开云体育

Hi jeff....if you can email me a photo or so of your vertical board to my personal email I can see whether the 465 I bought ...incorrect board for my 425M...but same fascia...It may not be worth the postage even if useful to you but that's all I'd ask. It has no attenuator knobs but the time base is also available if useful and cost effective, as I'm in Australia. Someone over your way may do better. My Regards

I got the distinct feeling that the stuff I am working on has been gone through. It dawned on me it was, by me ! But it also was before me. this is one we set aside a couple years ago to get a few other things done.

This one had no trace. The -8 supply was out with a shorted bridge rectifier which I took care of and still no trace except for in beam find. This one was a bit scary because it kinda looked like one of those unobtanium ICs might be bad. Luckily they weren't.

So as I get the weird ones as usual, I find the beam is banked of course and set out to find out why. I am not finding much so then I started unplugging things, one was a short. It was the chop banking from J349. The little wire on the end was bent over and shorting to ground. I corrected that and I got channel 2 but not 1. The symptom set was initially a bit confusing because in XY there was no spot and I know it unblanks on that setting. It was deflected (far far) off screen.

So looking around I had no choice but to just go through the stages, it had high DC offset so I was looking for that. Well I found it. One of the diff pair was missing, Q182 to be exact. I temporarily replaced it with a 2N3906 and she worked.

I would rather have the right transistor in there, it calls for an SAB4113. Google disavows any knowledge of such a part number, at least for anything like this.

The new 2N3906 has long leads and I don't want to cut them anyway, plus I don't really want it left in there. I found a couple of transistors in an old 422 carcass which seem to work fine. However I can't be sure of their frequency response. In the manual for the 422 it says "replaceable by 2N3251". That transistor has an FT of 300 MHz which should be adequate BUT, replaceable by does not mean that's what it is. The 422 is only a 15MHz scope so who knows ?

I can confirm that it does produce a waveform at 83MHz, the highest generator I have at the time but is not suitable for aligning this. It is also not a clean sine wave and I can see odd order harmonics on it so it is confirmed to hit 200 MHz, but is the response flat ? Better to just use the right part if possible.

Thing is I know the frequency, it is obvious. Silicon, PNP all the basics but I have no idea of the gain. I think it is 200 for the 2N3251 but that again does not mean that the original transistor had that gain. Nothing indicates that it is a Darlington, they almost always mention that so I am confident it is not.

So does anyone know of a "recommended" replacement for that SAB4113 or perhaps more detailed specs so I can find one ?

Next problem is a slight overshot in channel 1, I doubt the FT is too high causing that. They wouldn't hand pick for FT would they ? I looked for things like open variable resistors or whatever that could cause overpeaking but all of them I found can only cause underpeaking if open, and they don't short. Usually...

The overpeaking is occurring on the vertical preamp board indicated by the fact that it shows up at T178. For reference I checked and it is not there at T278 which is the channel 2 equivalent, using the same input.

Now on this one I found I had to clean the attenuator. On that recent 465B there was at least one bad solder connection, the first I had ever seen in a Tek. Cleaning was not an issue.

You may remember that I need the attenuator for the 465B because the PC foils are not in the greatest of shape. I am not all that bad at soldering but this thing did not want to cooperate, it is as if there is a contaminant on the foils that was there before the original soldering, something I HAVE seen before but not in a Tek. (the solder balled up on the pin of the /100 module)

Originally I thought the attenuator boards were not compatible. I saw the section later in the vertical which on the 465, 465M and a few other similar models does the /2 and /4 functions downstream whereas the /10 and /100 is handled right at the front end. The 475 looked like that but it isn't. It is just like the 465B except that the 2mV/div range is added. The board is the same but the cam has an extra position which leaves the main attenuator in 5mV/div but kicks up the gain later in the chain.

That means if anyone would be willing to part with that part from a 475 I can use it in the 465B.

Other than the transistor and attenuator, I would like to know if there is a way to check the frequency response. Not necessarily to align it, just to check it. I suspect it will be fine once I find the cause of the overpeaking, about which I am accepting suggestions as well. I have not turned up anything as of yet.

What the hell can give it too much high frequency response ? Maybe a filter after a decoupling coil on a power supply line ?

Any ideas on that are welcome. In fact I have other ones with not so perfect response and eventually I would like to see all them perfect as well, whether they are to be sold or kept.

Thanks in advance.

On Sat, 17 Nov 2018 22:53:21 -0500, you wrote:

“Look at HP's Benchview”

Does it only work with HP instruments? It seems I looked in to Agilent or
Keysight bench software and every module was something like $750. Want to
control the 33250a? $750. What to get voltage readings from the 34401a?
$750., etc.,

Well, THAT is off the list. At the time it was introduced, I was told
that it was (more or less) free, and that you could define your own
instrument.

