Date   

5 photos uploaded #photo-notice

TekScopes@groups.io Notification <noreply@...>
 


Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.

 

Interesting... talking about electro-mechanical computer, I inherited some modules I wonder if anybody can shed some light on them.

See the pictures (https://groups.io/g/TekScopes/album?id=257222)
Lots of resolvers and syncros inside. Looks very much aeronautic... maybe something european, Tornado?

cheers
Martin


Re: Horizontal Display switch shenanigans.

Dave Peterson
 

I don't have it out of the board yet, but I could measure the new one. They're thick - like 2mm? I'd have to measure, and I'm shutting down for the day. Thanks for the offer. I'll look at it tomorrow.
Dave


Re: Horizontal Display switch shenanigans.

Ananda
 

Now that you have it out of the board, what is the size of the pin? Like I said, I can send a couple of them in the mail.


Re: Horizontal Display switch shenanigans.

Dave Peterson
 

Ooo. Thanks for that! Not only does that make for a viable solution, I've been wondering about a suggestion from an EEVBlog thread in which someone replaced soldered wire connections with connectors. These would work for that too perhaps. The bigger lead here is thinking about going Mouser for such construction solutions. I'm learning.

Thanks for the tip!Dave

On Friday, November 27, 2020, 11:00:39 PM PST, adesilva_1999 via groups.io <adesilva_1999=yahoo.com@groups.io> wrote:

Hi Dave,
Check this: https://www.mouser.com/ProductDetail/TE-Connectivity/510-AG90D-10?qs=%2Fha2pyFaduhM4gHyZk8iA5%252BbCzoO6EXmbo0JD0Y5IKbJxRi4JyNZJA%3D%3D

You can get something like this and break off just one pin and solder in place. Depending on the diameter of the pin on the switch, It might mate with the open end. If you need to test it out, I can send a couple of the to you.

One other method is to wrap around a similar diameter copper wire (single strand) and solder it close to the bottom of the switch leg. and slightly bend it to go in the PCB hole. I will PM you if you want to talk.

Ananda


Re: There is no good time to be SICK

Glydeck
 

Dennis,

Be well. Thanks for all you do for this group.

Kindest regards,

George

On Nov 27, 2020, at 2:48 PM, Siggi <siggi@undo.com> wrote:

back


Re: Horizontal Display switch shenanigans.

Ananda
 

Hi Dave,
Check this: https://www.mouser.com/ProductDetail/TE-Connectivity/510-AG90D-10?qs=%2Fha2pyFaduhM4gHyZk8iA5%252BbCzoO6EXmbo0JD0Y5IKbJxRi4JyNZJA%3D%3D

You can get something like this and break off just one pin and solder in place. Depending on the diameter of the pin on the switch, It might mate with the open end. If you need to test it out, I can send a couple of the to you.

One other method is to wrap around a similar diameter copper wire (single strand) and solder it close to the bottom of the switch leg. and slightly bend it to go in the PCB hole. I will PM you if you want to talk.

Ananda


Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.

stevenhorii
 

Yeah, I think smartphones can also triangulate off of cell towers. I have
had the experience with my in-car GPS of driving in a new housing
development that was likely not in the map database the car had. It showed
me in the middle of a field. My funniest experience with GPS was when I
returned from a trip to Berlin. I was trying to use what is really an
automotive GPS for walking around the city. I had loaded my location and it
showed it correctly on the map, but it would simply not update correctly
when I was walking around the city. I put the unit away until I got home.
The next time I used it, I took it with me from where I was living in
Maryland to Los Angeles on a flight. I turned it on for the first time
since using it in Berlin and when I put in my uncle's address in LA and it
spent a LOT of time calculating the directions. It came up with "drive 5400
miles east to I-405 South" as the first direction. I then had it reset to
the local position (I must have told it to use my last known destination as
the start) to get the right directions. I got a laugh out of that.

On Fri, Nov 27, 2020 at 8:41 PM Jim Ford <james.ford@cox.net> wrote:

