Date   

Asking for Help with Verifying Genuineness of 2465B from Ebay

Mr. Eric
 

Hi Everyone,

I just purchased a 2465B from ebay. I'm trying to verify that it actually is a 2465B and not a rebadged and hacked lower bandwidth tek scope. From my understanding the best way is the serial number from the A1 board which I got. 670-9268-07. I looked up in the service manual and I saw that the A1 boards listed were:
670-9268-02
670-9268-04
670-9268-06
But I didn't see any mention of my A1 board: 670-9268-07 in that manual.

I also noticed that the last 2 digits "07" on my A1 board is actually a little white sticker with 07 written on it. I looked under the sticker and I didn't see anything else.

I'm a little thrown off, and I was wondering if anyone here had more insight to this. I just want to make sure that I indeed did get a genuine 2465B as I know others in this group have gotten "burned" on ebay. I did not purchase this 2465A from the ebay seller that has been mentioned in a few posts for hacking 2445s into 2465As.

Thanks in advance everyone!!!
Best Regards,
Eric


Thoughts About Modern Tek Scopes

 

I plan to get a modern DSO at some point, either a Rigol or Siglent 4 channel scope at 100 or 200 MHz, but just saw a TDS5054 on eBay for about the same price as the Siglent scope I've been thinking about. Aside from the higher bandwidth, the 5054 also has separate controls for each vertical input, which I would prefer to the the single multiplexed control on the Siglent (and most modern low-end DSOs).

My only concern is that the 5054 is clearly running Windows, which I don't like, but I feel that I should not dismiss it out of hand just because they used an operating system I detest.

I don't expect a modern DSO to deliver the same kind of user experience that I'm used to with the analog scopes from the 70s and 80s, but I'd like to know what other people's thoughts on using a newer Tek scope are.

So my questions:

Is this a good scope?
Is it worth getting this rather than newer Chinese scope?
What about buying a non-working unit, are they repairable?

-- Jeff Dutky


Re: 475A Chop Blanking and a Theory Question

Jim Ford
 

Similar jokes about the first smartwatch; it was so clunky that people said, "I'll wait for the portable version!"    Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Tom Lee <tomlee@ee.stanford.edu> Date: 12/20/20 8:55 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] 475A Chop Blanking and a Theory Question Actually, the first Powerbooks were gray. They were preceded by the much less successful, light beige Portable which, given the bulky size and lead-acid battery, was an unintentionally comical name. But you could use them to jump-start your motorcycle in a pinch.-- Tom-- Prof. Thomas H. LeeAllen Ctr., Rm. 205350 Jane Stanford WayStanford UniversityStanford, CA 94305-4070http://www-smirc.stanford.eduOn 12/20/2020 20:17, Jeff Dutky wrote:> It's also fairly obvious that Apple took their design cues from GRiD with the first Powerbooks (also all-black, like the GRIDs, but without the magnesium case, sadly).> -- Jeff Dutky>>> >>


Re: 475A Chop Blanking and a Theory Question

Harvey White
 

I have software for that chip for both the AVR (it takes a good processor) and ARM (again ST micro F446 or better).  I have a TEK related project this (or something like it) will eventually show up in.

(C and/or C++)

Harvey

On 12/20/2020 11:17 PM, Jeff Dutky wrote:
Harvey,

Yes, that's a later model than what I have, I think it was called a GRiDPad. The first model was released just before the pen-computing craze of the early 90s. Prior to the GRiDPads they made the GRiDCase line of PC compatible laptops, and before that they made the GRiD Compas, which is well known as "the first laptop in space." GRiD also held the patent on the clamshell case design for many years. Prior to the GRiD Compass portable computers looked more like a portable oscilloscope (probably for the same reason: you needed space for the neck of the CRT). It's also fairly obvious that Apple took their design cues from GRiD with the first Powerbooks (also all-black, like the GRIDs, but without the magnesium case, sadly).

You are probably right about the interface to the gas plasma display having parallel data lines: there are eight lines with voltages in the mV range, as measured by my multimeter, that I hadn't figured out what they were for. I was just starting to get a good look at them with the scope when it blew a cap on the sweep board, and I started down my current path of acquisition, repair, and calibration.

The Epson part looks quite promising. I was expecting to put an Arduino between the RasPi and the laptop hardware, and bit banging the display interface from there, but this looks like a much better solution.

