EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: saturation on December 03, 2012, 06:24:09 pm
-
I've been waiting for a good version of either a 1992, 1996, 1998 or 1999 to pop up, and one finally did after some years of waiting. There are no tear downs of this model series on the Internet so here is an offering for those interested in acquiring any within the series and to discern internal differences [ the 1995 is without GHz capability, the 1996 is an upgrade of the 1994; they are designed to be rack mountable, while the 1992 design was transportable.]
The 1994-96 were made in the late 1980s and offered slightly more calculations or control over input signals than the 1992. They were less plagued with switch defects that appear in used models 1991, 1992. Because they were not made to be transported, the rack mount series are likely to be in better physical shape.
Large photos:
http://www.flickr.com/photos/igsaturation/8241558668/# (http://www.flickr.com/photos/igsaturation/8241558668/#)
(http://farm9.staticflickr.com/8064/8241558668_2240c7baa4.jpg)
(http://farm9.staticflickr.com/8486/8241557164_72366286f1.jpg)
All boards and components are easily accessed on this design compared to the compact 1992. The large green PCB is the dedicated 68000 computer board that does all the calculations. The gold board is the data input and preconditioning board. The "copper wire" seen crossing from the front to rear in the middle is a type SMB connector cable to the divide-by-64 prescaler for 1.5 GHz rated Input C. Item marked "B" in yellow is the ovenized oscillator.
(http://farm9.staticflickr.com/8207/8240493867_b655bcdc98.jpg)
(http://farm9.staticflickr.com/8479/8240493227_eae724bea8.jpg)
-
I have a 1992 and a 1998 counter, and I just love these Racal/Dana counters.
My 1998 is currently out of service because it has developed the front panel
switch problem that plagues these units, and I haven't yet figured out a nice
way to machine replacement switches.
I also have an EIP 545A microwave counter I'm just starting to play with.
Scott
-
The 199x series are all great units, a model for their entire class and still in demand. I found recently that BKPrecision makes a series of counters that at a high of ~ $500, will match the capabilities of a 1999 but without the risk of age related failures; so getting an old Racal is really tied to what price/performance you can muster over eBay.
Thanks slburris for your prior posts on them and photos. Worrying about having to replace those switches over time made me wait for the right one to come along, although appearance wise, the whole 199x series seems to have the same design but it maybe tied to when they were made, yet some have them, some not.
Do you know the build date of your 1998 and 1992? There are stickers or stamped dates all over the internals.
I have a 1992 and a 1998 counter, and I just love these Racal/Dana counters.
My 1998 is currently out of service because it has developed the front panel
switch problem that plagues these units, and I haven't yet figured out a nice
way to machine replacement switches.
I also have an EIP 545A microwave counter I'm just starting to play with.
Scott
-
Nice machine saturation.
The heart (counter and interpolator) seem similar
to the 1992, the single shot resolution is the same, but
this one has many more functions: rise and fall times for
pulses from 5nS, gate window programmable, higher voltage
capability and statistical calculation, so more useful than the
1992, good catch!
edit: also one more digit on the display 10 vs 9, easier to
read for high resolutions.
I found some specs here:
http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf (http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf)
What timebase do you have? If it's the 9462 (04E) should
be good, my 1992 holds pretty well against Rb clocks.
The 199x switch problems are annoying, but thanking to
them I was able to pay few dollars for very good counter, in
mint conditions, the fix was few hours of work and few
cheap switches :)
Fabio.
-
Thanks muvideo, and also thanks for your photos on the archives. That helped me a lot too. I think the prescaler board is identical too, I have blow ups on the flikr site and I compared it to your photos. The additional functions are great as it give me the capability to do some measurements that normally you'd need a 1 GHz grade scope to do.
Yes, it has the ovenized reference, 04e option. Its good to know it hold well against a Rb clock, so I can hold off on getting one for now.
