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Re: Tek 7834 Question
ycui7
I am seeing the same thing on mine. The same behavior also extends to my 7633.
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Yang Cui
On Wed, Apr 22, 2020, at 8:31 AM, Gerhard Hofbauer wrote:
Has anyone experience with the TEK 7834 400 MHz mainframe?
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Re: Tek 7834 Question
I also own a 7834.
Unless you'd really like to use bistable mode or just to be sure your 'scope is ok, I wouldn't bother about bistable storage. Its only benefit is the long storage time. For practical use, all other modes are far superior. Bistable mode is a relic from the time that no other modes existed. Raymond
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Re: SN7400N Quad opamp which side is pin 1?
DIP ICs mark the location of pin 1 in one of two ways. Some of them have a
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dot that is closest to pin 1. Others have a notch which is in the center of the end of the DIP where pin 1 is located; pin 1 is on the left side (looking at the DIP from above with the pins facing down toward the board) and the highest numbered pin is on the right side. Pins on a DIP are numbered counterclockwise (again looking from above); they go down the left side from 1 to N/2, turn the corner, and come up the right side from N/2+1 to N, where N is the number of pins on the package. Surface mount IC packages with a single column of pins or pads on each side, such as SOIC and TSSOP, are marked and numbered the same way.
On Wed, Apr 22, 2020 at 11:27 AM DW <wilson2115@outlook.com> wrote:
I had an interesting situation which I done that as well
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Re: Tek 7834 Question
Hi GerhardMine does the same , or it did before the power supply went into tick mode , not had time to fix that yet . I put it down to expectations of a bi-stable screen like that in a 564 or a 549 but I think it performs differently because of the multi-mode features as every one I have seen a photo of in bi-stable mode shows the same bright background giving you only something like a 3 or 4 to 1 contrast ratio .
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Brian
On Wednesday, 22 April 2020, 16:31:30 BST, Gerhard Hofbauer <gerhard.hofbauer@xerxes-tech.com> wrote:
Has anyone experience with the TEK 7834 400 MHz mainframe? About 20 years ago I bought a used 7834 mainframe for the 7S11/7T11 plug-ins. At that time I wondered about the storage function. When "Bistable" is pressed, the screen starts dark and gets completly bright after abot 5 seconds. No adjustments of intensity etc. can adjust the right brightness to get a good stored image. "Var Persistence" is fine. At the time I did not care, since I did not need any storage function. Last year I decided to repair the scope, and I did all the tests and adjustments of the service manual, but could not get even a bad "bistable" screen. I read the "Storage Cathode-Ray Tubes and Circuits" and "Oscilloscope Cathode-Ray Tubes" books and came to conclusion that the CRT is probably defective. So I bought another 7834 with some other defects (vertical), but it had the same screen effects. So my question is: Is this a common failure of CRT aging, or am I doings something wrong. (All voltages on the CRT are perfectly fine in each operation mode) br, Grhard. -- XERXES electronics GmbH Dammgasse 75 A-9020 Klagenfurt Tel.: +43-(0)463-890061-0 Fax.: +43-(0)463-890061-23 Mob.: +43 (0) 680 4405842 office@xerxes-tech.com www.xerxes-tech.com Firmenbuch : FN 307552h UID : ATU64037018
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Tek 7834 Question
Gerhard Hofbauer <gerhard.hofbauer@...>
Has anyone experience with the TEK 7834 400 MHz mainframe?
About 20 years ago I bought a used 7834 mainframe for the 7S11/7T11 plug-ins. At that time I wondered about the storage function. When "Bistable" is pressed, the screen starts dark and gets completly bright after abot 5 seconds. No adjustments of intensity etc. can adjust the right brightness to get a good stored image. "Var Persistence" is fine. At the time I did not care, since I did not need any storage function. Last year I decided to repair the scope, and I did all the tests and adjustments of the service manual, but could not get even a bad "bistable" screen. I read the "Storage Cathode-Ray Tubes and Circuits" and "Oscilloscope Cathode-Ray Tubes" books and came to conclusion that the CRT is probably defective. So I bought another 7834 with some other defects (vertical), but it had the same screen effects. So my question is: Is this a common failure of CRT aging, or am I doings something wrong. (All voltages on the CRT are perfectly fine in each operation mode) br, Grhard. -- XERXES electronics GmbH Dammgasse 75 A-9020 Klagenfurt Tel.: +43-(0)463-890061-0 Fax.: +43-(0)463-890061-23 Mob.: +43 (0) 680 4405842 office@xerxes-tech.com www.xerxes-tech.com Firmenbuch : FN 307552h UID : ATU64037018
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Re: SN7400N Quad opamp which side is pin 1?
