Date   

Re: Tektronix 2235 no horizontal sweep

paronaram
 

Yes, that's how I fixed Ch1 issue, but I did not replace them just did Deoxit, I can't find replacement part, also if I will not be able to fix the horizontal sweep issue, I will trash this scope. No need to spend more $, if scope is not working
And yes, it is Timebase board, not calibration board :) sorry

Deflection wire(s) on the bottom was loose, but not disconnected, used long nose pliers, to push them in, but issue still there.
Is there something I can measure on this Deflection wires? I am guessing voltage

[url=https://ibb.co/SBKmsNP][img]https://i.ibb.co/kXhDHKx/20200426-234422.jpg[/img][/url]


Re: Extender on eBay looks like 7000 series? 3 available

 

Hi John,

I hope the seller on ebay does not get mad if I pass you the information of the female connector he uses (picked it up from the photo of his board). It is
EORG 345-076-520-201, available at digikey.com for $5.63 a piece.

I might buy his kit for $70 if I run into insurmountable problems with my 7000 plugins. At this time, I think I could troubleshoot them through the side accesses of my 4 bay 7704A.

Ernesto


Re: Tektronix 2235 no horizontal sweep

Reddy
 

As a retired auto tech, I just grab a pair of extra long, double scissors, bent Snap-on needle nose pliers. Steady them with two hands. I have never had a problem.


Re: Tektronix 2235 no horizontal sweep

guy232
 

Curious as to what tool you use to reach the connectors? I had the same
issue in the past and used a bent hemostat for the bottom two connectors as
space was limited. Just wondering if there is a better tool for delicate
jobs like this.

On Sun, Apr 26, 2020, 1:35 PM Reddy via groups.io <wpost2=
verizon.net@groups.io> wrote:

I have had several 2235's come thru that have had the deflection wires
unplugged or just resting on the connector. They are the wires that are
half way down the crt and one set comes up from the bottom and another from
the side. The wires are quite stiff and will look like they are connected,
but sometimes they just vibrate down over time. All 2200 series I check
these wires whenever I open them. Wish you luck.


-----Original Message-----
From: baloyan <baloyan@...>
To: TekScopes <TekScopes@groups.io>
Sent: Sun, Apr 26, 2020 12:45 pm
Subject: [TekScopes] Tektronix 2235 no horizontal sweep

Hello Everybody, Just joined this discussion group. I am learning
electronics, reading here there, watching videos.. Trying to fix faulty
audio equipment; troubleshooting. I start purchasing some test equipment
for this task and that included Tek 2235 oscilloscope.
Scope was cheap because it it has ONLY "one" problem (as per guy who sold
me). It was listed no horizontal sweep on left side. I was hopping maybe
something with PS, but no.. And after troubleshooting more I find out that
I have no Ch1 as well ... :'(
Can someone help me find out where is this problems maybe coming from,
(tube looks ok)?
I checked all voltages on TP they are fine, was trying to do reverse by
adding signal on the Ch1 and see where it gets lost, but fist stage U10 is
buried under 3 PCBs, I don't even know how to check TP there ...
If I move the horizontal position pot wile holding "beam finder" dot does
move left side of the screen

PS: I was able to fix missing Ch by moving calibration pot on calibration
board.. sprayed Deoxit and channel came back up.

Thank you







Re: Extender on eBay looks like 7000 series? 3 available

Greg Muir
 

What bothers me is that the board copper is not plated leaving the bare copper surface which results in it starting to look very dingy through use as the acids in the moisture from your skin start to leave permanent fingerprints and coloration on the copper traces. In all he needs to tin plate the traces at a minimum to allow the extenders to not look like they have spent considerable time in the outdoors or in a contaminating environment. My biggest concern is that without plated copper you could probably also face corrosion on the board fingers leading to intermittent contacts.

Greg


Re: FS: Tek 335 vinyl cover $15

Mark Huffstutter
 

I would love to buy the case, if it's still available!

Mark

The Faux leather on the strap is cranked, but not peeling. Clean, supple,
and in good shape without cracks. Don't have the front cover.

Pics are here: https://www.n1oz.net/Tek335Case/

I'll put it in a large padded envelope and ship it for actual cost.

Oz, N1OZ (in DFW)




FS: Tek 335 vinyl cover $15

Oz-in-DFW
 

The Faux leather on the strap is cranked, but not peeling. Clean, supple, and in good shape without cracks. Don't have the front cover.

Pics are here: https://www.n1oz.net/Tek335Case/

I'll put it in a large padded envelope and ship it for actual cost.

Oz, N1OZ (in DFW)


FTAGH: Tek 1502 case parts

Oz-in-DFW
 

Free to a good home: Fragments of a case to harvest parts from or build test fixtures. Take one or both.

No, I won't pull the one screw you want.

Pics are here: https://www.n1oz.net/Tek1502CaseParts/

Shipping at whatever it actually costs. I'll box it up and drop it off.

Oz, N1OZ (in DFW)


Re: Tektronix 466 Probe Recommendation.

