Re: 2246 no display/odd behavior
Take note of where the grid bias R2719 is currently set by following the setup in the manual. You will do this in XY mode. See if you can get a dot displayed.
I agree that all the power supply rails look good.
The battery can be any 3.6 volt lithium cell with leads just for a test.
Good luck and regards
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2465B Parametric Freq Measurement Error
After successfully calibrating my 2465B, it reports "All tests passed" on start up. The question marks are all gone! My issue is with the parametric measurement of frequency. When I attempt to measure the frequency of a sine wave at frequencies higher than 10 MHz, the scope reports the frequency as 35.62 kHz. Any test frequency above 10 MHz gets the exact same report, 35.62 kHz. Below 10 MHz, it reports various incorrect values (i.e. a 4.89 MHz signal is reported as 6.35 MHz). At about 500 kHz and lower frequencies, the scope reports the correct frequency. I have replaced the PAL at U975 - no change. Any suggestions?
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My TDR Evaluation of the SG503 012-0482-00 Cable has been uploaded
I uploaded the results of my testing the SG503 012-0482-00 cable. In addition I compared it to two other similar cables: a Tektronix 012-0057-00 50¦¸ cable, and a Pomona Electronics 50¦¸ cable. It is located at: /g/TekScopes/files/Evaluation%20of%20the%20Tektronix%20012-0482-00%20cable%20for%20the%20SG503.pdf Dennis Tillman W7PF
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2246 no display/odd behavior
Ok. I've removed the battery - have a new one on order. When reassembling I found that J2208 was installed backwards initially. Corrected but no change in behavior. All further testing is done with the battery removed:
Exact voltages:
+131.34
+58.201
+15.052
+7.4913
+5.2186
-5.2245
-7.5541
-16.005
These all seem to be in spec.
I have a 6kV probe on order - should be here in a few days. I will probe the HV line at that point.
Beam finder does nothing. There is no display at all - no text, no beam. No change whether the front panel is powered up or not.
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Ok, compared the RG-58 Tektronix cable to an RG-400 I built of similar length.
At 200Mhz and 4Vpp (x1 amplitude) we have ....
The OEM Tektronix cable clocked in at 0.20 dBm low.
DIY RG-400 cable was only 0.01 dBm low!!
Now B4 you guys roast me over the Boonton 4210 microwattmeter with the 4210-4B sensor....
I make no claims, infer from the results what you will (expect 1.5% accuracy from the Boonton).
But...I feel pleased that the SG 503 combined with a RG-400 cable and the Boonton show what could be a nearly perfect output.
I must mention that I recently serviced the SG 503 using liquid de-oxit on the rotary frequency selector contacts and polished the brass nut and seat contact point on the variable tuning capacitor.
~A
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Re: 2246 no display/odd behavior
How can you edit a post on this system?
Anyway-
Have you replaced the battery yet? Should do that first and reboot the scope several times to get the ram initialized.
Pay attention to the adjustments section, especially the power supply and beam (grid bias) adjustments.
What are the _exact_ low voltage measurements?
The ripples shown on your pictures all look good.
Can you measure the -2.7 kV line safely? That can be accessed by looking at the cathode or filaments on the CRT.
Does the Beam finder button do anything?
Regards
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2246 no display/odd behavior
Ok so some updates:
I haven't found any previous posts that address my issues.
All voltages on the low side are in spec. Looking back at the ripple measurements in my first post I think they are all OK but a second set of eyes would be helpful. The p-p measurements seem high but there are very few points. The bulk of the points seem within the specs but there's some pronounced waveforms there that I don't know about being allowable.
I checked the ESR for all the electros on the power supply board - everything looks good (I used the Blue meter and tested in-situ).
Under the board I found a broken (lifted?) trace between C2244 and R2231. See here: I ran a jumper and re-assembled and no change in behavior. Still not display apart from a brief flash at power off and still the off behavior from the front LEDs where they don't power on unless I fiddle with the buttons.
There is a RIFA cap C2217 that looks a bit rough but not blown. I'm open to further suggestions or testing approaches. Still not sure if the two problems may be related or which I should focus on first. FWIW I can now get that PSU in and out in about 10 minutes flat... practice :D
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Re: Powering up a 577 for the first time
The 577 used one of the Tek custom potted SMPS transformers if my memory is correct. Next to a tube failure, that is your biggest worry.
