Date   

I need the following 7D02 Logic Analyzer Personality Modules

 

The 7D02 Logic Analyzer Plugin was designed to work with a dozen different
microprocessors that were popular in the late 1970s to mid-1980s.
In order to do that it needed a Personality Module that adapted it to the
specific microprocessor that was being analyzed.
I am looking for the following Personality Modules for the 7D02 Logic
Analyzer:
PM101 Option 02 6502 PERSONALITY MODULE
PM101 Option 01 8080 PERSONALITY MODULE
PM102 6800 PERSONALITY MODULE
PM108 Z8002 PERSONALITY MODULE
PM110 Z8001 PERSONALITY MODULE
PM111 6809 PERSONALITY MODULE
PM112 MULTIBUS PERSONALITY MODULE
If anyone knows where I might find these personality modules please contact
me off list at dennis at ridesoft dot com.
Thanks, Dennis Tillman W7pF


Re: Peter Keller Book Order INTERIM UPDATE

Timothy W. Koeth
 

Hi Dennis,

Thank you so much for doing this. I appreciate the magnitude of the work
that you are doing. No good deed goes unpunished! Again, I am deeply
grateful!

- Tim


Dr. Timothy Koeth
Assistant Professor
Material Science & Engineering
Institute for Research in Electronics and Applied Physics
University of Maryland
301-405-4952 (office)
609-577-8790 (cell)

https://mse.umd.edu/clark/faculty/676/Timothy-W-Koeth

radiation.umd.edu

Amateur radio call sign K0ETH "K-zero-ETH" (formerly N2LPN)


On Tue, Nov 17, 2020 at 4:04 PM Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

At this point I have 65 firm orders for Peter's book which is about 55 more
than I expected when I came up with this bright idea. I am delighted for
Peter although I'm going to be very busy mailing these.
The flood of orders has finally dwindled to a trickle although I will allow
several more days before wrapping this up at the end of the week.
At that time I will post a list of the orders I have received so you can
confirm you are on the list and I didn't miss you. I will also provide
instructions for payment via PayPal, Zelle, check, or money order.

If you are in the United States I will be buying corrugated book mailers
for
your order. They will be mailed Media Rate ($4.00) so the total shipping
cost will be $7.00 for each book.

If you are not in the United States postal rates overseas are much more
expensive. My friends at the post office assure me the lowest rate is with
a
flat rate Priority Mail International Padded Envelope (which can be
tracked). Postage for these envelopes going to Germany, France, The
Netherlands, and most of Europe is $37.45. To Japan it is $35.35. Because
these are large envelopes and they are flat rate I know I can fit at least
two books in each one (and maybe three books will fit). If that is the case
and someone in each country is willing to forward the additional copies you
can split the shipping charges two or three ways by combining shipping.
At the moment I have these foreign orders:
Five orders to Canada (Quebec, Ontario, one unknown address at this time,
two to Alberta);
Three orders to the UK (London, Surrey, and East Sussex);
Three orders to Germany (Windach, Gross-Zimmern, and one unknown address at
this time);
Two orders to The Netherlands (Uithoorn, and Amsterdam);
One order to Japan (Chiba);
One order to Singapore;
One order to Norway (Drammen);
One order to France (Castelnau sur l'Auvignon);

Dennis Tillman W7pF






Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

Richard in Edenton NC
 

Hi Dennis, is it too late to get one? I have been busy with a sick relative and not reading emails lately.

Thanks and 73

Richard W4MCD


Re: EZ Test for 4041

Gary Robert Bosworth
 

Monty: Thanx for your help with these tapes. They were never dropped by
me. They were always packaged good, so I cannot imagine how they saw any
violent physical shock. I sure hope that all 3 work good for you. I
cannot imagine how magnetic tapes could lose their flux density and fail so
bad in my system. My tape drive appears to be in perfect condition, and
was originally owned by NASA where it was not used much and was never
mistreated. Let's hope for the best. I do have 2 other tape drives, so I
might have to switch them which is difficult in that 4041 mainframe.

Gary

On Tue, Nov 17, 2020 at 4:52 PM Monty McGraw <mmcgraw74@gmail.com> wrote:

Gary,

I got your three tapes, removed the belts and plastic parts and put them in
my dehydrator at 135F.
Thursday I will remove them from the dehydrator and begin testing them this
weekend.

