sure. So I assume this filter is placed off board then.
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Walter
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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Link Posted: Wed Sep 02, 2009 1:31 pm Post subject: |
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WTS wrote: | Okay that could be the case for sure. So I assume this filter is placed off board then. |
Yes it's placed right on the mother board under the Blue tube where the P14 wire from the LVPS plugs to the mother board.
Mike Parker addresses this noise right on each VNB, not sure which method is best but i am sure both will make a difference
When i get some time I will try to draw this up with Eagle PCB design and maybe make a run of 20 boards. I think it be a fun project.
But this idea had me thinking of putting a daughter board filter right at each connector on the mother board that goes to each VNB, this filter could cover all the supply lines to the VNB's so the heater, 85vdc and 5vdc line can be cleaned up before they reach the VNB's.
Athanasios
_________________ Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
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WTS
Joined: 08 Mar 2006 Posts: 1276 Location: Calgary
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Link Posted: Wed Sep 02, 2009 6:07 pm Post subject: |
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Go for it.
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Walter
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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Link Posted: Tue Sep 15, 2009 4:14 pm Post subject: |
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Update to the CLM mod, do not replace the buffering caps x31 and x32, these are tied into the battery and will cause the battery to drain. if you replaced them with tants go back to the ceramics that where already there. looks like battery power on the CLM likes non polar caps.
here is another little tip for the extreme DIY'er. the battery on the CLM is hard to find and expensive when you do. If you take it apart very carefully you can find your own lithium battery of 3 volts and put yours inside. Use leads cut from a capacitor or a resistor to solder to the battery top and bottom then feed it through the holes in the battery holder. CAUTION!!!!!! I assume heat near the battery can cause it to explode, if doing it you might want to not solder it and make up some kind of clamp with the wire soldered to that. Use extreme caution and do not allow the battery to heat up to much . Also wear safety glasses for this job.
Pic of insides of Battery
Athanasios
_________________ Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan
One Smart Dog!!!
Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
Last edited by Nashou66 on Tue Sep 15, 2009 8:43 pm; edited 1 time in total
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1031
Joined: 22 Mar 2006 Posts: 657 Location: Finland
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PaulB
Joined: 26 Oct 2007 Posts: 359 Location: Bonnie (but rainy) Scotland
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Link Posted: Tue Sep 15, 2009 7:20 pm Post subject: |
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This is probably the best place for it Jarmo. I was only just ending the thread I'd started but as its really a maintenance solution having it in this thread is perfect!
_________________ Paul
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CRT_Ben
Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia
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Link Posted: Fri Sep 25, 2009 1:48 am Post subject: |
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Thanks to you Athan, my first heater mod was a success! I'm not sure why people say it ends up being a little low - when I first fired it up (p14 disconnected of course) I got 6.37v. Backed off the pot a few turns and now I have rock solid 6.35. I guess it's not my first Marquee Mod because I did the Thomas tubes, but it feels good to work on the machine again
Edit: under load with the tubes connected it drops to 6.29v. I could adjust it upwards but I don't think I'll bother.
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draganm
Joined: 08 Mar 2006 Posts: 8990 Location: Colorado
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Link Posted: Mon Oct 05, 2009 4:19 pm Post subject: |
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so to continue another thread and keep this one going, there was a discussion of doing something similar to the Jarmo Filament voltage line noise suppresion but doing it right at the VNB's.HK Steve suggested moving the 2 black jumper wires from the top of the card to the bottom side to prevent putting noise into the CL449 chip? Also, adding a couple of ferrite beads as filters.
What i like about this approcah is the fact that I already have the heat-sink off when i re-cap this board. Doing this little filter mod would be quick and easy for me right at the VNB without having to build a daughter board at the MB P14 connector. Also avoid the complexity of having to instruct end-users on how to add something extra to their machine when simple re-assembly is enough of a challenge for inexperineced hands..
So, Why not just replace the 2 Black wires with a through hole suppresion filter. Murata makes an interesting one part number BL02RN2R1N1A that just might fit under the heat sink? Maybe tie one end to a small ceramic cap to filter any residual HF noise that's leaks by the Filter? shield any exposed leg with simple Teflon tubing like you use on the Chrsity "line fix". Neat, effective, and all hidden under the card. My only concern is the 85C max temp. rating?