Regardless, I agree with your comments on any effort repair these! These counters are well worth the effort, my only fear is a firmware or memory failure, but in reviewing prior posts on any model in this series, no spontaneous failures have been reported unlike some early HP3456 DVM.
My unit had a small pouch will the old firmware ROMs still in them inserted on the mobo, so I have a backup in case of diasaster :-/O
FWIW, BK's model:
(http://www.bkprecision.com/photos/?src=images/products/photos/large/1823A_front_lrg.jpg)
Is actually fairly close to the 1999. Listed at $470, you can deal it down to the high $300s, which will match the highest end price some eBay sellers want for many 199x series.
Nice machine saturation.
The heart (counter and interpolator) seem similar
to the 1992, the single shot resolution is the same, but
this one has many more functions: rise and fall times for
pulses from 5nS, gate window programmable, higher voltage
capability and statistical calculation, so more useful than the
1992, good catch!
edit: also one more digit on the display 10 vs 9, easier to
read for high resolutions.
I found some specs here:
http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf (http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf)
What timebase do you have? If it's the 9462 (04E) should
be good, my 1992 holds pretty well against Rb clocks.
The 199x switch problems are annoying, but thanking to
them I was able to pay few dollars for very good counter, in
mint conditions, the fix was few hours of work and few
cheap switches :)
Fabio.
-
My 1998 has circuit boards with '88 date stamps and a QC sticker with an Apr '89 date handwritten
on it. I haven't cracked open my 1992 yet since it's working like a charm.
I saw another 1992 pop up on Ebay (it's still there) for $100, but it's from Surplus Test
Mart in Israel, and for some reason a lot of their stuff looks like it got run over by a tank.
This one is no exception -- it looks rather squished. Maybe you could harvest front
panel switches from it, but since they all seem to go bad eventually, that's probably
not a good investment.
And now darn it, I'm going to have to look at that BK model too.
The 199x series are all great units, a model for their entire class and still in demand. I found recently that BKPrecision makes a series of counters that at a high of ~ $500, will match the capabilities of a 1999 but without the risk of age related failures; so getting an old Racal is really tied to what price/performance you can muster over eBay.
Thanks slburris for your prior posts on them and photos. Worrying about having to replace those switches over time made me wait for the right one to come along, although appearance wise, the whole 199x series seems to have the same design but it maybe tied to when they were made, yet some have them, some not.
Do you know the build date of your 1998 and 1992? There are stickers or stamped dates all over the internals.
I have a 1992 and a 1998 counter, and I just love these Racal/Dana counters.
My 1998 is currently out of service because it has developed the front panel
switch problem that plagues these units, and I haven't yet figured out a nice
way to machine replacement switches.
I also have an EIP 545A microwave counter I'm just starting to play with.
Scott
-
Surplus Test is pricy and they are not very eager to accept a reasonable offer for something that obviously was picked up at a scrap yard and needs a lot of TLC to get it working.
Anyway, if you are going to spend a lot of cash on a frequency counter it might be interesting to know that many spectrum analysers have this feature as well. Another problem I've found with some frequency counters is that their sensitivity at higher frequencies is quite poor.
-
Yes, its impressive they want so much money for what I think are consistently the most battered equipment I've seen on eBay.
Yes, if you do get a modern SA, the counters in them are exceptional, like the new Rigol SA815. A good counter is a bit redundant now, also good SAs accept external references for improved accuracy. But until Rigols 815, most SA of some decency are in the $5k range, and in eBay, many sub $1000 used SA don't have high accuracy counters.
The Racal's are fairly sensitive throughout their range, you can read it on their spec sheet. The input C board for 1.5 GHz is 10x more sensitive than the mainboard A,B inputs.
Yes, I was under the impression that the 199x series was the year it was made, but its just a model number. The series begins in late 1980s and any future revisions can be found on the mobo and in the manuals, I think the most recent in mid 1995.
