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The ROM's on the A5 board contain everything they need to
know about being a 2467B, 2465B, 2445B, or 2455B.

The A5 controller's are interchangeably the same. You can
take one out of any member of the 24[4,5,6]5A or B family,
and swap around. The only significant difference has to do
with the separate Display board on A's, and early B's. You
can swap a controller/display board from an A into a late B,
and vice versa, if you want... [The "A" controllers have some
ROM omissions for the extra diddly stuff that the "B" can do,
and some changes in the calibration routines, battery voltage
sensing...]

The way the A5 controller knows what scope you have is by
reading the P/J512, pin 11, and pin 32. Pin 11 goes with
a jumper, W120, which if missing is a 2445B/2455B, if grounded,
is a 2465B.

P32 determines whether the scope is a 2465B, or a 2467B. The
significant difference (board wise) between a 65, and a 67, is
the HV power supply board, the 67 board has the control voltages
necessary for the MCP. As a result, the 67 Board grounds P32,
and passes the signal through the A1 motherboard to P/J512, P32,
on the A5 Controller board.

The only schematic where Tektronix forgot to erase this information
is the analog control <2> schematic for B050000 and above in the
2465B/2467B manual (070-6863-01).

Someone once said: "What a tangled web we weave, when first we
practice to deceive." One of the girl poets, as I recall. Emily
Dickinson maybe?

I hope you won't use this information for evil.

-Chuck Harris

Raymond Domp Frank wrote:

I took a look and that's what I see. The R364 on the divider board is a 1k resistor and the manual calls out a 100 ohm resistor.

DaveD

On Sat, Mar 3, 2018 at 02:59 pm, Sergey Kubushyn wrote:

A5 ROM has nothing to do with calibration -- that is stored in NVRAM -- but
it adds those higher sweep rates that 2445B doesn't have i.e. it changes the
scope identity.

ISTR that enabling 500 ps/div horizontal speed to a 2445B just takes adding a jumper near the edge of the main board, at one of the connectors. Sorry, don't remember exactly where and I have no doc. where I am at the moment. I trust this'll ring a bell with someone on this forum who has the details.

Raymond

I would probably just clip the leads as you suggested and solder the
new capacitor on from the top of the board instead of messing with it
and risking damage if you are not familiar with removal and assembly.

Wherever possible, I try and pull the leads by leaving a length while clipping, heating and pulling the remaining length, for fear of a remaining piece of wire dropping off inside while soldering the new part on top.

Raymond

I’m trying to approximate the year that my 555 was made. Maybe there’s some way other than just looking at the date codes on components? What I know is the serial number is 601 and the center strip on the scope head is chrome not Tek blue. To be fair I haven’t really poked around too much in the head as I’m working my way the through power supply first. If you have any thoughts or suggestions I’d love to hear them. Oh and the connections are all SO-239 which could be nothing more than an option but I don’t know. Thanks in advance!

All,

I found and ordered a 155-0239-02 at Qservice in Greece, so it should be in Spain and OK by the end of the week.

Un saludo,

Leo

About a repository... that's a good question for the group.
Each of the legacy "hallmark" test equipment manufacturers has gone through a lot of change and transformation.

Gary
Curious ..... what is the motivation in this day and age for Tektronix to keep a repository of 30+ year old applications notes?
-DC
manuals@...

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

Thank you Ronald. I hope you can find them. Hard to believe they are not readily available through Tektronix. Why can't Tektronix maintain a repository?

Gary

WOW did I miss the mark.

First I thought I was replying to the HP group.

Second I see where my website suggestion seems to have disappeared in a huge string of “stuff’.

So, regardless if your interest is HP, TEK or actually numerous other subjects it is worth visiting archive dot org.

Ken

Greetings,

I am only catching part of this conversation but allow me to suggest: www.archieve.org<>

Applying the search term "Hewlett Packard" brings up an enormous amount of material.

BTW, applying the search term "Tektronix" also delivers amazing results.

Regards,

Ken

Gary,

About 6-7 years ago I found these application notes, or most of them, online. Some are definitive tutorials and give procedures directly applicable to the J16 and its many probes. Pg 7 of the 1981 revision of the instruction manual provides the titles of the application notes. As I recall, I found them in an obscure website and am hunting around for them. Will post links with what I find.

Ron

From easy to difficult:

Almost all timebase calibration can be done with a 10 MHz function or
signal generator and frequency counter. The fastest sweeps with
magnification require a 100 MHz or faster source for linearity
adjustment but this is seldom needed.

Vertical calibration can be done with a function generator, AC
voltmeter, and some attenuators but a calibration generator like a
PG506 makes it much faster.

Transient response calibration requires a fast reference level pulse
generator. The PG506 fulfills this function up to at least 100 MHz
but 350 MHz and higher require a faster generator like the tunnel
diode pulser Tektronix recommends. Leo sells one which is suitable
and more than fast enough:



I have an SG503 for generating a leveled sine wave up to 250 MHz but I
have not required it for an oscilloscope calibration yet. The SG504
does not cover low frequencies so both are needed for a full range.

