What's wrong with my Electrophysics Micronviewer?

[Ben321]

Today I just received the Electrophysics Micronviewer 7290A that I bought on eBay last week. The seller didn't show any screenshots of a TV with the camera's video output onscreen, but when I messaged him, he said the camera does output video. I got it today, and tried it by connectiong it to the composite video input on my TV, but no video output on my TV screen. I connected up its video output to my Picoscoope USB oscilloscope and tried to see if it at least output something, maybe a waveform with the wrong frequency (maybe it had 50hz instead of 60hz video output, so wouldn't work on a US TV I thought), or maybe I could see some increase in electronic noise when the power was on, or maybe even a single transient voltage spike at the instant the power was turned on. But NOTHING. The video output port always had the EXACT SAME 0-volts output (with a slight amount of noise of a few mV) on my Picoscope, even when the scope was set at its highest sensitivity setting (50mV per division).

I even checked, and double checked, all of the power and video cable connections, to make sure nothing was loose. I made sure the power switch on the Micronviewer was turned on. I checked everything that could result in the camera not being powered, and nothing was wrong with any of my equipment setup. So the output of this thing is DEAD!

There's a number of things that could be wrong with it, from a loose solder connection somewhere on the board, to the power supply for the camera having no voltage output (dead power supply), to possibly even a crack in the glass of the SWIR vidicon tube in the camera (which could actually have been caused by poor handling of the package by the UPS crew, and not necessarily the eBay seller's fault).

Any ideas on what is most likely wrong with it, and what things I should be checking to see if I can fix it?

By the way, one thing that could help, is if somebody could provide the pinout for the power connector. It uses a non-standard power connector with 4 pins arranged in a square and an outer screw-on ring to hold the connector in place when it's connected to the camera. That way I could verify that the power supply is working at least, by testing it with a simple multimeter.

[DaJMasta]

Not output can be a lot of things.  If you power it off a bench supply (or otherwise measure current consumption), mine starts at 750-800mA at 12V and then settles into the mid/high 600mA range when in operation.  I've had one with an issue where it didn't not turning on far enough to see an image where after a few seconds of normal power consumption, it drops to below 600mA.

That said, using a USB dongle that can see either PAL or NTSC and reconfigure automatically, it still puts out a signal, it just never resolves to an image.  It will show some gray noise but will correctly output frame timing info required to get a video lock even when the tube isn't reading anything real, the output formatting electronics will do their thing fairly quickly after power on.

It's worth checking the obvious stuff though: change the gain setting knob, sometimes with some settings just a black screen is output, and listening to the slight whine of the switching electronics that drive the tube voltages - should be audible shortly after power on.

As for the power connector, if it's the 4 pin arrangement, it should be just power and ground, using a nominal 12V and connecting directly to a 7810 linear regulator on the inside for a 10V operating voltage for the boards.  There is another - I think seven pin - input connector that is for the versions with an integrated battery (which is NiCd and guaranteed to be dead), but the connections should be obvious if you take the lid off and look at the wiring on the inside face.  Maybe some of the documentation can show which pins are used.... or maybe even one of the threads?  I converted mine to a barrel jack and never looked back.

[Ben321]

It's worth checking the obvious stuff though: change the gain setting knob, sometimes with some settings just a black screen is output, and listening to the slight whine of the switching electronics that drive the tube voltages - should be audible shortly after power on.

That's one of the things I'm NOT hearing.  I don't hear the high voltage high frequency tube power supply circuit running. So I suspect that either the internal HV supply is dead, or the external 12V power supply is dead, or there's a loose solder point somewhere in the power circuits in the camera somewhere between the power-input jack and the HV power supply.

As for the power connector, if it's the 4 pin arrangement, it should be just power and ground, using a nominal 12V and connecting directly to a 7810 linear regulator on the inside for a 10V operating voltage for the boards. the connections should be obvious if you take the lid off and look at the wiring on the inside face.

What are the minimum number of screws that need to be removed to open it? There's 4 screws on top, 4 screws on the back, and 8 screws on the bottom. I wish I could get a service manual for it or something, that would show exactly the right way to open it. I want to be able to put it back together again.


It would be great if Fraser could show up in this thread. He usually has info on exotic IR equipment, info that I never thought anybody outside of the companies that make the equipment even had access to. Such info would be great in this thread, as it might help me fix my Micronviewer.