What ya guys think, am I off in left field?
http://search.murata.co.jp/Ceramy/CatalogAction.do?sHinnm=BL02RN2R1N1&sNHinnm=BL02RN2R1N1&sNhin_key=BL02RN2R1N1A&sLang=en&sParam=BL02RN2R1N1A
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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1031
Joined: 22 Mar 2006 Posts: 657 Location: Finland
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Link Posted: Mon Oct 05, 2009 5:36 pm Post subject: |
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draganm wrote: | so to continue another thread and keep this one going, there was a discussion of doing something similar to the Jarmo Filament voltage line noise suppresion but doing it right at the VNB's.HK Steve suggested moving the 2 black jumper wires from the top of the card to the bottom side to prevent putting noise into the CL449 chip? Also, adding a couple of ferrite beads as filters.
What i like about this approcah is the fact that I already have the heat-sink off when i re-cap this board. Doing this little filter mod would be quick and easy for me right at the VNB without having to build a daughter board at the MB P14 connector. Also avoid the complexity of having to instruct end-users on how to add something extra to their machine when simple re-assembly is enough of a challenge for inexperineced hands..
So, Why not just replace the 2 Black wires with a through hole suppresion filter. Murata makes an interesting one part number BL02RN2R1N1A that just might fit under the heat sink? Maybe tie one end to a small ceramic cap to filter any residual HF noise that's leaks by the Filter? shield any exposed leg with simple Teflon tubing like you use on the Chrsity "line fix". Neat, effective, and all hidden under the card. My only concern is the 85C max temp. rating?
What ya guys think, am I off in left field?
http://search.murata.co.jp/Ceramy/CatalogAction.do?sHinnm=BL02RN2R1N1&sNHinnm=BL02RN2R1N1&sNhin_key=BL02RN2R1N1A&sLang=en&sParam=BL02RN2R1N1A |
I see that problem different (noise at p14 line) When you add noise suppressor at VNB it has "jumped" allready to another lines (+-5v,+-15v etc) And there are allready two beadīs + diodes at near crtīs pins that where heatervoltage is enterd to tube. So noise is suppressed a little, before it hits filamentīs. Problem area is everything between MOBO -> those stock beadīs on VNB. Umbilical cord cable is one place that where noise is entered to another lines.
How hard it would be to end user to unplug P14 connector and add "filter box" between moboP14 connector / wiring harness P14 connector..
But still(with or without external P14 filter) i also recommend that those two "black wires" is best to route underside of VNB pcb.
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draganm
Joined: 08 Mar 2006 Posts: 8990 Location: Colorado
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Link Posted: Mon Oct 05, 2009 6:50 pm Post subject: |
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1031 wrote: | I see that problem different (noise at p14 line) When you add noise suppressor at VNB it has "jumped" allready to another lines (+-5v,+-15v etc) And there are allready two beadīs + diodes at near crtīs pins that where heatervoltage is enterd to tube. So noise is suppressed a little, before it hits filamentīs. Problem area is everything between MOBO -> those stock beadīs on VNB. Umbilical cord cable is one place that where noise is entered to another lines.
How hard it would be to end user to unplug P14 connector and add "filter box" between moboP14 connector / wiring harness P14 connector..
But still(with or without external P14 filter) i also recommend that those two "black wires" is best to route underside of VNB pcb. |
Nashou66 wrote: | Like jarmo mentions on the MMPE thread, the beads only address the noise to the heater elements, the reason cleaning up
right at p14 is it clears up any noise that can be transmitted to the other voltage rails in the umbilical cord which is all bunched together. My idea was a filter at each umbilical cord(after) but i milti filter for each voltage rail that goes to the vnb.
Athanasios | Well all good points. It seems like no matter how you do it it's not perfect. filtering at MOBO is probably the most effective but I just don't want to make those little boards if I don't have to. Yes, there are 2 beads and diodes at FB1,2 and D5/D7 but that's well into the boad as well. It seems like the majority of the noise is coming from the black wires and going into the CL449 chip and surrounding circuits,no? So If you were to filter right where the wires begin, labeled WH1 and WH3 (directly after the umbilical), you could at least eliminate the noise generated right at the board.
the other thing that comes to mind is the Marquee has the 380VDC G2 wire running right next to the VNB Umbilical, so if you filter at MOBO the P14 voltage could possibly pick up noise again before VNB? I don't know, it's all so confusing
I have a spare VNB to play with, I think i'll order some filters and see what I can come up with?
