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Re: 495P For Sale

 

I have been asked about price several times. I am asking $650 for the 495P and $500 for the TR503.

The screen discoloration is not burn in. It is really not an issue, but I want to want it out ahead of time.

Again, comments off the list please, unless your have suggestions for repair!

Gordon, KA2NLM

--- In TekScopes@..., "gldinnc" wrote:

I bought mine used from a local reconditioner several years ago and it has had several years of light use since then.

It has three flaws (other than these, it appears to work just fine and I have enjoyed using it):

1. Just recently, the green shift key failed to respond. While I believe it should be simple to fix and someone else can probably do the work quite easily and cost effectively, it is beyond my skill level to repair the problem.

2. There is a small crack in the RF Atten knob.

3. The surface of the screen has some discoloration. This is slightly visible in pictures, but it is not apparent when using it unless you look carefully for it.

Otherwise the display is bright and clear, and the control knobs are in great shape. It comes with the operating manual on CD. I also have the companion TR503 Tracking Generator for sale.

I have pictures I can share.

I would prefer to sell via the group. Please contact me off line.

Gordon, KA2NLM
Re: 2465 - impending U800 failure?

 

Is all of this heat related? One of the first things I did when getting my 2465BDM was strap a very large heat sink to the U800 chip with good quality thermal compound and very secure mounting. It's larger then the chip. It runs just over room temperature with the case on. I measured it with a type K probe through the vents and touching the middle of the heat sink with a dab of thermal compound over a half hour or so time frame.

I do notice mine drifts a tiny tiny bit on warm up, one or two mm to the left. It later snaps back about 1mm to the right.

Jeff

On 1/20/2013 2:00 PM, victor_j_silva wrote:

Hi Chip,

That was me! I do remember because you were very nice with the refund even though I had left Pos FB already. Not many would do that.

I have seen three main failure modes on U800:

1. The trace shifts to the left (operator's left when looking at the CRT) as the scope warms up, usually 5 to 10 minutes. These are the ones I baked and revived!
2. The chip is very noisy, by this I mean there is a lot of jitter on a very fast step response so that on every retrace the horizontal position of the rising waveform will vary by 500ps to 1ns. Unlike a good U800 which will show the retrace at the same position.
3. Outright dead.

The U800 you sold me was failure #2 type.

--Victor

--- In TekScopes@... <mailto:TekScopes%40yahoogroups.com>, "random.path" wrote:

I sold an apparently working U800 to a list member from an old 2445.
Though the scope seemed to function just fine on initial testing, he later emailed this back:

"I left FB after doing just a quick test at 1ms/Div. After more
testing I discovered that it is very noisy at 10X when time base is faster than 5ns/Div after a quick 2 minute warmup. This Horz Amp is not usable."

So I refunded his money. What I take this to mean is that the U800
can be failing or not meeting specs even without total failure. Just something to keep in mind.

Chip


--- In TekScopes@...
<mailto:TekScopes%40yahoogroups.com>, "victor_j_silva" wrote:

Sounds very much like the U800 issue.

About six months ago a posted about baking some U800s that had
failed this way and was able to rejuvenate them.

I put one of the U800s in a test scope and it's still working to
this day. I'm amazed.

--Victor

--- In TekScopes@...
<mailto:TekScopes%40yahoogroups.com>, "cmjones012003" wrote:

Hello all,

I haven't posted to this list in a long time but have just been
lurking, I'm afraid.
[SNIP]

Thank you in advance
Chris
Cambridge, UK

--
Re: Type 184 Time Mark Generator Transistor Question

 

Now that I think about that is the 2N198 missing a digit?

They are all listed in the SM as 2N198, semms like the last digit is missing?

--- In TekScopes@..., "andersen_bill@..." wrote:

I have another transistor question on this one.

The unit is up and running as stated and looks to be within specs.

I was checking the rest of the transistors on the countdown board and their are quit a few of the same type listed in the SM. Q193, for example. The service manual states for these, "replaceable by 2N198".

All of the ones in my unit are marked 2N3605. They appear to untouched and original.