[DaJMasta]

I think he's got one, but I've got one on the bench beside me so I can give you at least some info    I think the only manuals and things that have turned up have been linked in the main 7290A thread.

You only need to remove the four screws on top and the filter holder if your unit has one.  If your unit has the side handle (unlikely if you don't have the internal battery) then one of the screws for the handle goes into a standoff on the board and also needs to be removed.

[Fraser]

Quick observations.....

This will start as a standard ‘dead unit’ investigation. That is to say, Visual inspection for physical damage or visible component failures (including fuses!) followed by simple checks on power and control. If the basics are OK, you can then begin the fault tracing process on the PCB’s.

1. Always check for power at the connector, preferably inside the camera, to ensure that power is reaching the power input regulator board.
2. Check power output of regulator board mounted in the rear of the camera
3. Monitor current draw at a convenient point in the power supply rail.
4. Check that wiring from video connector to the PCB is intact.
5. If power is present, check for heater glow from the rear of the Vidicon tube.

If you have power at the output of the regulator board then the problem can be more complex in nature and further investigation of the PCB’s will be required.

A broken Vidicon tube will not cause a ‘no signal’ condition at the video output as other circuits produce synchronisation pulses even if the Vidicon signal is absent

WARNING : If you are not familiar with Vidicon cameras, be careful where you poke your fingers as high voltages are used for the tube and they will ‘bite’ if touched. Painful but not deadly.

Fraser

[Fraser]

In case you are wondering, SOFRADIR refuse to release the schematics or service information for the 7290A camera. It is basically a standard ‘late design’ of Vidicon CCTV camera though, so not hard to reverse engineer if you have the time. Start by downloading the data sheets for any chips found inside and that gives you test points to check 

Fraser

[Fraser]

As a side note, you may wish to start searching for a suitable lens for your camera, if it was not supplied with one.
The lens needs to designed for the old 1” Vidicon standard to achieve full coverage of the target. 2/3” and 1/2” lenses can cause vignetting. I bought a Fujinon 25mm F1.4 1” Vidicon lens with built in manual IRIS. It was not cheap ! These are excellent lenses but not able to extend much further into SWIR than 1.6 um as they are standard optical glass. They do not have an IR coating as found on some modern lenses and this is important. You want plain old fashioned uncoated optical glass. The good quality older CCTV lenses have been in demand in recent years as photographers use them in 4/3” photography. Prices are sadly higher as a result.

Fraser

[Ben321]

Quick observations.....

This will start as a standard ‘dead unit’ investigation. That is to say, Visual inspection for physical damage or visible component failures (including fuses!) followed by simple checks on power and control. If the basics are OK, you can then begin the fault tracing process on the PCB’s.

1. Always check for power at the connector, preferably inside the camera, to ensure that power is reaching the power input regulator board.
2. Check power output of regulator board mounted in the rear of the camera
3. Monitor current draw at a convenient point in the power supply rail.
4. Check that wiring from video connector to the PCB is intact.
5. If power is present, check for heater glow from the rear of the Vidicon tube.

If you have power at the output of the regulator board then the problem can be more complex in nature and further investigation of the PCB’s will be required.

A broken Vidicon tube will not cause a ‘no signal’ condition at the video output as other circuits produce synchronisation pulses even if the Vidicon signal is absent

WARNING : If you are not familiar with Vidicon cameras, be careful where you poke your fingers as high voltages are used for the tube and they will ‘bite’ if touched. Painful but not deadly.

Fraser

I was just going to start my testing, but found the 9V battery in my multimeter is dead, and I don't have any spare 9V batteries available. I need to buy some more.

I was able to get some pictures inside though. I numbered and named the pictures. I hope that maybe some defect on the boards (maybe some solder point that had come undone or something) that was to small to be obvious to me, may be easily seen by somebody else, and that these pictures will help them to help me pinpoint the issue with my camera.

[Ultrapurple]

I have no info on this camera but some experience in video.

Are you terminating the video out line with 75 ohm resistive?

