Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Mac Doktor]

> On Apr 17, 2021, at 10:23 PM, Yohan Park  wrote:
> 
> Yes, the ones I have also use an M22K (220K) resistor.
> The tubes in mine aren't labeled at all but they're the more common MTH-90 
> tube without a nipple on top and the unit has clear lenses.
> They come without any screws to attach the top cover to the lower part of the 
> case so it seems they're meant to be screwed on to something else.


I just received four more with clear lenses instead of red. The tubes have 
round lenses instead of nipples and are clearly marked "MTX-90" although that's 
difficult to see. The black plastic bases are identical. The lids are the same 
as the ones with red lenses although the plastic is slightly whiter. So far so 
good.

The big difference is the front panel. The plastic has the same whiteness as 
the lid but its surface is rough, not smooth, and the numerals are slightly 
different in shape. I suspect that it was made with a different die. There's 
another variant on eBay that has a gray panel and doubled numbers like this: 
"1(5)", "2(6)" and so on. I'm wondering if different panels were made for 
different applications.

If I get the chance I'll take some more pictures. I'm still wondering what 
their application was and how to wire one up.


Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com/

“...the book said something astonishing, a very big thought. The stars, it 
said, were suns but very far away. The Sun was a star but close up.”—Carl 
Sagan, "The Backbone Of Night", Cosmos, 1980


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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Yuriy Ovchinnikov]

If anyone is interested, then I have 50 pcs. MTX-90.

вс, 18 апр. 2021 г. в 05:23, Yohan Park :

> Yes, the ones I have also use an M22K (220K) resistor.
> The tubes in mine aren't labeled at all but they're the more common MTH-90
> tube without a nipple on top and the unit has clear lenses.
> They come without any screws to attach the top cover to the lower part of
> the case so it seems they're meant to be screwed on to something else.
>
> On Sunday, April 18, 2021 at 2:11:34 AM UTC+2 Terry Bowman wrote:
>
>> I did a quick search and these these things are for sale on Etsy and
>> various other merchant sites I've never heard of. Similar pricing but eBay
>> does give you something resembling a safety net.
>>
>> White plastic with red lenses seems to be the norm.
>>
>>
>> On Apr 17, 2021, at 5:49 AM, Dekatron42  wrote:
>>
>> I had one of these many years ago and if I remember correctly now it is a
>> resistor of some 100k, or perhaps it was closer to 1Meg, as it just limits
>> the current flowing in the trigger circuit. You can google these and find
>> circuits like the ones below:
>>
>>
>> I finally dug a meter out and checked the component marked "M22". Sure
>> enough it's a .22MΩ (220kΩ) resistor. It's connected directly to the
>> touch-sensitive "key" on the front.
>>
>>
>> On Apr 17, 2021, at 3:21 PM, Yohan Park  wrote:
>>
>> Ah yes I've found them. They're less suitable to use as an indicator.
>>
>>
>> The tubes in the ones I purchased are identical. There's no part number
>> and the only marking is "OTK 25". Apparently that means that quality
>> control inspector number 25 has approved the lamp as military spec. Feel
>> free to correct me if I'm wrong.
>>
>> I still can't figure out what they were used for. Functionally they're
>> just a box with five momentary sort-of isolated touch switches controlling
>> a 220V RMS mains load. Cheaper than using mechanical switches?
>>
>>
>> Terry Bowman, KA4HJH
>> "The Mac Doctor"
>>
>> https://www.astarcloseup.com/
>>
>> “...the book said something astonishing, a very big thought. The stars,
>> it said, were suns but very far away. The Sun was a star but close
>> up.”—Carl Sagan, "The Backbone Of Night", *Cosmos*, 1980
>>
>>
>> --
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> .
>

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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Yohan Park]

Yes, the ones I have also use an M22K (220K) resistor.
The tubes in mine aren't labeled at all but they're the more common MTH-90 
tube without a nipple on top and the unit has clear lenses.
They come without any screws to attach the top cover to the lower part of 
the case so it seems they're meant to be screwed on to something else.