In addition, smartphones use Wi-Fi and other comms methods to navigate.
Much superior to those TomTom boxes that only used GPS.JimSent from my
Verizon, Samsung Galaxy smartphone
-------- Original message --------From: stevenhorii <sonodocsch@gmail.com>
Date: 11/27/20 3:54 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re:
[TekScopes] (OT) Where to go for 70s IBM hardware? I'm looking for a
terminal. Jim,Yep. I'm pretty sure the navigation system in my car uses GPS
primarily butmust have a dead reckoning system as it shows me where I am
when I amdriving through an underground tunnel. The system updates as soon
as theGPS signals are again available, so there are sometimes funny jumps
fromshowing me somewhere off the highway to back on it. GPS-aided
inertialseems to be the way many navigation systems are being designed.On
Fri, Nov 27, 2020 at 6:46 PM Jim Ford <james.ford@cox.net> wrote:> FWIW
inertial navigation systems and GNSS (Global Navigation Satellite> Systems)
are complementary. INS tend to drift over time, and GNSS provide>
corrections. Navigation in GNSS-denied or -degraded areas is a whole
other> ballgame.Jim Ford Sent from my Verizon, Samsung Galaxy smartphone>
-------- Original message --------From: stevenhorii <sonodocsch@gmail.com>>
Date: 11/27/20 1:04 PM (GMT-08:00) To: TekScopes@groups.io Subject:
Re:> [TekScopes] (OT) Where to go for 70s IBM hardware? I'm looking for a>
terminal. Harvey and Bill,Yes - I've tried that trick. For small gyros it>
works. Gyros with electricspin motors tend to draw the most current at>
startup as do most motors.After that, the current usually drops quite a>
bit. Some of the 400Hz gyrosuse two-phase power. The usual trick is to put>
a capacitor across the twospin motor inputs - it provides the phase lag
for> the second phase. I haveNOT tried this, but I have seen some gyros ->
usually the small ones thatare about one-inch in diameter and three inches>
long and almost always rategyros - that had a phase-splitting capacitor>
already soldered in place.This white paper describes a basic 2-phase power>
supply for gyro spinmotors:>
http://usdynamicscorp.com/literature/general/AN-003%20USD%20Spin%20Motor%20Excitation.pdfI>
was fortunate - at a hamfest years ago, I picked up a couple of>
AbbottTransistor Labs inverters. These took 24-28 VDC and output AC 400Hz>
singlephase at up to about 2 amps. Not enough to run a large gyro, but>
enough forthe smaller ones. I even ran a fairly large gyro - a Honeywell>
rate gyro -with one of these. They do need a heatsink.I sometimes do an>
eBay search for "Behlman Invertron" as they made somevery useful frequency>
converters - 115 VAC to variable 400Hz AC. Some werevariable frequency and>
some versions also had single to three-phase output.They tend to be>
expensive (and heavy for the higher output ones) and Inever managed to
find> one at what I thought was a reasonable price. Someversions had>
interchangeable plug-in oscillators so you could run evenhigher frequency>
AC devices (some gyros use 800 Hz - the Apollo programgyros ran with 800>
Hz, 2-phase power). There are currently a couple ofBehlman Invertrons on>
eBay, though they are not cheap.If you can find them, some of the WW II
and> even early missile (Nike) gyrosran on DC (24-28 v). Those are fun to
run> up. However, I've had some forwhich the bearings almost certainly were
bad> - they were very noisy whenrunning and spin-down after power was
removed> was quite fast. Likely whythey were surplus.Years ago, a surplus
dealer on> Canal Street in NYC sold me a WW II Bendixvertical gyro. It was
a 400Hz> gyro and he told me I could run it on 60Hz ACby putting a current
limiting> incandescent lamp (no choices - there were noLED lamps then) in
the power> circuit and running at a lower voltage via aVariac. I did not
have the guts> to try it, but I do know those who did andsaid it works, but
you will not> get the gyro up to full speed.Messing about with gyros can
lead you down a> deep hole much as gettingfascinated by Tektronix equipment
and then> desiring to get some (plusspares "for parts" and all the
manuals). Now you> can get fairly accurategyros made using IC fab
techniques - the MEMS units.> These things live insmart phones and tablets
now. These plus GPS have> radically changedinertial navigation. Fun stuff,
though.Steve H.On Fri, Nov> 27, 2020 at 1:52 PM Harvey White <
madyn@dragonworks.info> wrote:> Hi-fi> amplifier of sufficient output
capability driven by a sinewave> generator> sitting at 400 Hz?>> Harvey>>
On 11/27/2020 11:52 AM, Bill E wrote:> > Even> though way off the off topic
topic (parse that), still a fun> discussion. I> scored a box of 10 real
gyros and logic pulled from DC-10s.> Cute little> rate gyro, etc. Problem
is, all that stuff takes 28v 400Hz.> Haven't gotten> around to making a
power supply for them yet.> >> >> >> >> >> >>>> >>>>> >>>





Re: Fair Radio Sales Lima Ohio

stevenhorii
 

All these stories about surplus made me wonder - is there a group dedicated
to surplus? The stories are usually great ones.

Steve H.

On Sat, Nov 28, 2020 at 1:22 AM Steven Horii <sonodocsch@gmail.com> wrote:

Tim,

Your story reminded me of my first date with my wife (we'll celebrate 30
years in 2021). I took her to Vulcan Surplus (closed years ago) in
Stamford, CT. I lived in NYC the first time I went and later when I lived
in northern NJ. We went to United House Wrecking afterward - they were an
outfit that salvaged stuff from houses and other buildings being torn down.
Not much electronics, but acres of other stuff. Some of those things would
likely have been worth the "investment" - old wooden public telephone
booths for example. Besides the surplus electronics I found at Vulcan,
there was also their huge stock of hardware, most of it stainless steel.
You could buy stainless steel screws, washers, nuts, etc. by the pound.
They did charge more for the really small stuff - stainless screws in 0-80
to 2-56 - a box of 100 of these (in the original manufacturer boxes) was
$1-2. I have been to Fair Radio Sales - my in-laws live in Ohio near Dayton
- but only a couple of times. Other stuff I bought from their catalogs. I
knew my wife-to-be at the time was the right person for me - she's not an
engineer but she did work (until she retired) as a systems analyst and
software development team manager.