On Sat, 03 Mar 2018 16:46:32 -0800, you wrote:

Hi,

Those of you who were following my "7603 working ... then blank" Thread will know that the problem was a shorted C492 Tanatalum cap on the Vertical Amp board.

To replace this cap, I could simply clip the leads and 'tack' on a replacement ..... or completely remove the old cap leads and properly solder in a new cap. The latter is my preferred solution .... but when I removed the Vertical Amp board (3 screws), the heatsink (aluminum plate) at the rear appears to be held to the circuit board by U450 .... thus restricting access to un-solder the caps leads from the back of the Vert. Amp. board. I did try to un-solder the cap from the top of the board, but not having worked on a Tektronix circuit board before, I was very reluctant to apply too much heat ... :)

The back of the board connects to the vertical CRT deflection pins.
The little collet sockets pull straight off of the pins but you still
have to be very careful.

U450 includes a threaded base (as per photo in Service Manual) .... and I am unsure as to how to remove it ... or whether I should even try .... :) ..... please advise any ideas?????????

Cheers,
Ian

I would probably just clip the leads as you suggested and solder the
new capacitor on from the top of the board instead of messing with it
and risking damage if you are not familiar with removal and assembly.
I have not actually done this on my 7603 but I have on my 78xx
mainframes.

On Fri, 2 Mar 2018 18:48:31 -0300, you wrote:

...

2. It came with 2 7B53As (the additional one with option 5, in the right
vertical slot... Maybe good to uh... Raster!?). This second one is not
functional at all.

Two timebases can indeed generate a raster in these mainframes. A
raster is also useful for verifying the condition of the CRT phosphor.

3. The vertical plugin (7A26) seems to be working fairly... But any
waveform greater than 4 div are clipped... I`m not sure if the mainframe
gain may be very low (or set such), so requiring the plugin's gain to be
increased beyond its dynamic range.
I don't think it's a problem of the vertical amplifier itself, as the
readout is showing well, close to the CRT's edges.

A 7B53A can also be used as a calibrated vertical amplifier in XY
mode.

The clipping does sound like a problem with the 7A26 but try testing
it in the right vertical slot also.

4. The "working" 7B53A is acting weird... It's sweeping backwards (from
right to left :-) quite funny) and in x1 magnification, it only fills about
3.5 divisions... Only with X10 engaged I can see a trace that crosses the
entire screen...
Nevertheless, at x10, it seems the scan is fairly linear...(well, at x1
too, but rather compressed).

I had a 7B92A which did this because the delayed timebase cam had
separated from the ends. Aligning it and gluing it to the ends with
plastic welding compound fixed it.

Luckily you have two 7B53As so between the two you may have a complete
set of replacement mechanical parts for any which are broken and the
second one can serve as a model for reassembling the other.

I can also see some upward bump of about 0.1div on the left end of the
trace (remember that the left end is actually where the end of the sweep
is) and a downward bump (of about the same 0.1 div) on the right end of the
sweep... I don't know what to think of that... maybe it's related to the
Hor. gain problem... Maybe it's some vertical channel switching artifact
(between the trace and the readout).

It is usual to see some tiny ripples at the beginning of the sweep
which are interference from the trigger but it sounds like you are
seeing something else. Check the regulated low voltage power supply
outputs for ripple.

6. The CRT... well that's where I have mixed feelings... For once, it's
definitely brighter than that of my poor 464...and that makes me happy
already, since I couldn't find a replacement for it.
But it also exhibits double peaking and a quite marked change of focus as I
increase the Intensity... But since the 7623A has Auto-Focus amplifier and
DC restorer (which the 464 lacks), there can be some plain electronics
fault at play.

Keep in mind that storage CRTs are not as bright as non-storage CRTs.

I will post some pictures as soon as I can take.

Do any of the above behaviors / defects ring your bells? Any First thoughts
are welcome!

One of the slower single trace vertical amplifiers like the 7B15A or
7B16A would be convenient for diagnostics and in place of a
standardizer. The single trace amplifiers are simpler inside
providing easier access to the interface signals than the dual trace
amplifiers.

Great, thanks!! Now after replacing 80% of the resistors, I can finally put this thing back together!!

-Brian

Manual error to be sure ...in my manual the parts list say 100 and the schematic says 1K ( base of Q366) ..my money is on 1K being correct. At 100 ohms I am guessing would pull the base voltage to low and Q366 would be turned off all the time

-DC
manuals@...

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

It is a typo in the parts list. On the schematic it is 1k. The part number is for a 1k (315-0102-00 is a 1k).



Regards.

I'm replacing out-of-tolerance resistors in my 2901 time mark gen and ran across a 1k resistor where the SM says it should be 100R. The resistor in question is R364 on the divider board directly behind Q347. This isn't a model number dependent resistor, but my SN is B041433.

Does anyone have a 2901 they can pop the top on and have a look?

Thanks,
Brian

Hello,

May or may not be a fit for your application or budget, but I saw this on page 69 of the March 2018 RSGB magazine:

Micsig DP10013 100 MHz high voltage differential probe, about GBP150

Also found on amazon.com for about $170



I do not have one, and have no affiliation with that company (I just subscribe to RSGB).

Hope that it helps.

Scott