Date   

Re: About the cable used in oscilloscope probes

Don Black <donald_black@...>
 

I think that's the same type of process as the ultrasonic tinning in that it lifts off the oxide layer. The ultrasonic cleaning probably cleans the entire surface better whereas the rubbing may miss spots. One's better for production, the other fine for one off's. I think any flux would have to be carefully selected to ensure no long term corrosion. The Wharfedale speakers are still going strong after 40+ years. With mechanical cleaning in the molten solder it shouldn't need any flux.

Don Black.

On 13-Jan-14 11:48 AM, wyzkydd2358@... wrote:
 

Aluminum can be easily soldered using regular old leaded solder using the right trick. You don't even need any special flux. Take your soldering iron and dab some fresh solder on so there's a ball of molten solder hanging from the tip and apply it to the aluminum to be soldered. Using the iron's tip lightly abrade the aluminum surface with a scraping motion, and the oxide layer will be wiped right off, allowing the solder to properly adhere.

On Jan 12, 2014 6:08 PM, David wrote:
 

I assume then that the aluminum tabs on can capacitors are tinned in this way. I
always wondered how they did that.

I have also seen copper plated aluminum wire.

On Mon, 13 Jan 2014 10:34:38 +1100, you wrote:

>I don't know what is used now but in his sixties books GA Briggs of
>Wharfedale speaker fame mentions they tinned the aluminium voice coil
>wire using an ultrasonic solder pot. The ultrasonic energy causes
>cavitation that strips off the surface oxidation under the solder
>surface, excluding the air.
>I think it would likely work with nichrome too.
>
>Don Black.
>
>On 13-Jan-14 4:16 AM, David wrote:
>>
>> Difficult to solder metals can often be handled by cleaning and
>> etching with
>> hydrochloric acid and then depositing copper via electrolysis and an
>> easily
>> acquired solution of copper sulphate or copper nitrate. I would worry
>> about
>> strain relief of the wire at the edge of the solder joint though.
>>
>> 12 Jan 2014 09:01:51 -0800, you wrote:
>>
>> > . . .
>> >
>> > BTW, as the center conductor is nichrome, you can't solder it. The
>> connections at the terminations are usually crimped on the wire.
>> >
>> > - Steve





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Re: Soldering and epoxying aluminium

 

I have used Miller Stephenson epoxy 907 to attach to aluminum for heat sinks and
such with good results:

http://www.miller-stephenson.com/products/detail.aspx?ItemId=60

I believe this is the same thing:

http://gokimco.com/hysol-epoxy-907-2-2oz-epk-kit-qty-10.html?gclid=CLOSkL3Q-rsCFaHm7Aod3W8Aaw

I wonder if enough carbon black could be mixed in to make it conductive enough
to be useful. It would be a lot less expensive then the conductive silver
epoxies they have.

On Mon, 13 Jan 2014 15:28:49 +1100, you wrote:

Here is a technique I have used a few times. I mix up some "24 hour
Araldite" - two part retail epoxy which takes about 24 hours at room
temperature to set.

I abrade both surfaces with emery paper ("wet and dry"), apply some
epoxy and then abrade some more. This removes the oxide layer and lets
fresh epoxy bond to the metal. At this point the formerly clear,
somewhat yellow, epoxy becomes opaque and grey.

Then the two surfaces can be brought together. Popping the item in a
not too hot oven for half an hour or so will harden the epoxy without
having to wait a day.

Perhaps this would work with silver-loaded conductive epoxy to make an
electrically conductive joint.


Re: Soldering and epoxying aluminium

 

On Mon, 13 Jan 2014 02:43:18 -0430, you wrote:

Actually about 14 yrs back I had reason to make an in tank electric fuel
(gasoline) pump become mounted externally. Was on a 1986 Mazda 626 GT.
I did eventually electroplate copper onto the cast pump manifold and
solder on copper tubing. Did it overnight with about a 250mA (per sq
inch of surface) current I believe.
The car is still running.

