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The term "rolling" is mentioned several replies earlier (in a post by ditter2
on 11 March 2019) it says the following:

My bad, I thought it was a new topic.

Looking at the waveform picture, I see that you're looking at speeding up the response of the TS detector, which is OK. I think I misunderstood that you were considering speeding up the actual TS edges. So, never mind about the edge speed admonition.

Ed

Current mirrors should work fine. I presume you meant to say four PNP transistors for the DAC and level shifting from ground referenced and +5V powered TTL/CMOS. I looked at all sorts of schemes back then, and concluded that the DACs were the way to go for my needs. You can get better performance from the current mirror if you use transistor arrays. I think a CA3046 or something in that family has enough NPNs to make two mirrors.

The edges of the TS signals are intentionally very slow, to minimize interference with the sensitive circuitry - do NOT make them go faster. As I recall, the readout system makes its decision on the value either in the middle of the TS, or right at the end, when it begins to turn off. The internal clocking is not precise in frequency (you actually don't want it constant), but the relative timing of each event is exact (all digital).

Ed

The term "rolling" is mentioned several replies earlier (in a post by ditter2 on 11 March 2019) it says the following:

While the chamfering reduces the likelihood of glass scraping the connector when mating,
the step where the circuit board foil trace mates would still scrape when it mates.
Tek prevented this by “rolling” the chamfered edge of the circuit board. The finished board
after plating is ran through a pair of conical rollers that actually smashes the circuit board
which reduces the thickness of the plated board fingers, allowing them to partially engage
into the connector before beginning to deflect the spring function of the contacts. Thus, there
is no edge scraping on the connector during the mating process. The board edge engages
before it begins to force the contacts open.

Now that I've read it again it sounds like this might be able to be done by hand applying a small amount of force to a steel bar angled from a point of contact with a flat surface and the point of contact with the edge of the connector fingers being "rolled".

I will have to examine some of the my TM500 plug-ins to see if I can measure the difference in thickness achieved by the rolling process. I can't detect any difference with my unaided eye or by touch, but a set of calipers or micrometer may be able to measure it.

-- Jeff Dutky

Thank you, Ken. This mod kit replaces early-production 500-series selenium rectifiers in the LV supply with silicon. There’s nothing for the HV supply; modded scopes continued to use 5642’s.

From: [email protected] [mailto:[email protected]] On Behalf Of Ken Eckert via groups.io
Sent: Tuesday, July 27, 2021 11:44 AM
To: [email protected]
Subject: Re: [TekScopes] 5642 rectifier tubes in a Tek 535: Replace or swap for silicone?

I don't know if this helps, but I have uploaded this mod kit instructions that is applicable to the scope

File name:

Tektronix 040-0395-00 mod kit instructions

I used a caliper to measure several of my plug-ins, and went with my best
estimates based on that, then tested with laser cut non-functional blanks
for fit. I only just got the boards back from fab, and so far, fit and
function seem good.
When I post the eagle files, people can just reuse the dimension layer, but
I will also see about producing a dimensioned drawing for more general use.
Let me see if I can make time for that tonight.

--
Andy

The upside-down black and aluminum cylinders look like British 9-pin loctal tubes, or more correctly, valves. The shorter aluminum ones are likely the famous EF50 <> (also called a VR. 91 or 10E/92b). Most EF50s are red, but I have some military surplus ones that have clear aluminum cans. The longer black ones are likely the Mullard EF55 (also called CV 173). The assemblies in the photo could be parts of an early post-war computer, but due to the lack of triodes are more likely radiation counters or the like.

Due to the moderately recent Tek scopes (475?) and PC clones in the picture, this has to be a vintage restoration project. BTW, I count six Tek scopes in the picture.

- John Atwood

What do you mean "rolling" on the fingers?
Do you mean the notch between 6A/B and 7A/B?

I'll probably create a project page somewhere with the eagle files, the
BOM, and progress as I work on cal/test fixtures, if anyone wants to follow
along. Look for an update when I get organized enough to do that.

What's the height or rather width you used for your finger connector?
I had a similar project for debugging purpose ().
However, I didn't add "margin" on top and bottom, so I have to manually align the extender when inserting.
And so far, I was not able to find mechanical data from Tektronix documentation

My current prototype does this with 4 NPN transistors sourcing 8-4-2-1
weighted currents into a wilson current mirror, nothing harder to source
than 2N3904, 2N3906 and some E96 resistors. Time will tell whether this is
fit for purpose, as always there are plenty of ways to address this issue.

