 |
|
| Science Forum Index » Electronics - Design Forum » SD-24 guts... |
|
Page 1 of 3 Goto page 1, 2, 3 Next |
|
| Author |
Message |
| John Larkin... |
 Posted: Fri Oct 30, 2009 4:12 pm |
|
|
|
Guest
|
|
| Back to top |
|
|
|
| ... |
| Posted: Fri Oct 30, 2009 4:12 pm |
|
|
|
Guest
|
On Oct 30, 5:12 pm, John Larkin
<jjlar... at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
[quote]We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
[/quote]
Oh my. I thought my S-6 was hardcore. |
|
|
| Back to top |
|
|
|
| Fred Bartoli... |
| Posted: Fri Oct 30, 2009 4:24 pm |
|
|
|
Guest
|
John Larkin a écrit :
[quote]We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
[/quote]
The funny thing is I just grabbed one on feebay for a good price and was
about to ask your opinion about how easy it is to repair...
Now I really hope it's working OK :-)
--
Thanks,
Fred. |
|
|
| Back to top |
|
|
|
| John Larkin... |
| Posted: Fri Oct 30, 2009 5:01 pm |
|
|
|
Guest
|
On Fri, 30 Oct 2009 23:24:56 +0100, Fred Bartoli <" "> wrote:
[quote]John Larkin a écrit :
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
The funny thing is I just grabbed one on feebay for a good price and was
about to ask your opinion about how easy it is to repair...
Now I really hope it's working OK 
[/quote]
About all you can fix is stuff outside the hybrids, like a dead eeprom
or something mechanical.
I can't imagine how much engineering went into this.
John |
|
|
| Back to top |
|
|
|
| Joerg... |
| Posted: Fri Oct 30, 2009 5:04 pm |
|
|
|
Guest
|
John Larkin wrote:
[quote]We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
[/quote]
Oh man, that doesn't look like it's going to be fun. I hope you've got
at least a schematic and a wire bonder. But in the Bay Area it should be
possible to find a shop that can do the bonding if needed.
I wonder if, with today's materials, it would be possible to achieve
similar performance with regular SMT parts on a material such as Rogers.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM. |
|
|
| Back to top |
|
|
|
| John Larkin... |
| Posted: Fri Oct 30, 2009 5:26 pm |
|
|
|
Guest
|
On Fri, 30 Oct 2009 16:04:23 -0700, Joerg <invalid at (no spam) invalid.invalid>
wrote:
[quote]John Larkin wrote:
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
Oh man, that doesn't look like it's going to be fun. I hope you've got
at least a schematic and a wire bonder. But in the Bay Area it should be
possible to find a shop that can do the bonding if needed.
[/quote]
We're just replacing dead eeproms. I wouldn't dream of touching the
wire-bonded stuff. Tek never revealed schematics on the 11801-series
scopes anyhow.
[quote]
I wonder if, with today's materials, it would be possible to achieve
similar performance with regular SMT parts on a material such as Rogers.
[/quote]
I met Agoston Agoston at a trade show once. He designed most of this
stuff. He has his own little company now, and did a 20 GHz sampler
with surface-mount parts on FR4. Check out his Tek patents. AA had a
deal with Tek that they wouldn't sue him if he didn't go past 20. He
was also involved in the PSPL shock-line 100 GHz super-sampler
project, which may or might not still be a real product.
There's a paper on this page about the 100G thing:
http://www.picosecond.com/product/category.asp?pd_id=17#
I got a half-bridge sampler to work nicely at 7 GHz without a huge
effort.
ftp://jjlarkin.lmi.net/Sampler1.JPG
I'd think that 20 GHz on FR4 should be reasonable with available
surface-mount parts. Aeroflex just announced some 0.08 pF packaged
schottkies.
I just got an SD-30 (50 GHz) sampling head for $1500. There's tons of
cheap Tek gear on the market now.
John |
|
|
| Back to top |
|
|
|
| BobW... |
| Posted: Fri Oct 30, 2009 8:08 pm |
|
|
|
Guest
|
"John Larkin" <jjlarkin at (no spam) highNOTlandTHIStechnologyPART.com> wrote in message
news:c3pme55c6ou1nbv4c7vfiro96pj0jl56te at (no spam) 4ax.com...
[quote]
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
[/quote]
What do you suppose that one long wire bond is for (right in the middle near
the 224BF marking)?
