Quality Measurement Systems

[bones518]

i have a bridgeport vertical mill with a Quality Measurement Systems Quality 800 digital readout that i bought used. the y axis measuement is messed up. i have narrowed it down to the reader. does any one know where i can get it fixed, or know where i can get a new or refirbushed reader??

Chris Harrington

[Jim Bass]

Hi Chris,

Some of the old QMS digital readouts used a small light blub in the reader head, with one end open on the scale and the system turned on look inside from the open end the small light blub should be lit. If not you may need a new blub.

If you need one I may have some.

Jim

[bones518]

this one does not have a light, i think that it has a magnetic reader

[One of Many]

Originally Posted by bones518 this one does not have a light, i think that it has a magnetic reader

Possibly a difference between the QMS 500 and 800? I don't recall any of these systems that used a magnetic head, but then I don't recall seeing any QMS 800 systems either. I thought they were all glass scale encoders. The newer ones were IR LED's and the older ones a small 5v or 12v lamp. The glass substrate was about 1/4" thick and the aluminum extrusions were very large(2x3"). The last of the scales did get smaller(1.5x1.5), but, the one I have is still glass.

I have a complete 500 system that I have considered selling off. It is made for a mill, but I wanted it for a lathe. There is no switch installed for DIA/RAD to make it direct reading on the X axis. I have been looking for a 127ppr 5v rotary encoder to replace the scale. Still no luck there.

DC

[bones518]

i opened the end of the x axis and i didnt see any light inside, but the y axis, the one im having troubles with works fine if i slide a flashlite inside scale, if i take the flashlight out it doesnt work. i also dont see where a bulb would be.

[One of Many]

Originally Posted by bones518 i opened the end of the x axis and i didnt see any light inside, but the y axis, the one im having troubles with works fine if i slide a flashlite inside scale, if i take the flashlight out it doesnt work. i also dont see where a bulb would be.

If this scale has the outside removable cover, that will get you access to the bulb. Otherwise you can remove the reader head out the open end very carefully.

The bulb or LED will be on the reader head that the wires go into. This unit extends inside the scale and is positioned with the light source on one side of the glass and the sensor pickup on the opposite side of the glass. If it is an infrared LED, you won't see any light. If it is a small bulb, they were about .125-.187 in diameter and about the same in length. If the bulb is glued to center it in relation to the pickup, you may have troubles getting the bulb off without breaking something or getting it repositioned to read properly.

Before you actually remove the bulb or LED. Check to see that power is getting to it still. Breaks in the cable could be the only problem. I think the bulb source at the display head was 12vdc, but the sensor output back to the display head was 5vdc.

The flashlight trick at least tells you all is not lost!

DC

[bones518]

on the reader there is a small circuit board with two little clear/white domes. then by what your saying they could be infrared leds. i know that they are not light bulbs, because on my working axis i cannot see any light. but they dont appear to be an ordinary LED shape, it looks like they are imbedded in some kind of metal.

[One of Many]

Originally Posted by bones518 on the reader there is a small circuit board with two little clear/white domes. then by what your saying they could be infrared leds. i know that they are not light bulbs, because on my working axis i cannot see any light. but they dont appear to be an ordinary LED shape, it looks like they are imbedded in some kind of metal.

Yes, that would be the surface mounted LED's of the infrared variety. I would check for power first. If it is not at the LEDs, you might need to check at the display head board level, connector or the wiring itself. These may only take 5v, but regardless there should be a current limiting/voltage dropping resistor somewhere in the line. You can check across the LED's with a diode mode meter or OHM meter. They should only conduct in one direction as any diode would. On a meter with diode checking mode, you will be able to see the voltage across the diode. These should be equal to each other. Typically this is around 1.2vdc for this type of diode, but could be from .6-2.4v. I'd need to confirm that on mine later, if you still need that information.


DC

[LMSC]

Hello Chris,

I was the west coast service engineer for QMS for many years. Please call me at 877-376-4373 and I can explain to you what you need to do to check the encoder.

Regards,

Tim Barnard
LMSC

Originally Posted by bones518 i have a bridgeport vertical mill with a Quality Measurement Systems Quality 800 digital readout that i bought used. the y axis measuement is messed up. i have narrowed it down to the reader. does any one know where i can get it fixed, or know where i can get a new or refirbushed reader?? Chris Harrington

[One of Many]

Originally Posted by LMSC Hello Chris, I was the west coast service engineer for QMS for many years. Please call me at 877-376-4373 and I can explain to you what you need to do to check the encoder. Regards, Tim Barnard LMSC

I did forget to mention the cable goes into the pre-amp board on the reader head that controls the LED's intensity and the sensors signal level among other things from the looks of it. The chip they used was proprietary. At least that is what the manufacturer told me. They no longer had data on the IC.

Nice to see you here, Tim. Since we have the slim opportunity......

I have one of the older(1975-78?) E/M Quality 500 QMS systems with the thumb wheel presets. I would like to use it on a lathe, but it was not originally set up that way. I see there is a spot on the board for the DIA/RAD switch.


Could you tell me if I can just add the DIA/RAD switch to the board or are there other modifications I would need to do. Like cut traces, jumpers or install additional components besides the switch?

Thanks for any help you can offer.

DC

[LMSC]

Hello DC,

As far as I remember, all you need to do is connect a switch and wires to the board and it should work. Remember that the readings will be double on that axis so if the scales are .0005", the display will read .001".

I could be wrong but it you connect the switch, nothing should be hurt.

Regards,

Tim Barnard
LMSC
877-376-4373

Originally Posted by One of Many I did forget to mention the cable goes into the pre-amp board on the reader head that controls the LED's intensity and the sensors signal level among other things from the looks of it. The chip they used was proprietary. At least that is what the manufacturer told me. They no longer had data on the IC. Nice to see you here, Tim. Since we have the slim opportunity...... I have one of the older(1975-78?) E/M Quality 500 QMS systems with the thumb wheel presets. I would like to use it on a lathe, but it was not originally set up that way. I see there is a spot on the board for the DIA/RAD switch. Could you tell me if I can just add the DIA/RAD switch to the board or are there other modifications I would need to do. Like cut traces, jumpers or install additional components besides the switch? Thanks for any help you can offer. DC

[One of Many]

Thanks Tim,

I will give it a try. These scales are actually in metric pitch and are converted to an english value. I have been looking for a quadrature miniscale of 20um metric pitch, but no luck so far on eBay. If I can connect the switch then the 10um should work, which are more common.

Would you happen to have any old schematics stashed away?

DC