My 1998 has circuit boards with '88 date stamps and a QC sticker with an Apr '89 date handwritten
on it. I haven't cracked open my 1992 yet since it's working like a charm.
Surplus Test is pricy ...
Anyway, if you are going to spend a lot of cash on a frequency counter it might be interesting to know that many spectrum analysers have this feature as well. Another problem I've found with some frequency counters is that their sensitivity at higher frequencies is quite poor.
-
Well that's interesting. I too have a 1996 off ebay and it had spare EEPROMs inside it. Are they included from the factory?
-
Not sure, but its the prior firmware revision in mine, so I have a backup should the old one die, FWIW!
Well that's interesting. I too have a 1996 off ebay and it had spare EEPROMs inside it. Are they included from the factory?
-
I've convinced myself I need multiple counters for my setup.
Normally, I run a Trimble Thunderbolt as an external 10Mhz reference to
all of my equipment. So I have one counter running off the Thunderbolt.
I use a second counter as a sanity check on the 10Mhz output of the
Thunderbolt.
Currently my 1992 is that sanity check. I'm quite impressed with the OXCO
in it. At maximum resolution, I'm seeing 10Mhz on the dot +- 1 digit even over
temperature variations in my lab room.
I do have a couple of rubidiums as backup, but I rarely power them up.
The talk of firmware reminds me I need to image my firmware in case of problems.
There isn't a list of firmware revisions floating around somewhere, is there?
Scott
-
Here's my 1996. It's reading a second 9462 I got along with the 1996. They're "off" .05ppm relative to each other. Unfortunately I can't figure out what the long term drift and/or aging is. The scope is showing 10Mhz from the second 9462, and 5Mhz from before the frequency doubler on the first one.(http://i.imgur.com/rQxOcl.jpg)
-
@poodyp: nice. You'll need time to calculate the long term drift rates; as these Racals are old units the good news is very likely the reference have stabilized, and at this point the drift rate would be at its lowest, unless is about to break!
@slburris: I think its always good to have a minimum of 2 of each type of equipment, if its mission critical to you. How can one know its off if we have but one device? I personally try to acquire 3 types of each so there is a tie breaker.
Can you compare the Racal XCO to the Thunderbolt? Being the latter is more accurate, I'd like to know how the Racal crystal compares. I've always read it compares very favorably, but never heard its quantified, say its off ppm or ppb.
-
Oooh, there's a 1992 on eBay right now for $80 with no bids. Looks to be in pretty decent shape.
I will not buy it. Say it with me.... :-)
Scott
-
I see it :scared:
I think final sale price of a 1996 is often close to a 1992; they have similar specs as counters but the 1996 has a stat function built in and voltage readouts too. I find the stat function very useful, as it simplifies making stability calculations and the large size of the chassis makes it easier to work with.
1992 is nevertheless, a good machine, looking for a good home!
-
You'll need time to calculate the long term drift rates
Oops, I meant to say I couldn't figure out what the rated long term drift was other than a single line in the manual stating "Aging: < 5 * 10-10 per day". I know it's highly unlikely to be too far off, I just need to get a thunderbolt or something to check against. The oscillator that came in my 1996 has the serial number of 300 something, so it could be very old, but I doubt it's drifted by ~5E-10 * 24 * 365.
-
5e-10 * sqrt(24 * 365) might be a better estimate, although you should be able to find at least 1y specs.
-
... yes in the end, a best test would be to compare it empirically against a Rb clock or a GPS disciplined one. The Racal's ovenized XO is not that far off. I've read 2 -3 reports of comparisons against a Rb clock stating its fairly close, alas, but not quantified with a number, one is by Fabio on this thread.
In his brief post he summarized all the key differences between the 1992 and 1996.
I meant to say I couldn't figure out what the rated long term drift was other than a single line in the manual stating "Aging: < 5 * 10-10 per day"...
Nice machine saturation.