On Sunday, April 18, 2021 at 2:11:34 AM UTC+2 Terry Bowman wrote:

> I did a quick search and these these things are for sale on Etsy and 
> various other merchant sites I've never heard of. Similar pricing but eBay 
> does give you something resembling a safety net.
>
> White plastic with red lenses seems to be the norm.
>
>
> On Apr 17, 2021, at 5:49 AM, Dekatron42  wrote:
>
> I had one of these many years ago and if I remember correctly now it is a 
> resistor of some 100k, or perhaps it was closer to 1Meg, as it just limits 
> the current flowing in the trigger circuit. You can google these and find 
> circuits like the ones below:
>
>
> I finally dug a meter out and checked the component marked "M22". Sure 
> enough it's a .22MΩ (220kΩ) resistor. It's connected directly to the 
> touch-sensitive "key" on the front.
>
>
> On Apr 17, 2021, at 3:21 PM, Yohan Park  wrote:
>
> Ah yes I've found them. They're less suitable to use as an indicator.
>
>
> The tubes in the ones I purchased are identical. There's no part number 
> and the only marking is "OTK 25". Apparently that means that quality 
> control inspector number 25 has approved the lamp as military spec. Feel 
> free to correct me if I'm wrong.
>
> I still can't figure out what they were used for. Functionally they're 
> just a box with five momentary sort-of isolated touch switches controlling 
> a 220V RMS mains load. Cheaper than using mechanical switches?
>
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"
>
> https://www.astarcloseup.com/
>
> “...the book said something astonishing, a very big thought. The stars, it 
> said, were suns but very far away. The Sun was a star but close up.”—Carl 
> Sagan, "The Backbone Of Night", *Cosmos*, 1980
>
>
>

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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Mac Doktor]

I did a quick search and these these things are for sale on Etsy and various 
other merchant sites I've never heard of. Similar pricing but eBay does give 
you something resembling a safety net.

White plastic with red lenses seems to be the norm.


> On Apr 17, 2021, at 5:49 AM, Dekatron42  wrote:
> 
> I had one of these many years ago and if I remember correctly now it is a 
> resistor of some 100k, or perhaps it was closer to 1Meg, as it just limits 
> the current flowing in the trigger circuit. You can google these and find 
> circuits like the ones below:

I finally dug a meter out and checked the component marked "M22". Sure enough 
it's a .22MΩ (220kΩ) resistor. It's connected directly to the touch-sensitive 
"key" on the front.


> On Apr 17, 2021, at 3:21 PM, Yohan Park  wrote:
> 
> Ah yes I've found them. They're less suitable to use as an indicator.

The tubes in the ones I purchased are identical. There's no part number and the 
only marking is "OTK 25". Apparently that means that quality control inspector 
number 25 has approved the lamp as military spec. Feel free to correct me if 
I'm wrong.

I still can't figure out what they were used for. Functionally they're just a 
box with five momentary sort-of isolated touch switches controlling a 220V RMS 
mains load. Cheaper than using mechanical switches?


Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com/

“...the book said something astonishing, a very big thought. The stars, it 
said, were suns but very far away. The Sun was a star but close up.”—Carl 
Sagan, "The Backbone Of Night", Cosmos, 1980


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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Dekatron42]

They are the same thryratron electrically but they have a different top, 
some come with this evacuation pip at the front and some come with a lens 
at the front and the evacuation pip at the bottom where the pins exit the 
glass.

