1. TekScopes@groups.io
   Date   
Re: Looking for

Dave Seiter
 

I *think* it was the other way round- Grass Valley group spun off from Tek.
-Dave

On Saturday, July 11, 2020, 09:32:58 AM PDT, stevenhorii <sonodocsch@gmail.com> wrote:


I have several older Tek NTSC video test items. I had a 1910 digital
generator that was useful in the days of SDTV. If I am not mistaken, Tek
acquired Grass Valley. Group. They made (make, I think) broadcast video
equipment. The Tek test signal generators, waveform monitors, vector
scopes, sync generators, etc. were made by Tek.

Steve H.

On Sat, Jul 11, 2020 at 11:27 Kurt Swanson <kurt2135@frontiernet.net> wrote:

I have a 7J20.  Unfortunately, I don't have the sampling head.  I've had
it for a long time, and when I got it, I knew it was uncommon, but I
figured a sampling head would eventually turn up.  No such luck - at least
so far.
I got it wanting to do some optical spectroscopy work, and still would
like to get it working for that purpose.

If anyone has a sampling head, let me know, otherwise I might reluctantly
let this one go for sale or trade (and I do mean reluctantly).

Regards - Kurt
Re: Looking for

Dave Daniel
 

I have a DP-100. It was pretty inexpensive. I remember wondering when I received it what I was going to do with it. I still haven't come up with anything.

DaveD

On 7/11/2020 12:32 PM, stevenhorii wrote:
For those seeking a 7J20/J20 or parts, after the other posts on this, I’ve
decided I won’t continue searching for one other than out of interest of
what the price might be. It would be a novelty for me as I have equipment I
need to do the testing I do.

By the way, there’s an interesting module on eBay:

https://www.ebay.com/itm/1pp-1-qty-tektronix-dp-100-digital-video-probe/264388939882

Apparently a TM500 plug-in (TekWiki) and a pod is shown with it on the
TekWiki page but not by the seller on eBay.

I have several older Tek NTSC video test items. I had a 1910 digital
generator that was useful in the days of SDTV. If I am not mistaken, Tek
acquired Grass Valley. Group. They made (make, I think) broadcast video
equipment. The Tek test signal generators, waveform monitors, vector
scopes, sync generators, etc. were made by Tek.

Steve H.

On Sat, Jul 11, 2020 at 11:27 Kurt Swanson <kurt2135@frontiernet.net> wrote:

I have a 7J20. Unfortunately, I don't have the sampling head. I've had
it for a long time, and when I got it, I knew it was uncommon, but I
figured a sampling head would eventually turn up. No such luck - at least
so far.
I got it wanting to do some optical spectroscopy work, and still would
like to get it working for that purpose.

If anyone has a sampling head, let me know, otherwise I might reluctantly
let this one go for sale or trade (and I do mean reluctantly).

Regards - Kurt



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Re: FG-504 not-so odd behavior

keantoken
 

10*10^2=1KHz, so it seems to be partly working. All functions should be 1KHz so something is off.
Check that the oscillation is coming from the oscillator. The oscillator may be behaving normally and the output amp is oscillating on it's own. If they are both oscillating at 25MHz then I would look at the decoupling caps or a broken ground causing feedback between the output amp and the oscillator.
I would try a little harder to identify the fault in the non functional one. It could be that when you find the problem it will suddenly work fine with no issues. On Saturday, July 11, 2020, 09:51:04 AM CDT, John Ferguson via groups.io <jferg977=aol.com@groups.io> wrote:

with the FG 504 set at start freq 10, stop freq 40, multiplier at 10^2,
sweep off,

measured on my 2445b, Sine freq 982.3 Hz, Sawtooth 975.9 Hz and Square
wave 24.5 mHz.

The square wave is an asymmetrical  sine wave, not the Sawtooth I was
expecting.

Since I have two of these things and this one at least does this, and
also the sweeps and other functions, all except a square wave, and the
other one does nothing, this might be the one to fix.

What do you think?


john
Re: Tek 465 Turns on, No Dot, No Trace

Stephen
 

On Sat, Jul 11, 2020 at 06:24 AM, Tom Miller wrote:


There is a wire jumper at board location A-5 that provides the ground to
the HV multiplier. (note that I am going from old memory so take with a
grain of salt). Measure to ground to see if it is grounded. It is next
to a mounting screw for the multi module. Just lift one end and see if
the HV osc comes up.

If the HV osc is not running, all the CRT vltage readings will be off.

Regards
Ok, so I did lift that jumper. GOOD MEMORY BTW!!! A-5 it was!! Remind me NOT to ever play Naval BattleS with you!

