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My son has acquired a 494AP marked to have Option 9. This option does not seem to appear in available manuals. Have others encountered this option?

Bruce, KG6OJI

On Thu, Feb 6, 2025 at 03:36 PM, Don N3DEB wrote:

rear tan plastic cover.

Does anyone know what kind of plastic that is?
For a start, is it a thermoplastic, or a thermosetting plastic?


--
Roy Thistle

Somewhere I recall seeing saw a list of recommended replacement capacitors for the power supplies in 49x-series analyzers, but have been unable to locate it. Does anyone happen to have a copy?

My so recently acquired a non-working 494AP that appears to have power supply issues.

Bruce, KG6OJI

It's on life support. In the year I've been on it I haven't seen a post. Maybe someone should unplug it, then plug it back in... :-)

As I noted before, there is a GIO group for B&K.
DaveD
KC0WJN

Bill P

As I noted before, there is a GIO group for B&K.

DaveD
KC0WJN


On Fri, Feb 7, 2025 at 14:12 Bill Perkins via groups.io <sales=
[email protected]> wrote:

This post is OT but possibly of interest to B&K 2012 owners.
There's a
slew of info on the 2012 in my site here:



and a lot of info on B&K in general in this directory:

I know this is not the natural place for this request, but perhaps there

are like minded people here?

Does anybody here have a copy of the boot code disk for the B&K 2012

analyser?

My unit has lost its memory after some years in storage.
The hardware is in good shape.
Any help would be appreciated.

Please contact me off list

Pete
G4GJL

Bill @ PEARL, Inc. - Canada

This post is OT but possibly of interest to B&K 2012 owners. There's a slew of info on the 2012 in my site here:



and a lot of info on B&K in general in this directory:

I know this is not the natural place for this request, but perhaps there are like minded people here?
Does anybody here have a copy of the boot code disk for the B&K 2012 analyser?
My unit has lost its memory after some years in storage.
The hardware is in good shape.
Any help would be appreciated.
Please contact me off list
Pete
G4GJL

Bill @ PEARL, Inc. - Canada

David,

Thanks for your comment!

No matter how low I turn down the Intensity you can still see this shadow. (Until both the trace and shadow go undetected.)

Barry

Hello N4BUQ,
I removed the knob and shaft in order to more easily probe the transistors under the shaft. I can still adjust the focus.
Thanks,

Barry

Looks like the FOCUS control knob and shaft is missing. That might also contribute to a bit of that as well, correct?

Thanks,
Barry - N4BUQ

Guys,

Thanks for showing consensus on this and the additional information. I feel more confident about my -0367- inventory.

I think the SC504 use a expansion mesh PDA. I that's the case, if you turn the brightness up to high levels you will get that effect.

David

Greetings,

What would cause this?

Thank you!

/g/TekScopes/photo/300558/3883505?p=Created%2C%2C%2C20%2C2%2C0%2C0

Benjamin,

I made an error in my previous response.

The junction between R2176 and R2275 is -5V.

Barry

Clark and Tom,
I agree with tom on this one. As always if the circuit is not working, then troubleshooting is necessary. These are 1.2Ghz Ft parts and as such have an incredibly low reverse break down. As low as 0.5 Vdc which is why a "component tester" will show a reverse diode. The reverse breakdown was confirmed with a curve tracer and a Keithly SMU so it is not a phantom. The KPS10 will "work" as a replacement but the Ft is only 650Mhz in testing the trigger limits of a 475 with all the transistor replaced and after a calibration it would still trigger WAY out of its triggers spec up at around 400Mhz but these days it does seem to be difficult to find discrete Ghz+ devices My current recommendation is if the trigger is working leave the 0367 parts in place. Calibrations and specification being king a scope will align and calibrate with both types in place.

Zen

I dabble in mmwave and have to deal with tiny diodes with 2 to 4 volt breakdowns. I purposely only use a cheap DVM that has a 2v compliance and 1ma max current in diode/ohm mode. My bench meter would blow them up! I don't understand why using some unknown brand tester is considered 100% accurate. P.s. I really need to make a curve tracer driven by an arb gen That I bet would be a good tester.