Bob
--
== All google group posts are automatically deleted due to spam == |
|
|
| Back to top |
|
|
|
| John Larkin... |
| Posted: Fri Oct 30, 2009 8:55 pm |
|
|
|
Guest
|
On Fri, 30 Oct 2009 19:08:44 -0700, "BobW"
<nimby_GIMME_SPAM_ at (no spam) roadrunner.com> wrote:
[quote]
"John Larkin" <jjlarkin at (no spam) highNOTlandTHIStechnologyPART.com> wrote in message
news:c3pme55c6ou1nbv4c7vfiro96pj0jl56te at (no spam) 4ax.com...
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
What do you suppose that one long wire bond is for (right in the middle near
the 224BF marking)?
Bob
[/quote]
Beats me. The whole thing is a mystery.
The black spec in the very center is an SRD sitting on two
parallel-plate caps. It appears to drive slotlines in both directions,
towards the sampling diodes. The wirebond likely tunes some behavior
of the slotlines; it appears to connect "ground" to "ground." The
other channel doesn't have it.
Even stranger are the trim tabs above the top of the arch of that
wirebond.
This looks like a 6-diode traveling-wave sampler using beam-lead
diodes. The TDR step generators are in separate cavities.
John |
|
|
| Back to top |
|
|
|
| arlo... |
| Posted: Sat Oct 31, 2009 5:53 am |
|
|
|
Guest
|
On Oct 30, 7:26 pm, John Larkin
<jjlar... at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
[quote]On Fri, 30 Oct 2009 16:04:23 -0700, Joerg <inva... at (no spam) invalid.invalid
wrote:
John Larkin wrote:
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
Oh man, that doesn't look like it's going to be fun. I hope you've got
at least a schematic and a wire bonder. But in the Bay Area it should be
possible to find a shop that can do the bonding if needed.
We're just replacing dead eeproms. I wouldn't dream of touching the
wire-bonded stuff. Tek never revealed schematics on the 11801-series
scopes anyhow.
I wonder if, with today's materials, it would be possible to achieve
similar performance with regular SMT parts on a material such as Rogers.
I met Agoston Agoston at a trade show once. He designed most of this
stuff. He has his own little company now, and did a 20 GHz sampler
with surface-mount parts on FR4. Check out his Tek patents. AA had a
deal with Tek that they wouldn't sue him if he didn't go past 20. He
was also involved in the PSPL shock-line 100 GHz super-sampler
project, which may or might not still be a real product.
There's a paper on this page about the 100G thing:
http://www.picosecond.com/product/category.asp?pd_id=17#
I got a half-bridge sampler to work nicely at 7 GHz without a huge
effort.
ftp://jjlarkin.lmi.net/Sampler1.JPG
I'd think that 20 GHz on FR4 should be reasonable with available
surface-mount parts. Aeroflex just announced some 0.08 pF packaged
schottkies.
I just got an SD-30 (50 GHz) sampling head for $1500. There's tons of
cheap Tek gear on the market now.
John
[/quote]
I suspect that sampling phase detector (SPD) modules might provide the
easiest
way to roll your own sampling head beyond about 5GHz. These modules
include an
SRD coupled by small caps to a series pair of Schottky diodes, and
seem to be
stocked by some distributors. The integration of SRD, caps, and
Schottkys
ought to avoid the killer parasitic inductances of common surface
mount
packages without resorting to beam leads or wire bonding.
I don't know if the unspecified(?) series caps in e.g. the Skyworks
SPD
would give an ideal sampling pulse shape for sampling oscilloscope
work.
Another interesting question is whether the SRD in a second SPD (these
are,
after all, fast SRD's stocked by some distributors) could be
pressed into service in a pulse generator usable for TDR.
James |
|
|
| Back to top |
|
|
|
| ChrisQ... |
| Posted: Sat Oct 31, 2009 6:29 am |
|
|
|
Guest
|
John Larkin wrote:
[quote]On Fri, 30 Oct 2009 23:24:56 +0100, Fred Bartoli <" "> wrote:
John Larkin a écrit :
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
The funny thing is I just grabbed one on feebay for a good price and was
about to ask your opinion about how easy it is to repair...
Now I really hope it's working OK :-)
About all you can fix is stuff outside the hybrids, like a dead eeprom
or something mechanical.
