Source for LCD monitor?

On Thu, 09 Apr 2009 22:31:31 +0000, DoN. Nichols wrote: ...

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A WeinCell MRB625 battery is supposed to be a proper $4 substitute for a PX-13 mercury cell, according to various web pages like <

They claim "WeinCell is a revolutionary new zinc/air battery designed to replace environmentally-unfriendly (banned) mercury batteries. ... Only WeinCells deliver exact voltage and stable output consistent with mercury batteries." ... "the WeinCell is not activated until the pull-tab is removed (removing batteries from equipment and replacing tabs prolongs battery life)." ...

"The WeinCELL MRB625 batteries last much longer than hearing aid batteries, some times up to a year. To achieve this longer life, the MRB625 used a proprietary electrolyte and has only two small air holes, instead of the 7 larger holes found in standard hearing aid batteries.", per

When I need a composite monitor, I go out to the garage and dig one out. I still have four working Commodore 1701 monitors, and a dozen or so monochrome monitors in aluminum cases. I also have a 23" monochrome security monitor, up on a shelf. :) One of these days I am going to have to get rid of a couple hundred monitors & terminals. :( Anyone need any TTL monochrome monitors? I think I still have a dozen 4" NCR ATM monitors. They had a problem with the cheap connector between the two circuit boards, but were easy to fix with a couple inches of ribbon cable.

I was fairly certain about what you were looking for, Rex, but the more I search, there just don't seem to be many LCDs in that size range that don't cost quite a bit (costing as much as a 17-19").

I think the market for 10-12" 4:3 aspect ratio monitors was fairly limited, mostly to commercial equipment, and essentially none were made as TV/DVD displays before home video equipment transitioned from 4:3 TV/VCRs to widescreen displays for DVDs.

I use a couple of smaller 4:3 LCDs for video camera images, but they might not be as comfortable to look at for your purpose.

SONY FDL-X600 5.9" color LCD presently going for ~$200 (orig $2300)

Everfocus E220N 5.6" CCTV/security color LCD going for $150+ (with accy pkg, MSRP ~$400)

I don't think you'd want to use a 6" LCD display for your lathe, and 10-12" seem to be non-existent. As I mentioned before, the smaller 7-10" widescreen TV/DVD screens may stretch the video width-wise.

Some 15" PC monitors may have a Video In connector (most/many do not), so

Unless you get lucky and find one that's cheap, LCD monitors made for the security/surveillance market are generally over-priced, probably just average quality for above average prices, although they may have some additional features that are of no interest to you.

Bill, my initial search seemed to indicate the things you mention. I originally posted in hopes someone knew of an obscure surplus seller that had some suitable special-purpose screens. The discussion has been interesting. I had not considered the asp[ect ration being a problem, so that was helpful.

But the bottom line is it works now, and the screen in place does fine. It's just a cheap Magnavox 80 monitor sitting on a very nice machine. It looks like the add-on it is.

I really appreciate all the input. It has been informative. I'll keep looking for something, with a better idea of what I need.

RB fired this volley in news:grnkjl$l3g$ snipped-for-privacy@nntp.motzarella.org:

Walgreens sells a cheap under-the-counter 10" or 12" LCD television that is native 4:3 ratio, and digital-ready, but not HD.

IIRC, it was under $120. Check and see if it has monitor inputs.

LLoyd

that would be interesting. I'll stop and check

Thanks

Sent an email to the address showing here, with the same subject line.

Do you have a "factory direct" or "Xess Cargo" type store in your area? They often have the dual screen DVD players on sale for less than the cost of a small TV - and the second screen is a simple composite video monitor - usually about 8". I got a Polaroid branded one last year for $129 Canadian - complete with 12vdc power converter for home use and a nice lithium battery pack for the player unit (which powers both screens when in use )

But since the B&S caliper needs *four* of them, that is a $16.00 replacement. (It is a "DIGIT-CAL II", FWIW.) (At least it is better than some adaptors which were supposed to convert something like a SR357 to fit the PX-13 profile, which were selling for something like $25.00 each. Five Chinese calipers are cheaper enough of those to run the caliper. :-)

The voltage is right (1.35 V), but none of the web pages show a side or angled view of the cell -- just a photo of it in a blister pack.

The shape of most cells is with a straight side, but the PX-13s have (had) a profile like this (view with a fixed pitch font to avoid distortion): - _--------_ _/__________\_ (_ _) |__________| + And the cell holder which snaps onto the back of the caliper

Snapping off the battery holder, removing two small Phillips screws, removing the four cells, and relacing the tabs -- certainly sounds convenient. :-) Well ... three of the four cells are held + side up, visible through apertures in the holder, but (assuming that is the surface with the holes to be covered) that still leaves one which requires the same disassembly sequence.

And -- they don't say how long it takes to come up to full voltage after removing the tabs each time. :-)

Since this does not require the sable voltage that an exposure meter (or one built into a camera), I'm more likely to machine a replacement holder using two CR3032 3V cells, with a silicon diode and two germanium diodes in series with them (for a total of about 1 V drop, since four mercury cells add up to 5 V, and the CR3032s are 3V each.) I'll first check how forgiving it is using a bench power supply to apply a full 6 V (working my way up from 5 V) and see whether it has problems with that.