Is this correct? Is their a more available replacemnt for this type?

Maybe with better performance?

Thanks


--- In TekScopes@..., "andersen_bill@" wrote:

I am repairing a 184 that has had transistors removed from the countdown board.

I am looking at;

Q104

Q114

Q134

SM says "selected from 2N3251"

I can get 2N3251A's local.

I looked at the data sheets. Specs are close. Looks like the A has higher ratings.

Does anyone know if they will work or do I need the non A part?

TIA

B
Re: Type 184 Time Mark Generator Transistor Question

 

I have another transistor question on this one.

The unit is up and running as stated and looks to be within specs.

I was checking the rest of the transistors on the countdown board and their are quit a few of the same type listed in the SM. Q193, for example. The service manual states for these, "replaceable by 2N198".

All of the ones in my unit are marked 2N3605. They appear to untouched and original.

Is this correct? Is their a more available replacemnt for this type?

Maybe with better performance?

Thanks

--- In TekScopes@..., "andersen_bill@..." wrote:

I am repairing a 184 that has had transistors removed from the countdown board.

I am looking at;

Q104

Q114

Q134

SM says "selected from 2N3251"

I can get 2N3251A's local.

I looked at the data sheets. Specs are close. Looks like the A has higher ratings.

Does anyone know if they will work or do I need the non A part?

TIA

B
Re: 2465 - impending U800 failure?

 

Hi Chip,

That was me! I do remember because you were very nice with the refund even though I had left Pos FB already. Not many would do that.

I have seen three main failure modes on U800:

1. The trace shifts to the left (operator's left when looking at the CRT) as the scope warms up, usually 5 to 10 minutes. These are the ones I baked and revived!
2. The chip is very noisy, by this I mean there is a lot of jitter on a very fast step response so that on every retrace the horizontal position of the rising waveform will vary by 500ps to 1ns. Unlike a good U800 which will show the retrace at the same position.
3. Outright dead.

The U800 you sold me was failure #2 type.

--Victor

--- In TekScopes@..., "random.path" wrote:

I sold an apparently working U800 to a list member from an old 2445. Though the scope seemed to function just fine on initial testing, he later emailed this back:

"I left FB after doing just a quick test at 1ms/Div. After more testing I discovered that it is very noisy at 10X when time base is faster than 5ns/Div after a quick 2 minute warmup. This Horz Amp is not usable."

So I refunded his money. What I take this to mean is that the U800 can be failing or not meeting specs even without total failure. Just something to keep in mind.

Chip


--- In TekScopes@..., "victor_j_silva" wrote:

Sounds very much like the U800 issue.

About six months ago a posted about baking some U800s that had failed this way and was able to rejuvenate them.

I put one of the U800s in a test scope and it's still working to this day. I'm amazed.

--Victor

--- In TekScopes@..., "cmjones012003" wrote:

Hello all,

I haven't posted to this list in a long time but have just been lurking, I'm afraid.
[SNIP]

Thank you in advance
Chris
Cambridge, UK

--
Re: Possible P6042 part...

 

You can often pick up a "for parts" P6042 for the price he is asking for just the sensor. The only problem with that approach is that you might end up with a few P6042s and no time to fix them...
Klaus

--- In TekScopes@..., "Alex" wrote:





That's why I said it's possible. Looks the same to me. Jam that guy in there and it should work.
The P6042 is captive to the main unit, and the A6302 is the same probe but with a connector and a different amp.
If the p/ns are different it's because the newer part uses a different potting compound AFAIK.

--- In TekScopes@..., David DiGiacomo wrote:

On Sat, Jan 19, 2013 at 6:10 PM, Alex wrote:
261114631650
Why do you say it's a P6042 part? The seller is claiming it's for an
A6302, is that incorrect?

I thought the P6042 used the 120-0464-00 and 120-0464-01.
475 progress but another road-block

i814u2.geo
 

So, with the help of the folks here and some troubleshooting, I've gotten my 475 closer to being usable again.

