Re: Lot of threads on 24xxB but few on 24xx"A" ...

Chuck Harris <cfharris@...>

The following is my opinion, and should not be taken as anything

The only "immediately fix" problem in *any* of the 2465 family is the
SMD capacitors on the post B050000 2465B scopes. Not even the RIFA
caps have that status. In the USA, the RIFA caps are not a problem
at all. I believe that Tektronix didn't care about the European
market much at all; their only concession to Europe was to put a 220V
power position on the back panel. They didn't go out of their way
to make sure that the parts they specified would work well long term
in the realities of a 240V utility... hence the RIFA problem. Metric?
What's that?

The 2465 was the penultimate version of the scope. It was intended
to be the flagship of the portable scopes, and Tektronix designed it
in a very organic way. There was just enough CPU to handle the scope's
needs, as designed. If there was a major flaw, it would be the LED's
behind the front panel were too dim for use in well lit areas.

The success of the 2465 caused tektronix to throw everything they had
at the upgrade, including cheapening it by removing most mechanical
switches and knobs that kept any state information. Their cheapening
also included using the same speed CPU as the 2465, but inserting the
CPU between virtually all of the switches and knobs in the scope and
the circuits they control. The only exceptions are probably the

[In the "Stupid pet trick" category, try turning the intensity up too
bright on your 2465A or B scope, and then turn the scope off. Next,
turn the intensity control fully CCW, then turn your scope back on.

I believe that the 2465B project spent too much money, and wound on too
long, as such projects often do, and Tektronix decided they needed to
get some return on their investment early, so they put out the 2465A

The 2465A models have all of the electronic changes as the 2465B, but
lack most of the software bells and whistles that the 2565B introduced.

As I stated earlier, there are no "must fix" parts in any 2465 family
scope, except the SMD electrolytic capacitors in the 2465B post B050000

-Chuck Harris

ulf_r_k via wrote:


Over the years, I have seen and read a lot of threads about 24xxB but very few regarding the "A"
version. Are there any similar "ouch" information apart from immediate replacment of
the RIFA capacitors in the AC power line filtering?


Ulf Kylenfall

Re: TM50X DC ripple?

Michael W. Lynch

On Fri, Feb 12, 2021 at 12:10 AM, Ed Breya wrote:

When it's sufficiently loaded, you may see volts of ripple, making it easy to
assess the condition of the caps, or compare different ones.
Being a novice at this game, this is why I asked. It may be anecdotal, but the original caps had much more ripple (unloaded) than was measured after the cap replacement by a factor of 10-20:1. My first indication of trouble was the malfunction of the PG506 and this has also been remedied. That being said, It is clear that I need to go back and measure the loaded ripple. I will do so and report the results.

Michael Lynch
Dardanelle, AR

Re: Tm500 Extender on eBay


I totally agree with Walter. I bought what I believe is the first one that was listed on epay 11/27/20. When I saw it listed as an opening bid of I think $30 and a buy it now of $70, it took about .5 sec to click buy it. The seller is in VA Beach and I am in Chesapeake, It was in my hands the next business day. The edges are chamfered and it has a nice fit in each power module that I tried it in. In some power modules it had a rather firm fit where others were an easier fit which is the same as plugging any module in them. To me it is a very good adapter at what I see as a reasonable price.

Re: Lot of threads on 24xxB but few on 24xx"A" ...


Hello and fine to hear from Scandanavia.

I had all three types, presently 2465B and 2467. There are many common parts and boards between 2465A and 2465B.
But 2465A were not manufactured in as large a quantity.

The power supplies all had similar recapping drills and RIFAs, especially important for 240V mains use!
Others on the forum can mention if the 2465A had A5 boards had the notorious SMD ELCOM/Lytics that leak or the battery powered NVRAM.

One great source is the TekWiki, with manuals, specs and PSU notes.

Bon Chance,


Re: Waking a slumbering 475


My understanding of WHY you would start an instrument on the variac is that you are trying to bring tubes up slowly, so that you don't blow any filaments by hitting them with full current. That is only valid for tube-based instruments, and the 475 is, with the exception of the CRT, all solid state. Is there any possible benefit to bringing up a solid state system slowly on the variac?

-- Jeff Dutky

Re: Waking a slumbering 475


Roy Thistle wrote:

PARD testing on SMPS and linear, uses a variable AC line voltage source... like a Variac autotransformer... to test for tolerance
within the specified line input range... but not below it.
That is true. Reading through the short form calibration process it appears that you never run the autotransformer below 103.5 V. It's been a while (well more than a decade) since I tried this on my 475, and my notes are frustratingly terse, but it looks like the 475 will actually operate at well below the indicated minimum line voltage (my notes say that the LOW LINE indicator came on a 70V and that there was a trace on the screen).

Reading through my notes is a bracing experience: I was so ignorant then. I drew a picture of the trace that appeared on the screen, presumably from connecting a probe to the calibration loop. The notes say "this is what I expect" but the drawn waveform clearly shows that there is a bad discontinuity in the channel (the wave form shows alternating positive and negative going spikes, not the square wave that should be expected).

I know that I put some more work into the scope after that, but I did not keep any written notes of it. My recollection is that I had to exercise the VOLTS/DIV and SECS/DIV knobs quite vigorously before the scope would appear to work even marginally well.