I've been considering this for a long time. I've got a Starrett A Mitutoyo digital caliper, a Chinese manufacture one, and the 12" Mitutoyo one.

But the interesting thing about this one is that it uses the same technology that the glass scales for DROs and for CNC feedback use, a barcode vacuum-plated on glass in the slot where the rack gear would be on a dial caliper, a pair of barcodes 1/4 out of phase mounted to the carrier, two leds and two photo-detectors. (The LEDs are probably why it kills batteries more quickly -- but at least when you press "off", it is *truly* off. :-)

Needless to say -- at this point I don't really *need* to have this working -- but it is a neat enough design so I would *like* to have it working. :-)

So -- why don't they bother showing the form of the case?

Hmm ... these may be right -- if the shape is as described, and if the caliper can tolerate 6.20 V.

I really need to contact Wein first and see whether they are truly the shape of the PX-13 cells.

Enjoy, DoN.

:-)

Of course, he doesn't *need* color. This is a purely B&W video output. :-)

Hmm ... depends on how his eyes are for close focus. The screen is something like 13 lines by 32 characters, so it may well remain legible. Put it on an arm so it is closer when you are programming. (It also serves as a DRO when manually moving things with the buttons.

I just checked, and my CRT monitor is 8.5" diagonal. It is on a shelf above the lathe, with a fluorescent light mounted to the underside to contribute to work lighting. (There is also a hinged arm one for spot lighting.

Again -- no problem. There are no graphics here -- just digits and upper-case only text. Zeros are slashed, and I'm not even sure whether any likely text uses a letter 'O' anyway. (Perhaps in one of the other languages supported.) It does not even bother explicitly showing the decimal point, it is simply assumed that the resolution is

I'm still not sure why he needs a LCD monitor instead of a small CRT monitor. The power consumption is not that different in sizes like that. And it can be plugged into an outlet on the back of the lathe to be powered on only when the lathe is switched on.

eBay has a 12" CRT monitor (auction #200294292553) currently for $48.51 (or best offer).

This one will probably be closed by the time you see this, but it is a 7" one (#180344067240) which works with PAL and NTSC and has RCA phono plugs for inputs. (I think that they are confused, however, as they show two connectors for video in, and one for audio -- the reverse of the normal with stereo audio. :-) Currently at $52.09 . But it needs

Oh yes -- it is also in Hong Kong. :-)

Hmm ... this one (# 120404335662) looks like what you need, except that you will need to make a housing for it. $22.50 and in California.

If you want to look through more of the listings (I'm about 3/4 of the way down the first page of 13 total), you might want to use my search string to limit the number of hits to something reasonable.

Good Luck, DoN.

The aspect ratio should *not* be a problem for text only, which is what you (and I) have from the Compact-5/CNC. It isn't doing any graphics displays of what the workpiece would look like (not likely with only a 6502 for brains). At most, your zeros and 'O's will look rounder. No problem in my book. If it were doing graphics, that would be a different matter.

I used a Commodore color monitor for several years, until I got the nice 8.5" B&W monitor (which looks more industrial), FWIW. I switched to the free 8.5" monitor to save power and shelf space more than anything else. I don't care wath it *looks* like, as long as it works. (I also have not stripped down an re-painted my older machine tools, and am unlikely to. The work, which is all that matters to me. (Granted, I've seen a Monarch 10EE painted candy-apple red, but if I had one like that, I would never use it for fear of spoiling the appearance. :-)

And try the search string and the comments from my just previous post in this thread. (I have no idea what order your newsreader will present them to you.) Among other things, there is a nice bare-bones LCD monitor for which you would need to make a case, and to add a 12V power supply capable of 1 A of output. You could build that into any kind of case which you liked.

Enjoy, DoN.

Perhaps not. I only thought of mentioning it once it was clear that it was being connected to an Emco Compact-5/CNC, which I know well, as I own one and use it regularly.

It is -- and I am sort of tempted to pick up one -- Hmm ... is that yet another of the Paypal-only ones?

And what about a switch to turn on or off an internal terminator for the 75-ohm line?

O.K. I'm sort of tempted to bend up a set of brackets to bolt to the underside of the shelf to support that little monitor, and thus make more space on the self itself.

Or perhaps bolt it to a swing arm of some sort or other.

Yes -- real controls easily within reach. The tiny one I have was free -- from the DC area "freecycle"

Also -- lower power than most CRT based monitors.

Yes -- it is reducing the number of vendors. We've lost one which used to be the largest (Gaithersburg). It moved from its original fairgrounds to two others, and finally back to the original after it was too late (perhaps 8% of the normal tailgating at the last one, and the fairground decided to charge for parking on top of the admission fee, so that killed it. The Manassas one has reduced by about 60% of tailgating area used. The Berryville one is still going strong, but it always had a different flavor to it. The Timonium and the Howard County ones have also gotten smaller.

Of course -- some of which you just stand there and scratch your head trying to identify.

