Date   
Re: Tektronix 222 mini scope repair, looking for schematics

satbeginner
 

Hi all,

a quick update, I cleaned the circuit board using alcohol, especially the area around the memory bus drivers and the memory chip, and behold: SUCCESS !!
I could not see any dirt or bad connections, but it appears there was something there.

A picture of this little beauty can be found here: https://groups.io/g/TekScopes/album?id=128546

A question for other 222 owners: I am under the impression that Self Cal only works when in Storage Mode?

Un saludo,

Leo

Re: Tektronix 222 mini scope repair, looking for schematics

satbeginner
 

Hello Håkan and others,

After our return to warm Spain I finally got to taking my 222 apart, and obviously I directly downloaded the schematics as provided by Håkan (Many, many thanks for the scan!).

My scope has the following going on:

Somebody already replaced the battery-pack using NiMh cells. (2x7 AA-cells, 7 pairs of two cells in parallel, connected in series)
It does turn on and it does show a sharp readout, but no trace(s)
Both button panels are responsive.
When I do the Align thing it does show a sharp matching set of rectangular figures using the entire screen, as shown in the manual.
When I perform a Self Cal on both Ch1 and Ch2 it nineteen out of twenty times comes with a Pass as result.

But...... during the Self Cal I only see the right half of the set of lines going up-and-down.
So, although the readout is using the entire screen, the traces (and only during Self Cal) use only the right half of the screen.

When I set the sensitivity on both channels to 5mV and touch the probe-tip I do see some (apparently un-triggered) noise on the right half of the screen.

My thinking so far:

The Analog part (attenuator etc) is OK; (because of Self Cal do Pass)
The Horizontal and Vertical Amps are OK; (because of readout and align pattern are OK)
The Z amplifier is OK; (because of the two assumptions above)

I am thinking of half the storage memory being dead, or not clocked properly?
- Assuming the Self Cal is reading the AD converter's data directly into the CPU, so the storage/display memory is not used at that time?
- Assuming the Align thing is directly generated by the CPU, so the storage/display memory is not used?

Any thoughts or suggestions?
Anybody already repaired one of these little beauties?

To be continued, un saludo,

Leo

Re: Tek 453A-1

Tom Gardner
 

On 01/11/19 12:05, Dale H. Cook wrote:
On 11/1/2019 6:52 AM, quadzillatech wrote:

well looks like ive wasted my time posting here so far !!
What are you in such a hurry for? I am sure that many who sub this reflector do not check it frequently. I hadn't checked it since your first post largely because, during most of that time, I was asleep.


On 10/31/2019 8:41 PM, quadzillatech wrote:

ive checked all the electrolytics for high esr,they all test good,
Did you do all of the power supply checks for the power supply adjustment? Which precision meter are you using for checking the low voltages? Which meter are you using for checking the HV test point? Do you have experience in troubleshooting and repairing instrumentation?

Do you have a second, working 'scope? The old adage is that you need a 'scope to fix a 'scope.
There is an "m3vuv" who is rebuilding a broken 30kV probe for use with a
Fluke 85 (and maybe an Avo 8),  choosing the resistors empirically.

https://www.eevblog.com/forum/projects/hv-probe/msg2761308/#msg2761308
Don't bother to read it all!

Re: Tek 453A-1

Dale H. Cook
 

On 11/1/2019 6:52 AM, quadzillatech wrote:

well looks like ive wasted my time posting here so far !!
What are you in such a hurry for? I am sure that many who sub this reflector do not check it frequently. I hadn't checked it since your first post largely because, during most of that time, I was asleep.


On 10/31/2019 8:41 PM, quadzillatech wrote:

ive checked all the electrolytics for high esr,they all test good,
Did you do all of the power supply checks for the power supply adjustment? Which precision meter are you using for checking the low voltages? Which meter are you using for checking the HV test point? Do you have experience in troubleshooting and repairing instrumentation?