I think if the plated nichrome is for heating purposes....you can't use
regular low temp solder. But u might be able to get by with a braze.
I have used silver brazing solder to attach to nichrome and stainless steel but
because of the temperature required, like 1300F, I would not consider this
viable for the thin wire used in probe cable.


Re: Soldering and epoxying aluminium

mosaicmerc
 

Actually about 14 yrs back I had reason to make an in tank electric fuel (gasoline) pump become mounted externally. Was on a 1986 Mazda 626 GT.
I did eventually electroplate copper onto the cast pump manifold and solder on copper tubing. Did it overnight with about a 250mA (per sq inch of surface) current I believe.
The car is still running.

I think if the plated nichrome is for heating purposes....you can't use regular low temp solder. But u might be able to get by with a braze.


Re: About the cable used in oscilloscope probes

stefan_trethan
 

You can solder right to glass with ultrasonic.
Check out the videos on the web, look for ultrasonic soldering iron.

Strange thing to see...

ST


On Mon, Jan 13, 2014 at 12:34 AM, Don Black <donald_black@...> wrote:


I don't know what is used now but in his sixties books GA Briggs of Wharfedale speaker fame mentions they tinned the aluminium voice coil wire using an ultrasonic solder pot. The ultrasonic energy causes cavitation that strips off the surface oxidation under the solder surface, excluding the air.
I think it would likely work with nichrome too.

Don Black.



Re: Introduction and looking for guidance on Tek 2246 troubleshooting

 

On Sun, 12 Jan 2014 23:49:56 -0500, you wrote:

I picked up an untested Tek 2246 on eBay relatively cheaply, and after
letting it warm up, connected my probes on channels 1 & 2 to the
square wave calibrator. For the most part, I believe things are
working as they should on channel 2. After adjusting the probes
themselves, I get a good looking square wave.
They are nice oscilloscopes and one of the last models with full service
documentation. They seem to have fewer problems than the faster 2465 series.

On channel 1, I get a square wave also, but the image intermittently
jumps position on the vertical axis up and down before it settles back
to the original location for awhile, and then repeats. It's the
entire waveform image shifting up and down as a whole. I was looking
for some advice on whether this is a common issue, and suggestions on
additional troubleshooting or fixes for this behavior. I'd like to
keep the scope if possible, especially if there is a relative easy fix
for it.
There might be something mechanically worn with the BNC connector. Channel 1
tends to get used the most so it usually wears out first.

Does the trace jump when you wiggle the BNC connector?

Does the behavior change with different input coupling settings?

The Uncal lights are also lit on the front panel.
The channel 1 and channel 2 volts/div controls and the A and B sec/div control
each have a small inner control marked VAR which varies the volts/div or
seconds/div continuously and has a detent in the fully clockwise position where
the UNCAL (uncalibrated) indicator should extinguish. On the 2246, the vertical
UNCAL indicator is shared between channel 1 and channel 2. The readout also
shows the UNCAL status by displaying a greater than symbol (>) next to the
appropriate displayed scale factor.

Under most conditions, the VAR controls should be fully clockwise and locked
into their detent. The vertical VAR controls are used for adjusting the
vertical gain to make rise and fall time measurements and can also be used to
adjust the DC common mode rejection when making differential measurements in add
and invert mode. I have never found a use for the horizontal VAR control.


Soldering Thermocouple Wires

 

The recent threads regarding soldering to difficult metals reminded me of a product I came across a few years ago while helping a Hydroplane boat racing friend. This is a very serious sport during the summers in Seattle (see http://www.seafair.com/ for more info). My friend wanted me to wire up (in series) the ten thermocouples placed around the body of the turboshaft engine in the unlimited class boat he was modifying. At first I told him this couldn’t be done because the thermocouple metals couldn’t be soldered, bla, bla, bla. But when he pointed out that this was the way all the boat drivers monitored the temperature of their turbine engines I started looking for a flux I could use. I finally found one called AQUA-FLUX which is made by Rectorseal in Houston, TX (USA). I contacted them with my needs and they sent out a small jar of it at no charge for me to use.