The sad bit is when surplus dealers go out of business and with no one to
take it over, stuff often goes to scrap dealers. I am pretty sure that this
is what happened to Omnibus Electronics on Long Island. Lou Lasser owned
the place and there was an associated business that did contract
electronics work. Lou bought a lot of stuff from the aerospace companies on
Long Island so it was like a candy store for me - I spent a lot of money
over the years on Apollo surplus from Grumman and Kollsman Instrument. I
still have boxes of small parts from the Apollo optical stuff. Sadly, four
Apollo Lunar Module Alignment Optical Telescopes got scrapped. Brand-new in
the NASA blue transit cases. I managed to get some of the eyepiece
assemblies and various spares, but no complete telescopes. Also scrapped
were three of the much more elaborate Apollo Command Module Optical Unit
Assemblies - they housed the sextant and telescope assemblies used for
updating the inertial navigation system. Lou claimed he told one of the
guys who scrapped stuff not to scrap the LM AOT and CM OUA, but the message
never got to the other guys and when Lou was out on a buying trip, the
person he told not to scrap the Apollo stuff was out making a delivery and
the other guys went after the Apollo stuff with hammers. They sold the
scrap beryllium for about $120 a pound. I saw (and bought) the remains of
these, so I don't doubt he had the complete units. The CM OUA had about 60
pounds of beryllium in it (actually, the whole casing was a large beryllium
piece). Lou had a second building he used for storage - he let my friend
and I look around, but he said the later Grumman stuff was in large crates
on pallet racks and getting them down would take too long. I did buy some
test equipment from him, but not much Tek stuff - a couple of letter and
1-series plug-ins. His prices for test equipment were a little too high. He
moved the business years later and my buddy and I went out there - also
still on Long Island. We both found interesting stuff and bought it. He
showed us several rows of truck trailers in his back lot full of all that
stuff that had been in the storage warehouse - so we still never got to see
it because it was late in the day by that time and getting into those
trailers would have been a difficult task. The next time we called him, the
number had been disconnected and we were told he had passed away. No one
could tell us who purchased the building and lot - my friend went by and
both were empty. We have no idea what happened to all that stuff. If there
was a lot of space program surplus from Grumman, it has not shown up on
eBay or in the space program auctions. It either went to scrap or someone
is hoarding it. If anyone on this thread had been to Omnibus or knew Lou
Lasser, I'd love to know more. Lou was a very nice guy and he always had
great stories about getting the surplus stuff he did acquire.

On Fri, Nov 27, 2020 at 8:21 PM Tim Laing <laingt@wcoil.com> wrote:

Hello, I live about 2 miles from Fair radio. I know the owner Phil, not
a close friend though. I am not sure what will happen when he retires....
I do not know if the show room is open to the public at this time. I
can do some checking. I can stop in but if I do I generally need to have at
least 2 hours free to wander around and get my fix.... I have gone there
on missions for other people in the past. I could check on plug ins.
My first visit was probably when I was 13 or 14 years old, I am 59 now.
I took my future wife to Fair Radio on our first “date”. Maria and I
are still Married going on 31 years.
Prices are not cheap but he has a lot of overhead costs. I have a
bunch of pictures that I have taken there in the past, I am afraid of the
day I find out they are closing. I wish I had taken pictures in the old
dairy buildings located on Eureka Street. Tim Laing






Re: Fair Radio Sales Lima Ohio

stevenhorii
 

Tim,

Your story reminded me of my first date with my wife (we'll celebrate 30
years in 2021). I took her to Vulcan Surplus (closed years ago) in
Stamford, CT. I lived in NYC the first time I went and later when I lived
in northern NJ. We went to United House Wrecking afterward - they were an
outfit that salvaged stuff from houses and other buildings being torn down.
Not much electronics, but acres of other stuff. Some of those things would
likely have been worth the "investment" - old wooden public telephone
booths for example. Besides the surplus electronics I found at Vulcan,
there was also their huge stock of hardware, most of it stainless steel.
You could buy stainless steel screws, washers, nuts, etc. by the pound.
They did charge more for the really small stuff - stainless screws in 0-80
to 2-56 - a box of 100 of these (in the original manufacturer boxes) was
$1-2. I have been to Fair Radio Sales - my in-laws live in Ohio near Dayton
- but only a couple of times. Other stuff I bought from their catalogs. I
knew my wife-to-be at the time was the right person for me - she's not an
engineer but she did work (until she retired) as a systems analyst and
software development team manager.

