1L10 crystal needed (Newbie)


Joel B Walker
 

Hello All,
New member here. I have a Type 1L10 Spectrum Analyzer plug-in that I've owned for several years. It's nice and clean, however the previous owner removed some parts for some reason. It was missing the 100 kHz crystal, the 49.3 MHz crystal, the 900 kHz crystal, and one of the SMA jumpers. I found something to use for everything except the 900.000 kHz crystal. I have looked EVERYWHERE. The Tektronix part number is 158-0021-00. I'm not real pleased with what I found for the 49.3 MHz crystal, so if someone knows where one of those is would be nice. That one is Tektronix part number is 158-0020-00 Thanks in advance, and I look forward to reading lots of good things on this forum.


Tom Lee
 

Now, THAT's a museum piece! Please take some pics of its innards and outards when you get a chance. I'll rummage through my Mystery Box of Crystals (a cousin of Jeff's probe box) and see if by some miracle I have a 900kHz crystal. What package is it in?

Cheers,
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 1/23/2021 15:16, Joel B Walker wrote:
Hello All,
New member here. I have a Type 1L10 Spectrum Analyzer plug-in that I've owned for several years. It's nice and clean, however the previous owner removed some parts for some reason. It was missing the 100 kHz crystal, the 49.3 MHz crystal, the 900 kHz crystal, and one of the SMA jumpers. I found something to use for everything except the 900.000 kHz crystal. I have looked EVERYWHERE. The Tektronix part number is 158-0021-00. I'm not real pleased with what I found for the 49.3 MHz crystal, so if someone knows where one of those is would be nice. That one is Tektronix part number is 158-0020-00 Thanks in advance, and I look forward to reading lots of good things on this forum.




Dick Benson
 

Joel,

Maybe a source here: http://www.quartslab.com/

Regards, Dick


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Joel,

I have a working mint condition 1L10 that I'm not planning to ever use. Would trade it for a working 1A4 or 1S2.

Regards,

John


snapdiode
 


Ed Breya
 

The 1L10's 900 kHz crystal appears to be for an oscillator, so you could make a 9 MHz - a very common crystal frequency - oscillator and divide it by 10, if you can't find a 900 kHz one.

Ed


tgerbic
 

Could also get a programmable oscillator from someone like Digikey and request it be programmed for 900Khz. I think they have oscillators down to +/-15ppm for ~$5. Might need a buffer/driver. Would replace the entire oscillator circuit.

Tony


Tom Lee
 

Ed has an excellent idea (as always). There could be a small issue related to the additional mixing products you would get from the harmonics of the square wave output typical of such oscillators, so you might end up wanting to add a filter between any such oscillator and where it plugs in (P218? I was looking at the schematic earlier, but may be mis-remembering the plug/socket identifier). I haven't looked at the circuit closely enough to see if this is truly a big enough problem to worry about, though.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 1/24/2021 15:01, Ed Breya via groups.io wrote:
The 1L10's 900 kHz crystal appears to be for an oscillator, so you could make a 9 MHz - a very common crystal frequency - oscillator and divide it by 10, if you can't find a 900 kHz one.

Ed




Harvey White
 

Use a 74LS90, which is a divide by 2, and a separate divide by 10.  (This assumes a 9 Mhz can oscillator, and that it's 5.0 volts supply, and that the rest of the circuit needs a 5 volt signal.

Note that some oscillators put out a sine wave, and some put out a square wave.  This only works with a square wave output oscillator.


If you use a 74LS192 (also a divide by 10), the only output is either the Q4 (divide by 8, but high for two clock cycles), or carry (one clock pulse).  These aren't symmetric.  Most crystal oscillators are 50% duty cycle, spending the same amount of time as  a 1 as a zero.  These implementations don't do that.

Simple fix.  Connect the 74LS92 divide by 5 to the 9 Mhz.  This gives you a 1.8 Mhz asymmetric clock.  Big deal.  Then connect the 1.8 Mhz output of the divide by 5 to the input of the divide by 2 section, which gives you a guaranteed 50% duty cycle 900 Khz clock.

If the rest of the circuit expects that 50% duty cycle, you have it now.

Harvey

On 1/24/2021 6:01 PM, Ed Breya via groups.io wrote:
The 1L10's 900 kHz crystal appears to be for an oscillator, so you could make a 9 MHz - a very common crystal frequency - oscillator and divide it by 10, if you can't find a 900 kHz one.

Ed





Tom Lee
 

Hi Harvey,

Yes, those are among the multiple ways to generate a good square wave at 900kHz. The stock 900kHz oscillator to be replaced produces a sinewave to heterodyne with an 800kHz signal, so what is yet to be determined is whether the harmonic content of a square wave is acceptable here, or whether some filtering will have to be added.

--Cheers,
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 1/24/2021 17:00, Harvey White wrote:
Use a 74LS90, which is a divide by 2, and a separate divide by 10. (This assumes a 9 Mhz can oscillator, and that it's 5.0 volts supply, and that the rest of the circuit needs a 5 volt signal.

Note that some oscillators put out a sine wave, and some put out a square wave.  This only works with a square wave output oscillator.


If you use a 74LS192 (also a divide by 10), the only output is either the Q4 (divide by 8, but high for two clock cycles), or carry (one clock pulse).  These aren't symmetric.  Most crystal oscillators are 50% duty cycle, spending the same amount of time as  a 1 as a zero.  These implementations don't do that.

Simple fix.  Connect the 74LS92 divide by 5 to the 9 Mhz.  This gives you a 1.8 Mhz asymmetric clock.  Big deal.  Then connect the 1.8 Mhz output of the divide by 5 to the input of the divide by 2 section, which gives you a guaranteed 50% duty cycle 900 Khz clock.