The CRT came to life. I had something when playing With the Intensity and pushing the Beam Finder. But at the same time I did this, I heard some weird cracklings noises coming from the HV area, and a funny smell. Nothing caught fire though. I turn everything down and released the B Finder. Then I turned it off.
What say you? Is this good or bad? What are my options?

Best Regards
Re: Tektronix Blue paint - source in the UK ??

Robin_Birch
 

I can get that done in the U.K. so I guess it’s still common

Robin

On 11 Jul 2020, at 17:09, Dave Daniel <kc0wjn@gmail.com> wrote:

The other problem is that once mixed, it is difficult (but not impossible) to spray it on the parts to be painted. If one has a paint sprayer, it’s not too big a deal, except for having to clean the sprayer afterwards.

I heard a while back that one or more paint vendors would mix it and package it in spray-paint cans. I don’t know that was or still is the case.

DaveD

On Jul 11, 2020, at 11:57, Robin_Birch <robinb@ruffnready.co.uk> wrote:

Yes,
All automotive paint suppliers will colour match and create a good match for you. The problem with quoting a specific paint supplier’s base or mix colours is that only works where that manufacturer’s colours are available.

Cheers

Robin
On 11 Jul 2020, at 15:31, Stephen Hanselman <kc4sw.io@kc4sw.com> wrote:
I’m not sure about folks outside of the US but if it were me I’d take a side panel down to the paint store and have them color match it. I’ve used this method on my house where it works well, no reason it shouldn’t work on test equipment

Regards,

Stephen Hanselman
Datagate Systems, LLC
On Jul 11, 2020, at 04:26, Colin Herbert via groups.io <colingherbert=blueyonder.co.uk@groups.io> wrote:

There has been communication on Tek blue paint ever since I joined this Forum. May I respectfully suggest that you have a search through the past posts to find all you can. There is a lot of information there, though a good deal relates to US providers, I am sure that some UK-dwelling members have contributed.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of chris gare
Sent: 10 July 2020 11:41
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix Blue paint - source in the UK ??

I'm from the UK and don't quite understand the "Bluebase 79126" reference? The the other colors are fine as they are in Ounces?

Help please anyone!

Chris
Re: FG 504 function generator odd behaviour

Harvey White
 

Generic steps:

turn scope off, wait 5 minutes or so, turn scope on.  See if -25 is good (something could have latched up).

with power off, check continuity of fuses or with power on, check for very low voltage drop across the fuse.  There must always be a voltage drop because the fuse acts like a resistor.

Look at the bulk supply for the -25.  Check against voltage readings on the schematic.  Go through regulator circuit to output and see what doesn't match.  Any transistor where the base-emitter voltage is the wrong polarity indicates transistor is off.  Any transistor (except a darlington) where the B-E voltage exceeds 0.7 volts is likely bad.

Typical things to fail:  pass transistor.

in the event of a short circuit, check the current sense resistor (the low value one from the pass transistor to the output) and then check the (frequently done like this) transistor which has the base/emitter junction connected across the resistor.  Too much current and the transistor turns on, stealing base drive from the pass transistor, and turning it off.  Current limiting.

In many tek supplies, the - supply is a positive supply in topology, with what would be the ground being the negative lead, and what you'd think ought to be the positive output grounded. The voltage across the pass transistor is the difference between the bulk supply and the desired voltage.

Check also to see what the reference voltage is for the -25 volt supply.  It must be exact, otherwise the supply will be off.

Harvey

On 7/11/2020 1:56 PM, Colin Herbert via groups.io wrote:
Oops! I have checked the voltages and while the +25V (+24.99), +15V (+14.98)
and -15V (-14.98) are just about bang on, the -25V is sitting at -3.58V. I
really can't remember if this was the case when I checked previously, but it
is now. I did manage to short something out with the DMM probes, so that may
have given this problem, but sure as sure it needs to be fixed, but how?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave
Daniel
Sent: 10 July 2020 18:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] FG 504 function generator odd behaviour

The first thing to do is measure the power rails to make sure that the
voltages are in spec and clean.