I have seen video output circuits that rely on a DC path to ground via the 75 ohm load at the 'far end of the coax'. Connecting a capacitively-coupled or high impedance load results in zero video output. I have no idea if this is the case with the Micronviewer but I have seen other perfectly good kit scrapped because the technician had tested it with a non DC-coupled monitor and decided, erroneously, that the device was dead.

[Fraser]

Ben321,

You can use your Picoscope to measure DC voltages so you can do the described tests without the multimeter.

Fraser

[Ben321]

I have no info on this camera but some experience in video.

Are you terminating the video out line with 75 ohm resistive?

I have seen video output circuits that rely on a DC path to ground via the 75 ohm load at the 'far end of the coax'. Connecting a capacitively-coupled or high impedance load results in zero video output. I have no idea if this is the case with the Micronviewer but I have seen other perfectly good kit scrapped because the technician had tested it with a non DC-coupled monitor and decided, erroneously, that the device was dead.

I didn't even hear the high pitch tone of the flyback transformer, for the vidicon tube when I was testing it. Furthermore, my first test was one where I actually hooked it up to the composite video input of my TV, not my Picoscope with a high impedance impedance. The specification for composite video inputs them to have a 75ohm DC resistance to ground. So if that was the only issue with my camera when testing with a picoscope, then it still would have worked with the TV, and if it worked with the TV, I never would have needed to test it with anything else, and this thread asking for help wouldn't exist. And the camera wasn't having an issue no video content either, as in that case the sync pulses would still be present, and my TV would display a black screen without any error messages. However with this camera, my TV displayed a "signal not found" type of message, meaning that there was literally no signal coming out of the camera's video-out port.

[DaJMasta]

If it's this dead and you paid for a working one, I personally wouldn't hold onto it unless it was heavily discounted, but if you want to check voltages, you can do that with a scope and a 10x probe, as mentioned, making sure you're within your probe's operating specs.

As said before, input should be 12VDC across the two connected terminals of the jack, they should go straight into a 7810 regulator (looks like it's on the board attached to the back panel on your unit, but I've seen it strapped to the bottom chassis as well) where you should get 10V out.  On the smaller of the two side boards there is a TO-220 with a piece of metal heatsink which goes across the tube, and this is the primary 5V regulator, so it should be 10V in, 5V out, and system ground.

For a more in depth check, looking at the larger of the two side boards, you can check the circled and numbered pins near the potentiometer marked "Target".  Each circled pin with a number is the corresponding voltage test point, and all of these are derived from the main switching transistor (a TO-220 and an inductor in the lower left of the larger board when looking at it installed on the camera), so if there are voltages in the right ballpark present, then the tube is being driven by something, at least.  Don't probe the 300V or 450V marked ones if your probes are not rated for it, and probably don't probe any of them (maybe with the exception of the target voltage itself) if you're using a 1x probe.  The only units I've worked with do have a slight whine from the switching or from the Hsync generation, but the units I've worked with also show a blank output with signs of doing something rather than no signal when powered on, so if you have 10V and 5V on the board, your problem probably lies within video signal generation, not driving the tube and not reading from the tube.

Again, unless you have an arrangement with the seller it seems odd to be poking around in there, but none of what you describe is normal behavior for a working or nearly working unit, in my experience.

[Ben321]

Ok got a new 9V battery for my multimeter. I measured the voltage across the pins in the power supply and 0V. So either the power supply is dead, or else whoever wired the power supply's output connector soldered the output wires to the wrong pins on the output connector. The connector has 4 pins, but only 2 of them are used. So my next step is to cut output cable from the power supply,  and directly measure the voltage without the end connector.

[Ben321]

Ok so I cut the power supply output cable and directly measured the voltage coming out of the cable. It is 12V just as it's supposed to be. As for the power output connector, I used the resistance setting on my multimeter and found that there's infinite resistance from all 4 pins to both wires in the cable! So that means NO PINS on the power supply's output connector are actually wired into the power supply! I have no idea how that happened, but at least this seems to be the problem, meaning the camera itself is likely still good. I could spend hours trying to manually solder the power connector myself (though I don't even know how to open the power connector to expose its solder points, and even if I could the pins are so close together that my hands wouldn't be steady enough, as I tend to have a tremor in my hands when trying to do precision work, which ironically I DON'T have when NOT trying to do precision work). It seems that my best bet may be to simply contact whoever makes (or used to make) these cameras, and ask if they can send me a new power supply for it.