The heart (counter and interpolator) seem similar
to the 1992, the single shot resolution is the same, but
this one has many more functions: rise and fall times for
pulses from 5nS, gate window programmable, higher voltage
capability and statistical calculation, so more useful than the
1992, good catch!
edit: also one more digit on the display 10 vs 9, easier to
read for high resolutions.
What timebase do you have? If it's the 9462 (04E) should
be good, my 1992 holds pretty well against Rb clocks.
The 199x switch problems are annoying,
Fabio.
-
... yes in the end, a best test would be to compare it empirically against a Rb clock or a GPS disciplined one. The Racal's ovenized XO is not that far off. I've read 2 -3 reports of comparisons against a Rb clock stating its fairly close, alas, but not quantified with a number, one is by Fabio on this thread.
Hello, it happens that now I have on the bench
a GPS, some Rb clocks, the counter and some
logging scripts on the pc. So I could try to quantify
the statement I made before, I need only to find
some free time for some time tests... :)
Fabio.
-
:-+ Awesome! As your time allows, thank you, Fabio!
... yes in the end, a best test would be to compare it empirically against a Rb clock or a GPS disciplined one. The Racal's ovenized XO is not that far off. I've read 2 -3 reports of comparisons against a Rb clock stating its fairly close, alas, but not quantified with a number, one is by Fabio on this thread.
Hello, it happens that now I have on the bench
a GPS, some Rb clocks, the counter and some
logging scripts on the pc. So I could try to quantify
the statement I made before, I need only to find
some free time for some time tests... :)
Fabio.
-
Well, I couldnt resist the tentation to make a quick check
of the absolute error of my unit.
Please consider that I'm still learning to deal with precise
time measurements, so feel free to check and correct my
procedures. Also the room temperature is far from ideal.
Measuring the output of a pair of FE5680A that I trimmed
against GPS (manually, no GPSDO still in my hands), the
counter was aroud 70-75 mHz high, so I was expecting
the internal oscillator a little on the low side, and it was low
by about 7.3x10^-9 :
(https://www.eevblog.com/forum/reviews/racal-dana-1996-frequency-counter/?action=dlattach;attach=36457)
The interesting part is top right, where I have data and linear
interpolation together. The line is the phase between
the GPS pps and internal 10MHz reference, so a positive
slope means that the 10MHz is lagging the pps -> slow.
It's not bad, the counter was never touched by me, and
probably not trimmed from a lot of time. According to the
manual it was still in spec, since the manual calls for recal
only past +-3x10^-8 deviation.
Ok time to try to trim the counter, I lightly touched the
fine adustment, after turning the pot the counter moves
back and forth slowly a pair of times, it takes several minutes, and
then stabilizes very slowly. Not an easy process, better to take
note of the screwdriver movements, and wait many minutes
between the adjustments. This is how the phase changed
from lagging to tracking the pps while I corrected the frequency:
(https://www.eevblog.com/forum/reviews/racal-dana-1996-frequency-counter/?action=dlattach;attach=36459)
This means that the two signals track each other, and
a quick check with the FE5680A confirms that I'm near,
somewhere around 2x10^-10 slow:
(https://www.eevblog.com/forum/reviews/racal-dana-1996-frequency-counter/?action=dlattach;attach=36461)
Now time to go to bed. As I have more data I will post them,
I think it will be difficult to show aging effects (unless I log the
unit for many days or the quartz is gone), since the unit
is aged and the aging should very slow now. Probably
it will be easier to try to see temperature effects.
Fabio.
-
Most excellent Fabio, this is the best characterized data for the 199x series with OXCO against a better standard. Your performance improvement is fantastic :-+ but I'd risk it only myself if I had a better standard to compare it against, as you have. :-+ :-+
-
Here's the schematic if anyone needs it: http://www.schematicsunlimited.com/?z=racal_dana (http://www.schematicsunlimited.com/?z=racal_dana)
-
Most excellent Fabio, this is the best characterized data for the 199x series with OXCO against a better standard. Your performance improvement is fantastic :-+ but I'd risk it only myself if I had a better standard to compare it against, as you have. :-+ :-+
Thank you saturation, but that was only early data,
against a gps.