I agree with others.
Clean, repair power cord, fuse, power, debug any failure.
There are quite a few threads here on fixing a577.
Keep us up to date.
Sent from kjo iPhone
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Re: Powering up a 577 for the first time
I think a good visual inspection followed by the use of an ohm meter would be my first plan. Then repair the cord and install the correct fuse. If you have an ESR meter, check the bulk capacitors and replace as necessary.
Power it up directly and measure the power rails next. I usually follow the performance section of the service manual as it will show you what works.
Calibration would be your next step and lead you to any troubleshooting that might still be needed.
Good luck and nice find with the cover still there.
Regards
toggle quoted message
Show quoted text
On 4/27/2019 6:35 PM, groups@... wrote: All,
While I was searching eBay for a transistor adaptor for my 576, I came across a parts 577 in good condition with both the adaptor and an original safety cover for a low price... and ended up snagging it, too.
It was advertised as not powering up - and on closer inspection, the power cable's strain relief is loose, and there's no fuse present. I can obviously fix both, but I'm wary of powering it up given that perhaps there's a reason the fuse is absent (although I'm comfortable checking rail voltages with suitable precautions once it's up). Any advice? Would a variac help?
Thanks,
Neil
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Re: Powering up a 577 for the first time
If you use the correct fuse then the fuse will protect the equipment. If the fuse blows then you need to go into troubleshooting mode.
toggle quoted message
Show quoted text
On April 27, 2019 4:35:59 PM MDT, groups@... wrote: All,
While I was searching eBay for a transistor adaptor for my 576, I came
across a parts 577 in good condition with both the adaptor and an
original safety cover for a low price... and ended up snagging it, too.
It was advertised as not powering up - and on closer inspection, the
power cable's strain relief is loose, and there's no fuse present. I
can obviously fix both, but I'm wary of powering it up given that
perhaps there's a reason the fuse is absent (although I'm comfortable
checking rail voltages with suitable precautions once it's up). Any
advice? Would a variac help?
Thanks,
Neil
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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Re: Wanted: Earth leads with croc-clip for P6139A
I'm still wanting these if anyone can help.
Thanks
David
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of David C. Partridge Sent: 04 April 2019 18:55 To: [email protected]Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A Yes I'm in the UK. You may be able to send them quite cheaply (about ten dollars for up to 8oz) if you use a pre-paid padded envelope 1st class international mailer. Anyone closer? David -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Stephen Hanselman Sent: 04 April 2019 17:34 To: [email protected]Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A OK, I do have a bag of 6 inch long "ring" mount style and have verified them on my P6139. They have an alligator clip on the end. Are you in the UK? Shipping will be more than the cost of the clips I'm afraid steve -----Original Message----- From: [email protected] < [email protected]> On Behalf Of Stephen Hanselman Sent: Thursday, April 4, 2019 8:35 AM To: [email protected]Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A I¡¯m pretty sure I have a bundle of those I¡¯ll check when I get to the office Regards, Stephen Hanselman Datagate Systems, LLC 3107 North Deer Run Road #24 Carson City, Nevada, 89701 (775) 882-5117 office (775) 720-6020 mobile s.hanselman@... www.datagatesystems.com a Service Disabled, Veteran Owned Small Business DISCLAIMER: This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments. On Apr 4, 2019, at 06:22, David C. Partridge <david.partridge@...> wrote:
No, those are the older ones the ones I'm looking for look like this:
<>
Dave
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Colin Herbert via Groups.Io
Sent: 04 April 2019 13:13
To: [email protected]
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A
Would these do?
eads-w
ith-Alligator-Clip-Tektronix-HP/222659358233?ssPageName=STRK%3AMEBIDX%
3AIT&_
trksid=p2060353.m1438.l2649
They have a length of 7 inches (17.5 cm). I bought some a while ago
and they are fine, if possibly not genuine Tek. He also has the "witches hat"
grabbers for P6139, etc. probes. Be careful, though, as while he will
offer combined postage, eBay doesn't seem to go along with that. It
took me some time to get combined postage when I bought three items
from him. Of course, this might have improved, now.
Colin.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of David C.
Partridge
Sent: 04 April 2019 12:03
To: TekScopes
Subject: [TekScopes] Wanted: Earth leads with croc-clip for P6139A
I'm looking for the earth leads with crocodile clip to fit the P6139A
and similar probes.
