jamesmking

bit of both. working distance is ok for either a hot air handle or a soldering iron. It takes some getting used to since you have a fixed defined viewing circle, you can't move your head and have to organise everything around that. I personally found that exact head positioning was very critical to get a good 3d perspective view and this meant I wanted to minimise the number of times I looked up away from the microscope.

I purchased a cheap rebranded scope from amazon one a few years back for smd and pcb inspection It looks identical to this one: https://amscope.com/collections/student-microscopes-low-power-stereo/products/se420xyz-2l it works. My only complaints are 1. it does not have a zoom 2. its not trinocular so you can't add a camera look through it at the same time 3. there is no real X and Y adjustment. instead it pivots around which makes moving around a pcb a bit of a pain. 4. because the objective lenses are housed in a rectangular box you cant fit a ring light easily. 5. the objective lenses are not a "standard" mount and that limits you options for different lenses

The calculation are based on some assumptions and tradeoffs. Ideally you need to know some things about the high voltage power supply the secondaries will be powering. 1. you need to know the minimum voltage input to the power supply to get the required regulated output at the required current. (the minimum input will usually increase with higher current draw). typically this will be a fairly small additional voltage above the output voltage for low voltage power supplies e.g. a few extra volts for the golden reference low voltage and typically in the few 10s of volts extra for the golden reference high voltage power supply. Since this is the absolute minimum you probably want a little more input voltage than that to be safe. 2. the voltage out of the wall also varies. In many countries during peak demand the power companies can reduce the voltage - typically by up to about 5 to 10% so you need about 10% more voltage on the output side than you might think to compensate the electrical grid giving you less than you expect. So we multiply the total secondary output voltage by 1.1 i.e. add 10% 3. Competent transformer design is also assumed. The more current you draw from a transformer the more inefficient it becomes. Which is why you specify the output voltage of the secondaries at the current draw you expect. If the manufacturers are crap and only design the transformer secondary output based on no load being applied you can have issues where the psu loads the secondaries and the output of the secondaries drops so much you don't get enough voltage for the psu to maintain regulation. Conversely if the manufacturers design the transformer properly, specifying a transformer with a much higher secondary current draw than it will actually experience will result in the secondary voltage being higher than expected. Any voltage going into the psu above the minimum amount required to regulate will be converted into additional heat. Any voltage below the minimum to regulate will result in loss of regulation and the output voltage dropping with greatly increased levels of ripple and noise. you also need to make sure the input capacitors in the power supply can handle the peak voltage going into them or their life expectancy will be reduced and in more extreme overload conditions they can fail completely. (the output caps are mostly isolated from the varying input voltage and should only see the DC voltage output the power supply is setup to output assuming there is no failure in the psu which causes the regulation to be bypassed/short out and pass all the available voltage to the output e.g. the pass transistor to be fully switched on or become shorted) [Since minimum dc voltage input for regulation - DC output voltage] is the additional voltage needed to regulate at the required current draw. secondary VAC = (minimum dc voltage input for regulation *1.1 )*0.707 Or secondary VAC = ((DC output voltage + minimum additional voltage for regulation)*1.1 )*0.707 so if we assume 10V more input is needed to regulate than output for 400V output we get: secondary VAC = ((400+10)*1.1)*0.707 = 319VAC

Here are a few suggestions. My apologies if you have tried any of these already. If the hum is changing after a few minutes then this implies to me that thermal expansion could be the cause. Are you sure all the pins of any socketed components are gripped well by their sockets? I believe there have been cases where over time some of the teflon tube sockets pins have started to lose their grip.. I would also very careful with the amp off and all capacitors in the psu drained and using a high resolution multimeter check the resistance between the psu connectors and the amp boards to make sure there is not a poor wiring connection due to oxidized wires etc this test will also check for any potential problems with an umbilical if you have the psu in a seperate box from the amp with seperate wires for the left and right channel. I think at this stage you need to start being very systematic and seeing what is going on.. so do you have access to an oscilloscope? I don't have a KGST but I assume it has separate and identical + and - amplification stages for each channel with a phase splitter at the input stage to allow single ended or balanced input... With a scope you can CAREFULLY (10x probe and dont connect the probe ground lead to anything that is live) probe the output pins at the stax socket one by one AVOIDING the bias pin and see if you have hum on both the + and the - outputs of a channel or if it is only the - or + half. This could potentially eliminate half the components of a channel from being faulty. If both - and + of a channel has hum then suspect something common to both which is usually the psu or input phase splitter. If you have seperate psus for each channel then you need to look at the psu rails to see if there is excessive ripple on one of the psus. If each channel shares the psu and only one channel has an issue then its very unlikely to be the psu but it could be the wiring from the psu to the effected channel. If all else fails a scope is an essential debugging tool and you are going to have to compare the good and bad channels and see what is different. good luck regards James