However, I'm stuck at a new spot now. I am getting almost perfect voltages at each test point except for the 110V TP which shows roughly 112.4 (which is still within tolerance, just not ideal).
The odd thing is that when I test resistance to ground, only about half of the points are within tolerance. 110, -15, U50, and 105 all show much more resistance than they should. Especially -15 which is showing several K of resistance (book shows it should be 480 ohms).

At some point, I also found a trace that was broken and made the repair. I now get a display if I use the beam finder button. However, I do not get a display without using that button. When I adjust knobs on the front, that "beam found trace" does move (mostly as I would expect). It doesn't seem to stay perfectly still in all cases, but I'm assuming that is because something is still bad and causing issues (including the resistance variances).

I do not have another scope in order to test ripple. I've been trying to follow the troubleshooting flow chart in the manual, but I may be getting confused. If I press the beam finder and adjust the trace to the center, but then release the beam finder button and still see no trace, should I be disconnecting the delay line as my next test?
Or have I gotten ahead of myself?

-Josh
Re: Anybody know the difference between a 475M and 475?

 

--- In TekScopes@..., David DiGiacomo wrote:

On Sun, Jan 20, 2013 at 11:00 AM, Steve wrote:
TekScopes@..., David DiGiacomo wrote:

The 475M service manual is Army TM 11-6625-2735-14-1.

You can download it here:


David,

I respectrully dissagree.

This model is the contract version of the standard 475, with option 4 or option 4&7. It shows the scope operating with the 1106 power supply in an opt 7 configuration, and the front cover is the standard plastic one shipped with all 475s. The military recently retired this scope, and there are many of them showing up on e-pay now. They can be identified by the aluminum plate on the rear which identifies the contract.

The 475M is actually marked "475M" on the face plate. The cover is as I mentioned hard deep drawn aluminum, with rubber gasket and retaining hasps to keep it in place. I don't think it was ever offered in option 7, (mine is not, and the two others I have seen are standard.)
Well, that's confusing. There are several sources that list the
military OS-261B(V)1/U as a 475M, and then several others that list it
as 474/04. (The OS-261C(V)1/U is the 475/04/07.) Do you think
there's any electrical difference between the 475M and the 475/04?
I can't say for sure if circuits are different. It has the same appearance as a stock 475, other than the case. The V/div and time/div ranges are the same. But so are those onthe 465 and 465M which share virtually no circuits. In the case of the 475M, it is possible that it is basically the same circuits, with some redesign if portions did not meet the extended environmental requirements.

I don't have the time now to pull the case and do a thourough side by side examination with a stock 475, and I don't have a manual that covers this specific model.

- Steve
Re: Possible P6042 part...

Alex
 

That's why I said it's possible. Looks the same to me. Jam that guy in there and it should work.
The P6042 is captive to the main unit, and the A6302 is the same probe but with a connector and a different amp.
If the p/ns are different it's because the newer part uses a different potting compound AFAIK.

--- In TekScopes@..., David DiGiacomo wrote:

On Sat, Jan 19, 2013 at 6:10 PM, Alex wrote:
261114631650
Why do you say it's a P6042 part? The seller is claiming it's for an
A6302, is that incorrect?

I thought the P6042 used the 120-0464-00 and 120-0464-01.
Re: Possible P6042 part...

 

On Sat, Jan 19, 2013 at 6:10 PM, Alex <alexeisenhut@...> wrote:
261114631650
Why do you say it's a P6042 part? The seller is claiming it's for an
A6302, is that incorrect?

I thought the P6042 used the 120-0464-00 and 120-0464-01.
Re: Possible P6042 part...

Alex
 

It's not the greatest, sure, but it might be good enough for someone.
It is expensive though.

--- In TekScopes@..., "Steve" wrote:

--- In TekScopes@..., "Albert" wrote:

Why would someone remove the coil/core section from "a working probe" ?
Albert

--- In TekScopes@..., "Alex" wrote:

261114631650

FYI.
The same seller was offering the core and lid as seperate listings.
The core and lid are a matched set, and the offest calibration is based on the pairing. You can not replace one without the other, unless you plan to pick your own offset bias resistor.