DaveD

On Jul 10, 2020, at 13:04, Colin Herbert via groups.io
<colingherbert=blueyonder.co.uk@groups.io> wrote:
I have an FG 504 which is showing some odd behaviour. The triangle-wave
shows asymmetry in that the negative peaks of the wave are rounded-off at
any frequency and the positive ones have a similar but lesser problem at
higher frequencies. This also seems to manifest itself as what looks like
cut-off on the negative peaks of the sine-wave and lesser cut-off on
positive peaks. While the triangle-waves are more-or-less symmetrical, the
sine-waves are definitely not so, showing a nearly three-to-one voltage
ratio in favour of positive peaks. There is also noticeably overshoot on the
square-waves at anything above 1kHz and only a DC offset at frequencies
below 80Hz.
I am totally ignorant of how this function generator produces
triangle-waves, but I do understand that the square-waves and sine-waves are
derived from the triangle-wave. Does anyone have any help that they can
offer? I would be grateful to get this useful function-generator working
properly.
Colin.
Re: FG 504 function generator odd behaviour

Colin Herbert
 

Oops! I have checked the voltages and while the +25V (+24.99), +15V (+14.98)
and -15V (-14.98) are just about bang on, the -25V is sitting at -3.58V. I
really can't remember if this was the case when I checked previously, but it
is now. I did manage to short something out with the DMM probes, so that may
have given this problem, but sure as sure it needs to be fixed, but how?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave
Daniel
Sent: 10 July 2020 18:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] FG 504 function generator odd behaviour

The first thing to do is measure the power rails to make sure that the
voltages are in spec and clean.

DaveD

On Jul 10, 2020, at 13:04, Colin Herbert via groups.io
<colingherbert=blueyonder.co.uk@groups.io> wrote:

I have an FG 504 which is showing some odd behaviour. The triangle-wave
shows asymmetry in that the negative peaks of the wave are rounded-off at
any frequency and the positive ones have a similar but lesser problem at
higher frequencies. This also seems to manifest itself as what looks like
cut-off on the negative peaks of the sine-wave and lesser cut-off on
positive peaks. While the triangle-waves are more-or-less symmetrical, the
sine-waves are definitely not so, showing a nearly three-to-one voltage
ratio in favour of positive peaks. There is also noticeably overshoot on the
square-waves at anything above 1kHz and only a DC offset at frequencies
below 80Hz.
I am totally ignorant of how this function generator produces
triangle-waves, but I do understand that the square-waves and sine-waves are
derived from the triangle-wave. Does anyone have any help that they can
offer? I would be grateful to get this useful function-generator working
properly.
Colin.
Re: Tektronix 2230

Saroj Pradhan
 

Hi Raymond
Thank you for the information.
Saroj
Re: Tek 465 Turns on, No Dot, No Trace

Tom Miller
 

There is a wire jumper at board location A-5 that provides the ground to the HV multiplier. (note that I am going from old memory so take with a grain of salt). Measure to ground to see if it is grounded. It is next to a mounting screw for the multi module. Just lift one end and see if the HV osc comes up.

If the HV osc is not running, all the CRT vltage readings will be off.

Regards

On 7/11/2020 6:31 AM, Stephen wrote:
I notice something I didn’t pay attention to before. That is TP1486 should go from 15V to 75V depending on the position of the Intensity control knob. However, mine goes from 15V to only 31V with the intensity maxed out...
Hmmmmm.... Interesting... There is definitely something there as well.

PS: Where do I lift the HV multiplier lug?

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Re: Looking for

stevenhorii
 

For those seeking a 7J20/J20 or parts, after the other posts on this, I’ve
decided I won’t continue searching for one other than out of interest of
what the price might be. It would be a novelty for me as I have equipment I
need to do the testing I do.

By the way, there’s an interesting module on eBay:

https://www.ebay.com/itm/1pp-1-qty-tektronix-dp-100-digital-video-probe/264388939882

Apparently a TM500 plug-in (TekWiki) and a pod is shown with it on the
TekWiki page but not by the seller on eBay.

I have several older Tek NTSC video test items. I had a 1910 digital
generator that was useful in the days of SDTV. If I am not mistaken, Tek
acquired Grass Valley. Group. They made (make, I think) broadcast video
equipment. The Tek test signal generators, waveform monitors, vector
scopes, sync generators, etc. were made by Tek.

Steve H.

On Sat, Jul 11, 2020 at 11:27 Kurt Swanson <kurt2135@frontiernet.net> wrote:

I have a 7J20. Unfortunately, I don't have the sampling head. I've had
it for a long time, and when I got it, I knew it was uncommon, but I
figured a sampling head would eventually turn up. No such luck - at least
so far.
I got it wanting to do some optical spectroscopy work, and still would
like to get it working for that purpose.

If anyone has a sampling head, let me know, otherwise I might reluctantly
let this one go for sale or trade (and I do mean reluctantly).

Regards - Kurt
Re: Tektronix 2230

Saroj Pradhan
 

Hi Satbeginner

Understood
Thanks

On Sat, Jul 11, 2020, 10:12 PM satbeginner <castellcorunas@gmail.com> wrote:

Hi Saroj,

Connect one winding to oscillator, also Ch1 of the scope to the same
winding.

