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Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version.
I would much appreciate if any of you experts could shed some light on this.
Raymond
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Of course, where I wrote "...the maximum signal that...", I meant to write "...the maximum *frequency* that..."
Sorry for the inaccuracy.
Raymond
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--- In TekScopes@..., "raymonddompfrank" <r.domp.frank@...> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version.
I would much appreciate if any of you experts could shed some light on this.
Raymond
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The early 7B92A had amplifiers in the signal path before the tunnel diodes. Amplifiers help keep the tunnel diodes safe, but they tend to reduce trigger bandwidth. Contrast this with the 5T1A of a decade earlier, where the trigger signal is passively coupled to the "trigger recognition" tunnel diodes. The 5T1A is electrically fragile because of this design.
Also, the fastest triggering is really "HF sync" mode, not true bistable-multivibrator mode. HF sync mode exists in several Tek products using passive coupling of the trigger input to the tunnel diode (e.g., 7T11, 5T3, 519).
-Kurt
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--- In TekScopes@..., "raymonddompfrank" <r.domp.frank@...> wrote:
Of course, where I wrote "...the maximum signal that...", I meant to write "...the maximum *frequency* that..."
Sorry for the inaccuracy.
Raymond
--- In TekScopes@..., "raymonddompfrank" <r.domp.frank@> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version.
I would much appreciate if any of you experts could shed some light on this.
Raymond
|
On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@...> wrote: Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the trigger circuits were monolithic ICs, but maybe not. I have found the early version to be faster, but others disagree.
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On Sun, 1 Jul 2012 20:59:15 -0600, David DiGiacomo <daviddigiacomo@...> wrote: On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@...> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the
trigger circuits were monolithic ICs, but maybe not.
I have found the early version to be faster, but others disagree. I only have the later 7B92 plug-ins or I would do some tests. Both versions include the HF Sync mode. I like them because they trigger more cleanly than the 7B53A which is to be expected. I thought they used monolithic ICs instead of hybrids also but that could still be the case. Tektronix may have used that package for an IC simply because it was the highest frequency IC package available to them. It is too bad there are no details on it.
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Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
Raymond
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Show quoted text
--- In TekScopes@..., David <davidwhess@...> wrote:
On Sun, 1 Jul 2012 20:59:15 -0600, David DiGiacomo
<daviddigiacomo@...> wrote:
On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@...> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the
trigger circuits were monolithic ICs, but maybe not.
I have found the early version to be faster, but others disagree. I only have the later 7B92 plug-ins or I would do some tests. Both
versions include the HF Sync mode. I like them because they trigger
more cleanly than the 7B53A which is to be expected.
I thought they used monolithic ICs instead of hybrids also but that
could still be the case. Tektronix may have used that package for an
IC simply because it was the highest frequency IC package available to
them.
It is too bad there are no details on it.
|
I just recently acquired and repaired an SG503 that was suffering from bad TI sockets. I do not have anything suitable to test triggering above its 250Mhz maximum frequency. Did your non-tunnel diode based 7B92A timebases have lower trigger sensitivity with the same setup? On Sun, 15 Jul 2012 20:19:12 -0000, "raymonddompfrank" <r.domp.frank@...> wrote: Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
Raymond
--- In TekScopes@..., David <davidwhess@...> wrote:
On Sun, 1 Jul 2012 20:59:15 -0600, David DiGiacomo
<daviddigiacomo@...> wrote:
On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@...> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the
trigger circuits were monolithic ICs, but maybe not.
I have found the early version to be faster, but others disagree. I only have the later 7B92 plug-ins or I would do some tests. Both
versions include the HF Sync mode. I like them because they trigger
more cleanly than the 7B53A which is to be expected.
I thought they used monolithic ICs instead of hybrids also but that
could still be the case. Tektronix may have used that package for an
IC simply because it was the highest frequency IC package available to
them.
It is too bad there are no details on it.
|
Hi David,
I got this "hybrid" 7B92A through a swap with my earlier tunnel diode based unit. I only received my SG504 (and SG503) after that so I don't know my earlier 7B92A's trigger behavior by comparison. That was the very reason for starting this thread. In fact, until about a week ago, the max. freq. that I could test at was 2MHz (FG503)... Also, my fast pulse generators have only come to live with me since about the same time. All after the 7B92A swap.
Raymond
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Show quoted text
--- In TekScopes@..., David <davidwhess@...> wrote:
I just recently acquired and repaired an SG503 that was suffering from
bad TI sockets. I do not have anything suitable to test triggering
above its 250Mhz maximum frequency.
Did your non-tunnel diode based 7B92A timebases have lower trigger
sensitivity with the same setup?