I kept retouching the trim in last two days, last adjustments
are very very touchy. Now I'm unexspectly seeing a second
order change in drift, so I'm seeing the oscillator change
frequency, and I still dont know if it is it's natural aging
or it's stabilizing after the trimming. The fact that it's slowing
is compatible with the fact that it was low, I was not expecting
such a visible drift, but I've still not wotked the numbers, I will
wait few days and log the behaviour.
I'm now regretting to have changed the trim so early,
I should have logged the counter for a week before,
just to see the stability level it had before trimming.
I will post more details net week, and will describe
the setup I'm using, it's easy to setup.
Fabio.
-
I keep meaning to ask, where are you finding the BK counter under $470?
I was also wondering if you had an opinion on the 1856D, their 3.5 GHz counter for about $525?
Scott
Thanks muvideo, and also thanks for your photos on the archives. That helped me a lot too. I think the prescaler board is identical too, I have blow ups on the flikr site and I compared it to your photos. The additional functions are great as it give me the capability to do some measurements that normally you'd need a 1 GHz grade scope to do.
Yes, it has the ovenized reference, 04e option. Its good to know it hold well against a Rb clock, so I can hold off on getting one for now.
Regardless, I agree with your comments on any effort repair these! These counters are well worth the effort, my only fear is a firmware or memory failure, but in reviewing prior posts on any model in this series, no spontaneous failures have been reported unlike some early HP3456 DVM.
My unit had a small pouch will the old firmware ROMs still in them inserted on the mobo, so I have a backup in case of diasaster :-/O
FWIW, BK's model:
(http://www.bkprecision.com/photos/?src=images/products/photos/large/1823A_front_lrg.jpg)
Is actually fairly close to the 1999. Listed at $470, you can deal it down to the high $300s, which will match the highest end price some eBay sellers want for many 199x series.
Nice machine saturation.
The heart (counter and interpolator) seem similar
to the 1992, the single shot resolution is the same, but
this one has many more functions: rise and fall times for
pulses from 5nS, gate window programmable, higher voltage
capability and statistical calculation, so more useful than the
1992, good catch!
edit: also one more digit on the display 10 vs 9, easier to
read for high resolutions.
I found some specs here:
http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf (http://www.teknetelectronics.com/DataSheet/RACALDANA/RACAL_199590030.pdf)
What timebase do you have? If it's the 9462 (04E) should
be good, my 1992 holds pretty well against Rb clocks.
The 199x switch problems are annoying, but thanking to
them I was able to pay few dollars for very good counter, in
mint conditions, the fix was few hours of work and few
cheap switches :)
Fabio.
-
Hi Scott,
http://www.tequipment.net/BK1823a.html (http://www.tequipment.net/BK1823a.html)
http://www.transcat.com/catalog/productdetail.aspx?itemnum=1823A (http://www.transcat.com/catalog/productdetail.aspx?itemnum=1823A)
Wait for live chat to come on line and ask for the best price, its not advertised ... the price I received was before 2012 when everyone was doing holiday sales and end of year sales target attempts.
I don't own either, but the 1856D has less measurement functions, it more a raw counter. The 3.5 GHz input use an N connector.
The measurement capabilities of these counters are limited to the A channel, B is used for comparisons against A, C is typically just a frequency counter.
I keep meaning to ask, where are you finding the BK counter under $470?
I was also wondering if you had an opinion on the 1856D, their 3.5 GHz counter for about $525?
Scott
-
Saturation,
here the results, almost 4 days after trimming,
the OCXO now is slowing constantly about 1x10^-10 par day.
I stopped the logging because the lab temperature is so
low that the results are not that meaningful, but the counter
will be kept working, I will recheck the drift after some monthes
to see if it will be changed. Surely it will slow down, since it
was more stable before the trimming.