Jim Ford
 

Should be http://w140.com/tek_probe_crossref_1990.pdf

Sorry about that. Trying to do stuff on my phone instead of laptop computer. Doesn't always work so well...

Jim Ford

------ Original Message ------
From: "Roy Thistle" <roy.thistle@...>
To: TekScopes@groups.io
Sent: 4/26/2020 3:48:15 PM
Subject: Re: [TekScopes] Tektronix 466 Probe Recommendation.

Hi: I found the "Tek Scopes and Vertical Amplifiers to Tek Probes Cross-Reference" pdf at
http://w140.com/tek_probe_crossref_1990
the link at
http://w140.com/tek_probe_crossref_1990.pdf.Another
reports "Missing." with Firefox.



Re: EP53A Gain Set Adpater

Brenda
 

Hello everyone! I have actually managed to find a EP53A! It's in very nice condition other than some of the "fingers" are a little black. I was able to take this apart as I wanted to make sure that the capacitors and the resistor was still good and within tolerance. There were 2 .1uf capacitors marked GOOD-ALL, and I was able to test them for leakage with my version of Mr. Carlson's capacitor leakage tester. The value was also well within tolerance. The 220K resistor is another story. That resistor is way out of tolerance which was 10% at 299K, so that must be replaced. I have looked at previous posts and have gotten myself all confused about types of resistors to use. I do have 220K 1/2W resistors that are carbon film, would these be okay to use?


Re: Tektronix 466 Probe Recommendation.

Roy Thistle
 

Hi: I found the "Tek Scopes and Vertical Amplifiers to Tek Probes Cross-Reference" pdf at
http://w140.com/tek_probe_crossref_1990
the link at
http://w140.com/tek_probe_crossref_1990.pdf.Another
reports "Missing." with Firefox.


Re: Extender on eBay looks like 7000 series? 3 available

John Griessen
 

On 4/26/20 4:04 PM, John Williams wrote:
More extender kits for 7000 series on eBay:
https://www.ebay.com/itm/TEKTRONIX-067-0589-00-7000-Series-Plug-In-Extender-substitute-IN-KIT-FORM/324147508439?epid=1801597927&hash=item4b78b274d7:g:apgAAOSwmcRepe-x
I approve of this kit and am officially out of the flex extender business now, except to sell of my RG274 coax cables I have left to any one wanting, and a stack of pcbs I have if anyone wants them. His kit has no coax, but you can cut trace and add it. He's found a good looking 38x2 connector for the female. Using CNC and bare 2 sided FR4 is a fine innovation that lets him skip the PCB fab steps and offer low effort of kit assemble compared to soldering 60 24 gauge wires.

Maybe he'd sell his connectors separately to use with my PCBs to make flex extenders?
But a rigid extender is such a small amount of assembly time it is the lower total cost of ownership.

--
John Griessen


Re: Extender on eBay looks like 7000 series? 3 available

John Williams
 


Re: Tektronix 2235 no horizontal sweep

Reddy
 

I have had several 2235's come thru that have had the deflection wires unplugged or just resting on the connector. They are the wires that are half way down the crt and one set comes up from the bottom and another from the side. The wires are quite stiff and will look like they are connected, but sometimes they just vibrate down over time. All 2200 series I check these wires whenever I open them. Wish you luck.

-----Original Message-----
From: baloyan <baloyan@...>
To: TekScopes <TekScopes@groups.io>
Sent: Sun, Apr 26, 2020 12:45 pm
Subject: [TekScopes] Tektronix 2235 no horizontal sweep

Hello Everybody, Just joined this discussion group. I am learning electronics, reading here there, watching videos.. Trying to fix faulty audio equipment; troubleshooting. I start purchasing some test equipment for this task and that included Tek 2235 oscilloscope.
Scope was cheap because it it has ONLY "one" problem (as per guy who sold me). It was listed no horizontal sweep on left side. I was hopping maybe something with PS, but no.. And after troubleshooting more I find out that I have no Ch1 as well ...  :'(
Can someone help me find out where is this problems maybe coming from, (tube looks ok)?
I checked all voltages on TP they are fine, was trying to do reverse by adding signal on the Ch1 and see where it gets lost, but fist stage U10 is buried under 3 PCBs, I don't even know how to check TP there ...
If I move the horizontal position pot wile holding "beam finder" dot does move left side of the screen

PS: I was able to fix missing Ch by moving calibration pot on calibration board.. sprayed Deoxit and channel came back up.

Thank you


Re: 577 Device Under Test Interlock Switch

 

Hi David,

It looks like Tek put a black plastic plug in the hole where the switch
would have been on your front porch. So you could easily open up your 177
and add a push button override switch, or a single pole ON-OFF-MOMENTARY
toggle switch like the C&K 7207P3DZQE (125VAC Paddle Lever for comfort that
I used) to eliminate the need to repair the plastic safety cage.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
Berlind
Sent: Friday, April 24, 2020 11:56 AM
To: TekScopes@groups.io; Dennis Tillman W7PF <@Dennis_Tillman_W7pF>
Subject: Re: [TekScopes] 577 Device Under Test Interlock Switch

In case you don't have a 577/177 handy to see what this looks like, I took
pictures of the front porch on mine. They show the tooth on the plastic
cover and the safety button that it engages on the porch's frame. I don't
have the push button for disengaging the switch. I must have a newer model.

https://photos.app.goo.gl/6BJLee5k8PhqJvrP8

On April 24, 2020 2:29:56 PM "Dennis Tillman W7PF" <@Dennis_Tillman_W7pF>
wrote:

Since the 577 device interlock switch came up in a recent post I
thought I would mention a minor change that was made to the 177 "front
porch", probably by Tek corporate lawyers, to protect the company from
lawsuits.