I can't imagine how much engineering went into this.
John
[/quote]
Not only that, but that's 70's technology. They were way ahead of the
curve at the time, but what did it cost ?.
If you have stuff like this now you need to take good care of it.
Replacements are getting scarce and there's little affordable modern kit
to replace it with...
Regards,
Chris |
|
|
| Back to top |
|
|
|
| Gerhard Hoffmann... |
| Posted: Sat Oct 31, 2009 8:34 am |
|
|
|
Guest
|
On Fri, 30 Oct 2009 15:12:31 -0700, John Larkin <jjlarkin at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
[quote]We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
[/quote]
Hi, John,
I can ping your server, but when I try to get the file,
the connection is reset. (Firefox or Filezilla)
This has happened for weeks.
Does anybody else have this problem?
regards, Gerhard |
|
|
| Back to top |
|
|
|
| ... |
| Posted: Sat Oct 31, 2009 8:58 am |
|
|
|
Guest
|
On Oct 31, 9:34 am, Gerhard Hoffmann <dk... at (no spam) hoffmann-hochfrequenz.de>
wrote:
[quote]On Fri, 30 Oct 2009 15:12:31 -0700, John Larkin <jjlar... at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
Hi, John,
I can ping your server, but when I try to get the file,
the connection is reset. (Firefox or Filezilla)
This has happened for weeks.
Does anybody else have this problem?
regards, Gerhard
[/quote]
I'm using Firefox. I see it fine.
--
Cheers,
James Arthur |
|
|
| Back to top |
|
|
|
| John Larkin... |
| Posted: Sat Oct 31, 2009 9:32 am |
|
|
|
Guest
|
On Sat, 31 Oct 2009 15:34:45 +0100, Gerhard Hoffmann
<dk4xp at (no spam) hoffmann-hochfrequenz.de> wrote:
[quote]On Fri, 30 Oct 2009 15:12:31 -0700, John Larkin <jjlarkin at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
Hi, John,
I can ping your server, but when I try to get the file,
the connection is reset. (Firefox or Filezilla)
This has happened for weeks.
Does anybody else have this problem?
regards, Gerhard
[/quote]
It's supposed to be an anonymous FTP site. I've never had trouble
pointing other people to the files, using various browsers. Maybe
somebody who knows more about this sort of thing can offer
suggestions.
John |
|
|
| Back to top |
|
|
|
| John Larkin... |
| Posted: Sat Oct 31, 2009 9:52 am |
|
|
|
Guest
|
On Fri, 30 Oct 2009 23:24:56 +0100, Fred Bartoli <" "> wrote:
[quote]John Larkin a écrit :
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
John
The funny thing is I just grabbed one on feebay for a good price and was
about to ask your opinion about how easy it is to repair...
Now I really hope it's working OK
[/quote]
If the mainframe doesn't recognize it, it's a dead eeprom, which can
be fixed. Anything else is usually un-fixable. Often one channel will
be zapped on cheap ebay heads, so you at least get to use the other
one.
John |
|
|
| Back to top |
|
|
|
| Jim Thompson... |
| Posted: Sat Oct 31, 2009 9:53 am |
|
|
|
Guest
|
On Sat, 31 Oct 2009 15:34:45 +0100, Gerhard Hoffmann
<dk4xp at (no spam) hoffmann-hochfrequenz.de> wrote:
[quote]On Fri, 30 Oct 2009 15:12:31 -0700, John Larkin <jjlarkin at (no spam) highNOTlandTHIStechnologyPART.com> wrote:
We were fixing a broken Tek SD-24 20 GHz TDR/sampling head and took a
bunch of pix. Here's one:
ftp://jjlarkin.lmi.net/SD24_8.JPG
Hi, John,
I can ping your server, but when I try to get the file,
the connection is reset. (Firefox or Filezilla)
This has happened for weeks.
Does anybody else have this problem?
regards, Gerhard
[/quote]
No.
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
In Memoriam...
Duane Lee Thompson
October 31, 1972 - April 20,2006
4th Child, 2nd Son, of Jim & Naomi Thompson
Victim of Colon Cancer
Would Have been 37 Today |
|
|
| Back to top |
|
|
|
|
|
All times are GMT - 5 Hours
The time now is Fri Dec 11, 2009 10:40 am
|
|