-- Jeff Dutky





Re: 475A Chop Blanking and a Theory Question

Tom Lee
 

Actually, the first Powerbooks were gray. They were preceded by the much less successful, light beige Portable which, given the bulky size and lead-acid battery, was an unintentionally comical name. But you could use them to jump-start your motorcycle in a pinch.

-- Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 12/20/2020 20:17, Jeff Dutky wrote:
It's also fairly obvious that Apple took their design cues from GRiD with the first Powerbooks (also all-black, like the GRIDs, but without the magnesium case, sadly).
-- Jeff Dutky




Re: 475A Chop Blanking and a Theory Question

 

Harvey,

Yes, that's a later model than what I have, I think it was called a GRiDPad. The first model was released just before the pen-computing craze of the early 90s. Prior to the GRiDPads they made the GRiDCase line of PC compatible laptops, and before that they made the GRiD Compas, which is well known as "the first laptop in space." GRiD also held the patent on the clamshell case design for many years. Prior to the GRiD Compass portable computers looked more like a portable oscilloscope (probably for the same reason: you needed space for the neck of the CRT). It's also fairly obvious that Apple took their design cues from GRiD with the first Powerbooks (also all-black, like the GRIDs, but without the magnesium case, sadly).

You are probably right about the interface to the gas plasma display having parallel data lines: there are eight lines with voltages in the mV range, as measured by my multimeter, that I hadn't figured out what they were for. I was just starting to get a good look at them with the scope when it blew a cap on the sweep board, and I started down my current path of acquisition, repair, and calibration.

The Epson part looks quite promising. I was expecting to put an Arduino between the RasPi and the laptop hardware, and bit banging the display interface from there, but this looks like a much better solution.

-- Jeff Dutky


Re: When a metal pin comes off the back of a CRT

Dave Seiter
 

I've never had an issue with the rear pins, but the deflection pins scare me. I've heard they are delicate, so I'm always really careful when removing and installing their leads.  I bent one on a 7488 once (maybe 30-35º), and bent it back very gently without a failure.  If it was a 7104 crt, I would have probably just left it as is.  If I did it again, I'd probably hold the bent portion stationary and make a new bend further out to get it pointed in the right direction.
-Dave

On Sunday, December 20, 2020, 02:06:38 PM PST, DW <wilson2115@outlook.com> wrote:

Thanks for the reply

This type of incident probably rarely happens where more often the pins just get bent.

I have dealt with removing various plugs and boards off CRT's before, I gently pull on the plug while very slightly rocking around until I work it off. When I install I make sure I am aligned and with a gentle push and slight rocking around I work the plug back on until it is fully seated. This technique seems to be the most gentle with the least amount of force.


Re: Readout for 5s14n - please validate my idea

Michael W. Lynch
 

It might be more difficult on the 5xxx and 51xx, but it can be done. How it is done and the black magic or witchcraft that is involved; is way over my head. However, the 5D10 Digital Storage plug in adds display readouts to the lowliest versions of the 5000 series Scopes.

--
Michael Lynch
Dardanelle, AR


Re: Firmware for Tektronix 492/496 spectrum analyzer

J. L. Trantham
 

The MC68766 is programmable with the BP Microsystems programmers, at least with the 1410 (and likely later and perhaps some earlier programmers).

I can certainly program the chips you need if you have the chips and tell me what specific files need to be programmed.

I looked at your link to the images and I can download the files and program the chips. However, it seems you don't need these two but your 'error' suggests you have a problem with a chip you do not have installed.

I guess I'm confused.

Happy to help if I can. I'm in NW FL USA.

Merry Christmas and Happy New Year.

Joe

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Steve Dench
Sent: Saturday, December 19, 2020 9:54 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Firmware for Tektronix 492/496 spectrum analyzer

There are a number of 24 to 28 pin adaptor boards on eBay as Ye Old
Commodore 64 computers have the same issue. I used some in my 468 some time
back with the usual Mostek Rom failures. Some of these adaptors are very
slim and fit the 468 well.

On Sun, 20 Dec 2020, 2:11 pm vk2bea via groups.io, <vk2bea=
yahoo.com@groups.io> wrote:

I have a 492 Spectrum Analyzer that has developed a fault with the ROM
(self test indicates a checksum failure).
The test blinks 14 times which, according to the manual, means that U2012
fails checksum. I do not have this ROM populated on the board (just U2023
and U2028)

Does anyone know what's going on here?