On Sun, 15 Jul 2012 20:19:12 -0000, "raymonddompfrank"
<r.domp.frank@...> wrote:
Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
Raymond
--- In TekScopes@..., David <davidwhess@> wrote:
On Sun, 1 Jul 2012 20:59:15 -0600, David DiGiacomo
<daviddigiacomo@> wrote:
On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the
trigger circuits were monolithic ICs, but maybe not.
I have found the early version to be faster, but others disagree. I only have the later 7B92 plug-ins or I would do some tests. Both
versions include the HF Sync mode. I like them because they trigger
more cleanly than the 7B53A which is to be expected.
I thought they used monolithic ICs instead of hybrids also but that
could still be the case. Tektronix may have used that package for an
IC simply because it was the highest frequency IC package available to
them.
It is too bad there are no details on it.
|
Gotcha. It is funny how these things work out. I guess we need to find someone with both 7B92A versions and an SG504 or equivalent to measure any difference in the triggering sensitivity. I thought maybe I had an old tunnel diode based 7B85 timebase because it does not match any of my other 7B85 timebases but apparently some were produced in the middle of the serial number range where the front panel timebase markings are rotated about 4 detents CCW. On Sun, 15 Jul 2012 23:20:19 -0000, "raymonddompfrank" <r.domp.frank@...> wrote: Hi David,
I got this "hybrid" 7B92A through a swap with my earlier tunnel diode based unit. I only received my SG504 (and SG503) after that so I don't know my earlier 7B92A's trigger behavior by comparison. That was the very reason for starting this thread. In fact, until about a week ago, the max. freq. that I could test at was 2MHz (FG503)... Also, my fast pulse generators have only come to live with me since about the same time. All after the 7B92A swap.
Raymond
--- In TekScopes@..., David <davidwhess@...> wrote:
I just recently acquired and repaired an SG503 that was suffering from
bad TI sockets. I do not have anything suitable to test triggering
above its 250Mhz maximum frequency.
Did your non-tunnel diode based 7B92A timebases have lower trigger
sensitivity with the same setup?
On Sun, 15 Jul 2012 20:19:12 -0000, "raymonddompfrank"
<r.domp.frank@...> wrote:
Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
Raymond
--- In TekScopes@..., David <davidwhess@> wrote:
On Sun, 1 Jul 2012 20:59:15 -0600, David DiGiacomo
<daviddigiacomo@> wrote:
On Sun, Jul 1, 2012 at 5:29 PM, raymonddompfrank <r.domp.frank@> wrote:
Recently, I acquired a 7B92A that in contrast with the unit that I had, turns out to have no (discrete?) tunnel diodes in the trigger circuits but instead, uses hybrids packaged like the ones in e.g. a 7904A's vertical amp. I have seen references to this newer version of the 7B92A but haven't been able to find any description of the reasons why and any possible consequences. I would guess (and could appreciate) lower cost, higher reliability?
I wonder whether the circuits in these hybrids still contain circuits with tunnel diodes or do they contain more traditional circuits and if so, are there any functional differences? i could imagine that the maximum signal that the unit will trigger on would be lower than the tunnel diode-equipped version. No, there are no tunnel diodes in the late version. I thought the
trigger circuits were monolithic ICs, but maybe not.
I have found the early version to be faster, but others disagree. I only have the later 7B92 plug-ins or I would do some tests. Both
versions include the HF Sync mode. I like them because they trigger
more cleanly than the 7B53A which is to be expected.
I thought they used monolithic ICs instead of hybrids also but that
could still be the case. Tektronix may have used that package for an
IC simply because it was the highest frequency IC package available to
them.
It is too bad there are no details on it.
|
Hi Raymond,
Tried a tunnel diode based 7B92 in a 7904A/7A29, with input from a TG501 and internal triggering. At 2 ns and 1 ns the TG501 "pulse" stream is nearly a sine wave. At 2 ns (500 MHz) the 7B92 triggers well in Norm mode with signal less than 0.5 div. At 1 ns (1 GHz) it fails in Norm mode but syncs in HF Sync mode (and signal far below 0.5 div). But a 7B15 performed far better with a much sharper trace, so with much less jitter. Even at 1 GHz the 7B15 would trigger in Norm mode.
Checking TB performance this way in a 7904(A) is somewhat undefined since it's not clear what trigger amplitude arrives at the TB. Testing in a 7104 would give better information.
The 7B92 was "as is", so other units might perform better.
Albert
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Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
Raymond
|
I have a few 7B92's here. How do I tell which ones have TD's in them. Is there
a particular place on the board to look for them ?
Tnx, Dick, W1KSZ
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On Mon, Jul 16, 2012 at 2:15 PM, Albert <aodiversen@...> wrote:
?