The sad bit is when surplus dealers go out of business and with no one to
take it over, stuff often goes to scrap dealers. I am pretty sure that this
is what happened to Omnibus Electronics on Long Island. Lou Lasser owned
the place and there was an associated business that did contract
electronics work. Lou bought a lot of stuff from the aerospace companies on
Long Island so it was like a candy store for me - I spent a lot of money
over the years on Apollo surplus from Grumman and Kollsman Instrument. I
still have boxes of small parts from the Apollo optical stuff. Sadly, four
Apollo Lunar Module Alignment Optical Telescopes got scrapped. Brand-new in
the NASA blue transit cases. I managed to get some of the eyepiece
assemblies and various spares, but no complete telescopes. Also scrapped
were three of the much more elaborate Apollo Command Module Optical Unit
Assemblies - they housed the sextant and telescope assemblies used for
updating the inertial navigation system. Lou claimed he told one of the
guys who scrapped stuff not to scrap the LM AOT and CM OUA, but the message
never got to the other guys and when Lou was out on a buying trip, the
person he told not to scrap the Apollo stuff was out making a delivery and
the other guys went after the Apollo stuff with hammers. They sold the
scrap beryllium for about $120 a pound. I saw (and bought) the remains of
these, so I don't doubt he had the complete units. The CM OUA had about 60
pounds of beryllium in it (actually, the whole casing was a large beryllium
piece). Lou had a second building he used for storage - he let my friend
and I look around, but he said the later Grumman stuff was in large crates
on pallet racks and getting them down would take too long. I did buy some
test equipment from him, but not much Tek stuff - a couple of letter and
1-series plug-ins. His prices for test equipment were a little too high. He
moved the business years later and my buddy and I went out there - also
still on Long Island. We both found interesting stuff and bought it. He
showed us several rows of truck trailers in his back lot full of all that
stuff that had been in the storage warehouse - so we still never got to see
it because it was late in the day by that time and getting into those
trailers would have been a difficult task. The next time we called him, the
number had been disconnected and we were told he had passed away. No one
could tell us who purchased the building and lot - my friend went by and
both were empty. We have no idea what happened to all that stuff. If there
was a lot of space program surplus from Grumman, it has not shown up on
eBay or in the space program auctions. It either went to scrap or someone
is hoarding it. If anyone on this thread had been to Omnibus or knew Lou
Lasser, I'd love to know more. Lou was a very nice guy and he always had
great stories about getting the surplus stuff he did acquire.

On Fri, Nov 27, 2020 at 8:21 PM Tim Laing <laingt@wcoil.com> wrote:

Hello, I live about 2 miles from Fair radio. I know the owner Phil, not a
close friend though. I am not sure what will happen when he retires....
I do not know if the show room is open to the public at this time. I
can do some checking. I can stop in but if I do I generally need to have at
least 2 hours free to wander around and get my fix.... I have gone there
on missions for other people in the past. I could check on plug ins.
My first visit was probably when I was 13 or 14 years old, I am 59 now.
I took my future wife to Fair Radio on our first “date”. Maria and I
are still Married going on 31 years.
Prices are not cheap but he has a lot of overhead costs. I have a
bunch of pictures that I have taken there in the past, I am afraid of the
day I find out they are closing. I wish I had taken pictures in the old
dairy buildings located on Eureka Street. Tim Laing






Tektronix scope issues

Thomas Dodge
 

Hi,
This is Tom Dodge, and I am posting this topic again because I didn't post it right before. I have three Tektronix scopes. I have a Tektronix 533 that doesn't work. When I turn it on, it does not have a trace at all, and just a beam. I also have a Tektronix 7704 which I just powered on. I got it from a friend, and when it is on, it just shows a beam that is very bright, so I turn it off so it doesn't burn the CRT. The switches for the Time Base and the Volts per Division have no effect. I also have a Tektronix 684A which shows the most promise. I bought it from a surplus place, and is in very good condition. When I took it home and powered it on, it didn't come on at first, but after a few more tries, it did power on and went through the Self Test process, and it seemed to be ok. When I turned it off and on again, it worked ok. When I powered it on the other day, panel lights came on, but the CRT did not. I even tried to connect an external monitor using the VGA output ii the back, and I didn't get any signal. I remember reading somewhere about this issue, and the solution was to replace a chip on the board, but I can't verify that. I did look at the manual to see what it said if the self test doesn't work, but I didn't see anything. Does anyone have any ideas about this? Thanks.

Thomas Dodge


Horizontal Display switch shenanigans.

Dave Peterson
 

While pulling apart this 465 parts scope I tried removing the pushrods from the Horizontal Display switch on the A7 board. Working on the bottom "B DLY'D" pushrod the push button came out of the switch. I thought at first that it must be a simple mechanical assembly thing that I could put back together. When I had the chance to study it I realized that the plastic of the button had broken. I thought I must have done it trying to take the pushrod off, but then I noticed that the internal plastic button narrows to a very small "T" cross section. See the pictures in:

https://groups.io/g/TekScopes/album?id=257214

Notice the dirtiness of the cross section at the break. If the button was intact before I tried taking the pushrod off it must have been just by the top of the "T" and taken very little force to break it. I suspect it was already broken actually, and that having the board out of the scope allowed the pushrod to rotate down so that the button could come out of the switch assembly. When held horizontal the notches in the button catch on the ratchet mechanism of the switch, holding it in. When it rotated down it just came out with no force, nor did it make any noise. It just kind of fell out in my hand.

The back of the plastic internal button when complete has two channels that hold the metal spring contacts, which slide between the switch posts. I don't know if that's clear in the pictures or not. The point being, if this back piece with the contacts breaks off it ends up inevitably in the back of the switch. In the depressed position. I never turned this scope on - it wouldn't have worked with C1419 shorted anyway. I also didn't capture the back of the switch in any pictures nor notice if the button was visible from the back. They are when in the depressed position. So it's kind of lucky that I found this. If I'd tried the scope it would probably would be stuck in B DLY'D, or something worse with B DLY'D selected and whichever of the other buttons in the HORIZ DISPLAY group would be depressed. It's a pretty devious failure mode, and I have to wonder how common it is, given the fragility of that cross section.

