Author Topic: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]  (Read 70988 times)

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Offline uncle_bob

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #150 on: February 15, 2016, 06:41:16 pm »
Hi

I have a few examples of the white wire as well. It was well done and properly cleaned after the fact. The replaced IC's I've found and other components ... not so much. I can indeed believe that a test select component might be a flux monster. That sort of thing might be done by a tech who isn't very careful .... (or by some guy named Bob ..). On the replaced IC's, I just don't think that is what happened. That sort of work would go to a repair station and be done properly. If they do the wire right, they do the repairs right ....

Bob (the guy with the giant flux bottle ...)
 

Offline TheSteve

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I finally found a box I really like to mount one of these Rb standards in. It is a Hammond # 1455NHD1601. I would have preferred the black version but I only came across a good deal on the clear anodized. The BNC jack is mounted such that 4 more can be added in the future. I am pondering adding a buffered version of the internal 5,10 and 20 MHz square wave signals as well as a generated 1 PPS. I used a single dual color LED with a common cathode for status indication. The only change to the Rb itself was the addition of a 1K resistor in parallel with the lock signal 2.2 K resistor to brighten up the red LED. The 2.1mm input power jack has a polarity protection diode and a few capacitors for noise filtering. I am using a 24 VDC @ 2.7 amp laptop style switching power supply for power. The Rb heatsink is bolted to the box on the bottom. The top has an extra piece of aluminum bar stock added which is a wedge fit between the top of the Rb standard and the top cover for better heat transfer.
VE7FM
 

Offline TiNTopic starter

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Nice box, I bought some too, hoping to integrate Rb+GPSDO+RPI with OLED 16x2 (which did not work on Keithley 2304) together and make Stratum-1 box/reference  :)
Only issue to find time to do all that.
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Offline uncle_bob

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I finally found a box I really like to mount one of these Rb standards in. It is a Hammond # 1455NHD1601. I would have preferred the black version but I only came across a good deal on the clear anodized. The BNC jack is mounted such that 4 more can be added in the future. I am pondering adding a buffered version of the internal 5,10 and 20 MHz square wave signals as well as a generated 1 PPS. I used a single dual color LED with a common cathode for status indication. The only change to the Rb itself was the addition of a 1K resistor in parallel with the lock signal 2.2 K resistor to brighten up the red LED. The 2.1mm input power jack has a polarity protection diode and a few capacitors for noise filtering. I am using a 24 VDC @ 2.7 amp laptop style switching power supply for power. The Rb heatsink is bolted to the box on the bottom. The top has an extra piece of aluminum bar stock added which is a wedge fit between the top of the Rb standard and the top cover for better heat transfer.

Hi

The heatsink on these gizmos was designed for high air flow. They run hotter sitting on the bench than most of the other telecom Rb's. That's not a scientific observation, just what I notice picking them up after they have been running. I would strongly recommend getting a fan into any enclosure you use for one of these. The failure rate goes up quickly as they get hotter. You really want to keep the case under 40C.

I've killed a lot of surplus Rb's over the years by ignoring this point. Fans are really easy to talk yourself out of. They are noisy, they cost money, they are hard to mount, they pack dust in to things. M100's die when they get hot. FRK's die when they get hot. LPRO's die when they get hot. FE5680's die when they get hot. All of those live a good long time if you keep them cool. SR10's die weather they are hot or not.

Bob


 

Offline TheSteve

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I suppose in the telecom market fans are very common, as is loud equipment. In my home lab I have no interest in extra fans. I think I'd rather have the Rb unit die. It would be nice if they would build them a little bigger with the PCB insulated from the Rb cell/heater but I know they are building for a target size or rack thickness etc. I will thermal probe the unit when I have time but I believe the heatsinking on the box is enough to keep the unit well within the Temex published spec's. Of course it probably still cooks itself at those temps. Either way if it only lasts a few years that is fine, it owes me nothing and the caps are easy to replace.
VE7FM
 

Offline uncle_bob

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I suppose in the telecom market fans are very common, as is loud equipment. In my home lab I have no interest in extra fans. I think I'd rather have the Rb unit die. It would be nice if they would build them a little bigger with the PCB insulated from the Rb cell/heater but I know they are building for a target size or rack thickness etc. I will thermal probe the unit when I have time but I believe the heatsinking on the box is enough to keep the unit well within the Temex published spec's. Of course it probably still cooks itself at those temps. Either way if it only lasts a few years that is fine, it owes me nothing and the caps are easy to replace.

