Date   

Re: 7603

Chuck Harris
 

The 7603 screen is bigger, sharper, and brighter than the
7623 and 7633 storage scopes. The7603 is dead easy to work
on, when compared to the storage scopes.

The military bought gobs and gobs of the 7603's for their
technicians. They even had a ruggedized version made.

The 7633 is very useful for the 7L13, but the 7633 gives a
lot more working space for the 7L5, and 7L18.

I use my 7603 as a base for my 7D20. It is nice!

-Chuck Harris

Harvey White wrote:

Let's see (opinions only)

1) the 100 Mhz bandwidth is adequate for a lot of projects unless you go for maximum
bandwidth (if you can).

2) the plugins that do not require more than 100 Mhz bandwidth are significantly
cheaper.

3) large screen is good (all other options aside)

4) CHEAP is GOOD!  (ask your boss).

5) increased market share (see #4 and #1 and #2) means more production,  hence more
available

6) Storage was more expensive, and most people didn't see why you need it.

7) did I mention less expensive?

Harvey


On 7/12/2020 4:15 PM, Stephen wrote:
I was wondering about this the other day...  many times I see people write
something like: “My venerable and trusted 7603”, or some along those lines.  And
I‘ve come across this kind of comments quite numerous times.  Why is that?  Why
does it seems to be more popular than a 7623?  Is it because of the bigger screen? 
Is it because back in the day it was perhaps cheaper, and therefore more people
opted for it instead of the one with “storage”?  I’ve never had a 7603, but I do
have a 7623 (not A), that I really like, and that is always on my bench despite the
smaller screen.






Curve tracer as a power supply

DW
 

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...

However I have a 577 curve tracer. My initial thoughts is to set the collector polarity to AC and the voltage to 25V and the series resistance 1 ohm or below. This headphone amplifier only takes 500 mA it claims to run it along with a 1 amp slow blow fuse. I think I should be fine but just incase I would like to get a second opinion here, thanks


Re: Unknown Type 547 add-on circuit.

John Griessen
 

On 7/12/20 8:00 PM, Dave Wise wrote:
Can anyone identify the circuit shown in the photo album? It's in a Type 547 I got off craigslist for $10.
https://groups.io/g/TekScopes/album?id=250335

I can't get that to show in firefox or chrome. I'm logged in, but that URL redirects to https://groups.io/g/TekScopes with no mention of albums anywhere...


Re: Unknown Type 547 add-on circuit.

Dave Wise
 

Beware that the 547 and 549 are susceptible to a high-voltage transformer problem. Tek switched to an epoxy-based winding impregnant which has become lossy. The symptom is loss of high voltage, sometimes after a short time on the order of minutes to a couple hours. Chuck Harris is working on an industrial-grade rewinding operation, or you can try my low-tech DIY approach documented in topic and album titled "453 HV Transformer Rewind". The 547 transformer winding spec is available at TekWiki, w140.com .

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Seiter via groups.io <d.seiter=att.net@groups.io>
Sent: Sunday, July 12, 2020 5:55 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Unknown Type 547 add-on circuit.

A nice haul! I have a 549 around somewhere that I've been meaning to restore; thanks for reminding me!
-Dave
On Sunday, July 12, 2020, 05:03:39 PM PDT, Martin Hodge <mhodge@...> wrote:

Actually the total bill was $60, for a 535a, 547, 549, 575, 585a and a little Heathkit scope. I was very pleased, but the suspension on my van was not.

I was really after the 575. I'd been wanting a curve tracer and the other units were gravy. The 585a and the heathkit were unfortunately rotted away far beyond saving. But I've got the 575 and the 535a working nicely and calibrated. The 547 I've just finished but haven't calibrated yet. The 549 storage scope is going to have to wait, it needs two 8608 tubes in the vertical amp (gassy) which are very expensive.

The 535a has a beautiful, bright and razor sharp aqua colored trace and is completely transistor free when equipped with a Type 53/54K. I feel like a bolt of lightning could hit it and it would keep right on ticking.


Password not working

Mark Vincent
 

Dear Sir,

Please send me the password to log in. For some reason, the one I used is
not working. Thanks.

Mark


Re: Unknown Type 547 add-on circuit.

Dave Wise
 

That was an unbelievable deal. I'd be pinching myself to prove I was not dreaming it.