Anyone else with experience with this kind of pushbutton failure?

But wait, there's more!

After finding this broken switch I looked it up by the Tektronix part number from the service manual I have - Fig 2 Circuit Boards, item 124: 260-1423-00, "SWITCH, pushbutton--HORIZ DISPLAY". I found a NOS listing from a company called "Talon Electronics LLC". I ordered it, but was surprised to find on my order after a day some notes from someone in the shipping department which read "cut pin", and submitted a refund for me. But then also shipped it anyway noting "might work in his application". Aw! How nice of them!

So the part came the other day. I unpacked it and compared to my A7/switch. Look at the last two pictures in the above album. Sure enough there's a "cut" pin, but note there's also a cut pin on the existing B DLY'D switch. But look closer: the new part has the wrong pin cut! The new switch in the picture is "on its back". It would be flipped over putting the cut pin at the front side of the board, not the back! Ahg! At least I got a refund. How the heck did this NOS part get in the system in the first place!? Bo-bo in the manufacturing process? Someone had too much to drink the night before and cut a whole batch of switches with the wrong leg cut?

So now what? I'm thinking what I'll do is cut the rearward pin of the new B DLY'd switch, and then cut the existing switch forward pin leaving it soldered into the board. Then when I mount the new switch I'll solder the new switch cut pin to the existing post from the old switch? Maybe place a piece of lead along the post and solder that?

Any other ideas or suggestions for this? I do see another one on eBay, but used. So no assurance that it's in good working order.

But what a convoluted situation! I wanted to share the failure of the switch. It seems like a hidden failure that someone might benefit from the experience. I'd also love to hear any ideas for "fixing" the new switch. Or should I just buy the used one on eBay?

Dave


Re: 528A TV waveform monitor.

Michael A. Terrell
 

All of the RCA studio cameras that I maintained came with the RM529. They
had a large circular connector to connect them to the CCU.
I don't remember the model of the Monochrome camera I serviced in the '70s
for the Army, but the color Cameras at WACX were TK46A, a beautiful four
Plumicon design.

On Fri, Nov 27, 2020 at 4:49 PM stevenhorii <sonodocsch@gmail.com> wrote:

Roy,

If you do any standard-definition TV (SDTV) work - such as converting older
videocassette or other SDTV recordings to DVD, both a waveform monitor and
vectorscope would be useful. A timebase corrector might also be helpful.
All of this stuff can now be obtained at relatively low cost. But I don't
know of non-SDTV uses for these items. It's too bad because they are great
instruments. I had a Tektronix 1900 and then a 1910 TV signal generator.
These had digital signal generation but converted to analog output for
driving monitors and the like for testing. Tektronix had quite a product
line to support the television industry. Tektronix equipment (along with
Grass Valley Group which Tektronix acquired) was likely in almost every TV
studio in the US. I think the huge 2" quad video machines came with a
Tektronix waveform monitor and vector monitor installed in them, at least
the vintage RCA and Ampex ones I have seen did.

There must be some collectors or users of SDTV stuff out there. I have seen
prices of the old Sony U-Matic machines (the studio ones) sell for higher
prices than one would expect (the broadcast version of the Sony U-Matic
machine - the BVU-950 - sells for over $2000). Even the Sony BVH-3100
one-inch C-format machines sell for over $1000 (on eBay) and shipping for
these things would be a quarter to half of that cost.

Steve H.

On Fri, Nov 27, 2020 at 3:19 PM Roy Thistle <roy.thistle@mail.utoronto.ca>
wrote:

Hi All:
I am getting one.
My question is... what do I (What can I) do with it?...I know it is/was
intended for monitoring the NTSC television broadcast signal.
I do have a pdf of the user/service manual.










Re: Fair Radio Sales Lima Ohio

Michael A. Terrell
 

I first visited Fair Radio around 1970. A lot of other Ohio based surplus
dealers are long gone.I worked for an asset recovery company in the Orlando
area in the early '90s. Part of the business was to sell scrap mainframe
boards to IC recovery businesses. The people that ran these companies were
mostly stupid. The would measure the remaining length of IC leads on the
solder side of boards, and reject most of them as too short to reuse. Thes
boards were almost as thick as the tapered part of the pins were long, so I
started recovering and selling popular ICs to our regular customers. The
only condition was that they had to buy entire tubes of one part number. I
could recover, and retin the leads of several thousand DRAMs per day. We
sold them for $2.75 each. The IC recovery companies had turned them down at
15 cents each. The same for common EPROMs at the time. They offered a
nickel, each for the few that they bought. I sold them for $1.50 each. Just
those two groups supported a lot of small computer stores, and development
companies. As stated above, most people have no clue of the value of
surplus. A lot of businesses were started from WW-II surplus, Millions were
made from what most thought was trash. The termination of many government
contracts dumped billions of components on the surplus market. Many claimed
that early Heathkit scopes were built from mostly surplus, and some parts
had a pre war look to them. A lot of kids went into Electronics because of
the availability of cheap surplus components.