Now use Ch2 of the scope to check the other windings.

I would connect the dot-side of the first winding to the signal generator,
the other side of the winding to ground.

That way on the other windings the dot-side should be in fase with the
winding connected to the oscillator.

Keep going, success,

Leo
Re: Tektronix 2230

satbeginner
 

Hi Saroj,

Connect one winding to oscillator, also Ch1 of the scope to the same winding.

Now use Ch2 of the scope to check the other windings.

I would connect the dot-side of the first winding to the signal generator, the other side of the winding to ground.

That way on the other windings the dot-side should be in fase with the winding connected to the oscillator.

Keep going, success,

Leo
Re: Tektronix 2230

Saroj Pradhan
 

Hi Satbeginner
Right now I am looking for kapton tape in the market. Yes, I have another
scope and signal generator.If I am not wrong, probing at dotted points
scope should show voltages at same phase.
Thanks
Saroj

On Sat, Jul 11, 2020, 3:04 PM satbeginner <castellcorunas@gmail.com> wrote:

Hello Saroj,

Another thing popped into my mind:

Before putting the transformer back, if you have another scope and a sine
generator, you could verify the fase of the windings.

And another one:

Once you are at the point of powering on again, connect a voltmeter to the
first switcher to check the 43V it is supposed to generate.

It could be the first time -because of the wrong feedback signal- the
voltage of the first switcher was way to high, and the scope was saved by
the second regulator and the crowbar circuit.

Succes!!

Leo
Re: Tektronix Blue paint - source in the UK ??

Dave Daniel
 

The other problem is that once mixed, it is difficult (but not impossible) to spray it on the parts to be painted. If one has a paint sprayer, it’s not too big a deal, except for having to clean the sprayer afterwards.

I heard a while back that one or more paint vendors would mix it and package it in spray-paint cans. I don’t know that was or still is the case.

DaveD

On Jul 11, 2020, at 11:57, Robin_Birch <robinb@ruffnready.co.uk> wrote:

Yes,
All automotive paint suppliers will colour match and create a good match for you. The problem with quoting a specific paint supplier’s base or mix colours is that only works where that manufacturer’s colours are available.

Cheers

Robin
On 11 Jul 2020, at 15:31, Stephen Hanselman <kc4sw.io@kc4sw.com> wrote:

I’m not sure about folks outside of the US but if it were me I’d take a side panel down to the paint store and have them color match it. I’ve used this method on my house where it works well, no reason it shouldn’t work on test equipment

Regards,

Stephen Hanselman
Datagate Systems, LLC
On Jul 11, 2020, at 04:26, Colin Herbert via groups.io <colingherbert=blueyonder.co.uk@groups.io> wrote:

There has been communication on Tek blue paint ever since I joined this Forum. May I respectfully suggest that you have a search through the past posts to find all you can. There is a lot of information there, though a good deal relates to US providers, I am sure that some UK-dwelling members have contributed.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of chris gare
Sent: 10 July 2020 11:41
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix Blue paint - source in the UK ??

I'm from the UK and don't quite understand the "Bluebase 79126" reference? The the other colors are fine as they are in Ounces?

Help please anyone!

Chris
Re: Looking for

Dave Daniel
 

The J20/7J20 spectrometer had two (optional) fiber optic probes available. As nearly as I can tell, the base instrument did not come with a probe. One of the optional probes was described in the (1975) catalog as transferring light to the entrance slit. The second was described as a UV quartz fiber optic probe for transferring UV light. Both came with mounting rings (there are photos of the UV probe on the TekWiki site).

There were also an external normalizer and a filter holder available as accessories.

In some 20-odd years of looking for this instrument I have only ever seen one J20/7J20 come up for sale. I’ve never seen a standalone probe come up for sale.

DaveD

On Jul 11, 2020, at 11:26, Kurt Swanson <kurt2135@frontiernet.net> wrote:

I have a 7J20. Unfortunately, I don't have the sampling head. I've had it for a long time, and when I got it, I knew it was uncommon, but I figured a sampling head would eventually turn up. No such luck - at least so far.
I got it wanting to do some optical spectroscopy work, and still would like to get it working for that purpose.

If anyone has a sampling head, let me know, otherwise I might reluctantly let this one go for sale or trade (and I do mean reluctantly).

Regards - Kurt
Re: Tektronix Blue paint - source in the UK ??

Robin_Birch
 

Yes,
All automotive paint suppliers will colour match and create a good match for you. The problem with quoting a specific paint supplier’s base or mix colours is that only works where that manufacturer’s colours are available.