Guess I'll just write my own for what I need to do, sooner or later.

I'll keep looking.

Harvey

On Sat, Nov 17, 2018 at 1:13 PM Harvey White <madyn@...> wrote:

On Sat, 17 Nov 2018 01:24:45 -0500, you wrote:

“

Thanks I am interested in that. Do you know about how much Labview would
cost to get started?”

Look at HP's Benchview, it was free the last time I looked and you may
be able to define instruments.

Harvey

I just looked in to Labview tonight. $3000! Wow, I know it’s a great tool,
and probably easier, and more versatile, to program in than VBA, or VB6,
but $3000? I’ll stick with manually writing my own test software VBA ( I
actually prefer it, because databasing collected data is a natural with
Access/VBA). Screw. Shots through a utility like OpenChoice Desktop and
GPIB is quite good. You grab a screen shot and paste it in to your
Calibration document in Word. OpenChoice. I do love my TDS3032s for that.
They are getting old too.

Dave

“Look at HP's Benchview”

Does it only work with HP instruments? It seems I looked in to Agilent or
Keysight bench software and every module was something like $750. Want to
control the 33250a? $750. What to get voltage readings from the 34401a?
$750., etc.,

“Trying to use Matlab from now on.Probably I will try Python to control my
instruments in my garage lab at some point“

I’m not familiar with either one. I use VBA/VB and write controls modules
for each instrument I use.

My unstanding with something like labview, you tell it you want PP data
from the scope. It matters not what brand or model of scope, it knows how
to talk to any scope.

My method is not so easy.

Dave

@ Dave - here is the channel link -

--
/Rajesh

On Sat, 17 Nov 2018 11:52:21 -0500, you wrote:

Thanks, I'll give it a try, standard PLA and we'll see what the
settings may do.

I have a modeled (and working) design for the TM5000 latches and pull
tab.

Harvey

On Thu, Jan 11, 2018 at 9:19 AM Siggi <siggi@...> wrote:

Hey Rick,

I 3D modeled the two parts for these latches and did a couple of test 3D
prints. The models are fine, I think, but the printers and materials I have
access to don't make useful parts at this scale. The dimensions are off and
the strength isn't up to snuff. This may simply be due to my overabundance
of thumbs when it comes to 3D printing - I may not have sufficient
tolerance for fiddling with the print settings :/.
I uploaded the models to ShapeWays, which will do dimensionally accurate
prints with excellent strength, though I haven't tried printing them yet.
The PCB bracket I modeled for FG504 <

has held up well, and I know others have bought prints.

I can send you my models if you'd like to try printing some yourself, or I
could make the Shapeways models available for general use. Shapeways
per-part price comes to $1.63 and $1.73 per lock button and swivel piece or
$3.63 for the pair. I'd guess by modelling e.g. 5 pairs of pieces in a
single model the per-item price might come down a bit.

I got a query about these, so I finally got off my derriere and made the

models public on ShapeWays:




ShapeWays wants $5 a piece, which seems pretty dear. I wonder if modeling
sets of these strung on a runner would make them less expensive each. I
believe the originals were independently injection molded, and printing
these on a runner would leave a blemish where the runner had to be cut off.
Also note that I've never printed these, so YMMV.

If you want to play with the model, then here's a Fusion 360 link:
. This is converted from the original FreeCad model,
which means the construction details of the bodies has been lost. Wonders
of file formats...

Siggi

On Sat, 17 Nov 2018 01:24:45 -0500, you wrote:

“

Thanks I am interested in that. Do you know about how much Labview would
cost to get started?”

Look at HP's Benchview, it was free the last time I looked and you may
be able to define instruments.

Harvey

I just looked in to Labview tonight. $3000! Wow, I know it’s a great tool,
and probably easier, and more versatile, to program in than VBA, or VB6,
but $3000? I’ll stick with manually writing my own test software VBA ( I
actually prefer it, because databasing collected data is a natural with
Access/VBA). Screw. Shots through a utility like OpenChoice Desktop and
GPIB is quite good. You grab a screen shot and paste it in to your
Calibration document in Word. OpenChoice. I do love my TDS3032s for that.
They are getting old too.

Dave

On Thu, Jan 11, 2018 at 9:19 AM Siggi <siggi@...> wrote:

Hey Rick,

I 3D modeled the two parts for these latches and did a couple of test 3D
prints. The models are fine, I think, but the printers and materials I have
access to don't make useful parts at this scale. The dimensions are off and
the strength isn't up to snuff. This may simply be due to my overabundance
of thumbs when it comes to 3D printing - I may not have sufficient
tolerance for fiddling with the print settings :/.
I uploaded the models to ShapeWays, which will do dimensionally accurate
prints with excellent strength, though I haven't tried printing them yet.
The PCB bracket I modeled for FG504 <

has held up well, and I know others have bought prints.