On Fri, Nov 27, 2020 at 8:21 PM Tim Laing <laingt@wcoil.com> wrote:

Hello, I live about 2 miles from Fair radio. I know the owner Phil, not a
close friend though. I am not sure what will happen when he retires....
I do not know if the show room is open to the public at this time. I
can do some checking. I can stop in but if I do I generally need to have at
least 2 hours free to wander around and get my fix.... I have gone there
on missions for other people in the past. I could check on plug ins.
My first visit was probably when I was 13 or 14 years old, I am 59 now.
I took my future wife to Fair Radio on our first “date”. Maria and I
are still Married going on 31 years.
Prices are not cheap but he has a lot of overhead costs. I have a
bunch of pictures that I have taken there in the past, I am afraid of the
day I find out they are closing. I wish I had taken pictures in the old
dairy buildings located on Eureka Street. Tim Laing






Re: 528A TV waveform monitor.

greenboxmaven
 

There were several Tektronix TV studio vectorscopes. They were of three designs- stand alone, high precision like the 520, smaller simpler and less precise self contained models with the color decoder built in for use with video recorders, and simple X-Y displays like the 602 that had no decoding circuitry and were used in video recorders and with video monitors like the 650. Most you will find will have been on constantly for years and the jugs will take fifteen minutes to come up to their best brightness. They are not of much use for anything besides monitoring 480 I video, but if you collect and restore older studio equipment they are all quite useful. VHS and even old DVDs are having a quiet resurgence in popularity, and these monitors are valuable for working with this older equipment. Try to find them a home instead of trashing them.

Bruce Gentry, KA2IVY

On 11/27/20 5:30 PM, Ed Breya via groups.io wrote:
I just took a quick look at the 528 on tekwiki. As it is, it's pretty much only good for the original purpose. But, it appears to have an electrostatic deflection CRT (since it's basically a scope, not a TV display, which would tend to use raster-scan), so you could convert it to a nice little low speed X-Y monitor, with simple changes to the guts, if you're so inclined, and need such a thing. I don't know if the graticule is built into the CRT face (probably) - if so, you'd be stuck with the IRE etc scales, instead of a nice grid. If you really want to fix and make it into an X-Y monitor, you can probably find some Tek scope or other CRT that is the same except for the faceplate, and swap it in.

Ed





Re: Fair Radio Sales Lima Ohio

Dave Seiter
 

When I started going to surplus stores in the mid to late 70's, we had many options.  The best was Haltek.  Being in Mountain View, it was full of both ancient (to me) oddities, and recent scrap.  When I was building my first PET computer from scrap, I needed "storage", and Haltek just happened to have a large box of Commodore cassette drives and some test shot or prototype cases. I even sold them some of my findings.  
They are long gone, as are Allied Electronics in Palo Alto (the junk store, not the disty), two places in Sunnyvale I can barely recall, Halted (Haltek's overpriced competition; which moved a while back, then closed.  Apparently they are open again, having been sold to Excess Solutions); Even the newer Weird Stuff is gone, but I rarely found anything I was looking for there.  I have vague memories of short-lived stores further south too. 
Rents are so high now that an existing store would need to own it's building outright and sell a lot of material just to survive.  Most people want shiny, new things these days, not dusty old scrap.
-Dave

On Friday, November 27, 2020, 08:12:36 PM PST, ken chalfant <kpchalfant@msn.com> wrote:

Greetings,

I feel like I’m jumping in somewhere in the middle of this story (thread), but I can’t help it.  This sounds all too familiar.

I live in Colorado Springs, Colorado.  There has been a “surplus” electronics store here for 34 years and I have been a customer for all that time.  It’s funny now that I think about it.  I was 34 when they opened, now I’m not.

Anyway, they started trying to go out of business in mid to late 2019 and finally managed to close the doors for the last time just a couple of weeks ago.  That store was priceless to me and others and it is a great loss although many may never realize that.  For years I cared for old, obsolete printing equipment as well as other machines and equipment.  Often what had failed on a machine was as obsolete as the machine itself.  On very rare occasions I would find the exact - otherwise unobtainable part - waiting for me on a shelf.  Other times I would stand there in an aisle and design a repair solution from what lay before me.

If I hadn’t kept those old machines running people would have lost their jobs.

Now that store is gone - forever.

Funny though, in the last fleeting moments I couldn’t let it all go so I bought all the semiconductors.  I don’t even know yet what I have, but the store owner guessed I bought about 100,000 individual parts.  Fortunately, it was all in bin boxes but even so it required two full loads of a topper covered 3/4 ton truck and about 5 loads of my topper covered smaller truck.

Crazy huh…

I have known about Fair Radio as far back as I can remember and I have purchased a few items over the years.

I think these stores are far more important than most realize.  Not everything in the world is shiny new and a lot of people depend on some very old and sometimes very tired “things” to keep their lives moving forward and even the thought of another such place approaching the end of the line is very, very sad.

Forgive my use of our bandwidth to take a walk down memory lane.