The setup:
the system I'm using seem unnecessary complex, the
reason is I have it ready for use for other purposes.
I'm using the counter in TI A->B mode,
Input A DC falling edge and input B DC rising edge COMA
(I.E. connected to input A) so I can measure the width of
a negative pulse.
I have a frontend that takes the 10MHz and GPS PPS and
emits the negative pulse.
The falling edge of this pulse is synchronized to PPS rising
edge, the rising edge is syncronyzed to the second rising
edge of the 10MHz reference that comes immediately after
GPS rising edge.
The result is a pulse that goes from 100nS to 200nS that
represents the phase between the 10MHz and PPS.
If the 10MHz is too slow it's phase will raise from 100 to 200nS
and then restart.
If the 10MHz is too fast the pulse will go from 200nS to 100nS.
The only limit is that the frequency must be enugh close to
have enough points between rollovers, otherwise the data can
be unusable or worse aliased. For example to have at least 10 points
before rollover the 10MHz need to change phase less than 10nS
per second, this translates in one part in 10^-8, i.e. less than 0.1Hz
of error on the 10MHz.
The remaining work is done by a script that unscrambles the data and applies
some processing.
I attach two graphs:
the first is phase data
- top left raw data, pulse width
- top right unscrambled data
- bottom left the same that top right, but with a linear drift removed, not very useful here
- bottom right ambient temperature
second graph:
- top left is the unscrambled data averaged
- top right is the first derivative of phase, i.e. relative error of 10MHz period,
when it's zero the frequency is spot on, now is 2.8x10^-10 i.e. the frequency is
2.8x10^-10 low, i.e. 0.0028Hz low.
- bottom left is second derivative, i.e. relative error variation per second, last
reading is 1.3x10^-15 (x86400=1.1x10^-10 per day)
Fabio.
-
Nice work there muvideo! :-+ :-+
-
Thanks Fabio, for the good data and your extensive work; I think you have the best characterized effect of trimming an ovenized clock on the net; others who have posted were not as thorough.
What I was surprised to find is how long the clock will take to settle, so one should not touch adjustments unless one's reference is known stable and reliable as tracking drift will require dedication for some time, weeks at least.
I am on time-nuts too [ readers here should read the archives there for the story]. It reads others have experienced adjustment instabilities but didn't document as well as you, Fabio, kudos! :-+
Saturation,
here the results, almost 4 days after trimming,
the OCXO now is slowing constantly about 1x10^-10 par day.
I stopped the logging because the lab temperature is so
low that the results are not that meaningful, but the counter
will be kept working, I will recheck the drift after some monthes
to see if it will be changed. Surely it will slow down, since it
was more stable before the trimming.
-
Same goes from me Fabio.
I have a Racal 1991 here , and a OPT-4E OCXO waiting to be installed in there
I have a PM6680 to test the Racal with , and a Tbolt for 10Mhz.
If you'd post the schematic of the phasedetector it would be nice
/Bingo
-
Thank you robrenz,
saturation are you one of the participants of this topic over there (time nuts)?
Bingo, the 6680 is a very capable timer, 250ps single shot,
should be nice for interval measurements, you are well equipped for time
measurements with that and the Thunderbolt.
The schematic is the logic part of this circuit, the output is OUTD pin:
(https://www.eevblog.com/forum/reviews/racal-dana-1996-frequency-counter/?action=dlattach;attach=37136)
Measuring this OCXO for the first time I was feeling the real accuracy
and stability of an average Rb oscillator. So I tried to make a a comparison:
I used the same setup with an Rb, it's period error was around -1x10^-11,
the period error variation is less than 10^-16 per second -> less
than 1x10^-12 per day, but buried in the noise, so these data are
not really accurate. (See second attachment below).