If the rest of the circuit expects that 50% duty cycle, you have it now.

Harvey


On 1/24/2021 6:01 PM, Ed Breya via groups.io wrote:
The 1L10's 900 kHz crystal appears to be for an oscillator, so you could make a 9 MHz - a very common crystal frequency - oscillator and divide it by 10, if you can't find a 900 kHz one.

Ed








Harvey White
 

Then that answers the question.  There is a 900 Khz packaged oscillator out there, but mouser doesn't have any, and they are NRFD.  SIne wave  output.

Harvey

On 1/24/2021 8:17 PM, Tom Lee wrote:
Hi Harvey,

Yes, those are among the multiple ways to generate a good square wave at 900kHz. The stock 900kHz oscillator to be replaced produces a sinewave to heterodyne with an 800kHz signal, so what is yet to be determined is whether the harmonic content of a square wave is acceptable here, or whether some filtering will have to be added.

--Cheers,
Tom


Joel B Walker
 

Wow. Lots of good info here. I truly wasn't expecting such a large response. I had thought about using one of the small can crystal oscillators, but was hoping for an actual crystal from somewhere. The case style is HC-6U. Not sure if it is standard height or not. I'm sure I could make do with a different case style with the exception of maybe the FT-243. The 49.3 MHz crystal was obtained from eBay. It is actually for a PRC-6 military radio. Therefore I'm not convinced it will work.


SCMenasian
 

Back, when I was a graduate student, I had great success retuning crystals. I had several ~1.7 MHz crystals and was able to raise their frequencies by 5% or so by opening (unsoldering) the case, carefully removing the crystal and, using fine abrasive, raising the frequency to a value just above my target by lapping it in stages on one side. I made an oscillator circuit connected to a jig with an electrode on one side for holding the crystal and checking the frequency. Once I had overshot the target by a few kHz, I lowered it to the target by coating the lapped side with a film of silver (telescope mirror coating technique) and electroplating more silver, in successive stages, until I was on target. The crystal had to be dried in an oven after each electroplating stage. Once one gets the technique down, important information is gained (i.e. N lapping strokes raises the frequency by x kHz; M seconds of electroplating lowers it by y kHz and drying it out produces a z kHz increase.)

A big project - but fun!!

I checked with Surplus Sales of Nebraska but the closest frequency they have is below 800 kHz.

Stephen Menasian


Joel B Walker
 

Interesting!! I'd heard of doing that to FT-243 style crystals but never to the smaller ones. I had looked at Surplus Sales of Nebraska, also emailed Fair Radio. International Crystal is out of business. One place I found on Google specializes in low frequency crystals but hasn't responded to me yet. Probably won't since I only need one and not 10000.


SCMenasian
 

If you have access to an evaporator, you can skip the messy chemistry/electroplating steps.
I think that, one time (and perhaps now), crystal manufactures did final tuning in an evaporator.
Also, some film thickness monitors for evaporators were, essentially, crystals whose frequencies
were continuously monitored during the evaporation process.


Miguel Work
 

Yes!, I had working with Leybold vacuum plasma chambers with xtal vacuum meter. It was a naked crystal with electrodes inside the chamber connected to a little oscillator and a long coaxial cable. Chambers were used to make opticals filters by salts deposition


Google:

[PDF]
074-156K Standard, Compact, Dual Sensors Operating Manual


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Miguel Work
 

https://www.recycledgoods.com/inficon-ic-6000-quartz-crystal-oscillator-013-001-xtal/

-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Miguel Work
Enviado el: lunes, 25 de enero de 2021 20:42
Para: TekScopes@groups.io
Asunto: Re: [TekScopes] 1L10 crystal needed (Newbie)



Yes!, I had working with Leybold vacuum plasma chambers with xtal vacuum meter. It was a naked crystal with electrodes inside the chamber connected to a little oscillator and a long coaxial cable. Chambers were used to make opticals filters by salts deposition


Google:

[PDF]
074-156K Standard, Compact, Dual Sensors Operating Manual


Scanned by McAfee and confirmed virus-free.
Find out more here: https://bit.ly/2zCJMrO


Joel B Walker
 

Hello all,
Since posting here last I have tried a few places. Quartslab, which is in Great Britain, advertised that they will make custom one-off crystals, and the price list they showed seemed reasonable. There was a guy named Dave that I corresponded with. He was very helpful. The normal range of frequencies they deal with bottoms out at 1.5 MHz. He stated they could make me one anyway for about $100.00 including shipping as an estimate. That was a lot, but I said go ahead and do an official quote. Well, the quote ended up being $195.00!! Not worth it. The other place that specialized in low frequency crystals never responded to 4 emails from me. I contacted Walter Shawlee of Sphere and he didn't have the 900 kHz one, but he DID have a new Tektronix 49.3 MHz crystal for $5, which I ordered. Thanks, Walter! So I'll ask again, PLEASE look in all y'all's junk boxes or where ever and find me a 900 kHz crystal. Thanks.


Roy Thistle
 

Hi Joel:
I thought I'd seen something about 49.3 MHz crystal before.
Was it you on Antique radios, almost 8 years ago, and hundreds of crystals later?


Joel B Walker
 

Yes that was me. No luck there either. I ran a classified ad there and got several replies about both crystals, but no one had any. One member offered to sell me his 1L10 but wanted too much for it. And even if I had bought it I would still be looking for crystals for mine. Surely there is ONE 900.000 kHz out there somewhere.