Date   
Re: The Everlasting 547 HV Transformer topic

Chuck Harris
 

Hi Leonard,

I replied to you minutes after your first request, and the same
after your second request. But your spam filter obviously doesn't
like me. I suggest you check your spam folder.

Here is what I replied:
----------------------------------------
Hi Leonard,

I sent you the below message at 12:53 on Feb 5th.
-------------------------------------------------------------------------
Hi Leonard,

I am working feverishly on finishing my new winding machine.
It is computer controlled, and will make winding HV transformers
much easier, and more reliable.

I have been promising that I would be ready really soon now, for
about the last 5 years... I don't like making promises that I can't
keep.... so I won't do that anymore.

However, I am now retired, so in theory, I have more time on my
hands.

I will post an announcement on the tekscopes, and tekscopes2 groups
when I am ready to start winding again.

-Chuck Harris
----------------------------------------

leonard scheepsma wrote:

Guys,
I've once again restored a 547 almost at the edge of the dirt container, got it working (except then both time-bases A & B do not trigger but that's for later as I run an 1S2 right now which doesn't need it anyway) but the scope shows all symptoms of a defective HV transformer (20 mins show time and then dies on me..)

So, I read Chuck Harris is the man who could possibly make me a replacement. For a 549 I have as well, I got an Xfrm winded locally, but that was no success (spraying), for that scope a small blower entered the HV case which solved the problem as the temperature doesn't rise so much. For this 547 I'm very interested to have a real good replacement.

I've sent a direct email to Chuck a few times but got no response yet. He is around right?

Thanks Leonard



Re: 475 Module: Anyone need it?

Renée
 

Hi Bruce-
I use the 475  as my preferred scope...so If it is still available...I will take it.
we should do this off list from here ....k6fsb dot 1 at the gmail place
Renée

On 2/16/20 10:43 AM, Bruce Lane wrote:
Fellow Tekkies,

While hunting for a part this morning, I came across a Tektronix module
which I think is the vertical driver board for a 460 or 470 series. The
part number is 670-3023-02.

I don't need it, as I sold my 475 some time ago. First offer of $5 plus
postage gets it, priority to those who might need the thing to repair an
existing 'scope.

Thanks much.

475 Module: Anyone need it?

Bruce Lane
 

Fellow Tekkies,

While hunting for a part this morning, I came across a Tektronix module
which I think is the vertical driver board for a 460 or 470 series. The
part number is 670-3023-02.

I don't need it, as I sold my 475 some time ago. First offer of $5 plus
postage gets it, priority to those who might need the thing to repair an
existing 'scope.

Thanks much.

--
---
Bruce Lane, ARS KC7GR
http://www.bluefeathertech.com
kyrrin (at) bluefeathertech dot com
"Quando Omni Flunkus Moritati" (Red Green)

The Everlasting 547 HV Transformer topic

leonard scheepsma
 

Guys,
I've once again restored a 547 almost at the edge of the dirt container, got it working (except then both time-bases A & B do not trigger but that's for later as I run an 1S2 right now which doesn't need it anyway) but the scope shows all symptoms of a defective HV transformer (20 mins show time and then dies on me..)

So, I read Chuck Harris is the man who could possibly make me a replacement. For a 549 I have as well, I got an Xfrm winded locally, but that was no success (spraying), for that scope a small blower entered the HV case which solved the problem as the temperature doesn't rise so much. For this 547 I'm very interested to have a real good replacement.

I've sent a direct email to Chuck a few times but got no response yet. He is around right?

Thanks Leonard

Re: Repairing my Tektronix 454 oscilloscope need some advice

Victor
 

Albert,

Thank you for your comments.
I check again the CRT circuit and fuse F1437 is ok, the capacitor C1437 is new (I have change it last week) and Q1430 is ok also. Nevertheless I believe something is wrong on the CRT circuit. I measure voltage on Q1414, Q1413 and Q1423 and some voltages are not as the indicate on the manual... transistors has been tested and are on the specs,so may be some diode or resistance is bad....
Unfortunately, during my investigation I face another issue. The Line EMI filter just dead. So I'm looking for a part that can be installed in the exiting space,and then I can restart my circuit test.

Regards,
Victor

Re: DC508A Frequency Range

 

Hmm...would like to know as well.
I have a DC505a counter, but went with an HP5386A for bigger range afterward. Most of my older HF gear to 3Ghz is combined Tektronix & HP/Agilent. RiGOL for the newer 'daily use' stuff, a bit more user friendly and portable.

Re: 5116+5D10 intensity problem

Harvey White
 

You definitely want to look into one of two things, either bad/reduced high voltage (symptoms would be magnified deflection because a slower electron stream is easier to deflect), and then the cathode/grid bias, but right now, I'm betting on the high voltage.

I wouldn't change the horizontal or vertical gain, but I'd check the outputs of the amplifiers for normal signal levels.  I seem to remember that when the 5000 series was mentioned, there may have been some problems with an epoxy coated HV transformer, which may need to be replaced.  However, I'd check the HV oscillator circuit to see what's going on there.  If, for instance, there is an HV multiplier block (possible), feeding a separate accellerator, then failure of that block causes the image to bloom.