- Steve
Re: Need for Termination Feedthrus

 

On Sun, Jan 20, 2013 at 11:08 AM, Philip <ndpmcintosh@...> wrote:
Sure but the question remains--why? If I know that the signal amplitude is within range for the task and my cables are short then why would I want to stick an additional 50 ohm feedthru in the signal path?
To avoid reflections from the unterminated input of the scope.

Try connecting a fast rise generator (10MHz square wave would be fine)
to the scope through an unterminated cable, then add a terminator.
You'll see a huge difference.
Re: Anybody know the difference between a 475M and 475?

 

On Sun, Jan 20, 2013 at 11:00 AM, Steve <ditter2@...> wrote:
TekScopes@..., David DiGiacomo wrote:

The 475M service manual is Army TM 11-6625-2735-14-1.

You can download it here:


David,

I respectrully dissagree.

This model is the contract version of the standard 475, with option 4 or option 4&7. It shows the scope operating with the 1106 power supply in an opt 7 configuration, and the front cover is the standard plastic one shipped with all 475s. The military recently retired this scope, and there are many of them showing up on e-pay now. They can be identified by the aluminum plate on the rear which identifies the contract.

The 475M is actually marked "475M" on the face plate. The cover is as I mentioned hard deep drawn aluminum, with rubber gasket and retaining hasps to keep it in place. I don't think it was ever offered in option 7, (mine is not, and the two others I have seen are standard.)
Well, that's confusing. There are several sources that list the
military OS-261B(V)1/U as a 475M, and then several others that list it
as 474/04. (The OS-261C(V)1/U is the 475/04/07.) Do you think
there's any electrical difference between the 475M and the 475/04?
Re: designspark

 

I have run KiCad under MacPort wine very well on an older Mac with no issues.

On 2013-01-20, at 7:08 AM, willprice94 <will.price94@...> wrote:

I don't know how powerful your mac is, but you could try running a light linux distribution in a virtual machine.

For example:


are both very lightweight, I'm sure you'd have no trouble running them in virtualbox ().

I personally use Arch Linux and have been using the gEDA suite. I initially tried eagle (too restrictive) and KiCAD (had a few irritating UI bugs, too annoying for me to use).

Both CrunchBang and lubuntu are based on Ubuntu/Debian and so have a rich software repository, of which I'm certain KiCAD is present, if not I'm sure there is a ppa repository that can be added to provide packages.

--- In TekScopes@..., "scott_dixon" wrote:


Sadly, KiCAD is pretty poor on Macs. I just last week gave it another try with the latest Mac build I could find. I didn't try the schematic capture but I did try to do some track routing in the PCB module and found it crashed every few minutes even when doing very simple things. There seems to be little work on getting KiCAD working well on Macintoshes so I have given up on it again.
-scott
--- In TekScopes@..., Don & Karen Patterson wrote:

Can anyone advise on how well kicad runs on Macintosh?

Thanks and take care,

Don


On Jan 13, 2013, at 5:01 PM, Veronica Merryfield wrote:

Try the original home¡­
O
n 2013-01-13, at 10:53 AM, Michael Shiloh wrote:

Yep; looks like a problem at the site.

By the way, I'm planning on using KiCad for a class I'm teaching next
week; I've tested it over the past couple of weeks and am quite happy.

I'll be happy to share my experiences and observations as my class
progresses, if there is interest.

Michael

On 01/13/2013 10:42 AM, Ray wrote:
When I try to call up , all I get is a "System
Error". Is anyone else having a similar problem?

Ray, W4BYG


On 1/12/2013 11:51 AM, Gordon wrote:
On 12/01/2013 15:51, jerry massengale wrote:
What free stuff do most use? Sorry again.
Tried Design Spark, didn't like it. It might have improved but I found
the footprint editor primitive to say the least. I use Kicad which does
pretty much everything I want. The Kicad footprint editor isn't
fantastic but it's adequate. and
it's free:) You probably won't find all the footprints/symbols you want
in any package but personally, despite the amount of time it takes I
prefer to do my own. You probably won't need *that* many and at least
you'll know whether they've been marked up for insertion or not and that
they're the right size. Any time I screw a board up it's almost always
down to using someone else's footprint/symbol marked up with pin names
instead of numbers.