To test a part at collector voltages higher than 100V the part had to
be under a protective plastic cover that activated a safety switch
with a small tab that was part of the safety cover.

This safety cover was a good safety feature in principle if the curve
tracer was used by inexperienced users on a production line for
example. But to a design engineer the safety cover was extremely
inconvenient. Usually something would be jammed into the hole to
disable the safety feature permanently so the safety cover was no
longer needed. At this point the safety cover would be placed
somewhere for safe keeping, and it would never be seen again.

If I am not mistaken the original 177s had a small momentary push
button switch below and to the left of the Left - Off - Right toggle
switch. This push button over rode the safety feature. This way there
was no need to jam something in the hole to disable the safety
feature. That push button was a good solution but it disappeared on later
177s.

I replaced the momentary push button on the 177 I currently use with a
small
3 way center off toggle switch. In the down position the safety
feature is disabled. In the center position it is enabled. In the up
position which is momentary the safety feature is disabled for as long
as I hold it up. The advantage of this arrangement is that under
occasional use of high voltages I hold the toggle up with my finger
for a few seconds to disable the safety feature and as soon as I am
finished and let go the safety interlock is activated automatically.
When I am testing a lot of HV parts I flip the toggle down where it
stays. When I am done, as long as I remember to flip it back to the middle
the safety interlock will be activated again.

That's the catch. Yes, I have forgotten to flip the toggle back to the
middle and I have gotten bitten because of it. That works to remind me
for the next few months to flip the toggle back to the middle.

Dennis Tillman W7pF








--
Dennis Tillman W7PF
TekScopes Moderator


Re: 577 Device Under Test Interlock Switch

Chuck Harris
 

I am sure that the crack in no way affects the security cover's
ability to perform its primary purpose as a container for the odd
screw, transistor adapter, or other doo-dad... ;-)

-Chuck Harris

Robert Shank wrote:

Thanks, David. My 577 front porch security cover has a crack in the same place as yours :)




Re: Low Vertical Trace On 2465B

Chuck Harris
 

Where is the readout displayed? (Is that what you mean
by "... along with the measurement output..."?

If everything, including the readout is shifted downwards,
there are a couple of usual causes:

1) deflection plate connection has come undone.
2) there is a trimmer pot for adjusting the vertical centering...
and another for the vertical amplitude.

Unless someone has been monkeying around in your scope, the
pot could go bad, and shift things in such a way. Or, someone
could have given it a spin thinking they were adjusting something
else..

What about this baffles you?

-Chuck Harris

Singerj181@... wrote:

I'll be posting a photo on here shortly but I have a Tektronix 2465B that has the entire trace for all four channels along with the measurement output shifted down an entire division. I have read that this could be a u400 problem. Could this be the case? I would love to have some input before I spend the money to get a replacement u400 Hybrid channel switch. Personally this problem rather baffles me so more input would be great.




Re: Tektronix 2235 no horizontal sweep

chipbee40
 

Short Timebase sweep is often caused by the tube connection being loose. Look under the tube midsection, there are 2 wires to pins on the tube, CAREFULLY push them on. Intermittent timebase scan is usually R740 on the timebase board, replace it. If the A timebase is bad, usually the B timebase will also be bad, R730 (1K pots if I remember correctly) . Loss of CH1/CH2 is as you found intermittent balance pots, a drop of deoxit and rapid operation usually cures. Redo the balance after, its easy enough.


Tektronix 2235 no horizontal sweep

paronaram
 

Hello Everybody, Just joined this discussion group. I am learning electronics, reading here there, watching videos.. Trying to fix faulty audio equipment; troubleshooting. I start purchasing some test equipment for this task and that included Tek 2235 oscilloscope.
Scope was cheap because it it has ONLY "one" problem (as per guy who sold me). It was listed no horizontal sweep on left side. I was hopping maybe something with PS, but no.. And after troubleshooting more I find out that I have no Ch1 as well ... :'(
Can someone help me find out where is this problems maybe coming from, (tube looks ok)?
I checked all voltages on TP they are fine, was trying to do reverse by adding signal on the Ch1 and see where it gets lost, but fist stage U10 is buried under 3 PCBs, I don't even know how to check TP there ...
If I move the horizontal position pot wile holding "beam finder" dot does move left side of the screen

PS: I was able to fix missing Ch by moving calibration pot on calibration board.. sprayed Deoxit and channel came back up.

Thank you


Re: 577 Device Under Test Interlock Switch

Robert Shank
 

Thanks, David. My 577 front porch security cover has a crack in the same place as yours :)