Date   

Re: 7A13 Knob

Nathan Johnson
 

I'm going to buy the used knob from the member who offered it above, and then
try to make several Tek knobs.
A coworker with a lathe is making metal inserts, and with some decent CAD, I'll
probably send the files to Shapeways. Probably won't be anything like perfect
looking, but functional.
Nathan KK4REY

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On Sat, Mar 12, 2016 at 15:29, @Raymond [TekScopes]
<TekScopes@...> wrote:
The problem with the "replacement" knob on the 'bay is that the Al insert is
more in front (from the faceplate) than with the original. The hex fastening
screw is as well. I'm not at all convinced that it (the inner knob) would fit,
even after removing the plastic black insert. I have both one of those knobs (I
think). I'll be in my lab again early next week and can try if it fits my 7A13.


Raymond

[Non-text portions of this message have been removed]


Re: 465 foot 3d model

John Clark
 

I do have a few 314/335 feet now but I'm clueless when it comes to the 3D modeling software. I'm good at a lot of things but 3D drawing has never been one of them. I installed Sketchup a while back for another project I wanted someone to print for me but finally gave up after it kicked my behind. Makes me feel like an idiot, too, since everything I read about it says it's so easy to use.

John

Any chance you can create a 3D model of a 335 foot? I'd like to try to print some for my 335 whose feet were completely perished when I got it.
--

Soren


Re: 7854 RAM card upgrade only - any interest?

 

The scan of the service manual from Artek Manuals covers the late
7854.

On 12 Mar 2016 05:12:48 -0800, you wrote:

...

3- Is there a downloadable/purchasable manual for this above B1000000 version? I would like to have a copy.

...


Re: Tektronic 466 - Storage Modes inop

 

It would be nice to know what caused the failure. CR1947 is there to
prevent reverse breakdown of the base-emitter junction of Q1948.

I would also check for a shorted capacitor or open resistor.

On 12 Mar 2016 10:34:30 -0800, you wrote:

Perfect - Thanks!

I buzzed out the rest of the transistors and diodes across the A10 board, and found only one more - CR1947.


Re: 465 foot 3d model

Malcolm Hunter
 

On 12 March 2016 at 19:22, Soren Jorvang @soren [TekScopes] <
TekScopes@...> wrote:

Any chance you can create a 3D model of a 335 foot? I'd like to try to
print some for my 335 whose feet were completely perished when I got it.
​I don't have an original foot to work from, so that wouldn't be feasible
I'm afraid. If someone wants to send me one, I could work from that (I'm in
the UK). The 465 foot only took a couple of hours. It's not a perfect copy,
but close enough to be quite functional.

Malcolm

Malcolm​


[Non-text portions of this message have been removed]


Re: 465 foot 3d model

 

On 12 Mar 2016, at 19:41, John Clark johnclark05@... [TekScopes] <TekScopes@...> wrote:
As a side note, I sent him some 335 & 314 feet to reproduce and, in my opinion, he did a fine job on them, though he wasn't as happy with the end product so he decided not to continue making any more. On these particular feet the rough side ended up having to be the face/bottom of the feet and he didn't like the way they turned out. Since the 335/314 feet are unavailable anywhere (and they're worse than the 4xx feet for breaking) ‎I am 100% satisfied with them. It's off topic for this thread but if anyone is interested in 335/314 feet let me know off list. If there are enough out there maybe he'll make some more for us, casting imperfections aside.
Any chance you can create a 3D model of a 335 foot? I'd like to try to print some for my 335 whose feet were completely perished when I got it.


--
Soren


Re: 7854 Repair & Restoration

 

On 12 Mar 2016 08:08:09 -0800, you wrote:


I have always been suspicious of the mini-Berg sockets and have run
into a couple cases where good contact was not being made. I think
the machined collet pins which you mention below are more reliable.
What I can do while I have the amplifier/driver out is take a 22 gauge wire, insert it into the socket, and check continuity/resistances while I give the wire a wiggle. If one of those sockets shows an intermittent connection or a resistance, would you suggest I replace all of them with augat machined sockets? I have some 24pin dip sockets I can pull apart. I also have the berg sockets from some old 475 boards.
If I was going to do that, I would use a stronger and thinner wire
like the lead from a 1/4 watt resistor or small signal diode like a
1N4148 to avoid damaging the socket. If there is a problem with the
mini-Berg sockets, just reseating U50 will likely fix it.

I would consider reflowing all of the solder joints around U50 whether
a detailed inspection reveals a problem or not as long as the board
removed.

A question for you that's a bit off topic - I want/need a decent current probe for troubleshooting these 485's. (I'm sure I'll want it for other things in the future as well.) Can you recommend a good current probe arrangement that I can keep an eye out for that actually might show up on the market for less than a couple hundred dollars? I'd like to get something close to or sub $100, but I don't want to go over $200.