FWIW

Gordon


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What is the logic in Tegams Serialnumbers?

 

Hi to All,

Still puzzling about the Tegam Serialnumbers? Are the four latest e.g. the month and year of production? Anybody?

Greetings,

Egge Siert
Looking for Tekmate 2402(A) system software

raymonddompfrank
 

If anyone could help me with getting the system software for a (working) Tekmate 2402A, I would be very grateful.
Currently, it runs MS-DOS only...

Of course, I'd be willing to financially compensate.

Raymond
Re: 2465 - impending U800 failure?

 

I sold an apparently working U800 to a list member from an old 2445. Though the scope seemed to function just fine on initial testing, he later emailed this back:

"I left FB after doing just a quick test at 1ms/Div. After more testing I discovered that it is very noisy at 10X when time base is faster than 5ns/Div after a quick 2 minute warmup. This Horz Amp is not usable."

So I refunded his money. What I take this to mean is that the U800 can be failing or not meeting specs even without total failure. Just something to keep in mind.

Chip

--- In TekScopes@..., "victor_j_silva" wrote:

Sounds very much like the U800 issue.

About six months ago a posted about baking some U800s that had failed this way and was able to rejuvenate them.

I put one of the U800s in a test scope and it's still working to this day. I'm amazed.

--Victor

--- In TekScopes@..., "cmjones012003" wrote:

Hello all,

I haven't posted to this list in a long time but have just been lurking, I'm afraid.
[SNIP]

Thank you in advance
Chris
Cambridge, UK

--
Ground leads on 6108 Passive Probes

 

I have a a number of P6108 passive probes without ground leads. Looking in the little plastic sleeve where they go I see the metal shows signs of wear indicating ground leads have been installed in the past.

I have a tektronix ground lead with alligator clip, but, I see no way that the little metal contact can be installed in the plastic sleeve. Are there special clips that only go with certain probes?
Re: Need for Termination Feedthrus

 

Sure but the question remains--why? If I know that the signal amplitude is within range for the task and my cables are short then why would I want to stick an additional 50 ohm feedthru in the signal path?

And thanks for the book recommendation. Ant other will be welcome also.

--- In TekScopes@..., David wrote:

On Sat, 19 Jan 2013 20:19:08 -0000, "Philip"
wrote:

As I gather up all the stuff I need to test and maintain my newly purchased 2235 I am wondering how necessary it is to use a 50 ohm feedthru termination when sending test and calibration signals into the scope. Can one not construct their own device that perform the same purpose as a factory-built feedthru?
A T-connector with a termination on one end will work for
oscilloscopes that lack internal switchable terminations which
generally only have a bandwidth that extends to 100 MHz anyway.

And, can anyone recommend a good book that goes into detail on the theory of construction and operation of oscilloscopes? The ones I have gotten at the library are pretty superficial.
Jim Williams' book has a great section on oscilloscope vertical
amplifiers among other things:
Re: Anybody know the difference between a 475M and 475?

 

TekScopes@..., David DiGiacomo wrote:

The 475M service manual is Army TM 11-6625-2735-14-1.

You can download it here:


David,

I respectrully dissagree.

This model is the contract version of the standard 475, with option 4 or option 4&7. It shows the scope operating with the 1106 power supply in an opt 7 configuration, and the front cover is the standard plastic one shipped with all 475s. The military recently retired this scope, and there are many of them showing up on e-pay now. They can be identified by the aluminum plate on the rear which identifies the contract.

The 475M is actually marked "475M" on the face plate. The cover is as I mentioned hard deep drawn aluminum, with rubber gasket and retaining hasps to keep it in place. I don't think it was ever offered in option 7, (mine is not, and the two others I have seen are standard.)

- Steve
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