One thing I noticed, two of the tape reels showed the tapes were dropped
and the edge of the reels were up to the top of the case :(

I pushed gently on the high edge to roughly center the tapes on the reels
before putting them in the dehydrator.

I did not dehydrate those tapes before sending them to you - I'm hoping
everything will be fine after they bake for two days.

I plan to install new belts on all three tapes.

Monty

Monty

On Mon, Nov 9, 2020 at 12:33 PM Gary Robert Bosworth <grbosworth@gmail.com
wrote:

Monty: I have 3 tapes that have gone bad. I don't understand why they
went bad. My tape drive seems to be running smooth. I will be happy to
send the failed tapes to you to see what you can do with them. Please
send
me your snail mail address so I can get these in the mail as soon as
possible. Thanx.

Gary Bosworth
grbosworth@gmail.com


On Sun, Nov 8, 2020 at 2:54 PM Monty McGraw <mmcgraw74@gmail.com> wrote:

Gary,

I would like to try recovering the files on your EZ-Test tape if you
still
have it.

Monty





--
Gary Robert Bosworth
grbosworth@gmail.com
Tel: 310-317-2247









--
Gary Robert Bosworth
grbosworth@gmail.com
Tel: 310-317-2247


Re: Q122/222 Jfet J300 subs for 2215A scope ?

dave G8SFU
 

Hi Tom, my thinking went thus::

I understood from previous posts that there were a pair of identical fets. I similarly understood they were "selected".

If these two statements are correct I stand by my original suggestion.
I should admit I have not worked on a 2215 and base my opinion on reading the thread, not looking at the actual circuit.

Regards dave
⁣Sent from BlueMail ​

On 18 Nov 2020, 10:17, at 10:17, Tom Lee <tomlee@ee.stanford.edu> wrote:
Hi Dave,

Keep in mind that this is a 60MHz scope, and that the circuit in
question is a simple buffer. I don't see how adding a new constraint of

matching helps to fix it. I still think that the OP either has a
collection of JFETs that Murphy has arranged to have extremely off-spec

IDSS (hence my advice to simply measure it; it's trivially easy to do),

or hasn't gotten the pinouts quite right (there is not a single
standard
pinout). It is also possible that there is a separate hardware problem
that is making one channel excessively finicky. It's straightforward to

eliminate or verify possibilities 1 and 2, so if it's neither 1 nor 2,
the OP should move on to 3. It's not hard to debug the bias loop, so if

he eliminates 1 and 2, getting through 3 should be fairly quick.

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 11/18/2020 01:55, dave G8SFU via groups.io wrote:
Can I add a further thought to Ed Breya's suggestions.
By all means use Ed's procedure to get the best possible spec for the
required fet.
But then try and match a pair of new ones. It seems to me much more
likely to work than matching a 40 year old one with a 'new' one.
Regards.  Dave.

⁣Sent from BlueMail ​

On 17 Nov 2020, 20:58, at 20:58, "Ed Breya via groups.io"
<edbreya=yahoo.com@groups.io> wrote:
It may be good to rethink and summarize what's going on with these
parts. Here's my take on it, presuming I haven't missed something.

1. There is one "good" original J310 that works properly in either
channel. This indicates the circuits for both are likely OK, as long
as
the "right" JFET characteristics are present.

2. The main issue is finding another JFET - a J310 or similar one -
that has the "same" characteristics as the good one. Alternative
part
trials so far have been unsuccessful.

3. The input circuit of the 2215A is of the opamp-stabilized type,
so
should be quite tolerant of JFET DC characteristics.

4. The "proper" part is 151-1124-00 = Siliconix J2400, which
apparently
is not a standard commercial part.

5. You have to get the pinout right, and we're assuming a TO-92
package.

6. Measuring Idss

Recommendations:

1&3. You can be pretty confident that both channel circuits are OK.
However, it's possible that one may have a minor fault or part out
of
tolerance such that it's OK with the good J310, but another part
that's
close and should work, doesn't quite. For now I think it's safe to
say
both are OK, and can be determined once a "right" part is found.

2. All along, the discussions have been mostly about getting Idss
right
- this is still the case, for DC conditions, one way or another. If
you
can find a VHF-class JFET (more on this in #5) that you can select
to
be close to the good J310, then it should work.