I'll crank up a proper schematic and post here.

I'm currently de-mystifying the timing of the TS<n> signals. The pulses
seem to be approx 130uS wide, negative going 0 - -15V, but the slew rate of
approx 3us/Volt, so the pulse only sits at -15V for approx 20us.
See the yellow trace on this plot:
,
so it looks like I have around 30-40us to set up the 4 currents.
The blue trace on that plot is the derived TTL signal, mimicking the TS
interface circuit used in the 7M13. I am actively looking to change the
circuit to: a) not sit at 1.6V when "low", and switch on harder, and b)
transition faster to maximise the amount of time I have to set up the
current sinks.

On Tue, Jul 27, 2021 at 2:04 PM Ed Breya via groups.io <edbreya=
[email protected]> wrote:

Andy wrote: "For instance, my plan for the readout interface is to create
an SPI-based
sub-system that deals with all the current source and voltage adaptation,
so that it could be easily bolted onto any micro that can field an
interrupt and talk SPI at a reasonable rate."

7K readout interfacing is quite easy, once you're familiar with the
details. I'd recommend using DAC-08 or DAC-10 or equivalent to drive the
currents - these are an ideal match for the circuit conditions. You can
also use CMOS or JFET analog switches with weighting resistors, but the
DACs are more compact, and simpler to set up. You will also need to
synchronize the external control stuff to the internal readout timing to
know when to present the appropriate currents.

In my 7K test plug-in I started years ago, I used four (one for row, and
one for column current, for each channel) DAC-08s, three CMOS logic parts,
and a little diode logic, to make the readout exerciser. It presents all
fifty characters on both channels, ten at a time, in a five step sequence
at about one second per step. This was a simple implementation, due to
using plenty of DACs, which I had in stock. Other schemes could be done,
even with a single DAC and enough multiplexing/sampling/holding and such,
but the beauty of these DACs is that they take care of the level shifting
and current sourcing - no matter how you code and make the current signals,
the actual currents need to flow from the row and column inputs into minus
15 V (or at least some negative supply).

I have a bunch of DAC-08s and -10s set aside just for readouts in custom
plug-in projects. I think the MC1408 can work too. These are all oldies.
There should be newer and better equivalents available. The main thing is
to have 8 bits or more, current sinking output in the 1 mA FS range, and
running from -15 Vee, for simplest interface.

Ed

--
Andy

JLCPCB does it on boards > 5x5cm. I just made my first order from them but
not with edge fingers. I haven't seen the boards yet, so quality is TBD.
Located in China. (quality = ?TBD?, super unbelievably cheap!)

So far, I've been quite happy with all my orders with JLCPCB.
The only problem I had were cosmetic, some scratches on PCB.
You can have an idea of the board they produce: /g/TekScopes/album?id=243643

Andy wrote: "For instance, my plan for the readout interface is to create an SPI-based
sub-system that deals with all the current source and voltage adaptation,
so that it could be easily bolted onto any micro that can field an
interrupt and talk SPI at a reasonable rate."

7K readout interfacing is quite easy, once you're familiar with the details. I'd recommend using DAC-08 or DAC-10 or equivalent to drive the currents - these are an ideal match for the circuit conditions. You can also use CMOS or JFET analog switches with weighting resistors, but the DACs are more compact, and simpler to set up. You will also need to synchronize the external control stuff to the internal readout timing to know when to present the appropriate currents.

In my 7K test plug-in I started years ago, I used four (one for row, and one for column current, for each channel) DAC-08s, three CMOS logic parts, and a little diode logic, to make the readout exerciser. It presents all fifty characters on both channels, ten at a time, in a five step sequence at about one second per step. This was a simple implementation, due to using plenty of DACs, which I had in stock. Other schemes could be done, even with a single DAC and enough multiplexing/sampling/holding and such, but the beauty of these DACs is that they take care of the level shifting and current sourcing - no matter how you code and make the current signals, the actual currents need to flow from the row and column inputs into minus 15 V (or at least some negative supply).

I have a bunch of DAC-08s and -10s set aside just for readouts in custom plug-in projects. I think the MC1408 can work too. These are all oldies. There should be newer and better equivalents available. The main thing is to have 8 bits or more, current sinking output in the 1 mA FS range, and running from -15 Vee, for simplest interface.