Regards,

Ken


On 27Nov, 2020, at 6:21 PM, Tim Laing <laingt@wcoil.com> wrote:

Hello, I live about 2 miles from Fair radio.  I know the owner Phil, not a close friend though. I am not sure what will happen when he retires....
    I do not know if the show room is open to the public at this time. I can do some checking. I can stop in but if I do I generally need to have at least 2 hours free to wander around and get my fix....  I have gone there on missions for other people in the past. I could check on plug ins.
My first visit was probably when I was 13 or 14 years old, I am 59 now.
  I took my future wife to Fair Radio on our first “date”.  Maria and I are still Married going on 31 years.
    Prices are not cheap but he has a lot of overhead costs. I have a bunch of pictures that I have taken there in the past, I am afraid of the day I find out they are closing. I wish I had taken pictures in the old dairy buildings located on Eureka Street.  Tim Laing





Re: Fair Radio Sales Lima Ohio

ken chalfant
 

Greetings,

I feel like I’m jumping in somewhere in the middle of this story (thread), but I can’t help it. This sounds all too familiar.

I live in Colorado Springs, Colorado. There has been a “surplus” electronics store here for 34 years and I have been a customer for all that time. It’s funny now that I think about it. I was 34 when they opened, now I’m not.

Anyway, they started trying to go out of business in mid to late 2019 and finally managed to close the doors for the last time just a couple of weeks ago. That store was priceless to me and others and it is a great loss although many may never realize that. For years I cared for old, obsolete printing equipment as well as other machines and equipment. Often what had failed on a machine was as obsolete as the machine itself. On very rare occasions I would find the exact - otherwise unobtainable part - waiting for me on a shelf. Other times I would stand there in an aisle and design a repair solution from what lay before me.

If I hadn’t kept those old machines running people would have lost their jobs.

Now that store is gone - forever.

Funny though, in the last fleeting moments I couldn’t let it all go so I bought all the semiconductors. I don’t even know yet what I have, but the store owner guessed I bought about 100,000 individual parts. Fortunately, it was all in bin boxes but even so it required two full loads of a topper covered 3/4 ton truck and about 5 loads of my topper covered smaller truck.

Crazy huh…

I have known about Fair Radio as far back as I can remember and I have purchased a few items over the years.

I think these stores are far more important than most realize. Not everything in the world is shiny new and a lot of people depend on some very old and sometimes very tired “things” to keep their lives moving forward and even the thought of another such place approaching the end of the line is very, very sad.

Forgive my use of our bandwidth to take a walk down memory lane.

Regards,

Ken

On 27Nov, 2020, at 6:21 PM, Tim Laing <laingt@wcoil.com> wrote:

Hello, I live about 2 miles from Fair radio. I know the owner Phil, not a close friend though. I am not sure what will happen when he retires....
I do not know if the show room is open to the public at this time. I can do some checking. I can stop in but if I do I generally need to have at least 2 hours free to wander around and get my fix.... I have gone there on missions for other people in the past. I could check on plug ins.
My first visit was probably when I was 13 or 14 years old, I am 59 now.
I took my future wife to Fair Radio on our first “date”. Maria and I are still Married going on 31 years.
Prices are not cheap but he has a lot of overhead costs. I have a bunch of pictures that I have taken there in the past, I am afraid of the day I find out they are closing. I wish I had taken pictures in the old dairy buildings located on Eureka Street. Tim Laing





Re: 528A TV waveform monitor.

Glenn Little
 

If it was in use at a TV station, the CRT is probably shot.
The only use that I know of for this specialized scope is to monitor analog video to set levels and for signal verification.
It has use in amateur TV or if you are recording analog video.


Glenn

On 11/27/2020 3:19 PM, Roy Thistle wrote:
Hi All:
I am getting one.
My question is... what do I (What can I) do with it?...I know it is/was intended for monitoring the NTSC television broadcast signal.
I do have a pdf of the user/service manual.



--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: Resistor in series

Stephen Hanselman
 

Dennis,

I saw similar things when I was working on Silicon Valley 700W FM amplifiers. The physical orientation of the ATC caps was critical. We noted that sometimes two or three caps needed to be placed on edge or even stacked on top of each other.

RF is always fun but this added a new twist.

Regards,

Stephen Hanselman
Datagate Systems, LLC

On Nov 27, 2020, at 14:50, Dennis Tillman W7pF <dennis@ridesoft.com> wrote:

There is another explanation for doing something like this which is not as obvious.
If you look at the schematic for the 067-0681-01 Tunnel Diode Pulse Generator designed by John Addis at Tektronix
http://w140.com/tek_067-0681-01.pdf

There are three 1/8W 1Kohm resistors (R4, R5, and R6) connected in series going to the tunnel diode. Several years ago I asked him why he did not use one 3Kohm resistor instead. What he knew and I learned was that the body capacitance of each of these 3 resistors in series was far less than the body capacitance of one 3Kohm resistor. The TD is being driven by the collector of the transistor which is high impedance, and the three 1Kohm resistors in series reduces the time constant of the pulse going to the Tunnel Diode without adding any additional capacitance across the Tunnel Diode that would slow it down.

I doubt this had anything to do with Tek portable scopes since their frequency response is almost two orders of magnitude slower than the fast edge of the Tunnel Diode Pulse Generator but sometimes there are other explanations for why you might encounter things that are not obvious.