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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tse
Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.
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Link Posted: Tue Oct 06, 2009 12:15 am Post subject: |
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One thing that makes it difficult to filter the noise from the heater wires is that it is fairly low frequency. Like a few MHz or maybe 10MHz. Alot of filters are designed for 100MHz and up. They just won't do alot for the heater noise. Heater current for one tube is about 1/4A. Make sure the filter is good for more current than that.
Scott
_________________ "Were we directed from Washington when to sow and when to reap, we would soon want bread."
Thomas Jefferson
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mp20748
Joined: 12 Sep 2006 Posts: 5681 Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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Link Posted: Tue Oct 06, 2009 1:24 am Post subject: |
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The dominant frequencies on the filament are low frequency. From my measured notes, It's around 88KHZ on a perfectly good LVPS that has excellent caps on the 6.3v line.
from various testing, I've measured noise in ranges much higher. Likewise, the measured PP voltage range of noise is usually in a range of 11 to 15 volts (PP) on a perfectly good working LVPS. On an aged unit, it can get much higher.
When using the inductor that I'm showing in the picture, the noise level drops to 1.3vPP, with the frequency dropping to 43Khz @ 1.3KHZ.
I'm also showing two beads in the picture. In order to get any results from beads, they would have to be LARGE. Also, and as Scott pointed out, whatever you use, it would have to have a much higher current rating.
My test unit has that inductor in the picture right at P14. Jarmo's design seems to be better, because of the inductor its using.
The 88khz noise is only one of the noise components on that line, and it's the most aggressive (measurable) noise.
You can also use another method (shown in the picture below) by putting inductors on the filament lines on the neck board cables. In the picture, I'm filtering the +/- 5 volt rails to the neck boards. In this particular test Marquee, I'm also filtering the G2's lines.
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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draganm
Joined: 08 Mar 2006 Posts: 8990 Location: Colorado
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Link Posted: Tue Oct 06, 2009 3:53 am Post subject: |
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thanks for the responses, looks like the noise is low frequency which requires a big-ass inductor. That explains why Jarmo's big 25mm inductor worked well. I would have wasted a lot of time messing around with those cute little ones designed to filter very high frequency stuff.
I'm not ready to give up on my idea yet though because...................... I just don't know any better Plan B is to mill away 2 of the cooling fins directly above the Heater jumpers. Then use that cavity to nest a pair of these big Murata 18334C Axial inductors at least the specs looks good, low DC resistance and .73 amp power rating.
http://www.murata-ps.com/data/magnetics/kmp_1800.pdf
Last edited by draganm on Tue Oct 06, 2009 5:16 pm; edited 2 times in total
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1031
Joined: 22 Mar 2006 Posts: 657 Location: Finland
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draganm
Joined: 08 Mar 2006 Posts: 8990 Location: Colorado
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Link Posted: Tue Oct 06, 2009 4:59 pm Post subject: |
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I hear you JArmo, getting that noise reduction circuit really dialed in took some time, you can't just slap some beads or inductors in there and have it work perfectly. Your new P14 daughter board works very well, It's just that I'm looking for something really fast and easy that I can do for people without adding a lot of time or effort to the work I already do (which already takes a long time).
I have decided on this, moving the 2 jumper wires to the bottom of the VNB and simply adding a large(ish) ferrite bead to each wire. Yeah I know, it's a simpleton solution but it's neat , quick, and will look like factory work. That always appeals to me, when I'm done and return someone's boards they look like factory boards unless you are really familiar with original ones.
I found these last night at Mouser, they are 5 mm diameter and will fit under the heat sink. they offer 2 different materials , the FB73-422 start to show approx 50ohms impedance at about 1Mhz and filters up to 40 MHz. Impedance can also be increased by stacking a pair of these and if i'm lucky we could start seeing some filtering down as low as the 88Khz noise Mike talks about? At any rate it should be fairly effective for the higher frequency stuff Scott mentions.
http://www.bourns.com/data/global/pdfs/FB_series.pdf
at any rate, it will be a huge leap past the 2 little beads that come stock on the VNB and will be pulling that noise off right as it enters the circuit as opposed to where it terminates at tube pin-outs. I will order these today and hopefully drag a scope home this weekend for some measurements at the pin sockets.
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Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
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