[Fraser]

In case the information is useful to someone. I attach pictures of the dismantled connector and a link to the thread that identifies it and where to purchase one. The connector is from the Hirose (HRS) SR30 range.

https://www.hirose.com/product/series/SR30#

https://www.eevblog.com/forum/chat/mystery-industrial-camera-connector-help-please/

When soldering such a connector, it is relatively easy to make up a ‘jig’ to hold the connector and wires in place whilst applying the soldering iron and solder to the pins. It can be achieved with nothing more than some pieces of cardboard and tape 

Fraser

[Fraser]

A little hint for anyone who suffers from hand shake when micro soldering..... I use a small wheat pillow out of a microwaveable hot pad as a stable supporting surface on which to rest my hand whilst soldering. Any sort of relatively dense small pillow will work but I had some microwave heat pillows laying around. The wheat pillow also works well for supporting a PCB at an angle for soldering as it is heat resistant and mouldable to shape    These heat pads come in many sizes and can be expensive. Mine came out of a soft toy ‘Hottie’ Cat that is used where a hot water bottle might normally be used. There are all manner of shapes for placing around the neck and on limbs to treat pain. Do not overpay for such an item. My cat was around £7 and a neck warmer is about the same on Amazon. As an added bonus you can microwave it in winter to keep your hand warm or use it on aches and pains when not soldering 

https://www.amazon.co.uk/Microwave-Cushion-Reliever-Fragranced-Lavender/dp/B00NXZ7UV6/ref=asc_df_B00NXZ7UV6/?tag=googshopuk-21&linkCode=df0&hvadid=207995677378&hvpos=&hvnetw=g&hvrand=14394440764132575171&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9046142&hvtargid=pla-807623317674&psc=1

Fraser

[Bill W]

I could spend hours trying to manually solder the power connector myself (though I don't even know how to open the power connector to expose its solder points,

Just go onto the red and black wires inside with clips from a bench supply - then you'll see if it fires up and is worth the effort.

Bill

[Ben321]

Ok, so the power supply I ordered FINALLY came. I bought it from Cascade Laser (the same company that used to distribute these Micronviewer cameras). They charged me the RIPOFF PRICE of about $200 for the power supply! While I'm upset they decided to price gouge me, they did say that they had to contact their manufacturer to get one made (apparently these aren't a stock item, now that the camera itself is seems to be obsolete), so they may have considered it worth more as a custom item or whatever.

So, I got the power supply and plugged it in, and got some pics with my USB video capture dongle. I've attached these pictures to this post. They include pictures with no lens and AGC, and also with a lens with all 4 gain settings (AGC, MGC low, MGC medium, and MGC high), and with the lens capped on the first 3 gain settings (AGC, MGC low, and MGC medium). The no-lens picture (entire sensor illuminated with room light), showed an interesting rectangular feature that's at an angle. I'm not sure what it is. Is it normal or some defect?

The various gain pictures, show that not only is the gain (amplification) of the signal altered, but so is the offset (blackpoint). By the time you have the gain up to high, even WITH the lens cap in place (I didn't bother to test it with the lens cap off, as the entire picture would be washed out and useless), the entire picture appears white. Likewise, when the manual gain setting is medium, it appears a flat gray color across the image with the lenscap on, and with the lens cap off, the entire picture's blackpoint is this gray color (nothing appears any dimmer than that gray color). I suspect that this is NOT how the gain should be working. AGC however seems to work properly (adjusting only the gain, while keeping the proper blackpoint).

With the lens cap on, and AGC also on, I noticed that the last image the camera saw, appears to be "burned in" to the tube sensor temporarily, even if that image wasn't from a bright light source (just normal room illumination). It takes a minute or 2, for the image to finally return to normal (which with the lens-cap on is a flat gray, as the AGC finds the max and min levels are approximately the same, and so adjusts the picture to be mid-gray as the image brightness level).

Also, no matter how I adjust the lens, I can't get it to be very sharp. I suspect this may be an electron beam focusing issue in the image sensor tube. I may need to somehow calibrate the electron beam focusing.