4. Let me explain a little about Tek and selected parts. In the old
days, when particular characteristics were needed, if they could be
selected out from stocks of generic parts at reasonable yield, Tek
often did this in-house, and a dash-number was assigned to the base
part number. This assumed also that the generic parts were used in
sufficient quantity that those not selected out (usually the -00)
would
be used up elsewhere. Later, as the real cost of all the in-house
selection and inventory and tracking complications became evident,
there was a big push to reduce this sort of stuff. One way is to
have
the vendor pre-select for the desired characteristics, out of their
much larger volumes, and assign a custom part number. This can be
done
if you're a large enough customer, and you pay a little more for the
parts to cover the vendor's cost of doing it. The benefit is that
you
get what you need, under a single part number, and you know the true
arm's-length cost. So, the supposition that J2400 is a custom part
number is likely correct - it's selected by the vendor from one of
their generic types, and sold only to Tek.

5. The pinout is important - more than just getting it connected
right.
What you want is a TO-92, with the source lead in the middle. VHF
parts
typically have this arrangement to minimize proximity and
capacitance
between gate and drain leads. The exception is if it's for
common-gate
topology, where you'd ideally want the gate in the middle, and it's
RF-grounded, and shields the drain from source. So, in choosing
possible candidates for substitution, first they should be listed as
"VHF amplifier" in the application highlights. Then look at the
pinout,
and pick only those with the source on the middle pin. The drain and
gate on the outside don't matter - you can always flip them around,
but
of course be sure what's what when installing.

6. For Idss, the easiest is to use a curve tracer and measure the
original good one - it's the gold standard, so take good care of it.
If
you don't have a curve tracer, you can rig up a simple bias circuit
for
checking and comparing. The best would be to measure the DC bias
conditions in the actual working circuit. The gate is assumed at
zero,
so all you need are the source and drain voltages, and you can
estimate
the drain current. Then set up a resistor bias scheme that gives the
same conditions if the same JFET were present. Note that this is not
an
Idss measurement (unless the source happens to also be at zero) -
it's
even better - an actual in-circuit test that can be done on the
bench
to sort the best parts to try in the real thing. In reality, the
vendor
likely sorted for a certain Idss range at a certain drain voltage,
which you don't know, but an in-circuit equivalent should be as good
or
better. There is a simple proxy for Idss, that you can use to
pre-sort
parts, rejecting those that are very unlikely to land close. Just
measure the "on" resistance of the drain-source (with gate tied to
either), with an ohmmeter, compared to that of the gold standard. I
think you'll find that the switching type JFETs will be quite low
(10-50 ohms), and the small, slow ones (like for high-Z DC
amplifiers)
quite high (over about 200 ohms). The VHF and HF ones are typically
in
the mid-range around 50-200 ohms.

The idea of putting in a temporary socket is good too, but a little
awkward working down in the guts. That will certainly tell what
works
and what doesn't.

That's all for now. Good luck.

Ed







Re: Delayed Timebase on a Tek 2215A

satbeginner
 

Yep,

That's how it works.
B trigger level fully clockwise, than you can choose the part you want to expand.
If set to a certain trigger level, so not fully clockwise, it will jump from flank to flank when turning "B delay time position"

Saludos,

Leo


Re: Peter Keller Book Order INTERIM UPDATE

 

On Tue, Nov 17, 2020 at 10:04 PM, Dennis Tillman W7pF wrote:


Two orders to The Netherlands (Uithoorn, and Amsterdam);
Dennis,
Uithoorn and Amsterdam may be combined in one shipment to Uithoorn. The places are close together and I (in Uithoorn) will take care of it, once I know the name and address of the person in Amsterdam. BTW, my lab is in Uithoorn but I live in Amsterdam...

Also, I second Larry's suggestion to add a small amount to part-compensate you.

Raymond


Re: Peter Keller Book Order INTERIM UPDATE

Lawrance A. Schneider
 

Dennis,

Please add a couple of dollars to my cost for the book to cover your efforts.

I once did the same sort of thing for a group interested in a commercial 4DTV (4200?) It was a lot of work distributing the receivers to the people wanting it. If each of us were to add a dollar or so to your final 'deal', maybe you will again someday 'think up' something we would all appreciate.

Again, THANK YOU, larry


2465B OPT 09/11 cabling reassembly

Jean-Paul
 

Bonjour a tous,

This is a B060 SN scope, GPIB and CTT/WR options,

From epay as "defective power, works otherwise". It arrives with every cable disconnected from the power supply, and the supply completely blown.
I have removed the PSU and still working to fix or replace it. GPIB option was also removed, #671-0981-03
Question is how to replug all the option cables ?