 

Aqua-Flux did the trick. I soldered all the thermocouples in series without a problem and the resultant signal was large enough to drive an analog temperature meter mounted in the boat without any amplification whatsoever. I was pretty amazed that it was that simple. I never should have doubted my friend in the first place since he has been racing ‘hydros’ since the late 1960s.

 

I have no affiliation with Rectorseal, other than as an engineer that learned long ago it couldn’t be done.

 

Dennis Tillman W7PF


Re: CRTs on Ebay

Michael A. Terrell
 

Don Black wrote:

Hello Michael,
I agree with all you say, I'm aware that NTSC is the standards committee rather than the colour standard but NTSC is what the colour standard has become known as (at least outside the US).
I take your point about the US colour standard being capable of good results if all is well, however if you haven't experienced the two systems in operation you don't know just how much "hardier" and more stable the PAL system is. It takes truly awful reception to notice hue changes with PAL.
As I said, I have great respect for the development of the NTSC colour system , the fact it remained in use for so long speaks volumes.
I've seen PAL TV with PAL video tape. I wasn't impressed.


Re: Soldering and epoxying aluminium

Robin Whittle
 

Hi Eric,

Further to your notes on using ordinary (60/40 I guess) solder, perhaps
with a suitable flux, it would be possible to wet the aluminium surface
and the emery paper, and rub the two together, leaving the surface
covered in the flux. Then get to work with the soldering iron before it
dries.

- Robin


Re: Soldering and epoxying aluminium

EricJ
 

There aren't any non-cleaning fluxes for aluminum as far as I am aware. The single reason aluminum is difficult to solder is because of the "dirty" oxide layer that forms pretty much instantly in our atmosphere. Since this is separate from the other post I'll paste in my earlier response:

Aluminum can be easily soldered using regular old leaded solder using the right trick. You don't even need any special flux. Take your soldering iron and dab some fresh solder on so there's a ball of molten solder hanging from the tip and apply it to the aluminum to be soldered. Using the iron's tip lightly abrade the aluminum surface with a scraping motion, and the oxide layer will be wiped right off, allowing the solder to properly adhere.

It was mentioned that you need a sturdy iron to use this technique but that isn't really the case. If the aluminum to be soldered is mechanically or chemically cleaned (sandpaper, etc.) immediately before you attempt the solder joint, it takes little more force than a touch to remove the oxide layer.

--Eric

On Jan 12, 2014 11:20 PM, Michael Noone <nleahcim@gmail.com> wrote:

 

OK if we're talking about soldering to aluminum - I should mention my experience. I've used Indium flux number 3. It is designed for aluminum. It works great, but you absolutely have to wash it off afterwards as it is very corrosive. You can get it as a core inside of normal solders and it works very well for aluminum.

I would love to find a non-clean aluminum flux - but I don't think such a thing exists.

-Michael


On Sun, Jan 12, 2014 at 8:28 PM, Robin Whittle <rw@firstpr.com.au> wrote:

 

For the benefit of people searching the archives, this message is partly
to signal that some recent messages in the thread: "Re: About the cable
used in oscilloscope probes" concerned techniques for soldering
aluminium and also to mention my technique for epoxying it.

John Byers reported a technique of soldering the aluminium pieces
immersed in oil, which I found most surprising. wyzkydd2358@yahoo.com
wrote of simply using an ordinary soldering iron in a way which excluded
air and roughened the surface. Don Black mentioned that aluminium
loudspeaker coil wires could be soldered with an ultrasonic solder pot.

This arose from a discussion of soldering nichrome wire, which is
apparently used for the centre conductor of oscilloscope probe leads.
David Whess suggested treating the unsolderable metal with hydrochloric
acid and then electroplating copper.