The ROMs are 8K x 8 one time programmable (it appears) part. (its also
possible that it is an ee programable part but that is unlikely I think).
The chip markings are custom - 160-0839-00 & 160-0838-00 (Tek #) and
SCM92217CR (with Motorola logo) & data code of 8343 and 8402.
8K 24pin DIP parts seem scarce (Although I found a Motorola MCM68766 thats
pin compatible ... I just don't see how I'll program it 8-( )

What is the standard practice for this repair? Use a 28 pin package and
add the appropriate mod wires ?
I found the firmware binary here ..
http://w140.com/tekwiki/wiki/ROM_images






Re: TEK 7603 REPAIR

Tom Lee
 

Many things can cause diminished brightness. Don't overlook simple possibilities, such as misadjusted or noisy trigger thresholds and holdoff (or any other trigger-related controls).  Check easy stuff like that first, before going on to Z-axis circuit-related hypotheses.

--Cheers,
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 12/20/2020 16:46, David Collier wrote:
Dear 7603 owners,
I just got serial no. 704170 'parts and repairs' from ebay. Mostly it works, including the graticule bulbs. The regulator board already has an uprated 30K resistor as standard; there is also a fan.
I took apart the rectifier and regulator boards to check before switching on. All TO-3 transistors had betas in the high 30's. All electrolytics are original and with low ESR; when switched on the minus 50V was spot on.
I took apart everything with gay abandon, not noting what wire came from where. Was able to work out rectifier and regulator board connections and placement, but am now left with the signal output board: where is P339 (for a white plastic 4-pin plug), and where do the three left hand co-ax sockets connect to (one green 4-pin plastic plug and one brown 2-pin plug)?
There is a minor fault in that the trace is dim. Once it brightened up when selecting a low sweep speed, but then reverted to a trace that cannot be adjusted to be brighter (and goes out of focus when you try). Something to with the Z axis circuit? But all transistors are OK on this board, mostly already replaced with 2N3906 & 2N3904.
Next possibility the CRT control circuit, getting bias voltage via two 27pf capacitors?
Thanks & Regards,
David Collier




Re: TEK 7603 REPAIR

Jim Ford
 

Uh, (DC) bias wouldn't be provided through capacitors, that much I know.  (32+ years practicing EE; one of these days I'll actually get it right! ;))   Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: David Collier <dc888@tpg.com.au> Date: 12/20/20 4:46 PM (GMT-08:00) To: TekScopes@groups.io Subject: [TekScopes] TEK 7603 REPAIR Dear 7603 owners,I just got serial no. 704170 'parts and repairs' from ebay.  Mostly it works, including the graticule bulbs.  The regulator board already has an uprated 30K resistor as standard; there is also a fan.I took apart the rectifier and regulator boards to check before switching on.  All TO-3 transistors had betas in the high 30's.  All electrolytics are original and with low ESR; when switched on the minus 50V was spot on.I took apart everything with gay abandon, not noting what wire came from where.  Was able to work out rectifier and regulator board connections and placement, but am now left with the signal output board: where is P339 (for a white plastic 4-pin plug), and where do the three left hand co-ax sockets connect to (one green 4-pin plastic plug and one brown 2-pin plug)?There is a minor fault in that the trace is dim.  Once it brightened up when selecting a low sweep speed, but then reverted to a trace that cannot be adjusted to be brighter (and goes out of focus when you try).  Something to with the Z axis circuit?  But all transistors are OK on this board, mostly already replaced with 2N3906 & 2N3904.Next possibility the CRT control circuit, getting bias voltage via two 27pf capacitors?Thanks & Regards,David Collier


TEK 7603 REPAIR

 

Dear 7603 owners,
I just got serial no. 704170 'parts and repairs' from ebay. Mostly it works, including the graticule bulbs. The regulator board already has an uprated 30K resistor as standard; there is also a fan.
I took apart the rectifier and regulator boards to check before switching on. All TO-3 transistors had betas in the high 30's. All electrolytics are original and with low ESR; when switched on the minus 50V was spot on.
I took apart everything with gay abandon, not noting what wire came from where. Was able to work out rectifier and regulator board connections and placement, but am now left with the signal output board: where is P339 (for a white plastic 4-pin plug), and where do the three left hand co-ax sockets connect to (one green 4-pin plastic plug and one brown 2-pin plug)?
There is a minor fault in that the trace is dim. Once it brightened up when selecting a low sweep speed, but then reverted to a trace that cannot be adjusted to be brighter (and goes out of focus when you try). Something to with the Z axis circuit? But all transistors are OK on this board, mostly already replaced with 2N3906 & 2N3904.
Next possibility the CRT control circuit, getting bias voltage via two 27pf capacitors?
Thanks & Regards,
David Collier