Service manual and options manuals do not seem to have the exact cable configuration, in schematics or assembly diagrams,

IF anyone has the OPT 09 plus 10 configuration, I would appreciate photos of the cable/plugs on the PSU and GPIB board, to back panel and elsewhere.


Mille mercis pour votre aide gentil!

Many thanks for your kind assistance!

Jon .


Re: Delayed Timebase on a Tek 2215A

 

On Wed, Nov 18, 2020 at 12:21 PM, Jeff Dutky wrote:


Am I misunderstanding how the delayed timebase is supposed to work, or is
there a way to get the 2215A to allow a smooth scroll over the waveform like
the 2213?
I'm not familiar with the 2215A but I'd also suspect operator error. ISTR that you need to set the delayed trigger knob (top right hand side of front panel) clockwise all the way to set the B time base to "Runs after Delay". It seems you have it set somewhere intermediate where it sets the B trigger level.

Raymond


Delayed Timebase on a Tek 2215A

 

I purchased a cheap 2215A so that I could have a scope that had the delayed timebase ALT display function (where you get to see your A timebase waveform with the B timebase segment intensified, as well as showing the intensified portion of the waveform "zoomed in" to fill the width of the display). I already have a 475 and 2213, and I was hoping that the ALT display would allow me to scroll smoothly over the waveform the way I can with the 2213, but it seems to only allow jumping between one trigger point and the next, which isn't very interesting, at least not with a simple repeating waveform like the calibration signal.

Am I misunderstanding how the delayed timebase is supposed to work, or is there a way to get the 2215A to allow a smooth scroll over the waveform like the 2213?


Re: Replacing cable on P6075A probe

 

Daveolla wrote:

And then is the "Connector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box."
They dont tell you how to do that though. Perhaps the plastic has stiffened somewhat suggesting you need a good
pry from a screwdriver. Perhaps a blade edge of knife gently if a finger nail wont budge it. It can also be stuck and
needs to be cracked loose. If you nick or dint then you gotta fix that somehow........or I do. Leave no marks is the goal.
The probe and scope belonged to my father, he was the one who discovered that the probe was bad, I have merely verified the fact. He opened the compensation box himself, so I have no trouble getting it open now. I'm not sure what my father had to do to open the box, but I have used a nylon "spudger" to open it in order to minimize marring the surfaces.


Re: Q122/222 Jfet J300 subs for 2215A scope ?

Tom Lee
 

Hi Dave,

Keep in mind that this is a 60MHz scope, and that the circuit in question is a simple buffer. I don't see how adding a new constraint of matching helps to fix it. I still think that the OP either has a collection of JFETs that Murphy has arranged to have extremely off-spec IDSS (hence my advice to simply measure it; it's trivially easy to do), or hasn't gotten the pinouts quite right (there is not a single standard pinout). It is also possible that there is a separate hardware problem that is making one channel excessively finicky. It's straightforward to eliminate or verify possibilities 1 and 2, so if it's neither 1 nor 2, the OP should move on to 3. It's not hard to debug the bias loop, so if he eliminates 1 and 2, getting through 3 should be fairly quick.

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 11/18/2020 01:55, dave G8SFU via groups.io wrote:
Can I add a further thought to Ed Breya's suggestions.
By all means use Ed's procedure to get the best possible spec for the required fet.
But then try and match a pair of new ones. It seems to me much more likely to work than matching a 40 year old one with a 'new' one. Regards.  Dave.

⁣Sent from BlueMail ​

On 17 Nov 2020, 20:58, at 20:58, "Ed Breya via groups.io" <edbreya=yahoo.com@groups.io> wrote:
It may be good to rethink and summarize what's going on with these
parts. Here's my take on it, presuming I haven't missed something.

1. There is one "good" original J310 that works properly in either
channel. This indicates the circuits for both are likely OK, as long as
the "right" JFET characteristics are present.

2. The main issue is finding another JFET - a J310 or similar one -
that has the "same" characteristics as the good one. Alternative part
trials so far have been unsuccessful.

3. The input circuit of the 2215A is of the opamp-stabilized type, so
should be quite tolerant of JFET DC characteristics.