Here is a technique I have used a few times. I mix up some "24 hour
Araldite" - two part retail epoxy which takes about 24 hours at room
temperature to set.

I abrade both surfaces with emery paper ("wet and dry"), apply some
epoxy and then abrade some more. This removes the oxide layer and lets
fresh epoxy bond to the metal. At this point the formerly clear,
somewhat yellow, epoxy becomes opaque and grey.

Then the two surfaces can be brought together. Popping the item in a
not too hot oven for half an hour or so will harden the epoxy without
having to wait a day.

Perhaps this would work with silver-loaded conductive epoxy to make an
electrically conductive joint.

- Robin http://www.firstpr.com.au/tequip/


Re: Soldering and epoxying aluminium

uoficowboy
 

OK if we're talking about soldering to aluminum - I should mention my experience. I've used Indium flux number 3. It is designed for aluminum. It works great, but you absolutely have to wash it off afterwards as it is very corrosive. You can get it as a core inside of normal solders and it works very well for aluminum.

I would love to find a non-clean aluminum flux - but I don't think such a thing exists.

-Michael


On Sun, Jan 12, 2014 at 8:28 PM, Robin Whittle <rw@...> wrote:
 

For the benefit of people searching the archives, this message is partly
to signal that some recent messages in the thread: "Re: About the cable
used in oscilloscope probes" concerned techniques for soldering
aluminium and also to mention my technique for epoxying it.

John Byers reported a technique of soldering the aluminium pieces
immersed in oil, which I found most surprising. wyzkydd2358@...
wrote of simply using an ordinary soldering iron in a way which excluded
air and roughened the surface. Don Black mentioned that aluminium
loudspeaker coil wires could be soldered with an ultrasonic solder pot.

This arose from a discussion of soldering nichrome wire, which is
apparently used for the centre conductor of oscilloscope probe leads.
David Whess suggested treating the unsolderable metal with hydrochloric
acid and then electroplating copper.

Here is a technique I have used a few times. I mix up some "24 hour
Araldite" - two part retail epoxy which takes about 24 hours at room
temperature to set.

I abrade both surfaces with emery paper ("wet and dry"), apply some
epoxy and then abrade some more. This removes the oxide layer and lets
fresh epoxy bond to the metal. At this point the formerly clear,
somewhat yellow, epoxy becomes opaque and grey.

Then the two surfaces can be brought together. Popping the item in a
not too hot oven for half an hour or so will harden the epoxy without
having to wait a day.

Perhaps this would work with silver-loaded conductive epoxy to make an
electrically conductive joint.

- Robin http://www.firstpr.com.au/tequip/



Introduction and looking for guidance on Tek 2246 troubleshooting

Dylan Distasio
 

Hi all-

I wanted to introduce myself to the group. After gaining some
rudimentary electronics experience as a hobbyist, and getting
comfortable behind a soldering iron, I recently decided to take things
to the next level and purchase an oscilloscope. I would also preface
this discussion by commenting that I have never used an oscilloscope
before and am a complete beginner with them.

I picked up an untested Tek 2246 on eBay relatively cheaply, and after
letting it warm up, connected my probes on channels 1 & 2 to the
square wave calibrator. For the most part, I believe things are
working as they should on channel 2. After adjusting the probes
themselves, I get a good looking square wave.

On channel 1, I get a square wave also, but the image intermittently
jumps position on the vertical axis up and down before it settles back
to the original location for awhile, and then repeats. It's the
entire waveform image shifting up and down as a whole. I was looking
for some advice on whether this is a common issue, and suggestions on
additional troubleshooting or fixes for this behavior. I'd like to
keep the scope if possible, especially if there is a relative easy fix
for it. The Uncal lights are also lit on the front panel.