Re: 475A Chop Blanking and a Theory Question

Tom Gardner
 

On 20/12/20 22:12, Jeff Dutky wrote:
For the 6809 I was considering trying to dig up an AM9511/2 or WTL1032/3 coprocessor, but I'm not at that point yet. Using the LS181s to build an FPU is something of a departure from my plans, but it does tickle another long-standing interest of mine: implementation of floating point and extended precision math operations, so now I'll have to think about it
My first paid job, as a vacation student in 1976, was to implement 32-bit floating point arithmetic on a 6800. It wasn't that difficult, I still have listings somewhere, and IIRC sin/cos (using CORDIC) took around 40ms.

A few years later, I also remember being unpleasantly surprised how little speed improvement there was doing mul/div on some-ic-or-other external to a Z80.


Re: TEK176 fixing a shorted wet tatalum capacitor

 

Re. "Hermetic Tantalum caps": Perhaps it should be emphasized that the elastomeric seal traditionally used for wet tants, is *not* hermetic. Only glass seals are hermetic.

Raymond


Re: TEK176 fixing a shorted wet tatalum capacitor

 

On Sun, Dec 20, 2020 at 11:26 PM, Larry McDavid wrote:


I have personal experience with a metal-can, hermetic glass-seal wet tantalum
in a HP 8662 sig gen not only being electrically leaky but having
time-variable leakage.

The 8662 is just filled with those hermetic tantalums...

Larry,
More than likely, that was a solid tantalum. Wet tants were only used for higher working voltages (above 35 WV I guess) in that kind of equipment, and only if really necessary. The wet hermetic variety, if it even existed then, would have been very much more expensive than the solid hermetic variety and mostly reserved for space/avionics/hi-rel applications.

I'm sure the tantalums that the HP 8662 "is filled with" is the solid hermetic variety, like in all other HP (and Tek) equipment of the day.

Raymond


Re: 475A Chop Blanking and a Theory Question

Harvey White
 

I actually have (somewhere, I think) an older grid computer with attached pen.  Runs DOS and I'm not sure what else.

What you'd think you'd be getting on the display pin lines would be H and V sync, and then analog video.  Nope, H and V sync, pixel clock of 15 to 30 Mhz plus, and digital data of some sort, 8 lines perhaps, depending on whether or not the display can do any gray scale.  Being plasma, it's strictly monochrome and may pack more than one pixel into a data byte going in.  Not sure about other control lines.  Again, I'd recommend the S1D13781 (Epson) for a controller.  It's simple to use (and I have drivers that actually work), reasonably rugged, and about 10 dollars.  Can use either an SPI interface or a memory map into the processor.  Ask about details off list, and I'd be happy to tell you.  Runs TFT displays, passive displays, and perhaps plasma (no reason to think not).  Timing is VERY adjustable.  Has a bitblt engine for copying and filling in blocks.  QVGA displays get far more colors.

Harvey

On 12/20/2020 5:12 PM, Jeff Dutky wrote:
Harvey,

The old laptop is not what you would call "semi modern": it's a GRiDCASE 3 from 1985. The display, as I said, is a gas plasma display, and has a 20 pin connector (so it may, in fact, have a parallel interface, though I was expecting a serial interface that looked more like a component video signal, based on some data sheets for other plasma displays). Other than the power pins (+/- 15 V and + 5 V) the signals do look like TTL levels. This is about where my notes on the topic end, as this is when I went down the scope rabbit hole. I have learned a great deal, both about electronics in general, and about operating an oscilloscope in the intervening three months, so I don't expect to have much difficulty decoding the control signals when I return to the project.

For the 6809 I was considering trying to dig up an AM9511/2 or WTL1032/3 coprocessor, but I'm not at that point yet. Using the LS181s to build an FPU is something of a departure from my plans, but it does tickle another long-standing interest of mine: implementation of floating point and extended precision math operations, so now I'll have to think about it.

Dave Voorhis,

Yes, this was an older version (from the early 2000s) of a major vendor database. The dependency in our code base was, as far as I know, only documented in folklore (though there may have been some entries on the internal dev/ops wiki that discussed it). I only know about it because I worked closely with one of the senior developers years later, who recounted it when we worked on ad hoc reporting queries.