I'd suggest doing a search on the group archives for scope HV problems, which shows the steps you can take to troubleshoot the system.   You do need an HV probe.  It should be specified to work with the meter impedance you have, since it's a 1000 to 1 high voltage divider using the meter itself as the lower part.  10 meg meter needs 9990 meg resistive divider.

You might want to check the discussions on those, too, for additional information

Harvey

On 2/16/2020 2:46 AM, Yeun-Jung Wu wrote:
Hello Harvey:

Since the intensity went down in recent event it never came back. What this 5116 did after turned on was nothing on the screen, even if the intensity control knob was turned fully clockwise. I can tell it was powered on only when scale graticule illumination was fully on.

I guess turn down the vertical and horizontal gain would shrink the display to normal siize. This couldn't be a cure since most important task is to restore a visible trace in normal viewing condition. Once the intensity problem was solved the graticule scale would be normal again.

I did not have any other 5000 series plug-in's. I bought this broken 5116+5D10 with smashed LCD color shutter a few years ago and fixed 5D10 digitizer.

I up load three photos under the file name 5116. Signal to vertical amplifier was interesting: an old video game?

Regard,

Yeun-Jung Wu


Re: DS1742W-120 replacement adapter?

Tom B
 

Thank you.  That looks like a perfect solution.  I really like the idea of being able to change the battery.

Is anybody selling these boards?

Tom

On 2/16/2020 5:23 AM, Jay Walling via Groups.Io wrote:
Given that the Dallas DS1742W-120 is no longer available (excluding Chinese fakes), does anyone make an adapter board to use a more modern chip like the DS1744?
Yes.
https://urldefense.com/v3/__https://www.eevblog.com/forum/repair/tds3014-adventures-(seeking-75-75mhz-oscillator)/msg2766224/*msg2766224__;Iw!!KfGNmQmE!yGkfz7RRa63jEAJiomejYByJDC2uQCzVhb8FbMtFsaBNYgGxG6fKsPUx_m1q$

Re: DS1742W-120 replacement adapter?

 

Given that the Dallas DS1742W-120 is no longer available (excluding Chinese fakes), does anyone make an adapter board to use a more modern chip like the DS1744?
Yes.
https://www.eevblog.com/forum/repair/tds3014-adventures-(seeking-75-75mhz-oscillator)/msg2766224/#msg2766224

Re: 5116+5D10 intensity problem

Yeun-Jung Wu
 

Hello Harvey:

Since the intensity went down in recent event it never came back. What this 5116 did after turned on was nothing on the screen, even if the intensity control knob was turned fully clockwise. I can tell it was powered on only when scale graticule illumination was fully on.

I guess turn down the vertical and horizontal gain would shrink the display to normal siize. This couldn't be a cure since most important task is to restore a visible trace in normal viewing condition. Once the intensity problem was solved the graticule scale would be normal again.

I did not have any other 5000 series plug-in's. I bought this broken 5116+5D10 with smashed LCD color shutter a few years ago and fixed 5D10 digitizer.

I up load three photos under the file name 5116. Signal to vertical amplifier was interesting: an old video game?

Regard,

Yeun-Jung Wu

Re: 2465B Option 05 + 06 (TV/CTT)

cldaves@...
 

Chuck, I like your value system... it really does put things in perspective. 😝

Tektronix 2794 / 2756P Wanted

MARC CHRISTIAN
 

Dear Tektronix Group - Any Member have Tektronix 2794 or Tektronix 2756P For Sale ?

Regards Marc Christian

Re: DC508A Frequency Range

 

Hi Gary,
The DC508A and every frequency counter works down to almost DC limited by the duration of the period between measurements. A 1sec measurement period can measure to 1Hz. A 10 sec period can measure down to 0.1Hz. And so on. There is no lower limit. Without a long enough period you won't get any resolution unless you have a reciprocating counter.
For HF you will almost always use 50 ohm impedance. For low frequency work 1Mohm is more typical.

The manual clearly states the resolution enhancement circuitry only works between a certain audio frequency range. I don't recall the range off the top of my head. The answer is DEFINITELY in the service manual.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Gary Robert Bosworth
Sent: Saturday, February 15, 2020 6:02 PM
To: TekScopes@groups io <TekScopes@groups.io>
Subject: Re: [TekScopes] DC508A Frequency Range

Thank you Bruce. I already had the Operator's and Service Manuals. The specifications state that the 508A will work from 100MHz to 1.3GHz but does not state exactly how low it will work. It appears that there is a high-pass filter that passes frequencies above 100MHz, but I was hoping someone knows if the counter will readout at 50MHz without the error LED coming on. It is not made crystal clear. I have been coping with specsmanship since 1964.

Gary

On Sat, Feb 15, 2020 at 2:47 PM Bruce Atwood <atwood.1@...> wrote:

See http://w140.com/smb/DC508A_SM.pdf page 1-1.