Ed

Confirmed, OSHpark doesn't do chamfered/beveled edges, also they don't
offer hard gold as a finish, they only offer ENIG, which is not really upto
the task of many cycles. For a real run, we'd likely want to spec hard gold
finish and bevelling from a board house that can accommodate that.

However, for exploration and prototyping, I am happy with the OSHpark parts.

On Tue, Jul 27, 2021 at 11:38 AM Chris Wilkson via groups.io <cwilkson=
[email protected]> wrote:

I haven't used OSH Park before. But everyone knows those purple boards!
(beautiful!) :)
I don't think they offer chamfering unless it's recently changed. It's
been discussed in the past and it adds steps to the process (therefore
cost!).

Some board houses that I know will do beveling:
Advanced Circuits does it for sure. I have used them for plug in cards
before. Located in Denver, Colorado, USA. (very high quality but expensive)
Gold Phoenix does it for sure. For gold fingers they do it
automatically. For solder (HASL) fingers they will do it only if you
specifically ask. Located in China. (good quality,
inexpensive-to-reasonable cost)
JLCPCB does it on boards > 5x5cm. I just made my first order from them
but not with edge fingers. I haven't seen the boards yet, so quality is
TBD. Located in China. (quality = ?TBD?, super unbelievably cheap!)

--
Andy

Does anyone know where I might find a scan of the service manual and diagrams for a Kay Elemetrics 160KE Marka-Sweep generator?
I've been through most of the usual and some unusual sources without any luck.
It's a 0.5 to 500 MHz sweeper, which I now have working (repaired a bad solder joint, lubricated some controls, and gave it a cleaning).
I would now like to calibrate it.
I might also like to find or build some crystal maker modules, of which it accepts 6 internally.

Cliff

The following files have been uploaded to the Files area of the [email protected] group.

• /6127B/docs/Ballantine_6127B_Addendum.pdf
• /6127B/docs/Ballantine_6127B_Data_sheet.PDF
• /6127B/docs/Ballantine_6127B_Data_sheet_full.pdf

By: Ken Eckert <eckertkp@...>

Description:
Short and long data sheets along with the addendums to the manuals

The following files have been uploaded to the Files area of the [email protected] group.

• /Tektronix_492_to_492P_conversion.zip

By: Ken Eckert <eckertkp@...>

Description:
Tektronix 492 to 492P conversion

I don't know if this helps, but I have uploaded this mod kit instructions that is applicable to the scope

File name:

Tektronix 040-0395-00 mod kit instructions

The following files have been uploaded to the Files area of the [email protected] group.

• /Tektronix 040-0395-00 mod kit instructions.pdf

By: Ken Eckert <eckertkp@...>

Description:
Tektronix 040-0395-00 mod kit instructions

Yep, Manchester Baby it is. It's easy to match up parts with what's on
screen at 0:28 with the photograph.


-Bob N3XKB

On Tue, Jul 27, 2021 at 12:05 PM Raymond Domp Frank <hewpatek@...>
wrote:

Manchester (Baby or Mark I) fits the bill:
- UK (mains sockets)
- Modules (with big, vertical cans, orientation), see photographs on-line
- Williams Tube (memory, also visible in photographs on the web)
- Restoration project (age and looks of instrumentation and two guys
working on it)
- See "Manchester Baby: world's first stored program computer" on YouTube.
I think I may even see one of the guys in the photograph in that video.

Raymond

IIRC, Tek’s silicon upgrade mod kits focused on the Low-Voltage power supply, not the CRT.

Dave Wise

From: [email protected] [mailto:[email protected]] On Behalf Of Harvey White via groups.io
Sent: Tuesday, July 27, 2021 11:09 AM
To: [email protected]
Subject: Re: [TekScopes] 5642 rectifier tubes in a Tek 535: Replace or swap for silicone?

Since Tektronix did offer the silicon rectifiers as an upgrade, I'd
think either would be proper, depending on whether or not you want to be
serial number accurate.

As I remember previous discussions, the lack of filament drain from the
HV transformer will unload the supply a bit, and should make the parts
run a bit cooler. I do think you should check the HV for proper
readings after this. Tek WIKI may have the instructions for that
replacement kit.

Harvey

On 7/27/2021 1:10 PM, Joe wrote:

I am sure that substitute does the job well enough. Though - from the historian's point of view I still prefer the 5642 as long as they van be obtained. Tubes are something else than seleniums!
Joe