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Re: Viewing hoods for 7000 series

Steve Wiseman
 

It doesn't matter what software you use if your print bed isn't big
enough.

Not 100% true - some slicers let you split the model and add holes and pegs
to the individual parts to let you slot them together, or align them
accurately while the glue sets.
A too-small printer is only an irritation, not a showstopper.

Steve


Re: Model for digital inputs on more or less recent scopes

Sebastian Garcia
 

Jean-Paul,

Thanks but, may you be confused? I'm asking about the digital channels
D15..D0.

After some time of searching found it in an appendix of the user manual;
seems to be 100 kOhm in parallel with 3pF for the P6616 probe.

Sebastian.

On Tue, March 10, 2020 7:20 am, Jean-Paul wrote:
1 m or 50 ohm in parallel with input capacitor e.g. 20 pf.

Same as for analog scopes

Jean-Paul


Re: 466 Repair advice

 

Hi Earl,
The 466 is a very nice analog storage oscilloscope. Unfortunately, I don't have the time at the moment to assist. There's one advice though:
Make sure the brightness of the screen is not too high at any time. Storage CRT's produce less light than non-storage ones and can be burnt much more easily.

Raymond


Re: Ringing on 2235 100 volt supply

 

Hi John,
Happy that your 2235 is fine again. PSU problems can be nasty with these series but mostly it's flaky contacts, including adjustment pots, as in your case. Good that you found the flaky plate connection, since damage will be done if amp outputs touch e.g. a grounded point.
Thanks for letting us know what was wrong and how things went.

Raymond


Re: Model for digital inputs on more or less recent scopes

Jean-Paul
 

1 m or 50 ohm in parallel with input capacitor e.g. 20 pf.

Same as for analog scopes

Jean-Paul


Re: Viewing hoods for 7000 series

Jean-Paul
 

Hello all,
Seems easier to find the exact hood on epay, just needs patience.
I have acquired several of the 2465, 2467 and 7000 hoods years ago. then, I discovered that the old Polaroid Tek cameras can be Disassembled and the plastic housing used as a hood or to position a compact camera or mobile phone. Just a thought

Jean-Paul


Re: Viewing hoods for 7000 series

EJP
 

The outside dimensions of the SC504 screen frame are 3.25"W X 2.75"H.

It doesn't matter what software you use if your print bed isn't big enough.

EJP


466 Repair advice

Earl Stirling
 

A friend of mine gave me a 466 which seems to be in pretty good shape, though he said it "stopped working" recently.

I'm pretty familiar with digital scopes, this is my first analog, so I'm trying to learn the differences, and I'm willing to read lots, but was hoping you folks might have suggestions about where to look.

There are (at least) two symptoms:
-When I push in the REDUCED SCAN knob the dot slowly fades away.
-Also, the REDUCED SCAN LAMP never lights up when the knob is out.
-The INTEN knob is hard to turn... feels like it's a bit bent, corroded or perhaps needs lube
-No sweep. When I set it to a 'Normal Sweep Display' setup and hook a probe up to the CALIBRATOR loop, or set it to follow the line voltage, I just get a one short line.

I'm a pretty capable engineer, but definitely not a EE, so I'm hoping someone might take a moment to point me in the right direction. I can read a schematic, though slowly, I'm an accomplished solderer. I have another digital (Tek MDO) scope as well, and couple probably borrow a function generator if necessary.

Thanks in advance...

Earl


Model for digital inputs on more or less recent scopes

Sebastian Garcia
 

Hi there,

I'm wondering what's a proper electrical model for the *digital* input
channels on the MSO scope line (e.g., for the MSO4104).

Any comment will be greatly appreciated.

Thanks in advance,
Sebastian.


Re: Ringing on 2235 100 volt supply

John G
 

Hi Raymond,
It turned out to be a dirty R740 "A Sweep Gain" adjustment. I had a scope probe on both sides of it when it failed so I'm 99.99% sure that was it.
I did also have a flaky connection to the horz plates as you mentioned.
Thanks for your help!
John


Re: Viewing hoods for 7000 series

Harvey White
 

You may want to consider openSCAD, a very different tool that avoids on-line connections.  It's a programming/modeling tool, so you'll need to be able to program.  It's free.

Harvey

On 3/9/2020 11:55 AM, Mlynch001 wrote:
I use TINKERCAD, which is online, free and easy to use; in order to design items that can then be printed directly on a 3D printer. If you have the dimensions for the screen frame it is relatively simple to generate an STL using TINKERCAD that will allow you to print the model in one piece.


Re: 2465 U950 Z AXIS IC Chip 155-0242-01 Fails After Re-installation

Chuck Harris
 

Being as you are talking about a 2465 power supply ripple,
there is a change order for the power supply (B013900) that
reduces ripple on the 87V supply greatly. They left off a
0.1uf cap, later identified as C1222, that surrounds the
emitter and collector of C1222. It is shown on any schematic
you are likely to find.

Also, many 2465's have capacitors in the power supply that
are well beyond their sell by date. Replacing all of the
100uf caps on the regulator board lowers noise, as does
replacing the 180uf 40V, and 250uf 20V caps on the inverter
board (I use 330uf, 50V for both the 180uf and 250uf...).

There are lots of descriptions of how to perform this task,
and information on selecting the proper capacitors on this
message board... some of them by me.

Scopes with bad z-axis hybrids are showing up more and more
these days. Before you condemn your hybrid, first give it
a drop of deoxit on each pad of the hybrid, and reinstall.
Sometimes you get lucky.

When reinstalling the hybrid, you need to press it down
fully by hand (and hold it) while you put nuts on a
diagonal pair of studs. Overtightening the nuts does not
improve contact! They need to be just contacting, plus
1/4 turn, no more... just enough so the lock washers bite
in a little bit.