Hi

For a "no fan" structure, you get to a heatsink that is roughly 10" x 10" x 2". They aren't terribly expensive, but they are pretty big. That size assumes you have it vertical. The horizontal version is a bit bigger. A fairly small heatsink will do trick combined with a fan that is in the 19 dba range. If you can hear that on your bench ... you have a very unusual bench.

Bob
 

Offline Rémi

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #156 on: January 24, 2017, 08:44:07 am »
I bought two units and received them yesterday. I've ordered new electrolytic capacitors to replace the old ones.

I bought these capacitors on Ebay, Philips 123 47uF 35V 125°C Axial :
http://www.ebay.com/itm/122322378097?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Let's see if the units work when the capacitors are changed.
 

Offline CJay

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #157 on: January 24, 2017, 12:34:26 pm »
I bought two units and received them yesterday. I've ordered new electrolytic capacitors to replace the old ones.

I bought these capacitors on Ebay, Philips 123 47uF 35V 125°C Axial :
http://www.ebay.com/itm/122322378097?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Let's see if the units work when the capacitors are changed.

Interesting, was that from an eBay sale or somewhere else?

Out of curiosity, if anyone here in the UK has some of the original batch still knocking about on a shelf I might be interested in some on working ones?
 

Offline Rémi

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #158 on: January 24, 2017, 12:39:28 pm »
I bought two units and received them yesterday. I've ordered new electrolytic capacitors to replace the old ones.

I bought these capacitors on Ebay, Philips 123 47uF 35V 125°C Axial :
http://www.ebay.com/itm/122322378097?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Let's see if the units work when the capacitors are changed.

Interesting, was that from an eBay sale or somewhere else?

Out of curiosity, if anyone here in the UK has some of the original batch still knocking about on a shelf I might be interested in some on working ones?

Yes it was from an eBay sale, the same seller as TiN and other members have bought their units from. His username is yixunhk (http://www.ebay.com/usr/yixunhk?_trksid=p2047675.l2559). Unfortunately I think that I bought the two last units.
 

Offline Orange

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #159 on: January 24, 2017, 04:18:38 pm »
I bought two units and received them yesterday. I've ordered new electrolytic capacitors to replace the old ones.

I bought these capacitors on Ebay, Philips 123 47uF 35V 125°C Axial :
http://www.ebay.com/itm/122322378097?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Let's see if the units work when the capacitors are changed.
Those capacitors you bought might be bad as well. Philips stopped making them in 1999, their caps business was sold to Beyschlag Centralab components
AKA BCcomponents
http://www.vishay.com/company/brands/bccomponents/
 

Offline texaspyro

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #160 on: December 05, 2017, 04:48:27 am »
I recently bought a Spectratime SRO100 Rb.  Very small, 11-19V, can discipline itself to 1 PPS input.  I have Lady Heather working with it.   It seems to be a very nice and capable Rb.

I noticed that the LPFRS serial commands are very much like some of the SRO100 commands, so have also added support to Lady Heather for the LPFRS.  I just ordered an LPFRS to test that code.

I also did an adapter board to connect the SRO100 to my X72 signal breakout board (breaks out the signals to 5 BNC's and has a true RS-232 port).  I will probably also do a adapter board for the LPFRS.
 

Offline texaspyro

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #161 on: January 13, 2018, 01:56:11 am »

I noticed that the LPFRS serial commands are very much like some of the SRO100 commands, so have also added support to Lady Heather for the LPFRS.  I just ordered an LPFRS to test that code.

I also did an adapter board to connect the SRO100 to my X72 signal breakout board (breaks out the signals to 5 BNC's and has a true RS-232 port).  I will probably also do a adapter board for the LPFRS.

I have Lady Heather working with the LPFRS.  Attached is a plot of the LPFRS powering up.

The LPFRS adapter board for my X72 BNC board will have a PICDIV chip for generating a 1PPS output.   The adapter board should also work with the LPRO (but the LPRO has no serial port).

All the screws on my LPFRS heatsink were chowdered to hell and loctite'd in.  I had to use a dremel to turn them into slotted screws. Some required a little torch work to get them loose... grrrrr.

 

Offline texaspyro

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Re: Repair : TEMEX/SpectraTime LPFRS/LPRO 10MHz Rb generator [got GPSDO to cal]
« Reply #162 on: January 13, 2018, 02:03:47 am »
Oh, and here is an ADEV plot of the LPFRS output done with a TAPR TICC clocked by an HP-5071 cesium oscillator.  The unit was off -0.003 Hz.  I used the frequency setting commands to get it on freq.
 


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