That mod was available on most (all?) of the 500-series scopes, it gives direct access to the CRT vertical deflection plates so you can bypass the built-in vertical amp and drive them at frequencies far above spec with external equipment.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Martin Hodge via groups.io <mhodge=innocent.com@groups.io>
Sent: Sunday, July 12, 2020 4:17 PM
To: TekScopes@groups.io
Subject: [TekScopes] Unknown Type 547 add-on circuit.

Can anyone identify the circuit shown in the photo album? It's in a Type 547 I got off craigslist for $10.

https://groups.io/g/TekScopes/album?id=250335

It's only connections are a 4 pin xlr socket mounted thru a hole in the left cowling and 4 leads that clip directly to the CRT deflection plates. Apparently some kind of interface, but for what?


Re: Unknown Type 547 add-on circuit.

Dave Seiter
 

A nice haul!  I have a 549 around somewhere that I've been meaning to restore; thanks for reminding me!
-Dave

On Sunday, July 12, 2020, 05:03:39 PM PDT, Martin Hodge <mhodge@...> wrote:

Actually the total bill was $60, for a 535a, 547, 549, 575, 585a and a little Heathkit scope. I was very pleased, but the suspension on my van was not.

I was really after the 575. I'd been wanting a curve tracer and the other units were gravy. The 585a and the heathkit were unfortunately rotted away far beyond saving. But I've got the 575 and the 535a working nicely and calibrated. The 547 I've just finished but haven't calibrated yet. The 549 storage scope is going to have to wait, it needs two 8608 tubes in the vertical amp (gassy) which are very expensive.

The 535a has a beautiful, bright and razor sharp aqua colored trace and is completely transistor free when equipped with a Type 53/54K.  I feel like a bolt of lightning could hit it and it would keep right on ticking.


Re: Message from Dave Carpenter

DaveH52
 

According to my service manual page 6-12:
"0D,ABCC> is the cycle mode failure indicator.
When the CYCLE mode is activated (see CYCLE ERROR CLEAR Description), data will be written to the EAPROM about the first test failure that occurs. This information will be displayed until the operator performs the CYCLE ERROR CLEAR routine (Exerciser 03).


Re: Unknown Type 547 add-on circuit.

John Williams
 

Nice buy Martin! Wow that is a dream. I checked vacuumtubes.net and they are $25 each new. I am going to check and see how many spares I have. I will let you know if I can help. John


Re: Tektronix TM500/TM5000 extender version 1.0

DaveH52
 


Re: Need 067-1051-00 right angle extender for 7D20

Dallas Smith
 

Thank you Håkan,

Read your post, but this post: https://groups.io/g/TekScopes/message/106914
is exactly the same problem, the trace offset is triggering the wrong errors. I believe the large trace offset is the root cause of the problem. Both channels position will just show on the screen at full CW control position.

Checked my ROM versions: U500 & U700 Ver 03 all the others Ver 02.
The unit work for two years, how could a bug now be the problem, are your saying that the ROM;s have gone bad?
If a ROM lost a bit or two, that is a problem. These ROM's can only hold the data so long but can be freshened up by erasing and re-programming them.. Didn't find any firmware at 'KO04BB' or our files, anyone have these firmware bin's if needed?




Dallas


Re: Unknown Type 547 add-on circuit.

Martin Hodge
 

Actually the total bill was $60, for a 535a, 547, 549, 575, 585a and a little Heathkit scope. I was very pleased, but the suspension on my van was not.

I was really after the 575. I'd been wanting a curve tracer and the other units were gravy. The 585a and the heathkit were unfortunately rotted away far beyond saving. But I've got the 575 and the 535a working nicely and calibrated. The 547 I've just finished but haven't calibrated yet. The 549 storage scope is going to have to wait, it needs two 8608 tubes in the vertical amp (gassy) which are very expensive.

The 535a has a beautiful, bright and razor sharp aqua colored trace and is completely transistor free when equipped with a Type 53/54K. I feel like a bolt of lightning could hit it and it would keep right on ticking.


Re: New member with a currently-dead 2465

Siggi
 

On Sun, Jul 12, 2020 at 6:21 PM Vincent Mallet <vmallet@...> wrote:

I removed U2556 and replaced it with a new one from TI that I had around
and ta-da! It lives! Super exciting!

Congrats!

I had a couple of questions on the oscillating circuitry:

1/ R2553 is a 10K tied to -5V. What does that do? Why do we need to bring
-5V into the picture?
For the same reason that there's a 680Ohm pullup to the +5 I suspect, e.g.
to bias the inverter just so, to make sure it oscillates. That pullup is
particularly interesting, as it's on the driven output of a gate. As you
found, the circuit seems to be on a knife edge.