-Chuck Harris

Don N3DEB via Groups.Io wrote:

Update. Had some room on my bench and opened this up again.

The U950 wave forms are quite dirty/noisy compared to my good 2465.

Low voltage power supply voltages are all in spec, but P-P ripple is about double the spec on +10, +5, and triple on -15V.

Change PS caps before going further? Or continue looking at the Z-Axis circuit?


Re: TM500/TM5000 extender project

Ke-Fong Lin
 

"The handle offer correct grip"


Re: TM500/TM5000 extender project

Ke-Fong Lin
 

Hi everyone,

The PCB came back today from JLCPCB. With the covid-19 it may have been a week or so later than expected, but here they are!
I've add a new photo: https://groups.io/g/TekScopes/photo/239639/0?p=Created,,,20,2,0,0

I've done some quick test, the PCB edge connector fits properly in my TM503. I would need to check my TM5003 but I guess it won't be a problem.
The edge pads are a bit longer than needed, this may be due to the 1.2mm allowance for chamfer, or may be because I've also taken as reference 5000 series scope plugins, which have longer pads than TM500/TM5000.
The solder pads for the extending cables have quite tight tolerance, 22AWG fits closely, no floating expected during soldering.
The handle is quite tight, I can barely fit my fingers and my hands are small. But offer correct great and it may just be adequate enough.

Except from a few scratches, the quality from JLCPCB is good, especially the through hole platings, not much to say about.

Plan is to do the thorough testing this weekend: Both as extender and "debug" device with a bench power supply.
And when stuff is confirmed working, release v1.0 on github.

I've received 5 prototypes PCB, if some of you wanna try and help me debug. I can send you one for cost of shipping.

Best regards,


Re: 2465 U950 Z AXIS IC Chip 155-0242-01 Fails After Re-installation

KeepIt SimpleStupid
 

Aside (Upside down stuff):
Don't ask me how it happened, but the VERY FIRST SMD I replaced was a 40 pin CPU without the proper tools.  I cut the pins and removed the IC and cleaned up the solder.  I got some 63/37 solder which was new to me.  Tacked the corners.  Turned it upside down and dragged the solder across the pins.


On Monday, March 9, 2020, 2:14:56 PM EDT, Craig Cramb <@Manfromtrane> wrote:


I am a hobbyist, not a tech so once the troubleshooting exceeds the service manual steps the challenge ramps up for me.
Maybe if time and ability are an issue. Purchase a reconditioned PS from a member.

Craig
On Mar 9, 2020, at 11:46 AM, Don N3DEB via Groups.Io <dbawatsonville=yahoo.com@groups.io> wrote:

On Sun, Mar  8, 2020 at 11:54 PM, Robin_Birch wrote:

G5HI
I was wondering if the ripple is off enough to cause the problem, or is it just annoying sideshow. I just finished a 465B recap that went well, but I am hesitant to take on another recapping project and then not be able to solve the display problem. I am a hobbyist, not a tech so once the troubleshooting exceeds the service manual steps the challenge ramps up for me.


Re: 2465 U950 Z AXIS IC Chip 155-0242-01 Fails After Re-installation

Craig Cramb
 

I am a hobbyist, not a tech so once the troubleshooting exceeds the service manual steps the challenge ramps up for me.
Maybe if time and ability are an issue. Purchase a reconditioned PS from a member.

Craig
On Mar 9, 2020, at 11:46 AM, Don N3DEB via Groups.Io <dbawatsonville=yahoo.com@groups.io> wrote:

On Sun, Mar 8, 2020 at 11:54 PM, Robin_Birch wrote:

G5HI
I was wondering if the ripple is off enough to cause the problem, or is it just annoying sideshow. I just finished a 465B recap that went well, but I am hesitant to take on another recapping project and then not be able to solve the display problem. I am a hobbyist, not a tech so once the troubleshooting exceeds the service manual steps the challenge ramps up for me.


Re: 2465 U950 Z AXIS IC Chip 155-0242-01 Fails After Re-installation

Don N3DEB
 

On Sun, Mar 8, 2020 at 11:54 PM, Robin_Birch wrote:


G5HI
I was wondering if the ripple is off enough to cause the problem, or is it just annoying sideshow. I just finished a 465B recap that went well, but I am hesitant to take on another recapping project and then not be able to solve the display problem. I am a hobbyist, not a tech so once the troubleshooting exceeds the service manual steps the challenge ramps up for me.


Re: Viewing hoods for 7000 series

Mlynch001
 

My printers will print up to 225x225 x240 items. SC 504 looks like it has a similar screen frame to the 485, but I don’t have a SC 504 to measure.

--
Michael Lynch
Dardanelle, AR


Re: Viewing hoods for 7000 series

Mlynch001
 

I use TINKERCAD, which is online, free and easy to use; in order to design items that can then be printed directly on a 3D printer. If you have the dimensions for the screen frame it is relatively simple to generate an STL using TINKERCAD that will allow you to print the model in one piece.
--
Michael Lynch
Dardanelle, AR


Re: Ringing on 2235 100 volt supply

 

On Mon, Mar 9, 2020 at 04:12 AM, John G wrote:


Table 6.4 in the service manual shows 40.0 P-P Ripple (mv) as the limit on the
+100 V supply. I see about 90 mv P-P as pic 1 shows. Scope set at 20mv per
div.
Hi John,
So it's 40 - 90mV. That sort of ripple won't cause your (or any) real problem.
More often than not, it's just a loose or oxidized wire connecting the horizontal amp to the CRT. You'll find the connections underneath the CRT. Be careful not to short any to gnd (that includes the CRT's screen); it'll kill the amp.

Raymond