Do you have a second, working 'scope? The old adage is that you need a 'scope to fix a 'scope.
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/

Re: Tek 453A-1

Glenn Little
 

Be patient!! it has only been 10 hours since you asked for help.

Glenn

On 11/1/2019 6:52 AM, quadzillatech@... wrote:
well looks like ive wasted my time posting here so far !!


--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... 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: Tek 453A-1

quadzillatech@...
 

well looks like ive wasted my time posting here so far !!

Re: Free 535 with scope cart and extra plugins (Pittsburg)

Harvey White
 

anything at Sphere.

I live in Florida.

Harvey

On 10/31/2019 5:28 PM, Les WB6ORZ wrote:
   The Law of Letdown: The free great item will always be pickup in excess of a 4-day drive. Each way.    (((73)))    Les WB60RZ    Menlo Park, CA
-------- Original message --------From: Mlynch001 <@mlynch001> Date: 10/31/19 1:26 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Free 535 with scope cart and extra plugins (Pittsburg) That would be an excellent find for someone.  I don't do too much with the 5 series, but that price would be hard to resist.  If I was close, I would be sorely tempted, however, I'm not driving 1900 miles to get it.-- Michael LynchDardanelle, AR

Re: Free 535 with scope cart and extra plugins (Pittsburg)

Les WB6ORZ <wb6orz@...>
 

The Law of Letdown: The free great item will always be pickup in excess of a 4-day drive. Each way.    (((73)))    Les WB60RZ    Menlo Park, CA

-------- Original message --------From: Mlynch001 <@mlynch001> Date: 10/31/19 1:26 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Free 535 with scope cart and extra plugins (Pittsburg) That would be an excellent find for someone.  I don't do too much with the 5 series, but that price would be hard to resist.  If I was close, I would be sorely tempted, however, I'm not driving 1900 miles to get it.-- Michael LynchDardanelle, AR

Tek 453A-1

quadzillatech@...
 

Hi all,ive the above scope,i brought it as faulty with no trace,after some poking around i found a couple of transistors dead on the z axis board along with a few resistors out of spec due to age,i now have a trace but cant adjust the high voltage to - 1950v,the most i get is -1093,the hv adjustment pot R900 makes no difference to the voltage whatsoever ive renewed the door knob on the eht comp but no change,the cal is all to pot due to the low hv,any ideas where to look and what to check?,ive checked all the electrolytics for high esr,they all test good,cheers m3vuv 73.

Re: DM5010 DMM 5000 series module and TM5006 rack for parts

Ke-Fong Lin
 

Bonsoir,

Oui je suis en région parisienne.
Je vais vous envoyer un email.

Bonne soirée,

Re: "liquid crystal driver" sighting

Dave Daniel
 

Glenn,

I believe that there are quite a few people who can upload the photos and update or create the TekWiki page. I can do so if you wish. Just send the photos and any descriptive information you have.

DaveD

Sent from a small flat thingy

On Oct 31, 2019, at 14:32, Glenn Little <glennmaillist@...> wrote:

I will soon have pictures. How do I get these on TekWiki?

Glenn


On 10/17/2019 9:48 PM, p mc wrote:
Yeah, that.

But someone snagged it. Someone willing to pay for delivery by angel choir so I doubt they just wanted the 5A1xN plugins.

Someone here, perchance?
TekWiki would like to hear from you...


--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... 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: Free 535 with scope cart and extra plugins (Pittsburg)

Bruce Atwood
 

I wonder what an Uber to Columbus OhiO would cost.

--
Bruce Atwood PhD
Department of Astronomy
The Ohio State University
100 West 18th Ave., Room 4055
Columbus, OH 43210

Phone 614.314.0189
FAX 614.292.2928

Re: Free 535 with scope cart and extra plugins (Pittsburg)

Mlynch001
 

That would be an excellent find for someone. I don't do too much with the 5 series, but that price would be hard to resist. If I was close, I would be sorely tempted, however, I'm not driving 1900 miles to get it.