Dennis Tillman W7pF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Milan Trcka
Sent: Tuesday, November 24, 2020 9:09 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Resistor in series

Jeff, the resistors connected end to end are an attempt to make a required resistance that was not available as a standard resistor value. Shortage of parts? Engineering change? Select in test? Who knows. I have a few of those in my 453 scope.







--
Dennis Tillman W7pF
TekScopes Moderator





Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.

Jim Ford
 

In addition, smartphones use Wi-Fi and other comms methods to navigate.  Much superior to those TomTom boxes that only used GPS.JimSent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: stevenhorii <sonodocsch@gmail.com> Date: 11/27/20 3:54 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] (OT) Where to go for 70s IBM hardware? I'm looking for a terminal. Jim,Yep. I'm pretty sure the navigation system in my car uses GPS primarily butmust have a dead reckoning system as it shows me where I am when I amdriving through an underground tunnel. The system updates as soon as theGPS signals are again available, so there are sometimes funny jumps fromshowing me somewhere off the highway to back on it. GPS-aided inertialseems to be the way many navigation systems are being designed.On Fri, Nov 27, 2020 at 6:46 PM Jim Ford <james.ford@cox.net> wrote:> FWIW inertial navigation systems and GNSS (Global Navigation Satellite> Systems) are complementary.   INS tend to drift over time, and GNSS provide> corrections.  Navigation in GNSS-denied or -degraded areas is a whole other> ballgame.Jim Ford  Sent from my Verizon, Samsung Galaxy smartphone> -------- Original message --------From: stevenhorii <sonodocsch@gmail.com>> Date: 11/27/20  1:04 PM  (GMT-08:00) To: TekScopes@groups.io Subject: Re:> [TekScopes] (OT) Where to go for 70s IBM hardware? I'm looking for a> terminal. Harvey and Bill,Yes - I've tried that trick. For small gyros it> works. Gyros with electricspin motors tend to draw the most current at> startup as do most motors.After that, the current usually drops quite a> bit. Some of the 400Hz gyrosuse two-phase power. The usual trick is to put> a capacitor across the twospin motor inputs - it provides the phase lag for> the second phase. I haveNOT tried this, but I have seen some gyros -> usually the small ones thatare about one-inch in diameter and three inches> long and almost always rategyros - that had a phase-splitting capacitor> already soldered in place.This white paper describes a basic 2-phase power> supply for gyro spinmotors:> http://usdynamicscorp.com/literature/general/AN-003%20USD%20Spin%20Motor%20Excitation.pdfI> was fortunate - at a hamfest years ago, I picked up a couple of> AbbottTransistor Labs inverters. These took 24-28 VDC and output AC 400Hz> singlephase at up to about 2 amps. Not enough to run a large gyro, but> enough forthe smaller ones. I even ran a fairly large gyro - a Honeywell> rate gyro -with one of these. They do need a heatsink.I sometimes do an> eBay search for "Behlman Invertron" as they made somevery useful frequency> converters - 115 VAC to variable 400Hz AC. Some werevariable frequency and> some versions also had single to three-phase output.They tend to be> expensive (and heavy for the higher output ones) and Inever managed to find> one at what I thought was a reasonable price. Someversions had> interchangeable plug-in oscillators so you could run evenhigher frequency> AC devices (some gyros use 800 Hz - the Apollo programgyros ran with 800> Hz, 2-phase power). There are currently a couple ofBehlman Invertrons on> eBay, though they are not cheap.If you can find them, some of the WW II and> even early missile (Nike) gyrosran on DC (24-28 v). Those are fun to run> up. However, I've had some forwhich the bearings almost certainly were bad> - they were very noisy whenrunning and spin-down after power was removed> was quite fast. Likely whythey were surplus.Years ago, a surplus dealer on> Canal Street in NYC sold me a WW II Bendixvertical gyro. It was a 400Hz> gyro and he told me I could run it on 60Hz ACby putting a current limiting> incandescent lamp (no choices - there were noLED lamps then) in the power> circuit and running at a lower voltage via aVariac. I did not have the guts> to try it, but I do know those who did andsaid it works, but you will not> get the gyro up to full speed.Messing about with gyros can lead you down a> deep hole much as gettingfascinated by Tektronix equipment and then> desiring to get some (plusspares "for parts" and all the manuals). Now you> can get fairly accurategyros made using IC fab techniques - the MEMS units.> These things live insmart phones and tablets now. These plus GPS have> radically changedinertial navigation. Fun stuff, though.Steve H.On Fri, Nov> 27, 2020 at 1:52 PM Harvey White <madyn@dragonworks.info> wrote:> Hi-fi> amplifier of sufficient output capability driven by a sinewave> generator> sitting at 400 Hz?>> Harvey>> On 11/27/2020 11:52 AM, Bill E wrote:> > Even> though way off the off topic topic (parse that), still a fun> discussion. I> scored a box of 10 real gyros and logic pulled from DC-10s.> Cute little> rate gyro, etc. Problem is, all that stuff takes 28v 400Hz.> Haven't gotten> around to making a power supply for them yet.> >> >> >> >> >> >>>> >>>>> >>>

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