I'm glad to have found this group, and am looking forward to hopefully
learning a lot here, and eventually being able to contribute to the
discussion. Any advice on a great beginner's resource or books on
using oscilloscopes would also be very welcome.

Best,
Dylan


Re: Tektronix 1230 Logic Analyzer

Nguyen Van Minh Danh
 

Hi Lyle,


Thanks for the videos. I did come across the Youtube videos on the 1230 and the TLA manual that you posted too. :)


My logic analyzer seems to be working, except that the battery to keep the RTC time is dead (need to replace it soon). For now I am looking for user manual and the PC software to study the possibility of transferring the data to PC.


Hopefully other members will provide more information.



Re: Tektronix 1230 Logic Analyzer

Lyle Bickley
 

On Sun, 12 Jan 2014 20:21:50 -0800
Lyle Bickley <lbickley@bickleywest.com> wrote:

On 12 Jan 2014 20:05:41 -0800
<mdanh2002@gmail.com> wrote:

Hi,

I got this Tektronix 1230 logic analyzer for a cheap price from a
Singapore electronics equipment seller. It comes with no probes or
manual, just the unit. After a month of searching, I managed to
purchase the probes from eBay and now I am waiting for its arrival.
However I am still looking for the manual for this unit and the PC
software for remote control via RS232-C. I believe the PC software
for this unit is called as S43R101 by Tektronix. A Google search
reveals very little useful information, apart from this PDF
http://www.mgoodguy.com/specs/TEK1230.pdf
http://www.mgoodguy.com/specs/TEK1230.pdf which contains some basic
description on its features and part numbers, and another post on
the Microchip forum http://www.microchip.com/forums/m81437.aspx
http://www.microchip.com/forums/m81437.aspx from somebody who was
looking for the same. Any help is appreciated! Thanks.
Here's the "Quick Start User Manual" - which won't help service it,
but will help in using it:

http://engineering.unt.edu/electrical/sites/default/files/Tektronix%20Logic%20Analyzer%20TLA%20502.pdf
Oops, I goofed - somehow I ended up with a TLA analyzer.

Here's a couple of Tektronix Youtube training videos on the Tek 1230:

Part 1
https://www.youtube.com/watch?v=XETdhRQp1lA

Part 2
https://www.youtube.com/watch?v=fez6GqI6yxs

Lyle

--
Bickley Consulting West Inc.
http://bickleywest.com

"Black holes are where God is dividing by zero"


Soldering and epoxying aluminium

Robin Whittle
 

For the benefit of people searching the archives, this message is partly
to signal that some recent messages in the thread: "Re: About the cable
used in oscilloscope probes" concerned techniques for soldering
aluminium and also to mention my technique for epoxying it.

John Byers reported a technique of soldering the aluminium pieces
immersed in oil, which I found most surprising. wyzkydd2358@yahoo.com
wrote of simply using an ordinary soldering iron in a way which excluded
air and roughened the surface. Don Black mentioned that aluminium
loudspeaker coil wires could be soldered with an ultrasonic solder pot.

This arose from a discussion of soldering nichrome wire, which is
apparently used for the centre conductor of oscilloscope probe leads.
David Whess suggested treating the unsolderable metal with hydrochloric
acid and then electroplating copper.

Here is a technique I have used a few times. I mix up some "24 hour
Araldite" - two part retail epoxy which takes about 24 hours at room
temperature to set.

I abrade both surfaces with emery paper ("wet and dry"), apply some
epoxy and then abrade some more. This removes the oxide layer and lets
fresh epoxy bond to the metal. At this point the formerly clear,
somewhat yellow, epoxy becomes opaque and grey.

Then the two surfaces can be brought together. Popping the item in a
not too hot oven for half an hour or so will harden the epoxy without
having to wait a day.

Perhaps this would work with silver-loaded conductive epoxy to make an
electrically conductive joint.