DW
I had an interesting situation which I done that as well
On the PCB board of DC electronic load a white dot was marked to indicate pin 1, however on the IC socket it indicated the pin on the opposite side, I installed the IC that matched the mark on the PCB and quickly found out it was in reverse when I was reading 150 amps on the display with no load attached
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Re: SN7400N Quad opamp which side is pin 1?
Paul Amaranth
On Wed, Apr 22, 2020 at 08:08:13AM -0700, DW wrote:
Thanks for the correction and the valuable informationActually, you can see the notch and STILL install it backards. Been there, done that. Paul -- Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@AuroraGrp.Com | Unix & Windows
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Re: SN7400N Quad opamp which side is pin 1?
DW
Thanks for the correction and the valuable information
The reason for confusion is that In the past I have dealt with IC's that referenced pin 1 with a circle, you can see this in the link below https://groups.io/g/TekScopes/photo/245683/0?p=Created,,,20,2,0,0 Obviously we can see the circle is larger than usual, I can see the possibly with someone who is working quickly with their finger over the notch and they see the circle and install the IC in reverse.
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Re: Vacuum forming 7K interface "covers"
On Wed, Apr 22, 2020 at 02:33 AM, Chuck Harris wrote:
see www.hakanh.com/dl/docs/hardtofind/200-0950-00.pdf /Håkan
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Re: Vacuum forming 7K interface "covers"
I looked inside my 7704A and verified that all the 200-0950-00 COVER, ELEC CONN:PLASTIC are there.
I don't see them so fragile, and they are solidly attached (inserted?) to the connector body. But... plastic is plastic. They also seem to have an indentation for each contact tongue to fit inside, but I'm not completely sure. I like the good design of the connector, where the contact tongues protrude just a little beyond the edge of the cover, sufficient to make good contact with the inserted PC board, and stay at a safe distance from the opposing contact when not in use. Ernesto
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Re: Vacuum forming 7K interface "covers"
Chuck Harris <cfharris@...>
My saying "*About* 1 inch by 3 inch" indicates that it was just a
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guesstimate. I was giving an approximate size to eliminate any of the other parts, particularly any "prismatic" parts, from the mix. Since my mind's eyeball approximation isn't good enough: Measured with my caliper, I read: 3.855" x 0.764" It is injection molded, evidenced by mold fill marks, and a swirl in the plastic composition where the flows occurred. It has 8 sprues, arranged in a rectangular matrix. The plastic is white, translucent, and slippery, probably one of the polyethylene types of plastic. The plastic is slightly unstable, as it started to warp within minutes after my removing it from the connector. I don't want to burn it for further classification of the plastic, as the part is still serviceable. The cross sectional shape is complex in that it has special "hooks" that retain the part. It is loosely in a class called a "C" channel. It is not something that will be easy to make with a 3D printer of the hobby class, as it is only 29.5 thousandths of an inch thick, with some features that are less than 5 thousandths. It is in the shape of an extruded solid, so extrusion would be a good, though expensive, way of making this part, if you use the right plastic. The manufacturer (presumably Tektronix) obviously thought injection molding was much cheaper and easier, and probably used manufacturing equipment they already had on hand... Plus, it eliminates a special machining operation to cut the pieces to length. -Chuck Harris Colin Herbert via groups.io wrote:
I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two?
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Re: SN7400N Quad opamp which side is pin 1?
Tom Bowers
The notch is pin 1, lower left corner in your photo. the part number is
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near pin 7. This is a quad 2 input NAND gate device from the fist vintage of 7400 series TTL. Made in 1972. Tom Bowers
On Wed, Apr 22, 2020 at 8:33 AM DW <wilson2115@outlook.com> wrote:
https://groups.io/g/TekScopes/album?id=245683
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Re: SN7400N Quad opamp which side is pin 1?
Paul Amaranth
The notch identifies pin 1 which is at the lower left.
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That's also a quad nand gate, not an op amp. The circle is a mold mark.
On Wed, Apr 22, 2020 at 07:33:08AM -0700, DW wrote:
https://groups.io/g/TekScopes/album?id=245683 --
Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@AuroraGrp.Com | Unix & Windows
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Re: SN7400N Quad opamp which side is pin 1?
Carl Hallberg
I meant to say Quad Dual Input NAND device.
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Carl
On Wednesday, April 22, 2020, 9:33:18 AM CDT, DW <wilson2115@outlook.com> wrote:
https://groups.io/g/TekScopes/album?id=245683 Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.
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Re: SN7400N Quad opamp which side is pin 1?
Carl Hallberg
It is not an op amp. It is a quad nand gate. On round devices, the tab is the last pin.
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Carl Hallberg (W9CJH)
On Wednesday, April 22, 2020, 9:33:18 AM CDT, DW <wilson2115@outlook.com> wrote:
https://groups.io/g/TekScopes/album?id=245683 Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.