4. The "proper" part is 151-1124-00 = Siliconix J2400, which apparently
is not a standard commercial part.

5. You have to get the pinout right, and we're assuming a TO-92
package.

6. Measuring Idss

Recommendations:

1&3. You can be pretty confident that both channel circuits are OK.
However, it's possible that one may have a minor fault or part out of
tolerance such that it's OK with the good J310, but another part that's
close and should work, doesn't quite. For now I think it's safe to say
both are OK, and can be determined once a "right" part is found.

2. All along, the discussions have been mostly about getting Idss right
- this is still the case, for DC conditions, one way or another. If you
can find a VHF-class JFET (more on this in #5) that you can select to
be close to the good J310, then it should work.

4. Let me explain a little about Tek and selected parts. In the old
days, when particular characteristics were needed, if they could be
selected out from stocks of generic parts at reasonable yield, Tek
often did this in-house, and a dash-number was assigned to the base
part number. This assumed also that the generic parts were used in
sufficient quantity that those not selected out (usually the -00) would
be used up elsewhere. Later, as the real cost of all the in-house
selection and inventory and tracking complications became evident,
there was a big push to reduce this sort of stuff. One way is to have
the vendor pre-select for the desired characteristics, out of their
much larger volumes, and assign a custom part number. This can be done
if you're a large enough customer, and you pay a little more for the
parts to cover the vendor's cost of doing it. The benefit is that you
get what you need, under a single part number, and you know the true
arm's-length cost. So, the supposition that J2400 is a custom part
number is likely correct - it's selected by the vendor from one of
their generic types, and sold only to Tek.

5. The pinout is important - more than just getting it connected right.
What you want is a TO-92, with the source lead in the middle. VHF parts
typically have this arrangement to minimize proximity and capacitance
between gate and drain leads. The exception is if it's for common-gate
topology, where you'd ideally want the gate in the middle, and it's
RF-grounded, and shields the drain from source. So, in choosing
possible candidates for substitution, first they should be listed as
"VHF amplifier" in the application highlights. Then look at the pinout,
and pick only those with the source on the middle pin. The drain and
gate on the outside don't matter - you can always flip them around, but
of course be sure what's what when installing.

6. For Idss, the easiest is to use a curve tracer and measure the
original good one - it's the gold standard, so take good care of it. If
you don't have a curve tracer, you can rig up a simple bias circuit for
checking and comparing. The best would be to measure the DC bias
conditions in the actual working circuit. The gate is assumed at zero,
so all you need are the source and drain voltages, and you can estimate
the drain current. Then set up a resistor bias scheme that gives the
same conditions if the same JFET were present. Note that this is not an
Idss measurement (unless the source happens to also be at zero) - it's
even better - an actual in-circuit test that can be done on the bench
to sort the best parts to try in the real thing. In reality, the vendor
likely sorted for a certain Idss range at a certain drain voltage,
which you don't know, but an in-circuit equivalent should be as good or
better. There is a simple proxy for Idss, that you can use to pre-sort
parts, rejecting those that are very unlikely to land close. Just
measure the "on" resistance of the drain-source (with gate tied to
either), with an ohmmeter, compared to that of the gold standard. I
think you'll find that the switching type JFETs will be quite low
(10-50 ohms), and the small, slow ones (like for high-Z DC amplifiers)
quite high (over about 200 ohms). The VHF and HF ones are typically in
the mid-range around 50-200 ohms.

The idea of putting in a temporary socket is good too, but a little
awkward working down in the guts. That will certainly tell what works
and what doesn't.

That's all for now. Good luck.

Ed




Re: Q122/222 Jfet J300 subs for 2215A scope ?

dave G8SFU
 

Can I add a further thought to Ed Breya's suggestions.
By all means use Ed's procedure to get the best possible spec for the required fet.
But then try and match a pair of new ones. It seems to me much more likely to work than matching a 40 year old one with a 'new' one. Regards.  Dave.  

⁣Sent from BlueMail ​

On 17 Nov 2020, 20:58, at 20:58, "Ed Breya via groups.io" <edbreya=yahoo.com@groups.io> wrote:
It may be good to rethink and summarize what's going on with these
parts. Here's my take on it, presuming I haven't missed something.

1. There is one "good" original J310 that works properly in either
channel. This indicates the circuits for both are likely OK, as long as
the "right" JFET characteristics are present.

2. The main issue is finding another JFET - a J310 or similar one -
that has the "same" characteristics as the good one. Alternative part
trials so far have been unsuccessful.

3. The input circuit of the 2215A is of the opamp-stabilized type, so
should be quite tolerant of JFET DC characteristics.