- Robin http://www.firstpr.com.au/tequip/


Re: Tektronix 1230 Logic Analyzer

Lyle Bickley
 

On 12 Jan 2014 20:05:41 -0800
<mdanh2002@gmail.com> wrote:

Hi,

I got this Tektronix 1230 logic analyzer for a cheap price from a
Singapore electronics equipment seller. It comes with no probes or
manual, just the unit. After a month of searching, I managed to
purchase the probes from eBay and now I am waiting for its arrival.
However I am still looking for the manual for this unit and the PC
software for remote control via RS232-C. I believe the PC software
for this unit is called as S43R101 by Tektronix. A Google search
reveals very little useful information, apart from this PDF
http://www.mgoodguy.com/specs/TEK1230.pdf
http://www.mgoodguy.com/specs/TEK1230.pdf which contains some basic
description on its features and part numbers, and another post on the
Microchip forum http://www.microchip.com/forums/m81437.aspx
http://www.microchip.com/forums/m81437.aspx from somebody who was
looking for the same. Any help is appreciated! Thanks.
Here's the "Quick Start User Manual" - which won't help service it, but
will help in using it:

http://engineering.unt.edu/electrical/sites/default/files/Tektronix%20Logic%20Analyzer%20TLA%20502.pdf

Lyle
--
Bickley Consulting West Inc.
http://bickleywest.com

"Black holes are where God is dividing by zero"


Tektronix 1230 Logic Analyzer

Nguyen Van Minh Danh
 

Hi,

I got this Tektronix 1230 logic analyzer for a cheap price from a Singapore electronics equipment seller. It comes with no probes or manual, just the unit. After a month of searching, I managed to purchase the probes from eBay and now I am waiting for its arrival. However I am still looking for the manual for this unit and the PC software for remote control via RS232-C. I believe the PC software for this unit is called as S43R101 by Tektronix.

A Google search reveals very little useful information, apart from this PDF http://www.mgoodguy.com/specs/TEK1230.pdf which contains some basic description on its features and part numbers, and another post on the Microchip forum http://www.microchip.com/forums/m81437.aspx from somebody who was looking for the same.

Any help is appreciated! Thanks.


Re: About the cable used in oscilloscope probes

hpxref
 

<Aluminum can be easily soldered using regular old leaded solder
<using the right trick. You don't even need any special flux. Take
<your soldering iron and dab some fresh solder on so there's a
<ball of molten solder hanging from the tip and apply it to the
<aluminum to be soldered. Using the iron's tip lightly abrade the
<aluminum surface with a scraping motion, and the oxide layer will
<be wiped right off, allowing the solder to properly adhere.
----------------------------------------------------------------------------------
Yes, and you need a pretty solid tip on the iron too!
Another method :
When a 15 yo I bought a Sunbeam Twin 500cc motorcycle from a local
astronomer "dirt cheap"as it had a crack right round the aluminium
gear box casing where the lay-shaft bearing mount was.

Just owning a big bike was a big thrill for me as a 15 year old even if it couldn't be
ridden...then I was told of an old guy , an ex RAF aircraft mechanic who
had worked on antique planes in the UK and who was soldering up aluminum baffle
plates inside Al tanks for a local firm
I watched him fix my gearbox by taking the casing apart, cleaning it and immersing
it in light grade motor oil...then applying a HUGE soldering iron to it,
carefully soldering around the crack with the iron immersed in the oil as well
The oil prevented oxides from forming
It worked and (unlicensed) rode that bike around for weeks until I crashed it.
(Even after running into a power pole the repair was still OK)
Ive since soldered the seams of bent up small alum chassis together using a 150W "Scope"soldering iron
so can vouch for the method...messy and smelly, but worked "seamlessly"
Sometimes just coating the alum with oil works too for small jobs , but immersing seems always better
John


Re: 7Bxx MOD515C

 

Hi Steve,

The edge fingers of the circuit board are not good enough to support really HF signals. Tek had to modify them with floating edge connectors for the vertical deflection signals of the 7904, and later the 7104, to achieve the greater bandwidth these scopes needed. Even that design did not work above 1GHz which became the ultimate limit of the 7000 series.