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SN7400N Quad opamp which side is pin 1?
DW
https://groups.io/g/TekScopes/album?id=245683
Here is a rather unusual design at least for me. This chip contains both the notch and the circle, I want to say the notch is pin 1 but I am not 100% certain that might be the case, any thoughts? I am trying to be certain not to install it in reverse.
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Re: Vacuum forming 7K interface "covers"
Colin Herbert
Yes, Steve, that is what I understand to be the item in question. However, I wouldn't particularly call them "pins", more "connectors" as they are thin and flat; I think of "pins" as being more substantial and round or rectangular in cross-section.
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Some time ago I purchased one of these plastic side-covers on eBay from a UK seller, if I'm remembering correctly. I think the same seller has some of the "connectors" for sale currently on UK eBay and may still have some of the side-covers. It is worth noting that there are two types of the metal connectors. It may be that those used in the extenders differ from those in the back-plane connectors. One type is longer than the other but can be converted by careful use of wire-cutters. Colin.
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of stevenhorii Sent: 22 April 2020 14:57 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" Colin and David, If you look at eBay item: 133386313435 it is the plug-in backplane for a 7854. In the fourth photo, I believe it shows one of the connectors that is missing the cover on one side of the connector - you can see the exposed pins. In other photos, you can see connectors with both covers. I think this is what you are discussing if I am correct. Steve H. On Wed, Apr 22, 2020 at 09:30 Colin Herbert via groups.io <colingherbert= blueyonder.co.uk@groups.io> wrote: Thank You, David, I am now un-flummoxed. It is exactly the part that I was
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Re: Vacuum forming 7K interface "covers"
stevenhorii
Colin and David,
If you look at eBay item: 133386313435 it is the plug-in backplane for a 7854. In the fourth photo, I believe it shows one of the connectors that is missing the cover on one side of the connector - you can see the exposed pins. In other photos, you can see connectors with both covers. I think this is what you are discussing if I am correct. Steve H. On Wed, Apr 22, 2020 at 09:30 Colin Herbert via groups.io <colingherbert= blueyonder.co.uk@groups.io> wrote: Thank You, David, I am now un-flummoxed. It is exactly the part that I was
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Re: Vacuum forming 7K interface "covers"
Colin Herbert
Thank You, David, I am now un-flummoxed. It is exactly the part that I was thinking of, but the 3 inch measurement is way too short. As you suggest 4 inch is about right. These parts are also used on the 7000-series extenders, both the rigid and flexible versions (I know because I have one rigid and two flexibles).
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Colin.
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David C. Partridge Sent: 22 April 2020 14:17 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical parts breakdowns in all the 7000 series Service manuals. There are two of these used on each plugin socket on the main interface board to keep pressure on the contact fingers so they press onto the contacts at the rear of the plug-ins. I would say that 4" x 1" sounds roughly in the ball-park for size. David -----Original Message----- From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin Herbert via groups.io Sent: 22 April 2020 13:42 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two? Colin. -----Original Message----- From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris Sent: 22 April 2020 01:33 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" They are little plastic covers, very thin, and about 1 inch by 3 inches. Their purpose is to restrain the free ends of the gold socket pins. They are simply a thin sheet of plastic that is bent to a specific shape, probably with a vacuum forming method. They are prone to getting longitudinal cracks, and when that happens, they fall out, or simply stop retaining the socket pins. Often the pins will get crumpled by the plugin after this happens. At a minimum, they won't make uniform contact on all pins. -Chuck Harris Roy Thistle wrote: On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
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Re: Vacuum forming 7K interface "covers"
For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical parts breakdowns in all the 7000 series Service manuals.
toggle quoted messageShow quoted text
There are two of these used on each plugin socket on the main interface board to keep pressure on the contact fingers so they press onto the contacts at the rear of the plug-ins. I would say that 4" x 1" sounds roughly in the ball-park for size. David
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin Herbert via groups.io Sent: 22 April 2020 13:42 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two? Colin. -----Original Message----- From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris Sent: 22 April 2020 01:33 To: TekScopes@groups.io Subject: Re: [TekScopes] Vacuum forming 7K interface "covers" They are little plastic covers, very thin, and about 1 inch by 3 inches. Their purpose is to restrain the free ends of the gold socket pins. They are simply a thin sheet of plastic that is bent to a specific shape, probably with a vacuum forming method. They are prone to getting longitudinal cracks, and when that happens, they fall out, or simply stop retaining the socket pins. Often the pins will get crumpled by the plugin after this happens. At a minimum, they won't make uniform contact on all pins. -Chuck Harris Roy Thistle wrote: On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
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