But my first unix box came from the Gaithersburg hamfest. I was walking along looking from side to side, and then paused. Hmm ... that looks like two Motorola 68000 CPUs side by side. Looking at the part numbers told me that only one was the CPU and the other was the memory management unit (whose number I now forget) and about the time that I decided that it looked interesting enough to ask the price, the fellow told me that it was a unix box. I bought it ($15.00 IIRC). Got the name of the person who got the companion box with a Fujitsu 2312K disk drive (8" SMD interface) and 8" floppy in it. He bought it for the Fujitsu drive, so I got the rest of the box (power supply, floppy drive, and SCSI controller card for the drive), and the name of the company who got rid of it -- who I called and was able to pick up the original distribution floppys -- and later to buy the 1/2" tape drive from them, to have a complete unix system. I learned a lot from that system. My previous experience with unix was only from a non-root account.

I think that it was the same hamfest where someone had an AR-15 for sale -- but the hamfest was in Maryland, and I was in Virgina, so I could not buy it there.

Enjoy, DoN.

I can't quite parse that last sentence, but get the drift that the batteries get pricy (even if you buy 12/$40 from earlier link, ), possible costing more than a new cheap caliper.

...

True, putting the tabs back on doesn't sound like an easy fix for longer battery-life in that caliper. I included that bit in my earlier post not because it's useful, but because it's amusing that the seller suggests it. However, it might be practical to store the caliper in a box purged with nitrogen, argon, or CO2.

Depending on what the current draw is and how stable it is, you might be able to use something like the dual-diode BAV199 in a

The sentence *should* have read:

Yes.

Hmm ... if I had a TIG welding setup, the argon would be a good choice (along with machining up a metal case with an O-ring seal and a fill and vent valve). I wonder what would happen should I pump it down to a fairly good vacuum (other than it leaking air back in over time). I wonder whether the cells are allergic to vacuum.

Hmm ... I've not measured the current draw yet -- but I suspect that there will be a significant variation from displaying '1's to displaying '8's, since it is a LED readout, not LCD like most more recent ones.

About, yes.

Hmm ... he is using unfamiliar diode part numbers, except for the mention of the US 1N34A (which I have used in the past).

The mention of the gold bonded diodes reminded me of my first employer -- Transitron -- who got their start in the semiconductor industry by making good quality gold bonded diodes. I *think* that they actually invented the process. At the time, they were used heavily in logic circuits by the then growing mainframe computer industry. By the time I was working for them, they were making lots of silicon diodes and transistors -- in competition with Texas Instruments. I also remember interesting variants on the diodes called "stabistors" -- made specifically for the stability of their forward voltage drop -- and the temperature coefficient of that forward voltage. They were combined with a zener diode with the opposite temperature coefficient, and a selected transistor to make what was sold as a "ref-amp" (reference amplifier) which had a precise and stable forward voltage drop from the base out the emitter, and through the zener and the stabistors to provide a very stable reference, and to amplify any variation applied to the base to control a voltage regulator. The transistors, zeners, and stabistors were all tested in large racks under silicone oil at -50C,

I think that the company name is still around, but that they don't make semiconductors now.

They also had another device -- a 4-lead device in a TO-5 can which they called the "binistor". It was a mesa style silicon transistor with an extra lead bonded wrong -- overlapping two zones, and it behaved as a bistable device. So -- you could make a flip-flop with a single device -- before integrated circuits allowed it in a single chip. :-)

Enjoy, DoN.

I thought of vacuum also. A minute or two with google didn't answer that question, although it gave lots of links to old hearing aids that used a vacuum-tube rather than transistor, and vacuum-cleaners for hearing aids, and remarks that putting the tab back on a zinc-air hearing-aid battery apparently doesn't extend its life. You could see if a WeinCell survives vacuum ok and let us know :)

I misunderstood that earlier, and thought the LED referred to was used in position sensing, which would have a more stable current. But with an LED display, not only could there be large variations in current, it also might over-tax 2032 coin cells. Perhaps consider using four NiMH AAA's, for example lined up in a tube attached to the underside of the caliper. That would deliver about 5V through most of the discharge curve. Or maybe find a flat rectangular cell-phone battery the right size to attach on the back of the caliper, and use an LDO regulator (like TC10145.0VCT713) to get 5V.

I've heard of Transitron and stabistors, but don't recall binistors, even though I've got some 4-leaded parts with specs like that, from ca. 1966. It sounds like Transitron may have been an interesting place to work!

'Til next week -- off to Arches and Canyonlands tomorrow --

Probably not -- at least not now. I am fighting a sore throat which is a follow-on to Bacterial Conjunctivitis between my first and second Cataract surgery. (At least I don't have to use my throat to type. :-)

That was being used too.

Rather small LED readouts, so it may not be too bad. It remains to be seen when I feel up to testing the current from a lab bench supply.

Ugly! And awkward to handle.

That might work. But I would want a switch to turn off the regulator between uses.

This would have been about 1960. IIRC, the part number was 3N35 or 3N31 -- something close to that.

It was. But unfortunately, it was a summer job.

And the discovery of the binistor was through an accidental mis-bonding and someone seeing whether it could be salvaged by prper re-bonding. :-)

Enjoy, DoN.