/Martin

On Saturday, 17 April 2021 at 17:34:17 UTC+2 w...@kitsunegari.net wrote:

> There's something odd with the one in this listing: https://ebay.us/8EtaeL
> Check the 5th picture (close up of the tubes from the top).
> They don't look like MTH-90 since they seem to have a nipple on the top of 
> the tube (the side facing the lenses).
> Also, the bottom part (where the terminals are) is different from an 
> MTH-90.
> So this one seems to use a different type of thyratron but the question 
> is, which one?
>
> On Friday, April 16, 2021 at 8:48:38 PM UTC+2 Terry Bowman wrote:
>
>>
>> On Apr 16, 2021, at 1:36 PM, Keith Moore  wrote:
>>
>> Did you get any more information on these? 
>>
>>
>> I'm all ears as well.
>>
>> This seller just put up three BIN listings. They appear to be identical 
>> (you may have to scroll down the page):
>>
>> https://www.ebay.com/str/robotube?_trksid=p2047675.l2563
>>
>>
>> I wish now that I'd bought some of the ones with yellowed plastic. The 
>> light probably shines through unlike the white ones that are opaque.
>>
>>
>> Terry Bowman, KA4HJH
>> "The Mac Doctor"
>>
>> "If only you could see what I've seen with your eyes."—Roy Batty, *Blade 
>> Runner*
>>
>>

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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Yohan Park]

There's something odd with the one in this listing: https://ebay.us/8EtaeL
Check the 5th picture (close up of the tubes from the top).
They don't look like MTH-90 since they seem to have a nipple on the top of 
the tube (the side facing the lenses).
Also, the bottom part (where the terminals are) is different from an MTH-90.
So this one seems to use a different type of thyratron but the question is, 
which one?

On Friday, April 16, 2021 at 8:48:38 PM UTC+2 Terry Bowman wrote:

>
> On Apr 16, 2021, at 1:36 PM, Keith Moore  wrote:
>
> Did you get any more information on these? 
>
>
> I'm all ears as well.
>
> This seller just put up three BIN listings. They appear to be identical 
> (you may have to scroll down the page):
>
> https://www.ebay.com/str/robotube?_trksid=p2047675.l2563
>
>
> I wish now that I'd bought some of the ones with yellowed plastic. The 
> light probably shines through unlike the white ones that are opaque.
>
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"
>
> "If only you could see what I've seen with your eyes."—Roy Batty, *Blade 
> Runner*
>
>

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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Dekatron42]

I had one of these many years ago and if I remember correctly now it is a 
resistor of some 100k, or perhaps it was closer to 1Meg, as it just limits 
the current flowing in the trigger circuit. You can google these and find 
circuits like the ones below:

https://tubes-store.com/images/mtx90_02.jpg (I can recommend a high value 
resistor from 100k and up on the trigger pin so you don't touch any live 
parts accidentally! It will also protect a little bit if the tube shorts 
out)

http://www.elektronika.lt/schemos/ivairios/61/jutiklinis-jungiklis-su-mtx-90/ 
(this is a Doorbell, use Google Translate from Lithuanian to English)

/Martin



On Friday, 16 April 2021 at 20:48:38 UTC+2 Terry Bowman wrote:

>
> On Apr 16, 2021, at 1:36 PM, Keith Moore  wrote:
>
> Did you get any more information on these? 
>
>
> I'm all ears as well.
>
> This seller just put up three BIN listings. They appear to be identical 
> (you may have to scroll down the page):
>
> https://www.ebay.com/str/robotube?_trksid=p2047675.l2563
>
>
> I wish now that I'd bought some of the ones with yellowed plastic. The 
> light probably shines through unlike the white ones that are opaque.
>
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"
>
> "If only you could see what I've seen with your eyes."—Roy Batty, *Blade 
> Runner*
>
>

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Re: [neonixie-l] МТХ-90~MTH-90 Keypad from eBay - What is it and how do I hook it up?

[Mac Doktor]

> On Apr 16, 2021, at 1:36 PM, Keith Moore  wrote:
> 
> Did you get any more information on these? 


I'm all ears as well.

This seller just put up three BIN listings. They appear to be identical (you 
may have to scroll down the page):

https://www.ebay.com/str/robotube?_trksid=p2047675.l2563


I wish now that I'd bought some of the ones with yellowed plastic. The light 
probably shines through unlike the white ones that are opaque.


Terry Bowman, KA4HJH
"The Mac Doctor"

"If only you could see what I've seen with your eyes."—Roy Batty, Blade Runner

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