2/ Figure 3831-50 “Test waveform setup information” for A5 shows 3
waveforms, including “1” taken at U2556-4 and “2” taken at U2468-5. Both
waveforms seem to be centered around 0V with a +/- 2V swing around 0. How
do I interpret this? Why negative? If I probe U2556-4 (now that it lives) I
get a waveform that looks like what’s in the manual but it swings from 0V
to ~3.6V. Is it because I am supposed to be AC-coupled and ignore the
offset?

That seems weird. There's no way you see a TTL signal symmetrical about
ground so I guess those oscillograms were recorded by the intern?


Now I need to find some probes for this scope so I can try to quantify its
performance. The only probes I have are the ones bundled with my Siglent
DSO ("PP215 200MHz") and I don't know how good or bad they are.
If you read through the "performance verification" portion of the service
manual you'll see no mention of using probes for the verification nor for
the calibration. To verify or calibrate this scope you input the set of
signals specified in the "performance verification" portion of the service
manual and then interpret the results on the CRT. These signals are
generally hooked up with good quality coax cables.

See e.g. this video (https://www.youtube.com/watch?v=oxJQr4dKnys) and this
one (https://www.youtube.com/watch?v=OiAmER1OJh4) for some of the whats and
hows of probes.
If you can compensate your Siglent probes with the 2465, they'll probably
work OK to the limits of their frequency spec. If you can't compensate
them, you'll need probes with a suitable compensation range, but depending
on what you expect to look at, they don't need to match the scope's
bandwidth.


Re: Unknown Type 547 add-on circuit.

snapdiode
 

I think the bigger story here is a 10$ 547.


Re: DP512 12 GHz Digital Prescaler

Harvey White
 

Could you make a 3 wide frame from two defunct 500 series plugins?  Left, right and a center plugin to support the front panel, although you could argue the center one depending on what voltages you need.

Harvey

On 7/12/2020 4:39 PM, Dennis Tillman W7pF wrote:
Hi Egge Siert,
You have only part of the story.

There is a TM 500 Rubidium Standard. It is the PTB-100. It was made by the Efratom Division of Ball Aerospace which can be seen at
http://w140.com/tekwiki/wiki/Ball_Efratom_PTB-100
I have had two of these over the years.

There are at least two other TM500 GPS Frequency Standards. I made the first one in 2008 using a Rockwell-Jupiter GPS Receiver and a Phase Locked Loop designed by James Miller G3RUH. I found the design on the internet. They are no longer there but I saved a copy. I will include it in a PDF documenting both of the GPS frequency standards I built.

I built his design in a single wide TM500 prototype. I named it my "FS501 GPS Frequency Standard".
In 2012 John Miles KE5FX gave a much better GPS Receiver module. This was a Trimble Thunderbolt. I combined this with a wonderful Monitor program designed by Didier Juges KO4BB, who, among other things maintains the manuals depository at
http://www.ko4bb.com/getsimple/index.php?id=manuals
That became my "FS502 GPS Frequency Standard". That has been working ever since 2012.

I recently was given an HP Z3801A GPS Receiver which, according to John Miles is an excellent GPS receiver. Unfortunately the PC Boards inside it would require a triple wide TM500 to accommodate them. So I may not be able to make that the basis of another GPS plugin unless I can find a 3-wide TM5xx plugin to take apart for its case. I do have 6 Nixie Tubes for it because something this accurate only deserves the best possible display. I am pretty sure I can fit the Nixie Tubes into the HP Z3801A but it will be tight.

I really like how you did the front panel of the GS510. What did you use? I would love to be able to duplicate that same material and style that Tek switched to even if it is not as durable as the anodized aluminum front panels of most of the 7000 plugins and TM500 plugins.

Dennis Tillman W7pF.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Egge Siert
Sent: Saturday, July 11, 2020 1:37 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] DP512 12 GHz Digital Prescaler

Hi Joe,

From a German eBay Member (I assume a former Tektronix Germany employee) I got the following answer:
"Guten Tag, ja ich weiß es, es sollte mal einen Eigenbau eines Prescalers bis 14 GHZ werden, das Projekt wurde aber nie gestartet.

Mfg Klaus Chudzinski"

The earlier mentioned Rubidium Standard Plug-In was in fact a 10MHz GPS Standard named GS510. Pictures of it are now in the posession of TekWiki.

Greetings,

Egge Siert





Re: 7603

Harvey White
 

Let's see (opinions only)

1) the 100 Mhz bandwidth is adequate for a lot of projects unless you go for maximum bandwidth (if you can).