The funny thing it that the Rb was powered form cold immediately
before the start of the graph, the frequency error could be trimmed
out by the serial interface interface, but my Rb has no
thermostabilization yet, so nothing to gain.
The abrupt frequency variation at 90000s reflects an internal
DDS frequency variation, probably due to some temperature
compensation, I'm still figuring out this aspect.
That's all, for now :)
-
Fabio thankyou for the detailed explanation.
I'll see if i can hack a phasedetector together
/Bingo
-
Bingo, probably you know better than me, so what I write here
is not for you but for other readers, maybe can be userful...
That circuit is only a TAC (Time to Analogue Converter)
experiment. By the way, on time nuts, in a recent
discussion i was warned to use a different approach,
there is a very nice design example over there by
Dr Bruce Griffiths.
To make phase measurements a decent counter
is enough, just use two channels in start-stop mode,
and collect results.
Start with the PPS and stop with the reference.
Any decent counter like the Racal Dana or the
philips/fluke PM6680/81 or many HP 53xx can
cope with these intervals with nS or less resolution.
Fabio.
-
Here's the schematic if anyone needs it: http://www.schematicsunlimited.com/?z=racal_dana (http://www.schematicsunlimited.com/?z=racal_dana)
It seems there's like 2 copies of the manual out there, both the same scans, but one's completely out of order. Also I have no idea how part of the page gets cut off and put on the opposite side of the page. If I could find a paper manual I'd scan it myself if they weren't almost as much as what I paid for the 1996.
-
Download open source PDF architect and you can rearrange the pages, if you have time. These manuals aren't the best but its better than nothing, and these are widely available. I just rearrange pages in my head, its faster.
http://www.pdfarchitect.org/ (http://www.pdfarchitect.org/)
Here's the schematic if anyone needs it: http://www.schematicsunlimited.com/?z=racal_dana (http://www.schematicsunlimited.com/?z=racal_dana)
It seems there's like 2 copies of the manual out there, both the same scans, but one's completely out of order. Also I have no idea how part of the page gets cut off and put on the opposite side of the page. If I could find a paper manual I'd scan it myself if they weren't almost as much as what I paid for the 1996.
-
Thanks for these Fabio, I'm not a heavy participant on time nuts as I lack time to maintain my own atomic clock, but I'm very interested in the topic; its eventually how I settled on the 1996 versus any older HP counter, at least to 1.5 GHz. I need more volt nuts, so I spent more time posting there.
From what you've already posted, attempting to recalibrate the 199x is going to be time consuming, and one needs already a stable reference. As of this writing, at least the internal 1996 reference is rock stable and its measurements highly repeatable, so I can make relative measurements with high confidence and absolute ones may only need a simple algebraic correction to offset any error from my units calibration status.
Thank you robrenz,
saturation are you one of the participants of this topic over there (time nuts)?
Bingo, the 6680 is a very capable timer, 250ps single shot,
should be nice for interval measurements, you are well equipped for time
measurements with that and the Thunderbolt.
The schematic is the logic part of this circuit, the output is OUTD pin:
That's all, for now :)
-
I've was wondering if anyone has run into error code 63 when doing the self test on your 1996. I've had the unit I currently have for serveral years now and it's been working great other then failing this self test. The manual indicates that the error involves the input circuit but I haven't been able to trace it out on the schematic. One thing I did notice is that if I have the unit in standby overnight and power it up in the morning it pass the self check but after about 15 minutes I get the Error 63 again. Appreciate any input. Plus I've been checking it daily this against my GPS and Argo Systems AS210 and I'm usually running 10.00000003 MHz ±2 counts
-
Hi,
A common issue with system errors after warm up in old gear can be traced to the power supply, its the most likely item to go from age compared to all the subsystems [ other than the EEPROM]. It may pay to check the filter caps or the ripple on the main rails. It can save a lot of troubleshooting legwork.