 

I think you are mistaken about the holes. The 4 holes were a fundamental part of the 7000 plug-in rear molding by 1968 before production began in earnest on the 7000 series. This was 3 years before the 7A21N (which was designed to extend the bandwidth of the 7904 CRT) was designed in 1971.

 

Tek was already manufacturing the 576 with its fiber optic readout display which was one of the few bright spots (no pun intended) in the otherwise extremely expensive to manufacture, and therefore not very profitable, curve tracer. The fiber optic readout on the 576 was simple in comparison to what was needed for the 7000 series.  It was very late in the design phase of the 7000 when Barrie Gilbert, a relative newcomer at Tek, saw how Hiro was going to use the fiber optic readout concept on the 7000 series. It would have never worked reliably and it would have been a nightmare to support out in the field since the 7000 plug-ins already in late development by that time had many more possible readout combinations than Hiro could have handled with his system. The original fiber optic readout concept of the single purpose 576 was simple in comparison to what was needed for the much more versatile general purpose7000 series  laboratory oscilloscope.

 

Barrie Gilbert is not one to give up easily when he sees something he thinks is not going to work. The on-screen readout system he came up with was ideally suited to the technological advances in ICs that were taking place at Tek, and after demonstrating how his system would work to higher ups, Barrie got the OK to create the necessary ICs. When the 7000 series was introduced in 1969 HP ridiculed it as way over-priced and they derided the on-screen readout in a very unflattering ad as “bells and whistles”. Had Tek used Hiro’s fiber optic system it would have been even more expensive. Fortunately Barrie’s readout system proved to be extremely reliable and flexible enough to support the readout needs of 60+ different plug-ins. No one would even consider buying a scope today if it didn’t have on-screen readout.

 

As for the holes they have remained empty except for a very few exceptions. Almost all of the Tek production plug-ins do not use them. Not counting Mods (which are very different from Options) the 7A21N is the only exception I know of that Tek made which used the holes and it uses only two of the 4 holes. As Craig Sawyers pointed out they were used for position control DC levels on the 7A21N. I have a bunch of unusual plug-ins (all Mods) that use two of the 4 holes for special purposes. Rens’ plug-in (also a Mod) uses all 4 holes. That is the first one I have seen that uses all 4.

 

Unfortunately Mods (unlike options) were almost never documented since they were custom modifications.

 

In a sad, and bizarre note, Hiro was electrocuted many years ago while working on the wiring under his house. Barrie continues to develop amazing ICs to this day. He is a fellow at Analog Devices where he runs his own lab with a staff of IC designers not far from his home. He refuses to have anything to do with digital ICs. I hope to see him next month at the upcoming Rickreall swap meet.

 

Dennis Tillman W7PF

 

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of ditter2@...
Sent: Sunday, January 12, 2014 9:03 AM
To: TekScopes@...
Subject: Re: [TekScopes] 7Bxx MOD515C

 



No, they were intended for exactly what they are used for in the 7A21N.  The 50 ohm connection through the edge fingers of the circuit board is good, but not great and has reflections that would not allow a really high frequency connection.

- Steve



Re: CRTs on Ebay

Michael A. Terrell
 

Ed, k1ggi wrote:

As a fledgling design engineer dealing with broadcast video, I attempted to purchase a copy of the fabled RS-170-A from the EIA in the late 70s.

The EIA lady who answered the phone said there was no such thing.

However, if you bought EIA Tentative Standard Number 1, you got two nice covers with a single 11x17 drawing in between, which had RS-170-A in the title block.

NTSC was the National Television System Committee.

On topic: I have and still use a 528A.
I've used the 528, but prefer the 529 that I have. I also have several in the 17xx series.

83641 - 83660 of 186398