Thats whats needed but, stax logic is simple: why make a better product when you can sell something worse for much more and the hifi magazine reviewers are guaranteed to say its the best thing since non-sliced, small batch, organic artisan, seeded, whole meal, bread... *sigh* between on semi and Stax we just can't have nice things.

true, which is why I have been upgrading the axis bearings etc. I agree prevention is better than detection, which is why I am going for steppers with double torque than the originals, plus the software that comes with the closed loop system provides graphs, including positional error which will allow me to fine tune the pid parameters and see what is actually going on and give me more options to fine tune and correct. I am also learning a lot - which is fun too. I loved metalwork and woodwork at school but when the route of computer science, but have always enjoyed making things - even if it's just putting together flat pack furniture for friends or soldering pcbs.

junk z axis. holy crap, I just disassembled the Z axis. The entire spindle weight is held by a 12mm ball screw. On each end of the ball screw is just one f688z bearing - (8mm ID, 17mm OD with a flange 18mm diameter). These tiny bearings have no preload and not designed for axial loads and have axial play. Looks like fox alien are relying on the weight of the spindle alone to push down on the lower bearing and that's the only thing stopping the spindle from dropping. Piece of absolute SHIT! The bearing housing has no recesses, no preload mechanism, no adjustment mechanism, nothing it's just unbelievable. Looks like I'm going to need an entire new Z axis too... Does anyone know if there is a angular contact version of the f688z?? sigh single tooth carbide partial profile (so it will do multiple thread pitches and the tool pressure is a lot less than other threading tools.). It's more versatile and cost effective than buying complete profile thread end mills. With 5 thread mills I have every metric pitch (both fine and course) covered from m3 all the way to m10. https://www.shop-apt.co.uk/single-tooth-thread-mills-dlc-for-aluminium-internal-60/internal-single-tooth-carbide-thread-mill-partial-profile-05-10mm-pitch-dlc-coated-for-aluminium-39mm-head-diameter.html The thread mills don't come with all the necessary parameters (e.g. tooth height, distance from the centre of the tooth to the bottom of the end mill etc.) for the software I use so I had to take multiple measurements with a 0.001mm micrometer and average the results and guestimate other parameters. The threads are m6 I ran 7000rpm, 150mm/min feed, 70mm/min plunge 0.0054mm per tooth chip load, bottom to top cutting a right handed thread. This resulted in the threads being cut in two passes and the chips falling into the bottom of the hole (which I made 1.5mm deeper than needed to hold the chips). To make the thread go all the way through the 10mm mounting plate I found I had to start about 1mm below the bottom of the material, so I painters tapped and superglued a 3mm sacrificial aluminium plate underneath.