Frankly, Duff's device is what is most surprising to me. I have, for no good reason, implemented it using every compiler I have encountered since 2003, and it has worked every time. I would have expected there to be more variation in how compilers implement the switch statement, enough that the interleaving of a switch statement with a while loop would break on at least a few of them.

Here is the wikipedia entry on Duff's device. It's truly pathological: https://en.wikipedia.org/wiki/Duff%27s_device

-- Jeff Dutky





Re: TEK176 fixing a shorted wet tatalum capacitor

Larry McDavid
 

I have personal experience with a metal-can, hermetic glass-seal wet tantalum in a HP 8662 sig gen not only being electrically leaky but having time-variable leakage. This was the source of drifting frequency setting of a PLL. The cap looked in good condition and was not leaking electrolyte. Nasty to find; finally found through process of elimination. Problem duplicated when the cap was measured removed and on the bench. The 8662 is just filled with those hermetic tantalums...

Larry

On 12/20/2020 2:14 PM, Raymond Domp Frank wrote:
On Sun, Dec 20, 2020 at 11:04 PM, Roy Thistle wrote:


(and maybe eventually leak anyway?)
Yes, many non-hermetic ones eventually leak. The 576 curve tracer contains an infamous example, and doesn't the 465 contain one?
New ones are frightfully expensive. Because their electrolyte is a liquid, they seem to be self-healing to a degree, making the hermetically sealed variety more reliable even than the solid variety.
Raymond...
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)


Re: TEK176 fixing a shorted wet tatalum capacitor

 

On Sun, Dec 20, 2020 at 11:04 PM, Roy Thistle wrote:


(and maybe eventually leak anyway?)
Yes, many non-hermetic ones eventually leak. The 576 curve tracer contains an infamous example, and doesn't the 465 contain one?
New ones are frightfully expensive. Because their electrolyte is a liquid, they seem to be self-healing to a degree, making the hermetically sealed variety more reliable even than the solid variety.

Raymond


Re: 475A Chop Blanking and a Theory Question

 

Harvey,

The old laptop is not what you would call "semi modern": it's a GRiDCASE 3 from 1985. The display, as I said, is a gas plasma display, and has a 20 pin connector (so it may, in fact, have a parallel interface, though I was expecting a serial interface that looked more like a component video signal, based on some data sheets for other plasma displays). Other than the power pins (+/- 15 V and + 5 V) the signals do look like TTL levels. This is about where my notes on the topic end, as this is when I went down the scope rabbit hole. I have learned a great deal, both about electronics in general, and about operating an oscilloscope in the intervening three months, so I don't expect to have much difficulty decoding the control signals when I return to the project.

For the 6809 I was considering trying to dig up an AM9511/2 or WTL1032/3 coprocessor, but I'm not at that point yet. Using the LS181s to build an FPU is something of a departure from my plans, but it does tickle another long-standing interest of mine: implementation of floating point and extended precision math operations, so now I'll have to think about it.

Dave Voorhis,

Yes, this was an older version (from the early 2000s) of a major vendor database. The dependency in our code base was, as far as I know, only documented in folklore (though there may have been some entries on the internal dev/ops wiki that discussed it). I only know about it because I worked closely with one of the senior developers years later, who recounted it when we worked on ad hoc reporting queries.

Frankly, Duff's device is what is most surprising to me. I have, for no good reason, implemented it using every compiler I have encountered since 2003, and it has worked every time. I would have expected there to be more variation in how compilers implement the switch statement, enough that the interleaving of a switch statement with a while loop would break on at least a few of them.

Here is the wikipedia entry on Duff's device. It's truly pathological: https://en.wikipedia.org/wiki/Duff%27s_device

-- Jeff Dutky


Re: TEK176 fixing a shorted wet tatalum capacitor

Roy Thistle
 

On Sun, Dec 20, 2020 at 05:27 AM, Raymond Domp Frank wrote:


Wet tants are not hermetically (glass) sealed
There are... or there used to be... glass hermetically sealed wet tantalum capacitors.. with a tantalum case (not a silver case). They were... at least... used in some satellites, and aerospace stuff.
The more common type of wet tantalums used/use? an elastomer seal; but, these type can leak if there is a reverse voltage applied (and maybe eventually leak anyway?)

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