I can send you my models if you'd like to try printing some yourself, or I
could make the Shapeways models available for general use. Shapeways
per-part price comes to $1.63 and $1.73 per lock button and swivel piece or
$3.63 for the pair. I'd guess by modelling e.g. 5 pairs of pieces in a
single model the per-item price might come down a bit.

I got a query about these, so I finally got off my derriere and made the

models public on ShapeWays:




ShapeWays wants $5 a piece, which seems pretty dear. I wonder if modeling
sets of these strung on a runner would make them less expensive each. I
believe the originals were independently injection molded, and printing
these on a runner would leave a blemish where the runner had to be cut off.
Also note that I've never printed these, so YMMV.

If you want to play with the model, then here's a Fusion 360 link:
. This is converted from the original FreeCad model,
which means the construction details of the bodies has been lost. Wonders
of file formats...

Siggi

What is your channel?

--
Dave
Manuals@...
www.ArtekManuals.com

On Wed, Nov 7, 2018 at 08:11 PM, Rajesh VS wrote:

I am afraid that it is my channel & video.

Well I liked it. Good job!

--I haven't checked but I am assuming the 7834 reduced scan is the same as the 7934. It works by doubling the cathode voltage on the CRT so that the deflection sensitivity in X and are each reduced by a factor of two. In normal scan you would have had a substantial overscan that you can confirm with the horizontal position control on the timebase. I don't --suppose your timebase is in X10 expansion is it?

--Roger

Hi Roger,

thank you for your advice the relay K2014 was not switching, bad solder joint.

Best regards,

Fred S.

I'd say the thermal trip would be the most likely candidate (statistically-speaking!)
John

Yeah, Labview is easy to get a project started but not so easy to support.? We have a ton of Labview code at work, and it's a nightmare to change anything.? Trying to use Matlab from now on.Probably I will try Python to control my instruments in my garage lab at some point.Good luck!Jim FSent from my Verizon, Samsung Galaxy smartphone

“

Thanks I am interested in that. Do you know about how much Labview would
cost to get started?”

I just looked in to Labview tonight. $3000! Wow, I know it’s a great tool,
and probably easier, and more versatile, to program in than VBA, or VB6,
but $3000? I’ll stick with manually writing my own test software VBA ( I
actually prefer it, because databasing collected data is a natural with
Access/VBA). Screw. Shots through a utility like OpenChoice Desktop and
GPIB is quite good. You grab a screen shot and paste it in to your
Calibration document in Word. OpenChoice. I do love my TDS3032s for that.
They are getting old too.

Dave

“Do you actually have a 2430, or is it a 2430A? For a 2430A, you can
request an HP/GL screenshot by ”

I’m not in the shop right now, but I’m fairly certain it’s not an “A”.

I’m probably going to private sell this or eBay it. It works pretty good,
but I don’t have time anymore to hobby a scope. I would have loved this
scope 20 years ago. If anyone is interested PM me an offer. It would cost
$30 to have it double-boxed and then whatever the UPS or FedEx ground rate
is. It’s heavy do I would guess ~$50 shipping. With $80 shipping, no one is
going to want to pay. If you what you can get from Siglent for $380 and
no-cost shipping, who would want a 2439?

Have a good weekend everyone!

Dave

I have some sets of matched germanium diodes [sets of 4] if you can not find a matched pair.
Not sure of ratings have not had a need to use them. but if you need I can send.
Garth.

If the replacement attenuator works acceptably, I’ll use it. If not, I’ll pull the bnc from the new one and use my existing attenuator. Appreciate the suggestion re the possible source, though.

When I got this scope, for free, about two months ago, the ch 1 bnc was covered with duct tape and the statement that channel 1 didn’t work. Since then, I have visually inspected all of the caps, blown out the dust, verified the lvps voltages as correct and determined that the channel 1 issue seems to be cured by chilling U600. I suspect an intermittent terminal on U600 and will clean those contacts. All channels now work correctly, and the calibration seems pretty good still. Just working on the probe sensor ring and planning a future re capping right now.

This forum has been a great resource for me.

Thanks again for the offer re the bnc.

Greg

Just follow the AC in and check for it at each obvious point, if it gets to the main transformer, follow it on the secondary side to the full wave bridges, and so on.
This should be a simple fix...
tom jobe...

On Fri, Nov 16, 2018 at 2:22 PM Michael Wyatt via Groups.Io <microwyatt=
[email protected]> wrote:

Posted pics of the circuit
IMG_0760.JPG and IMG_0761.JPG

Album for posterity: /g/TekScopes/album?id=78665.