On Fri, Feb 7, 2025 at 02:17 AM, Szabolcs Szigeti wrote:

Szabolcs

Szabolcs, agree 100% with merit of fiber - good point. I always keep it on hand. There are also many epoxy fillers in addition to fabric for different applications. Marine supply is where I find these.

Yes, little stress where I used it and it seems strong enough that I could have used 75% less in hindsight. We will see if this was a good choice for my first experience with the product, if any issues I will follow up here.

It stayed in place very well even on the vent grill posts that were vertical, and was easy to use.

J&B others offer a plastic adhesive epoxy AND polyurethane and manufacturers state different applications, one being polyurethane has more flex than the epoxy. I have not used the epoxy products on plastic so I can't speak to that. I think it is important to note two part formulation is not exclusive to epoxy. I did not know this before I did my research, nor did about 50% of the internet experts so best one goes to the source.

I had related experience adhesives and coatings when I laminated a new transom for my ocean boat. This was 25 years ago and that work is still like new, well tested by chasing Pacific coast tuna far offshore. I bought a book on boat building and followed every product datasheet step to the letter. I used (expensive) epoxy resin instead of polyester and proper fiber additives, and finished with (very expensive) two part polyurethane coating applied by brush. It leveled out to a perfect gel coat like finish with no brush marks or runs, even on the vertical surfaces. It is beautiful.

Same boat, got tired of ugly cheap covers. Bought a book on canvas work, purchased high quality (again, expensive) acrylic fabric and made a cover. 25 years in the sun, still in great shape.

With quality (yes, usually expensive) products for the application and humble respect of reputable manufacturer instructions a hell of a lot can be accomplish. I hope everyone continues to take on these repairs and keep improving our collective knowledge.

It's not about me, I am not gifted. I just follow gifted people. That is why I am in this group.

Hi,

I had very good results using glass fiber reinforcement with epoxy. Usually
I only need a few strands of glass or an appropriately sized patch. One has
to figure out how the stress forces will go and place the fiber
accordingly. When wetted with the resin, it is practically invisible.
I used laminating epoxy used in marine construction, because that is what I
have, the only drawback in this case is that it cures fairly slowly, but
otherwise it is very strong once cured.

Szabolcs

victor.silva via groups.io <daejon1@...> ezt írta (id?pont:
2025. febr. 7., P, 2:18):

Hi Clark,

You might want to check out the summary that Zen (I believe) added to tekwiki:

In short: "Replace on sight" doesn't seem to be a good policy.

-- Cheers
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070

What was the prevailing opinion on the correct way to test for leakage (e.g. ICEO)?

Ed listed some sound reasoning, but I did not see agreement from other members that testing the reverse polarity, IECO was valid or invalid for this transistor. I am asking because I have a bunch of these transistor that seem good when crudely tested for leakage with a positive voltage from collector to emitter with the base open. I suspect that the reverse polarity will breakdown at the 3V limit for emitter to base.

Furthermore, it appears that there is an incorrect identification of the device package. The Tektronix Common Design Parts for semiconductors catalog from Oct 1982 lists this part as a TO-92 (EBC) with no optional pin scramble; however, the parts in my 7A26 and 7B85 are not TO-92. The plastic body looks like a TO-92 but the lead breakout is a triangular configuration. TO-92s are in a line as if stamped as a flat leadframe. TO-92s do not have legs with a circular cross section. The package that is the best fit for what is in my plugins is the X-55. I have never heard of it either but it is on page 9-6 of the Tek semiconductor catalog. The X-55 pins are also reversed relative to the flat face when compared to the standard TO-92. The X-55 matches the pinout of the TI A5T3571.

All of my -0367- parts are TO-92 and they are clearly labeled with the part number. Perhaps for improved reliability or simply a lower cost, Tek changed to a vendor that used TO-92s. I wonder if the "shoot(replace) on sight" declaration should be limited to the X-55 package.

Any further thoughts or guidance?

Clark