2) the plugins that do not require more than 100 Mhz bandwidth are significantly cheaper.

3) large screen is good (all other options aside)

4) CHEAP is GOOD!  (ask your boss).

5) increased market share (see #4 and #1 and #2) means more production,  hence more available

6) Storage was more expensive, and most people didn't see why you need it.

7) did I mention less expensive?

Harvey

On 7/12/2020 4:15 PM, Stephen wrote:
I was wondering about this the other day... many times I see people write something like: “My venerable and trusted 7603”, or some along those lines. And I‘ve come across this kind of comments quite numerous times. Why is that? Why does it seems to be more popular than a 7623? Is it because of the bigger screen? Is it because back in the day it was perhaps cheaper, and therefore more people opted for it instead of the one with “storage”? I’ve never had a 7603, but I do have a 7623 (not A), that I really like, and that is always on my bench despite the smaller screen.



Unknown Type 547 add-on circuit.

Martin Hodge
 

Can anyone identify the circuit shown in the photo album? It's in a Type 547 I got off craigslist for $10.

https://groups.io/g/TekScopes/album?id=250335

It's only connections are a 4 pin xlr socket mounted thru a hole in the left cowling and 4 leads that clip directly to the CRT deflection plates. Apparently some kind of interface, but for what?


Re: New member with a currently-dead 2465

Vincent Mallet
 

It lives!!

I'm definitely in here for the journey but it's nonetheless interesting to
see how someone with experience would zero in on the potential culprit and
how they'd move forward with the investigation.

Here I put things back together, removed all the probes except TP505 (far
enough from the circuit not to influence it) and tried a few power on/off
cycles to try to catch the oscillator napping... It was mostly hyper (i.e.
30MHz at pin-1, 3.75MHz at TP505). Caught it napping once, went to measure
voltage drop over R2559 with a DMM and that was enough to wake it up!

Gave up on that plan; I lifted a leg of each of the five resistors in there
to measure them out of circuit; they look impeccable:
R2549: 685R (specs: 680R 5%)
R2564: 330R (specs: 330R 5%)
R2571: 986R (specs: 1K 5%)
R2573: 997R (specs: 1K 5%)
R2553: 10K01 (specs: 10K 5%)

I removed U2556 and replaced it with a new one from TI that I had around
and ta-da! It lives! Super exciting!

I managed to remove U2556 without turning it into a sacrifice so I will try
to exercise it offline to see how it behaves.

I had a couple of questions on the oscillating circuitry:

1/ R2553 is a 10K tied to -5V. What does that do? Why do we need to bring
-5V into the picture?

2/ Figure 3831-50 “Test waveform setup information” for A5 shows 3
waveforms, including “1” taken at U2556-4 and “2” taken at U2468-5. Both
waveforms seem to be centered around 0V with a +/- 2V swing around 0. How
do I interpret this? Why negative? If I probe U2556-4 (now that it lives) I
get a waveform that looks like what’s in the manual but it swings from 0V
to ~3.6V. Is it because I am supposed to be AC-coupled and ignore the
offset?

Now I need to find some probes for this scope so I can try to quantify its
performance. The only probes I have are the ones bundled with my Siglent
DSO ("PP215 200MHz") and I don't know how good or bad they are.

Thanks!

Vince.

On Sat, Jul 11, 2020 at 8:21 AM Siggi <siggi@...> wrote:

On Fri, Jul 10, 2020 at 8:02 PM Tom Miller <@tmiller>
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: Need 067-1051-00 right angle extender for 7D20

 

On Sun, Jul 12, 2020 at 07:35 PM, Dallas Smith wrote:


but now have self test errors 65432 & 654321
Those exact error codes are the ones known to be possibly false due to F/W bugs I mentioned
in your previous post. If your F/W is lower than 1.03, (last numbers of the P/N -03) on U500 and
U700 it could be the cause.

/Håkan


Re: Tek 4041 GPIB Controller

Gary Robert Bosworth
 

Monte: I will send off $20 for the 3 volume set of 4041 service manuals.

Gary

On Sun, Jul 12, 2020, 14:15 Monty McGraw <mmcgraw74@...> wrote:

Actually there is a third volume in the latest service manuals and I will
include that link for the same price - I'm asking for $20 for the three
volume set.

Send me a PM if interested.

This is service manual 070-6967-00, I posted a cover page of this manual
in my forum photo album:
https://groups.io/g/TekScopes/photo/247590/0?p=Created,,,20,2,0,0

Monty