--
Michael Lynch
Dardanelle, AR

468 With Odd Trace Timing issue when in Vertical ALT Mode Only.

Mlynch001
 

All;

I recently bought a couple of 468 Scopes, I have very little invested, with the exception of shipping costs. I wanted to get at least one good working scope out of the two, with at least a pile of extra parts. Two working units would be awesome. I was able to get this one to work after a lot of cleaning of many dirty cam switches. These are my first 468's, so they are new to me. I have done some repairs on 465B and 475A's in the past, but have never encountered this before. LV Power supplies are spot on. Ripple on all supplies is within limits. HV Supplies check good. I have the Original Service Manuals. My issue now is that when in "Non-Storage" Mode, the A trace has a small gap or black spot in the A trace at low speeds and at higher TIME/DIV sweep speeds, it becomes a short trace on the left then what appears to be the beam switching from A to B and back again. In the A Trigger view, there is the same symptom This only happens with the VERT/ Alt button released (ALTERNATE Mode Only). When it is in "VERT Chop" (ALT Button Depressed) the anomaly disappears. This is not apparent in the lower TIME/DIV settings, but becomes more visible as the scope is set to fasted and faster speeds. The scope is pretty much useless at high speeds unless you switch to "CHOP". The problem is only apparent in the analog mode, it does not appear to affect the digital traces in any fashion. Storage seems to work quite well, even the cursors work and agree with the readout. I am thinking this is a "Pre-Digital" sweep timing or Channel blanking timing issue. My thought is that the trace is not beginning at the right time or the blanking circuit is out of time with the trace. I beleive that this fault is allowing me to actually witness the transition of the electron beam between the two alternating traces. Of course, when it is in "CHOP" the traces both appear normal. Since this is basically a 465B with digital storage added; and the DIGITAL portion does not seem to be affected, I thought some of you more experienced 465B people might have an idea about this. I have posted photos of the traces in the photo section.
--
Michael Lynch
Dardanelle, AR

Re: Free 535 with scope cart and extra plugins (Pittsburg)

Brenda
 

Wow, too bad that I am too far away. I love the 535 series and to top it off, has a Type D plug-in. I am always looking for those.....

Re: TDS500 series VGA output

@Arcticgeek
 

The VGA output of the TDS500/600/700 series scope support 640x480 resolution only. If the monitor you are considering will accept that resolution you will be okay, but if it ONLY supports 1024x768 you're probably SOL.
Mike

Free 535 with scope cart and extra plugins (Pittsburg)

Jamie Ostrowski
 

Re: "liquid crystal driver" sighting

Glenn Little
 

I will soon have pictures. How do I get these on TekWiki?

Glenn

On 10/17/2019 9:48 PM, p mc wrote:
Yeah, that.

But someone snagged it. Someone willing to pay for delivery by angel choir so I doubt they just wanted the 5A1xN plugins.

Someone here, perchance?
TekWiki would like to hear from you...


--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... 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: TekScopes and TekScopeArc are independent groups

pdxareaid
 

thanks for the explanation.
i am a relative newcomer (a few years of membership) and when i joined i got the impression
the ARC groups were an extension of the main group, due to storage limitations or the main group, and that
was where new contributions (files, databases, etc) were to be stored.
i think many people had/have that impression, regardless of the "owner" of the group.

My impression was further bolstered by noticing something i contributed to the ARC groups actually
made it to groups.io when the big push happened, though i am no longer the owner of the particular file which is fine.
i would not expect that if they were completely separate and am confused (as i think many are) as to what got
transferred from the ARC groups to groups,io (which is excellent btw).

I only write this to give voice to the confused masses (assuming that exists).
I am exceedingly happy with the transfer to groups.io and very much appreciate the work that has been done.
phil

TDS500 series VGA output

 

Does anyone know what resolutions the VGA out port of the TDS500/700 series
'scopes support?

Why? I'm in touch with a Chinese manufacturer who has 1024*768 6.5" open
frame monitor available and need to know if it would work.

Thanks
David