4. The "proper" part is 151-1124-00 = Siliconix J2400, which apparently
is not a standard commercial part.

5. You have to get the pinout right, and we're assuming a TO-92
package.

6. Measuring Idss

Recommendations:

1&3. You can be pretty confident that both channel circuits are OK.
However, it's possible that one may have a minor fault or part out of
tolerance such that it's OK with the good J310, but another part that's
close and should work, doesn't quite. For now I think it's safe to say
both are OK, and can be determined once a "right" part is found.

2. All along, the discussions have been mostly about getting Idss right
- this is still the case, for DC conditions, one way or another. If you
can find a VHF-class JFET (more on this in #5) that you can select to
be close to the good J310, then it should work.

4. Let me explain a little about Tek and selected parts. In the old
days, when particular characteristics were needed, if they could be
selected out from stocks of generic parts at reasonable yield, Tek
often did this in-house, and a dash-number was assigned to the base
part number. This assumed also that the generic parts were used in
sufficient quantity that those not selected out (usually the -00) would
be used up elsewhere. Later, as the real cost of all the in-house
selection and inventory and tracking complications became evident,
there was a big push to reduce this sort of stuff. One way is to have
the vendor pre-select for the desired characteristics, out of their
much larger volumes, and assign a custom part number. This can be done
if you're a large enough customer, and you pay a little more for the
parts to cover the vendor's cost of doing it. The benefit is that you
get what you need, under a single part number, and you know the true
arm's-length cost. So, the supposition that J2400 is a custom part
number is likely correct - it's selected by the vendor from one of
their generic types, and sold only to Tek.

5. The pinout is important - more than just getting it connected right.
What you want is a TO-92, with the source lead in the middle. VHF parts
typically have this arrangement to minimize proximity and capacitance
between gate and drain leads. The exception is if it's for common-gate
topology, where you'd ideally want the gate in the middle, and it's
RF-grounded, and shields the drain from source. So, in choosing
possible candidates for substitution, first they should be listed as
"VHF amplifier" in the application highlights. Then look at the pinout,
and pick only those with the source on the middle pin. The drain and
gate on the outside don't matter - you can always flip them around, but
of course be sure what's what when installing.

6. For Idss, the easiest is to use a curve tracer and measure the
original good one - it's the gold standard, so take good care of it. If
you don't have a curve tracer, you can rig up a simple bias circuit for
checking and comparing. The best would be to measure the DC bias
conditions in the actual working circuit. The gate is assumed at zero,
so all you need are the source and drain voltages, and you can estimate
the drain current. Then set up a resistor bias scheme that gives the
same conditions if the same JFET were present. Note that this is not an
Idss measurement (unless the source happens to also be at zero) - it's
even better - an actual in-circuit test that can be done on the bench
to sort the best parts to try in the real thing. In reality, the vendor
likely sorted for a certain Idss range at a certain drain voltage,
which you don't know, but an in-circuit equivalent should be as good or
better. There is a simple proxy for Idss, that you can use to pre-sort
parts, rejecting those that are very unlikely to land close. Just
measure the "on" resistance of the drain-source (with gate tied to
either), with an ohmmeter, compared to that of the gold standard. I
think you'll find that the switching type JFETs will be quite low
(10-50 ohms), and the small, slow ones (like for high-Z DC amplifiers)
quite high (over about 200 ohms). The VHF and HF ones are typically in
the mid-range around 50-200 ohms.

The idea of putting in a temporary socket is good too, but a little
awkward working down in the guts. That will certainly tell what works
and what doesn't.

That's all for now. Good luck.

Ed



Missing Addresses for two people who want Peter Keller's book

 

I need to receive mailing addresses for these two people if they still want
Peter Keller's book
Charlie Daves? (cldaves@...)
Jan Philipp Wuesten (Germany)

Dennis Tillman W7pF


Re: Tektronix 7D13 and 7A42 wanted

Ed Breya
 

Nevermind - I found it. The 7D20 has "EAROM" to store settings only - no waveforms. No battery is mentioned. Ed


Re: Tektronix 7D13 and 7A42 wanted

Ed Breya
 

Now I'm also worried about the 7D20 and whether it has a battery. I use it quite a bit, and I think it has some sort of NVRAM to save settings and waveforms, and no battery needed. Does anyone know offhand?