Also, in case you are wondering, the object this camera is pointing at is my bed. Above my bed is a solar system poster, and there also happens to be a cardboard box on the floor (I should have moved it before capturing these pictures). Also, I was only able to capture anything at all, because this camera can see both visible light and the NIR+SWIR parts of the spectrum. My room lights are incandescent, so emit almost 100% visible light. I'm still going to need to get an NIR or SWIR longpass filter for this camera. That will cost about $80 though, so I think I will wait a bit, as I've already spent $500 on the camera, and $200 on the replacement power supply.

[Ben321]

One more thing I noticed, is that the image appears to be offset (vignetting only on one side of the image). I don't think the lens holder is out of place, so I suspect this is an electron beam aiming issue (horizontal deflection coil calibration issue).

[Ben321]

Also, as can be seen in the attached picture, a bright light source, such as the IR LED in an TV remote control, even if not pointed directly at the camera, produces a dark artifact off to the right of the light source. Any idea why?

[Ben321]

Also it has some less than ideal response times for darker objects. I've attached 2 pictures. In the first picture, I'm moving my hand VERY slowly in front of the camera. My hand is darker than the background. Because my hand is moving at all, instead of staying absolutely still for like 10 to 20 seconds, my hand looks like a ghost image. Meanwhile, when I move my IR TV remote control in front of the camera, while holding down a button to activate its IR LED, every single bright pulse is captured completely, and leaves an after image that fades slowly.

Is these the kind of response times I should expect with this camera? Or is this a defect?

[Ben321]

One more issue I found. If I touch the metal part of the camera lens (but no part of the metal case), I see electronic interference in the image. I don't know why. I can only assume that the high speed signals (such as image generation electronics, and beam sweeping electronics) are somehow close enough to the lens, that the metal parts of the camera lens are capacitively coupled to these circuits, and that when I touch the lens, by body is actually altering the electronic properties of the circuit by changing a capacitance in the circuit (like a capacitive touch screen). Alternatively, my body may be acting as an antenna for other enterfering signals from other things (like switching power supplies in other electronic equipment), and while that's blocked by the metal case of the camera normally, when I touch the lens, which is appreciatively coupled into internal circuits, I'm basically acting as a receiving antenna, and the camera's electronics are being impacted by the external signals being coupled into them.

Is this something that can be compensated for? Is this a defect in my unit, or a common problem with Micronviewer units?

[Ben321]

So, as you can see, I have lots of issues here, and I don't if all of them are defects, or if some are just the way the camera works. I really need help identifying the defects, based on the pics and comments I've posted. And where the defects are, I'd like to know which ones could be fixed by myself, versus which would require sending my camera in to be repaired professionally. For the ones I can fix, I'd like some tutorials on how to fix those issues.

Maybe you @Fraser could help me. You think you know a lot about these tube-based cameras. Right?

[DaJMasta]

Some of these are discussed in the other thread, but they sound mostly normal.

For the rotation, it's either the focus pot, the pot with a similar function on the yolk board, or it's the rotation of the coils around the tube (there are set screws in the frame that can be loosened to change this).

For the dark artifact, I'm guessing it's that too high an exposure is causing an artifact because of saturating the detector in the region.  If you keep it moving, it probably won't still do it, and using a narrower iris setting on your lens or an off angle view of the LED will probably get rid of it.

Finally the interference - do you have the case on?  There's a reason there are several chassis to board grounding wires that are in place and the short of it is that the frontend is pretty sensitive to EMF and when you touch the lens or even get your hand near it, the EMF picked up on your hand is enough to cause visible noise.  The frontend FET is located on the side board, closest to the lens, which is on the right side of the camera when the lens is pointing away and you're looking down on the top, so you'll probably see the most noise getting close to that.  My unit shows the same when the cover is off, and none with it on, so if yours is showing it with the cover on, it's probably good to check the various ground tie points to the chassis, the shielding on the tube, and the boards to make sure they are all in place.

[Bill W]

Also, as can be seen in the attached picture, a bright light source, such as the IR LED in an TV remote control, even if not pointed directly at the camera, produces a dark artifact off to the right of the light source. Any idea why?

Input amplifier frequency response being shown up by the HUGE signal going in.  A similar effect can sometimes be seen on old Vidicon TV images where spot lamps are visible.

It looks reasonably OK to me, as the only adjustment was usually a capacitor value (based on Pevicon TIC cameras).

Bill