Well, I decided I needed to upgrade my CNC machine (replace almost everything from the original machine I purchased). having already upgraded the controller, spoil board, spoil board mounting and spindle it's time to look at the axes .... First I got myself an 80mm diameter er20 ceramic bearing 2.2KW water cooled spindle with labyrinth seals to replace the cheap 65mm 1.5Kw er 11. To fit the 80mm spindle I had to make a new mounting plate. This included experimenting chamfering and threading. I settled on 0.3mm chamfers at 45 degrees and experimented with thread milling. The result I think is ok: (full discloser I purchased tooling plate so the top and bottom surfaces were already machined flat, but all the other surfaces got machined. I have ordered 4 nema 23 closed loop steppers (3NM - about twice the holding torque of the original open loop steppers the machine came with), which will entail replacing most of the wiring loom, removing the existing open loop motor drivers, removing the motors, some software config of the new closed loop drivers and some changes to the controller wiring. The original divers have no error output pin so the controller has no idea if a stepper has an issue. The new drivers include error output pins so they will need to be connected to the controller. (stock jpeg from the ebay listing, I'm still waiting for delivery) I have also replaced the standard 'deep' groove (6001 series) bearings inside the bk12 bearing housings with angular contact bearings (7001 series) as per this you tube video: I also noticed that all the bearing blocks were attached to the machine with m5 bolts despite the blocks being designed for m6, So I plan to replace those bolts and find a way to make new threads in the machine housings. The nema 23 motors are also designed for m5 bolts but the machine uses m4 (on avery axis except Z), again I don't know why fox alien decided to use one size smaller bolts on everything that drives the axes so I will have to machine new back end plates/motor mounts too. After these upgrades and fixes the only original parts of the machine left will be the frame, axe and the metal case the electronics came in. It's so nice to have a cnc machine so I can make parts to upgrade my cnc machine...

portable if you are godzilla or king kong....

I thought I might post some of the modifications I have been doing to my Flox Alien vasto. I got fed up with the not so rigid spoil board and so filled in the bottom with 20mmx40mm aluminium extrusion... and replaced the thin t slot and mdf spoilboard with a 30mm thick mdf slab. The result is far more rigit and will take my own weight (60kg) with ease and no detectible flexing. The plan for the spil board is to have m6 threaded inserts on the underside of the board to allow me to screw in work holding clamps/brackets. A 20mm by 20mm grid engraved and a set of 3.175mm holes around the edge so I can insert small pegs to make lining up work with X and Y axis easier. I also got fed up with the cheapo controller. It has no rs485 support so it could not control my spindle vfd. I could not change spindle speed or direction in software. In fact the original unmodified machine could only switch on and off the cheap dc motor it was supplied with and had a potentiometer for manual speed control with no indication or rpms. It has no wifi support and no user interface, is also only 3 axis and completely undocumented. I opted to rip out the controller and put in a rootcnc controller (https://www.rootcnc.com/root-controller-iso-about/) running fluidnc (http://wiki.fluidnc.com/) control software. It took a while to configure fluidnc and re do all the control box wiring. I replaced the 2 pin spindle power socket on the back with a 4 pin to carry rs485 from the controller to the spindle vfd. I also removed the pause and resume buttons and replaced them with sockets for a tool height probe and a 3d probe. While I was at it I replaced the now redundant potentiometer that used to control the voltage on the original 48V spindle output with a fixed voltage divider of 12V so I could run a good quality noctura cooling fan and power diode lasers directly. I also got a cheap minbot labeller and went on a labelling spree. The result is I can store multiple profiles (one for the laser and one for the vfd spindle) in the controller flash, In fact rootcnc and fluidnc is versatile enough and has enough I/O I could run a vfd and laser at the same time if I could find a sensible way to mount both. I can control the spindle speed and direction in software and by using standard S and G3,4 and 5 gcodes, control the machine via the built in web server, usb or wifi and have much less fan noise, power 80W diode lasers directly from the control box and have 2 more axis. The spindle control and a spare axis makes an automatic tool changer such as the rapid change atc https://rapidchangeatc.com/ a viable option. I now have enough expandability that I could add control for a rotary axis, run a pendant or even consider automated tool changes... I have been experimenting with automated tool height measurement and have written some gsender macros to set the tool length offset using the tool height setter I recently purchased. I still have to manually remove and insert and screw down the tools but the aim is that I will then just press a button and the machine will measure the new tool height and Z axis work coordinate so the tip of the tool is at the same physical Z height as the previous tool. I chose the tool height sensor because it is also compatible with the rapid change atc.. Gsender has poor documentation for its macros so I got the source code and reverse engineered the macro language parser. I love open source software, if you can't find the information online you can always find it in the source code. The Z axis mount is too narrow to accept a mounting bracket for an 80mm diameter spindle. So at the moment I am stuck with 65mm spindles which limits me to only er11 collets and a maximum end mill diameter of 6mm. So when I have finished rebuilding the machine I will make a new zaxis mounting plate for 80mm spindle brackets and am looking at buying a 2.2KW er20 spindle with ceramic bearings and better dust sealing. Further in the future I would like to get the rapid change atc which will probably necessitate extending the y or x axis extend the x axis from 420mm useable to around 550mm or so. I'm also thinking about changing to closed loop steppers. happy cnc'ing James