I have the ones that connect to mini-grabbers, but lack the croc-clip
versions.
Does anyone have these available?
Cheers, David
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Powering up a 577 for the first time
All,
While I was searching eBay for a transistor adaptor for my 576, I came across a parts 577 in good condition with both the adaptor and an original safety cover for a low price... and ended up snagging it, too.
It was advertised as not powering up - and on closer inspection, the power cable's strain relief is loose, and there's no fuse present. I can obviously fix both, but I'm wary of powering it up given that perhaps there's a reason the fuse is absent (although I'm comfortable checking rail voltages with suitable precautions once it's up). Any advice? Would a variac help?
Thanks,
Neil
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Hello Everyone,
Thank all of you who responded to this query and Raymond in particular.? I hope that there are a few other people in the group who benefited from this discussion.? I certainly did.? My aha moment came when I saw Raymond's mention of the 25 ohm output impedance for the DUT (confirmed by the ABC's).? To summarize what I think I have learned:? Obviously capacitive loading of higher z circuits at high frequencies would be a problem with any sort of mechanical probe.? In order to be able to sell and have people be able to compare the performance of higher frequency probes, the industry(Tek) had to draw a line in the sand for comparison purposes and that was done at 25 ohms.? The typical probe impedances at rated frequency of about 500 ohms then make perfect sense as that represents somewhere around an additional 5% load on the circuit being measured.? If the user is bent on trying to measure higher impedance circuits at high frequencies, then as the younger generation says, It is what it is!
Thank you for your time and bandwidth,
Jack Reynolds
toggle quoted message
Show quoted text
On 4/27/2019 12:16 AM, Raymond Domp Frank wrote: On Sat, Apr 27, 2019 at 05:59 AM, Raymond Domp Frank wrote:
If you want to do measurements on high-frequency signals or signals with
high-frequency content, always consider using Lo-Z probes like 1:1 50 Ohm,
1:10 500 Ohm or even 1:100 5 kOhm probes. These have relatively constant
impedance and many can be made at home. Search for that on the Internet.
You may want to look for an old-fashioned Lo-Z probe like a P6056 (500 Ohm) or P6057 (5000 Ohm). Even with their standard BNC connection, they work well with your more modern digital 'scope and can be bought for little money.
Raymond
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11801 10x rise time measurement error
I just got bit by this yet again. Does anyone know if it was fixed and what ROM version fixes it?
Doing an "autoset" fixes it, but as I have not been able to identify what triggers it, it's hard to tell when I need to do an autoset again.
It is *really* annoying.
Thanks,
Reg
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Re: [Test-Equipment] Suggestions for going through Tek2465DVS/DMM?
Thank you Siggi for your email and information.
I'll work on the scope today, despite needing to assemble few computers for
my customers.....
I was working way to hard and sometimes I need to "recharge my capacitors"
with some troubleshooting I don't know anything about!
It is great to get something old working again, so it has a chance to live
for a long time - I hope.
The capacitors you are talking about are my next project, I'll test and
look over all of them, not just the "square once".
Several people had suggestions, including couple that mentioned the stuck
Beam Switch, so that is my first goal today.
You have a GREAT Weekend!
Tony
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On Fri, Apr 26, 2019 at 4:22 PM Siggi <siggi@...> wrote: Good luck,
the RIFA caps are worth replacing, especially if you're in 240V land. Make
sure you replace them with properly specified X or Y class capacitors, as
required. You can find plenty of info about what that means on the
interwebs, but I wouldn't buy those from any but reputable sources.
Those old scopes are a work of art, and the service manuals are an
education - you're in for a treat :).
Good luck,
Siggi
On Fri, Apr 26, 2019 at 12:34 PM Tony Fleming <czecht@...> wrote:
Thank you very much for comprehensive email, that is pointing me to the
right direction!
It seems to me that the Beam Switch is sticking for sure and could cause
most of my problems.
I'll try to update the videos as soon as I make some progress.
Should I also replace some of the square caps that are something like
0.006xx nF? Many people do this ASAP, since these caps are not a good
quality - despite most of the parts are very good quality.
Where should I buy the caps and other parts, if I'll need them?
I'm sure, China and eBay should not be on my list for caps - right?
Anyway, Have a great day and I'll post videos so you can see what I did and
the results that happen.