Hi Raymond,
Tried a tunnel diode based 7B92 in a 7904A/7A29, with input from a TG501 and internal triggering. At 2 ns and 1 ns the TG501 "pulse" stream is nearly a sine wave. At 2 ns (500 MHz) the 7B92 triggers well in Norm mode with signal less than 0.5 div. At 1 ns (1 GHz) it fails in Norm mode but syncs in HF Sync mode (and signal far below 0.5 div). But a 7B15 performed far better with a much sharper trace, so with much less jitter. Even at 1 GHz the 7B15 would trigger in Norm mode.
Checking TB performance this way in a 7904(A) is somewhat undefined since it's not clear what trigger amplitude arrives at the TB. Testing in a 7104 would give better information.
The 7B92 was "as is", so other units might perform better.
Albert
> Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course, amplitude isn't shown anywhere near correctly. 7B92A is specified to trigger "above 500MHz".
>
> Raymond
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The tunnel diode based 7B92A is serial number B069999 and below. Physically if you look inside at the two trigger circuit boards, the ones with tunnel diodes have 3 DIP packages in a row while the newer ones without tunnel diodes have a DIP package next to an X shaped IC or hybrid mount. On Tue, 17 Jul 2012 09:09:01 -0700, Richard Solomon <dickw1ksz@...> wrote: I have a few 7B92's here. How do I tell which ones have TD's in them. Is
there
a particular place on the board to look for them ?
Tnx, Dick, W1KSZ
On Mon, Jul 16, 2012 at 2:15 PM, Albert <aodiversen@...> wrote:
**
Hi Raymond,
Tried a tunnel diode based 7B92 in a 7904A/7A29, with input from a TG501
and internal triggering. At 2 ns and 1 ns the TG501 "pulse" stream is
nearly a sine wave. At 2 ns (500 MHz) the 7B92 triggers well in Norm mode
with signal less than 0.5 div. At 1 ns (1 GHz) it fails in Norm mode but
syncs in HF Sync mode (and signal far below 0.5 div). But a 7B15 performed
far better with a much sharper trace, so with much less jitter. Even at 1
GHz the 7B15 would trigger in Norm mode.
Checking TB performance this way in a 7904(A) is somewhat undefined since
it's not clear what trigger amplitude arrives at the TB. Testing in a 7104
would give better information.
The 7B92 was "as is", so other units might perform better.
Albert
Tried my newly acquired SG504 (with leveling head) and saw this 7B92A triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course,
amplitude isn't shown anywhere near correctly. 7B92A is specified to
trigger "above 500MHz".
Raymond
|
Thank you.
Mine are all above S/N B069999, so I guess I don't get to play !!
73, Dick, W1KSZ
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On Tue, Jul 17, 2012 at 9:46 AM, David <davidwhess@...> wrote:
?
The tunnel diode based 7B92A is serial number B069999 and below.
Physically if you look inside at the two trigger circuit boards, the
ones with tunnel diodes have 3 DIP packages in a row while the newer
ones without tunnel diodes have a DIP package next to an X shaped IC
or hybrid mount.
On Tue, 17 Jul 2012 09:09:01 -0700, Richard Solomon
< dickw1ksz@...> wrote:
>I have a few 7B92's here. How do I tell which ones have TD's in them. Is
>there
>a particular place on the board to look for them ?
>
>Tnx, Dick, W1KSZ
>
>On Mon, Jul 16, 2012 at 2:15 PM, Albert < aodiversen@...> wrote:
>
>> **
>>
>> Hi Raymond,
>>
>> Tried a tunnel diode based 7B92 in a 7904A/7A29, with input from a TG501
>> and internal triggering. At 2 ns and 1 ns the TG501 "pulse" stream is
>> nearly a sine wave. At 2 ns (500 MHz) the 7B92 triggers well in Norm mode
>> with signal less than 0.5 div. At 1 ns (1 GHz) it fails in Norm mode but
>> syncs in HF Sync mode (and signal far below 0.5 div). But a 7B15 performed
>> far better with a much sharper trace, so with much less jitter. Even at 1
>> GHz the 7B15 would trigger in Norm mode.
>> Checking TB performance this way in a 7904(A) is somewhat undefined since
>> it's not clear what trigger amplitude arrives at the TB. Testing in a 7104
>> would give better information.
>> The 7B92 was "as is", so other units might perform better.
>>
>> Albert
>>
>> > Tried my newly acquired SG504 (with leveling head) and saw this 7B92A
>> triggering happily at around 1.05 GHz on my 7904 + 7A19... Of course,
>> amplitude isn't shown anywhere near correctly. 7B92A is specified to
>> trigger "above 500MHz".
>> >
>> > Raymond
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David Hess