It's too bad that I didn't get in on the whole AM503 & probe market while they were going for $50 each...
P6021 and P6022 AC current probes regularly sell for under $200 but
they are somewhat fragile so finding a good one might be a problem.
They require either the passive termination they originally came with,
a Tektronix type 134 current probe amplifier, or a 7A14.


Re: 465 foot 3d model

Malcolm Hunter
 

On 12 March 2016 at 18:41, John Clark johnclark05@... [TekScopes] <
TekScopes@...> wrote:

Malcom, those look great!

​Thanks. I plan to add the 2mm nodules to keep the power cable in place.​

FYI, There's a guy selling reproduction feet for the 4xx scopes on eBay
(not the lathe-turned round ones‎.) I won't name him since he didn't give
me permission but some of you probably know him. He doesn't always have
them listed but I'll just say they're absolutely fantastic. They are
identical to the originals but with a bit harder plastic. He sells them for
$25 for a set. Their only downside (and it's very minor at that) is that
one side is a bit unfinished due to how they are cast but the set I put on
my 475 look and work great.

​Yes, I had those on my watch-list for a while​. They look pretty good and
made of a tough material, though I managed to get some original ones for my
465B from a very helpful chap on this list.

Malcolm


[Non-text portions of this message have been removed]


Re: 465 foot 3d model

John Clark
 

Malcom, those look great!

FYI, There's a guy selling reproduction feet for the 4xx scopes on eBay (not the lathe-turned round ones‎.) I won't name him since he didn't give me permission but some of you probably know him. He doesn't always have them listed but I'll just say they're absolutely fantastic. They are identical to the originals but with a bit harder plastic. He sells them for $25 for a set. Their only downside (and it's very minor at that) is that one side is a bit unfinished due to how they are cast but the set I put on my 475 look and work great.

As a side note, I sent him some 335 & 314 feet to reproduce and, in my opinion, he did a fine job on them, though he wasn't as happy with the end product so he decided not to continue making any more. On these particular feet the rough side ended up having to be the face/bottom of the feet and he didn't like the way they turned out. Since the 335/314 feet are unavailable anywhere (and they're worse than the 4xx feet for breaking) ‎I am 100% satisfied with them. It's off topic for this thread but if anyone is interested in 335/314 feet let me know off list. If there are enough out there maybe he'll make some more for us, casting imperfections aside.

John

Sent from my BlackBerry Z30 smartphone.
From: Malcolm Hunter malcolm.r.hunter@... [TekScopes]
Sent: Saturday, March 12, 2016 13:14
To: TekScopes@...
Reply To: TekScopes@...
Subject: [TekScopes] 465 foot 3d model


Hi,

I modeled a replacement cable-wrap foot (actually for my spares 475). It's
on Thingiverse if anyone would like to make use of it.

http://www.thingiverse.com/thing:1410827

I just needed something to stop the scope from tipping over. I used PLA,
which is good enough for that. I'm not sure what would be the best material
to print it with and how well it would hold up in general use.

Malcolm


[Non-text portions of this message have been removed]


Re: Tektronic 466 - Storage Modes inop

Jim McIntyre
 

Perfect - Thanks!

I buzzed out the rest of the transistors and diodes across the A10 board, and found only one more - CR1947.


Re: 465 foot 3d model

Tom Gardner
 

On 12/03/16 18:14, Malcolm Hunter malcolm.r.hunter@... [TekScopes] wrote:

I modeled a replacement cable-wrap foot (actually for my spares 475). It's
on Thingiverse if anyone would like to make use of it.

http://www.thingiverse.com/thing:1410827

I just needed something to stop the scope from tipping over. I used PLA,
which is good enough for that. I'm not sure what would be the best material
to print it with and how well it would hold up in general use.
I would expect
http://www.shapeways.com/materials/strong-and-flexible-plastic
to be a good starting point.


465 foot 3d model

Malcolm Hunter
 

Hi,

I modeled a replacement cable-wrap foot (actually for my spares 475). It's
on Thingiverse if anyone would like to make use of it.

http://www.thingiverse.com/thing:1410827

I just needed something to stop the scope from tipping over. I used PLA,
which is good enough for that. I'm not sure what would be the best material
to print it with and how well it would hold up in general use.

Malcolm


Re: Tektronic 466 - Storage Modes inop

Brian Bloom
 


Re: Tektronic 466 - Storage Modes inop

Jim McIntyre
 

Found 3 shorted transistors so far: Q1942, Q1944, and Q1948. Might be a few others in this area.

Any well-regarded cross reference for some of the Tek transistor p/n's?


Re: 7854 Repair & Restoration

Brian Bloom
 

I have always been suspicious of the mini-Berg sockets and have run
>into a couple cases where good contact was not being made. I think
>the machined collet pins which you mention below are more reliable.