Ed


Re: Tektronix 7D13 and 7A42 wanted

Jim Ford
 

I'll keep that in mind, Stephen (H). Thanks for mentioning Batteries+; there's one at the next exit off the freeway from my house.

Jim

------ Original Message ------
From: "Stephen Hanselman" <kc4sw.io@kc4sw.com>
To: TekScopes@groups.io
Sent: 11/17/2020 9:08:36 PM
Subject: Re: [TekScopes] Tektronix 7D13 and 7A42 wanted

If it’s a three battery pack in our area we go to batteries+ and pick up a three cell portable phone battery. Then solder the leads to existing wires and use double sided sticky tape. Works fine.

Regards,

Stephen Hanselman
Datagate Systems, LLC
On Nov 17, 2020, at 21:03, Jim Ford <james.ford@cox.net> wrote:

Speaking of NiCads in HP gear, I just closed up my 8350B sweep oscillator after replacing a slightly melted power inlet and the suspect Rifa cap soldered to it. I remembered somebody on the HPAK group mentioning NiCads in that very model, so I poked around and found them against the wall of the plug-in compartment with a pop-off lid. Pretty easy to check, certainly a lot easier than soldering and unsoldering 12 wires connecting to the power inlet with no service loop to speak of!
No leaks in my NiCads, but the voltage read really low. Still keeps its front panel settings, even when disconnecting the AC power cable. I'll write up the full repair on HP-Agilent-Keysight-equipment@groups.io.

And a couple years ago I designed a breakout box at work. It needed 2 AA batteries inside for powering a keep-alive interface. So I put 2 tip jacks on the box so that the keep-alive battery voltage could be measured with DMM probes without opening the box, which was secured with 4 screws. Well, the guys using the box gave me crap about using tip jacks instead of banana jacks so they could hook up a bench power supply. Well, you could always remove the tip jacks and replace them with banana jacks, after drilling the holes out a bit, I told them. You could do the same on your instrument, if you don't mind the aesthetics.

Jim Ford

------ Original Message ------
From: "Stephen Bell" <s.r.bell@snap.net.nz>
To: TekScopes@groups.io
Sent: 11/17/2020 6:54:00 PM
Subject: Re: [TekScopes] Tektronix 7D13 and 7A42 wanted

Dennis,

I fully agree with your comments that the battery leakage problem should have been anticipated by the design engineers.

Not only should they have put warning labels on the equipment they should have also provided an easy way to check the battery voltage. I check the batteries in my equipment on an annual basis but this usually involves considerable effort removing covers to get access. It would be so much easier if the design engineers had the forethought to provide easily accessible battery test points on the rear panel, or better still, provided a function whereby the battery status could be indicated from the front panel.

While you are complaining to Tek about their poor design decisions perhaps you could also complain to HP. In my opinion they were far worse with the widespread use of leaky NiCd batteries in their equipment.

Stephen Bell












Re: Replacing cable on P6075A probe

John Gord
 

Dave,
I think the main difference between the P6075 and P6075A was the ground lead attachment method. On the P6075 the lead screwed into a hole in the side of the probe. In the P6075A it attaches with the forked pincher into a groove on the probe (like most of the later probes of that general size).
--John Gord

On Tue, Nov 17, 2020 at 08:44 AM, Daveolla wrote:



On a side note, what is the difference in the plain P6075 and the A
version? I see the specs for the plain versions input impedance is
10meg within 0.4% and 0.5% for the A.

Dave


Re: Tektronix 7D13 and 7A42 wanted

John Gord
 

Tom,
I also had a summer job that included making a 1702 EPROM programmer. I resorted to using at least one genuine electromechanical relay to switch the HV.
(Carver Mead was my undergraduate advisor and had received some 1702 via former students at Intel.)
--John Gord

On Tue, Nov 17, 2020 at 06:40 PM, Tom Lee wrote:


Yes, thanks to Moore's law, life is quite different, for engineers and
everyone else.

One of my earliest college summer jobs was building a programmer for
1702 EPROMs. I thought I was being set up for a newhire hazing gag --
negative 48 volts on address and data lines?? Surely that had to be a
joke. But that was what it took to program those mighty bits.

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 11/17/2020 18:33, Stephen Bell wrote:
EEPROM type devices were around at the time but they were quite difficult to
use. Some required -30V supplies, had awkward logic levels and were
incredibly slow.

The performance and ease of use of modern non-volatile memory devices is
incredible when you look back at what was available to designers back in the
80's.




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