Have a great day and weekend!
Tony
On Fri, Apr 26, 2019 at 9:05 AM Siggi <siggi@...> wrote:
Hey Tony,
welcome to the group. I watched the videos you posted in another thread
detailing your 2465 CTS troubles <
>.
Here's my advice for how to proceed:
1. Get a service manual for your scope. You can download one from here <
>, or if you're not satisfied with the
scan quality you can buy a very good quality scan from Artek Manuals <
>.
2. Get familiar with the controls of your scope. Alan Wolke has a bunch
of tutorial-like videos on coupling and trigger setup and such, there's
a
list of his YouTube videos here <
>.
3. Read this document <
> on
how to troubleshoot oscilloscopes.
Now looking through your videos, I think you one problem for sure, and
possibly one more.
1. Your beam finder button sticks or glitches.
2. Something else, possibly more than one other problem.
It's very hard to reason about what the CRT is displaying while the
beam
finder is bad, but it's easy to fix. You can probably get by with isopropyl
alcohol - just squirt some into the switch and work it several times.
If
that doesn't do it, get yourself some kind of contact cleaner (Deoxit
D5
is
what I use), and clean the switch with that.
What makes me think that you may have a second problem is the fact that the
readout would sometimes shrink only in the horizontal, but it's possible
that this is simply due to a high-resistance beam finder switch, so fix
that first.
Once the beam finder switch is good, it's possible to move forward to
diagnose whatever else is wrong, if anything. A key question I found myself
asking while watching your videos was whether the intermittent
shrinking
affects only the readout, or whether it also affects the traces.
Unfortunately I didn't see the shrinkage occur while traces and readout
were both displayed.
Note that for the traces to be displayed, your triggering controls have to
be set up right. If you set the trigger to AUTO & CH1, then set the CH1
coupling switch to GND coupling, you should be able to display all
traces
reliably.
Siggi
On Fri, Apr 26, 2019 at 1:12 AM Tony Fleming <czecht@...> wrote:
I have the same oscilloscope. It is also listed under (at least that
is
what I found today) as Tektronix 2465CTS (or 2465 CTS) .
Mine has some problems, sometimes I loose the text on top and bottom
of
the display and also the FIND BEAM gets stuck, so I don't know
exactly
where to find the solution.
Anyway, I hope your scope is working.
Tony Fleming
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Re: SG503 amplitude precision
OK, thanks for this information Dennis! I think I wanted to make sure nobody's feelings are hurt.... But I'll stop answering the emails that aren't directly related to me. This setup is very different than any other group and system or the way this group works, but I'll learn. Today I'm gonna try to unstuck the Beam Switch, since it is a must for sure. I also had few responses from my videos on YouTube channel. I love how passionate Tektronix Users are! Just wish I have space and $$ to get more Tektronix stuff. Have a great weekend! Tony On Fri, Apr 26, 2019 at 6:00 PM Dennis Tillman W7PF <dennis@...> wrote: Hi Tony,
WE ARE THE RIGHT GROUP. The members of this group, as a whole, share a
common interest in ANY and ALL TEKTRONIX instruments even though Individual
members may only own one Tektronix instrument.
You just needed to change the subject of your email, as I suggested, so
our members understand what Tektronix instrument you need help with.
No need to apologize. STOP RESPONDING to the emails whose subject is
"SG503 amplitude precision".
You can read their contents but DON'T REPLY TO ANY MORE OF posts whose
subject is "SG503 amplitude precision".
Instead start a new thread with the subject that says: "I need help
troubleshooting my 2465".
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Tony
Fleming
Sent: Friday, April 26, 2019 9:37 AM
To: [email protected]
Subject: Re: [TekScopes] SG503 amplitude precision
I'm very sorry that I emailed the wrong group!
I'm little desperate and it shows!
I hope your group will forgive me and I'll try not to repeat my mistake!
Have a great weekend!
Thank you.
Tony
On Fri, Apr 26, 2019 at 11:34 AM Dennis Tillman W7PF
<dennis@...>
wrote:
Hi Tony,
The subject line of a thread tells our 8,000 members around the world
whether this is a topic that is relevant to them.
In this case the thread is about the SG503 amplitude precision. It
makes it simple for anyone who doesn't own an SG503 to delete this
email without spending any time reading it.