I've was wondering if anyone has run into error code 63 when doing the self test on your 1996. I've had the unit I currently have for serveral years now and it's been working great other then failing this self test. The manual indicates that the error involves the input circuit but I haven't been able to trace it out on the schematic. One thing I did notice is that if I have the unit in standby overnight and power it up in the morning it pass the self check but after about 15 minutes I get the Error 63 again. Appreciate any input. Plus I've been checking it daily this against my GPS and Argo Systems AS210 and I'm usually running 10.00000003 MHz ±2 counts
-
Well, it turns out my 1992 is deaf on the channel C input.
So I went ahead and picked up the BK precision counter and
it seems to work like a charm. It's nice to have 1 working
fully functional counter.
It's got a few things to complain about compared to the 1992.
Doing high precision measurements takes a gate time of 10sec.
The 1992 is much faster, presumably because it uses a different
measurement technique? The internal oscillator seems more
drifty than my 1992, which has the ovenized standard.
You can't get more than 8 digits without using an external standard,
presumably due to the same drifty internal oscillator.
I'm using it now in external standard mode, connecting it to my
Trimble Thunderbolt.
The 1992 is still in service for frequencies less than 160Mhz, but
nominally goes on my list of things to repair, which is quite long now:
Racal Dana 1992
Racal Dana 1998
EIP 545A 18Ghz frequency counter
Heathkit GC-1000 clock
Tektronix 2246A scope
Tektronix 2465 scope
Heathkit H8 computer
and a few other odds and ends.
Scott
-
Well, it turns out my 1992 is deaf on the channel C input.
<snip>
The 1992 is still in service for frequencies less than 160Mhz, but
nominally goes on my list of things to repair, which is quite long now:
Racal Dana 1992
Racal Dana 1998
EIP 545A 18Ghz frequency counter
Heathkit GC-1000 clock
Tektronix 2246A scope
Tektronix 2465 scope
Heathkit H8 computer
and a few other odds and ends.
Scott
In case you haven't thought of it, a quick thing to do for your deaf 1992 is to check the fuse that's hidden inside the connector.
Also, your list of things to fix seems rather short. You're not trying very hard, are you? ;)
Ed
-
..list of things to repair...
Racal Dana 1992
Racal Dana 1998
Take the 1.3Ghz prescaler out of the 1998 and put it in the 1992 (assuming that it's not why the 1998 needs repairing).
I'm pretty sure that they are the same board.
Service manuals readily available for both on the 'net
-
My 1996 on arrival had trouble with Channel C. I reinserted the board, it read erratically but worked. I then connected the 10 MHz out of the Racal into C to check the calibration, it read the signal and worked fine every since.
-
Great forum. Found while researching some new equipment. I've had a 1996 for several years. I worked last time I powered it up, maybe 9 months ago. When I turned it on earlier this week to test a new pulse generator I got pretty much nada. No error codes. Some evidence a POST was start by a number of LEDs coming on for a half second and then stalling with only the GATE and both TRIG LEDs on. I see some evidence of charring around negative voltage regulator U49 but I don't think it is recent. +5 and +15V testpoints show the correct voltage.
I'm currently without a scope until January. A component failure I can maybe fix. One fear is the EPROMs have gone senile. Looking for any hints before I start digging deep. Thanks.
-
Assuming the PSU is fine, a can't hurt test is reseating all socketed boards and ICs, taking due static precautions.
Great forum. Found while researching some new equipment. I've had a 1996 for several years. I worked last time I powered it up, maybe 9 months ago. When I turned it on earlier this week to test a new pulse generator I got pretty much nada. No error codes. Some evidence a POST was start by a number of LEDs coming on for a half second and then stalling with only the GATE and both TRIG LEDs on. I see some evidence of charring around negative voltage regulator U49 but I don't think it is recent. +5 and +15V testpoints show the correct voltage.
I'm currently without a scope until January. A component failure I can maybe fix. One fear is the EPROMs have gone senile. Looking for any hints before I start digging deep. Thanks.