What I can do while I have the amplifier/driver out is take a 22 gauge wire, insert it into the socket, and check continuity/resistances while I give the wire a wiggle. If one of those sockets shows an intermittent connection or a resistance, would you suggest I replace all of them with augat machined sockets? I have some 24pin dip sockets I can pull apart. I also have the berg sockets from some old 475 boards.


A question for you that's a bit off topic - I want/need a decent current probe for troubleshooting these 485's. (I'm sure I'll want it for other things in the future as well.) Can you recommend a good current probe arrangement that I can keep an eye out for that actually might show up on the market for less than a couple hundred dollars? I'd like to get something close to or sub $100, but I don't want to go over $200.

It's too bad that I didn't get in on the whole AM503 & probe market while they were going for $50 each...


Re: 7854 RAM card upgrade only - any interest?

bogroca
 

Hello all,


This is very interesting topic, to which I was somewhat familiar about 3-4 years ago.
Anyway:
1- I am interested in such a board, count me in, if ever gets produced.
2- I am also interested in David's board extenders (2 of them actually), if they get produced again.
3- Is there a downloadable/purchasable manual for this above B1000000 version? I would like to have a copy.
4- Late to the party, I know, but I managed to replace the FPLA, with code directly injected into the ROMs. If anyone interested, let me know. I still have the files, though you can find them here, if one is searching through my postings...


Best regards,
Bogdan


Re: 7A13 Knob

 

The problem with the "replacement" knob on the 'bay is that the Al insert is more in front (from the faceplate) than with the original. The hex fastening screw is as well. I'm not at all convinced that it (the inner knob) would fit, even after removing the plastic black insert. I have both one of those knobs (I think). I'll be in my lab again early next week and can try if it fits my 7A13.


Raymond


Re: 2465 failing EAROM

alfa beta
 

hi Laura, tried your procedure to no avail
While I was there I also tried the so called EXERCISER 03 (EAROM clearing) described at page 6-16 of the manual ( both in CAL/NO CAL position) : also to no avail : the dots re still there
Thanks anyway; let me know if you have any other idea
adri










---In TekScopes@..., <vegibear11@...> wrote :

Before you replace the old EAROM try this:

Turn the power off.
Move the cal/nocal jumper to cal.
Turn the power on.
Move the cal/nocal jumper to nocal.
Turn power off.
This will force a refresh write to the EAROM and may cure your dots.
Refer to the service manual page 5-9 if needed.

Laura

, I noticed on my 2465 a line of dots in the lower part of display, exactly as described by another member some months ago and documented by him with a clip you can see here


Re: OT 10Mhz references

Greg Muir
 

It's a matter of what kind of precision you need with regards to what you work with. I became a little frustrated with drift of some less-than-best reference oscillators in some of my test equipment when working at GHz frequencies. I now use a HP Z3816A GPSDO feeding a HP 5087A distribution amplifier whose multiple outputs feed all of the equipment on the bench via their external reference inputs. It's nice when generating or measuring a signal to know that you are basically spot on.

And the reference standard is there if needed to calibrate other oscillators. For that I use either a HP K34-59991A phase comparator, a 3575A gain-phase meter or simply an oscilloscope. The scope and K34 unit is for less demanding applications while the 3575A gives me reference/DUT phase comparisons at 10 MHz down to 1/10 of a degree accuracy.

And, no, I am not a "time nut." My wristwatch runs about 30 seconds fast each month and the old analog clock on the wall keeps me properly on time for everything in my life.

Greg


Re: 7854 RAM card upgrade only - any interest?

Cliff Carrie
 

The dongle makes economic sense if there is no keyboard (and no plans to add one). One D connector and a standard backshell - not costly at all, and no internal mods (except for plugging in the new memory card).

Good test from the keyboard connector. Was that on a B100000 scope or an earlier one? Should I repeat it on mine (B063xxx; old RAM & separate ROM cards)?


Everything in the mainframe that is MPU controlled and is not a physical control position seems to be backed up in RAM. The Vertical and Horizontal mainframe modes, the CRT Display Mode (Scope / Stored or Both), the cursor on / off state, the cursor positions, and all on-screen text are retained. Even the GPIB ID button version report comes back. You saw the Self Test Completed message in memory back up power on only because you did not clear it before turning the scope off. And as you said, it only beeps after a self test.


No plug-in information is stored, but the latching pushbuttons and switch settings don't need backing up. There are a few exceptions (7D11, 7M13 come to mind). Overall, this is as close to a non-volatile scope as you are likely to see. All the more reason to upgrade the memory to internal battery back up.


I think I would prefer to just tack 3 wires onto the A32 board and put the rest on a perfboard on the back of the switch. It can be preassembled away from the scope and means less fooling around with A32.


Cliff