When you used this"SG503 amplitude precision" topic to ask for help
with your 2465 two things happened:
1) You annoyed the members who are having a conversation about the SG503.
It is as if you are butting into a conversation among many people, you
interrupted what they were talking about, and you asked an irrelevant
(to
them) question that has nothing to do with their conversation.
2) No one who owns a 2465 is paying attention to a conversation about
the
SG503 so you will not reach the very people who can help you.
The proper thing to do is to start your own topic with a subject line
that clearly and succinctly states what you want. For example the
subject line might say "I need help troubleshooting my 2465".
So feel free to send a new email to TekScopes with a new subject line
and in the email state as clearly and succinctly as you can what the
problem is with your scope.
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Tony Fleming
Sent: Thursday, April 25, 2019 8:56 PM
To: [email protected]
Subject: Re: [TekScopes] SG503 amplitude precision
I'm new here and I'm looking for someone to help me with my
Tektronix
2465 DNS (aslo known as 2465 CTS ) I made few videos here:
about my sick scope.
Can anyone tell me where is a special group for my scope?
Thank you all for helping me and each others!
Have a great day!
Tony
On Thu, Apr 25, 2019 at 9:17 PM Rick <rpbale@...> wrote:
I may be a little late to the game but I posted this question to a
Tek expert on Youtube:
This comment/request might be a little out of scope, to calibrate
a Tek
SG503 Tek says a special cable is required, Tek part 012-0482-00.
This is an extremely expensive 3 foot 50 ohm BNC cable, $200+ on ebay.
There's a discussion going on at TekScopes@... about the need
for this cable and thought this was right up your alley for a
video. How do you make a precision application cable in the home
workshop? What is this cable doing that another 3 foot 50 ohm
terminated cable can't do? I'm a m addicted to collecting Tek 500
series plugins for my home lab and have a SG503 and would love to
make one. Thanks and love your videos.
His reply:
w2aew
I looked up the engineering specs for that cable - doesn't look
like anything super special. 012-0482-00 refers to a 36" +/-0.5"
long RG-58C/U cable with BNC connectors and strain reliefs. The
BNC connectors are to be per MIL-C-39012 spec, which basically
applies to most high-quality (reputable manufacturer) connectors,
rated to 4GHz, max insertion loss of 0.2dB at 3GHz, VSWR of 1.3:1
max with TFE insulation. Nothing super special, just a 3' 50ohm
coax made with
quality materials.
--
Dennis Tillman W7PF
TekScopes Moderator
--
Dennis Tillman W7PF
TekScopes Moderator
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Re: CRT Hood for 7000 series 'scopes?
Keep an eye out for a plastic flower pot at Home Depot.Cut or enlarge the hole in the bottom.
HankC, Boston, WA1HOS
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On Sat, Apr 27, 2019 at 05:59 AM, Raymond Domp Frank wrote:
All this is a matter of physics, not a matter of choosing the right probe to
completely get rid of the problem. You can only optimize by making the right
choices. You cannot get 10 Mohm or even 1 Mohm input impedance at high
frequencies with any regular (FET) probe.
Have a look here for something special, a bit more extreme: <> Raymond
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And a lot lower loss at higher frequencies. Loss can be
a little hard to gauge with the usual TDR.
The whole point behind the fancy tek cable is that the
amplitude accuracy of the SG503 requires the cable to be
lossless.... it isn't, but the lower, the better the
amplitude accuracy.
The SG504 reaches a range where the cable will lose a
db or two, so they put its level sensing circuitry right
at the DUT front panel connector.
-Chuck Harris
Craig Sawyers wrote:
toggle quoted message
Show quoted text
Hi Ancel, If everyone can be patient for a few hours more I will test both of those Tektronix cables on a 7S12
TDR along with a couple of commercial cables (Pomona for instance) so we can see what the
differences are in qualitative terms.
Dennis Tillman W7PF Having got one of the fancy Tek cables we've been discussing, I tried precisely that a couple of years
ago with my 7S12. I could find absolutely no difference at all between that and bog standard cables.
No distributed reflections, no connector reflection difference into a precision, wideband 50-ohm load
(the one that comes with a 1502 TDR).
The only thing that that the super-expensive Tek cable has going for it is that you can be sure that
it is going to work perfectly, and is ruggedly built.
Craig
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Ancel
David C. Partridge
Raymond Domp Frank