That would be very nice, but, I suspect given the general behaviour of the human race, that there is a giant no fly zone around the sol solar system. I also think "humanity" probably has developed immunity to kindness/forgiveness. The story goes that the Argentinians could not get the Exocet working so as part of the support package they had several french advisors fly to argentina during the war to help them use them against the uk ships.... (https://theweek.com/world-news/falkland-islands/45704/bbc-finds-evidence-french-helped-argentines-sink-our-ships) remember it pays to pay for the support package

latest stax announcement: Due to decreasing sales of the sr009 we are discontinuing the sr007 since we don't know how to increment the price to make as much profit on it as the sr009 series. (We also forgot how to make spares and repair it cost effectively). We are proud to announce the release of the sr007a mk3. This release solves all the warmth issues of the previous sr007 models and benefits from the added clarity, detail and speed which made the sr009 series such good sellers. Please ignore the sr007 mk3's cosmetic similarities to sr009, we assure you the mk3 is a completely reimagined and redesigned sr007 brought into modern profit levels using modern technology for only $9000. Available now from all two remaining authorised dealers in Japan. Stax would also like to announce a new energizer to partner with the all new sr007 mk3; the srm007C rap using state of the art TPA3255 driving a 1:10 step-up transformer. The srm007C rap is manufactured under license by our new partners the IAG group in their mega factory in Shenzhen. It offers class leading efficiency for those who can't afford the utility bills associated with a valve design. Finally and terminally Stax would like to announce a collaboration with Blackstone private equity where Stax will rent back its manufacturing space from Blackstone in return for access to Blackstone expertise in increasing profitability and reducing manufacturing costs..

So Stax kill about the only good headphones they sell. Welcome to second-hand sr007 prices skyrocketing...

Well its not DC coupled (i.e. NO capacitors in the signal path) and it has a very low voltage swing - 200Vrms... due to the fact it has pre-amp tubes in its output rather than power tubes like the EL34. The bandwidth is not great and there is no distortion specifications at all (nothing vs output voltage and nothing vs frequency) which is a bit suspicious. I suspect the amp will have trouble driving Stax sr007. There is little information about the power supply but it does not appear to be fully regulated. As such it certainly does not look to be even close to a blue hawaii, mini T2 or T2 in specs and capability. Even the all valve Megatron has more voltage drive and almost certainly a better power supply. It is not known if the amp uses anode load resistors (bad) or constant current sources (good) for the output valves, but I suspect it's resistors. On the plus side it does not appear to have an output transformer... unlike some crappy comercial designs and does not require any DIY skills. However, if you don't mind building your own amp you can almost certainly make something substantially better (fully regulated power supply, fully DC coupled, constant current sources for the power valves etc) for around the same price.

perhaps your last post is exactly why no one else replied. I would like to see a long term solution to the entire Palestine problem. For your information I have never protested on the topic in question for either faction and have no desire to, its complicated mess and saying one side is exclusively right is impossible and unhelpful to a long term solution. I could call you a bigot for implying the UN and therefore, probably by extension, the entire world plus all universities is anti-Semitic but that would achieve nothing, but your words, do show your silo mentality which I am afraid to say is all I have experienced every time this topic has been discussed, my father has experienced similar as well and I am slowly coming to the conclusion this kind of experience might be widespread. I could be insulted by your words saying you expect me to protest in support of the palestinians or to remove my head from my arse, (If I could bend around that flexibly the climbing problem I got stuck on today would be a breeze). But I refuse to be insulted. I would say insults are the arguments employed by those who are in the wrong, but I dont think all you say is wrong. I am afraid to say that, in my opinion it is people exactly like you who make it so hard to feel any connection or sympathy for the Jews, but I try to keep an open mind, since, just because the proponents of an argument speak objectionably, it does not mean their argument is without merit. However, I have no desire to further engage with you on this topic or any other.