--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247





--
Dennis Tillman W7PF
TekScopes Moderator

Re: DC508A Frequency Range

Gary Robert Bosworth
 

Thank you Bruce. I already had the Operator's and Service Manuals. The
specifications state that the 508A will work from 100MHz to 1.3GHz but does
not state exactly how low it will work. It appears that there is a
high-pass filter that passes frequencies above 100MHz, but I was hoping
someone knows if the counter will readout at 50MHz without the error LED
coming on. It is not made crystal clear. I have been coping with
specsmanship since 1964.

Gary

On Sat, Feb 15, 2020 at 2:47 PM Bruce Atwood <atwood.1@...> wrote:

See http://w140.com/smb/DC508A_SM.pdf page 1-1.



--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247

Re: DC508A Frequency Range

Bruce Atwood
 

DC508A Frequency Range

Gary Robert Bosworth
 

The DC508A is a 1.3GHz frequency counter. The left-hand side is for high frequencies at 50 Ohms. There is an LED labeled "Input Out Of Range". It lights if the input is not of high enough frequency or of proper voltage. The question is - What is the low end frequency of this input? I believe it requires a minimum of 100MHz at greater than 100mV p-p. Does anyone know for sure if this input will work down below 100MHz and how far down will it work???

Re: Repairing my Tektronix 454 oscilloscope need some advice

Albert Otten
 

Victor,

Just to be sure, did you test the fuse F1437 or the voltage across C1437. Also did you test as far as possible the driver transistor Q1430? Q1430 is not in the HV box. I think B, E and C can be reached between the back panel and the HV box.

Recently there were very long discussions here concerning 454 HV problems.

Albert

Re: Wondering if there is any out there

Eric
 

Sweet knowing that I looked up the service manual I defiantly need C632. Now I just need to see if i can dig one up some where.

On 2/15/2020 9:34 AM, Mlynch001 wrote:
On Fri, Feb 14, 2020 at 05:18 PM, Eric wrote:

The main unit serial number is B108698 the serial number of the 177 is
B059769
177 - B059769 appears to be the newest iteration of that unit. The last running change made was to C630 which was changed at B054650 and higher. Everything from that SN on is the most up to date as far as changes go.

577 - B108698 appears to be a newer iteration of that unit as well. The last running change made was to a large number of components at B104750 and higher, so you appear to have two newer production units. The 577 was subject to a whole host of running changes and the D1 and D2 models overlap in the parts list, so it is hard to be any more accurate.

Repairing my Tektronix 454 oscilloscope need some advice

Victor
 

Hi members,
I have since many years a tek 454. Few years ago the trace stop to show. Since I have more spare time to dedicate to my small lab I would like to repair it.
The first step was to repair the power supply witch is working now fine. Then I discover that the CRT circuit is not working (very low voltage on the TP 1469 (-1960V)) and no voltage on the CRT heater.
I test all the parts on the Z Axis circuit board feeding the HV voltage and I couldn't find any trouble. I open the plastic box containing the HV transformer for testing and all the parts seems fine except a 1 Mohm resistor which I replace it. Is not easy to work on this circuit with few information but I think the HV transformer is dead.
A very well know Canadian supplier for Tek parts doesn't have any spare available for the HV transformer. So I'm looking for some advice or any members experience on this scope or additional test to confirm my suspicion. Also any specs about the HV transformer will be welcome.
Thanks in advance.
Victor

Re: 5116+5D10 intensity problem

Harvey White
 

OK, then what I was looking for was a significantly larger ripple.  What happens, voltage wise, at the very beginning when you turn on power, and then after the trace starts to dim?  Is there a voltage change there?

Naturally, you do need to measure the HV, since that may be a problem.  Lower HV typically means dimmer trace, and depending on how the CRT is done, can make for a larger trace.

However, and you need to check when the trace goes bad, does the waveform at TP12 change?  If not, then the fault lies beyond that in the circuit.  (could likely be in the CRT circuit).  Since this is a 5116, did you mention if the problem exists with another set of plugins?  IF not, then it's looking as if the problem is rather specifically in the 5D10.

Not familiar with the setup, so I'm just working on symptoms.

Harvey

On 2/15/2020 1:15 AM, Yeun-Jung Wu wrote:
Hello Harvey:

Thank you for your suggestion.

I had checked the ripple content of power supply:

+30V: 20mV p-p; should be 3mV or less
-30V: 8mV p-p; should be 3mV or less
+200: 195, 1.5V p-p; should be 3V or less
+5: 8mV; should be 3mV or less

Plus 30V branch had significant larger ripple content, which may attributed to aging filter capacitor.

According the spec. the accelerating voltage was 4.5kV, pin 2 at CRT socket. My pocket DMM can measure voltage up to 1kV. A HV probe is needed.

Maybe I can order a new piece of 10kV/5mA diode first.

With Tek 485 probed at TP 12, I got an interesting picture of the vertical input signal when 5D10 display a standard graticule grid. It was digitally precise!

Best Regards,

Yeun-Jung Wu