Cheers

Robin

On 11 Jul 2020, at 15:31, Stephen Hanselman <kc4sw.io@kc4sw.com> wrote:

I’m not sure about folks outside of the US but if it were me I’d take a side panel down to the paint store and have them color match it. I’ve used this method on my house where it works well, no reason it shouldn’t work on test equipment

Regards,

Stephen Hanselman
Datagate Systems, LLC
On Jul 11, 2020, at 04:26, Colin Herbert via groups.io <colingherbert=blueyonder.co.uk@groups.io> wrote:

There has been communication on Tek blue paint ever since I joined this Forum. May I respectfully suggest that you have a search through the past posts to find all you can. There is a lot of information there, though a good deal relates to US providers, I am sure that some UK-dwelling members have contributed.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of chris gare
Sent: 10 July 2020 11:41
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix Blue paint - source in the UK ??

I'm from the UK and don't quite understand the "Bluebase 79126" reference? The the other colors are fine as they are in Ounces?

Help please anyone!

Chris
Re: tektronix 2465b rom.

James Theonas
 

Thank you my friend!

On Saturday, July 11, 2020, 5:12:06 PM GMT+3, Chuck Harris <cfharris@erols.com> wrote:

Yes, and no...

You know what the values should be, and you know
relatively where they exist in the calibration file,
but you have no idea how, or where, they exist in
the 2K RAM.

Tektronix went out if its way to avoid telling you
that little tidbit of information.

Looking at your screen pictures, and looking at the
data in a hex editor, you can probably figure out
where in the 2K byte RAM the constants are, but you
also have to figure out where the checksums for the
whole file exist.

I know there is a routine in the EPROM that lets
you write back the calibration data, but it is not
available to the unwashed masses.  Someone told me
about it once many, many, years ago, but I remember
nothing about it, only that it exists.

Well, that's not quite true, I recall it is a simple
button press from within the EXER02 routine.

Tektronix would never use such a routine, outside
of development, as they would simply recalibrate the
scope to restore any errant calibration data.

-Chuck Harris

James Theonas via groups.io wrote:
Hi guys! I opened exerciser 2 on my scope and copied all the data from 00 to ff by looping through all of them as I was recording a video. If I input the said data in my programmer and flash a new chip will it work? Is that all that is needed?

Thanks everyone for the fantastic people in this group!
Re: Looking for

Kurt Swanson
 

I have a 7J20. Unfortunately, I don't have the sampling head. I've had it for a long time, and when I got it, I knew it was uncommon, but I figured a sampling head would eventually turn up. No such luck - at least so far.
I got it wanting to do some optical spectroscopy work, and still would like to get it working for that purpose.

If anyone has a sampling head, let me know, otherwise I might reluctantly let this one go for sale or trade (and I do mean reluctantly).

Regards - Kurt
Re: New member with a currently-dead 2465

Siggi
 

On Fri, Jul 10, 2020 at 8:02 PM Tom Miller <tmiller11147@comcast.net> wrote:

Just replace U2556. It is a cheap part. Cut the leads close to the chip
package, remove the package, then unsolder and remove each pin one at a
time. Clear the holes and put in a new 74LS04. I wager a cheeseburger
that is the problem.
In an over-the-counter repair shop, this would be sage advice, and I'm not
sure I'd take you up on that bet.
I believe Vincent is, however, more interested in the journey than the
destination, and by measuring and thinking through all the things, you
learn more :).
Re: Cleaning TM500 module pushbutton switches

J Mcvein
 

Early on e.g. 1960's, WD-40 used fish oil. It changed to petroleum
around the 1970s when fish oil became more valuable as a food
supplement. That has not stopped the salmon fishermen out here
from spraying their herring baits with it. Old practices die hard.

JimMc

-----Original Message-----
From: "Greg Muir via groups.io" <big_sky_explorer=yahoo.com@groups.io>
Sent: Friday, July 10, 2020 9:18pm
To: TekScopes@groups.io
Subject: Re: [TekScopes] Cleaning TM500 module pushbutton switches



Roy,

My experience with WD40 came when working on a project in Hawaii under high humidity conditions. The stores sold WD40 in gallon cans because everyone was using it to prevent their tools from rusting.

I followed the crowd and applied heavy coatings to anything ferrous with the stuff. Some of the tools went for several months before they were brought into use. But when they came out it was found that the WD40 coating on them had turned into something similar to Cosmoline and required washing it off with solvents to clean them before they could be used.

Obviously the tools did not rust. But there was something at play here that made the WD40 very messy. May have been the humidity. And from that I decided that WD40 was not very useful other than for storing things and loosening frozen items.

I’m wondering if WD40 Company has changed the formulation since then.

Greg
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