I also notice, which more than a little horror, that I was following advice from the sci.electronics newsgroup to start the 2213 on the variac. It's a wonder that the scope survived.

-- Jeff Dutky

Re: Shipped They Are

Michael W. Lynch


THANKS for all your efforts! Looking forward to receiving mine in the mail.


Michael Lynch
Dardanelle, AR

Re: Tm500 Extender on eBay

Michael W. Lynch

I do not have the luxury of owning so many different examples of TEK extenders and the "Original Tek produced extenders" were all monstrously expensive when I went looking. Therefore, I ended up purchasing an excellent 3rd party flexible extender that includes test points and LED power indicators in its design.

To Walter's point about pricing, I bought 2 of these aforementioned "flex kits" for about the price of this one extender, and as I said, perhaps the seller was "too cheap" on the flex extender kits.

Walter is correct, plugging the flex extender into a loaded mainframe requires that an adjacent plugin be removed to insert the extender, not a big deal for me.

However, the flex extender allows the Device under repair to be moved and turned to almost any position when you are working on it; a considerable plus, in my opinion.

The flex extender also allows people with limited bench space to position the Plugin to take advantage of said limited space.

While the mainframe connectors certainly are quite robust, the rigid connector still will impart far more force on the connector and on the PC board of the extender itself. This would need to be dealt with in some form or fashion.

The quality appears to be very good, I have no concerns about that, other than what I have previously stated. If the chamfer did happen to be missing, that could be remedied with a few strokes of a file.

If I did not already have extenders, I would jump on one of these myself. If you are going to work on these TM500 plug ins, sooner or later you will need an extender or two (in some cases).

All in all, I do not find the selling price to be out of line in today's market. The seller deserves to make a profit and he must price the item accordingly (for the reasons that Walter mentions), especially with E-Bay taking their 12.35% cut.

I certainly appreciate Walter and his well reasoned comments and experience on this topic. looking forward to hearing his opinion after he tests one of these in person.

Another .02 cents added to the pot.
Michael Lynch
Dardanelle, AR

Lot of threads on 24xxB but few on 24xx"A" ...

Ulf Kylenfall


Over the years, I have seen and read a lot of threads about 24xxB but very few regarding the "A"
version. Are there any similar "ouch" information apart from immediate replacment of
the RIFA capacitors in the AC power line filtering?


Ulf Kylenfall

Re: Shipped They Are


Thank you so much Larry for your work making this happen! Looking forward to stuffing the boards.

Re: Stan Griffiths estate sale


David &/or others:

Could someone make contact with the daughters or the administrative person and get a Phone# or email address,
to allow us to contact them ?

-- Clearly there is interest in this collection.

For whatever reason, I am unable to click and 'connect' with any of the facebook or other hyperlinks.
They just don't work with my browser.

thank you,

Re: Hey this isn't even on Tekwiki!

snapdiode <snapdiode@...>

I just ctrl-f the main page and found nothing relevant for 183.

Re: Hey this isn't even on Tekwiki!


It's listed under "183"

Re: Tm500 Extender on eBay


A few comments on the ebay extender (which I have nothing to do with personally).

1. the edge fingers *ARE* chamfered, it is clearly shown in the pic, and it even says so in the text. I found all the bashing of that card on this topic totally uncalled for, and especially ironic considering that all the TM500 tester kits just delivered *ARE NOT *chamfered. I see that was "solved" by a few hits with a file, but apparently such a fix was not deemed possible for this extender card.

2. that rear backplane connector is strong as an ox. I have trouble picturing the case where it will be destroyed by this card. It is MUCH stronger than the 7K backplane connectors.

3. It would be EASY to add a correct height side plate or plates via stand-offs to fit into the cage height (maybe put some nylon edge guard on it to make it slide easier), to act as a strain absorber and positioner. it may  also be possible to just add a bit of nylon edge grommet to the board itself to do this, making any flexing on the connector a non-issue.

4. I own literally every extender that has been made for TM500/5K/7K plug-ins in cable and rigid styles, original and 3rd party. They all have their features and detractions. The actual Tek flexible cable for TM500 repair is Ok, but would have REALLY benefited from some status LEDs for power supply status (to quickly check all the fuse conditions), and it is incredibly hard to insert that short edge connector into the frame unless the adjacent plug ins are removed first, an issue this long card avoids.

5. The current long extender being offered seems pretty good to me, I would have added power supply LEDs, and polyswitches to the DC supply lines (can't be done on the AC lines except by fuses) to prevent damaged plug-ins from cratering the frame, but that could in fact be added easily.  A little bit of mechanical support to engage the frame for stress relief, and voila, total happiness could be yours.

6. The price is not bad, that is a LOT of PCB area, with  GOLD chamfered edge fingers, solder mask and slots, all extra cost adders for fab. I'm going to buy one and test it for myself to see how it compares to the cable types.
I should point out that very similar VME single connector extenders are hundreds of dollars (I have those too),
so I don't really begrudge the maker a some extra revenue for his time and design.

just my $0.02 worth on this topic.

all the best,
walter (walter2 -at-
sphere research corp.

PS: Tons of power supplies and audio goodies being added daily to the *stuff season page*, it's almost  ready to go,
and you can grab stuff now. Vu-data items added to the Tek section.

Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:-
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Re: Looking for 067-0625-00 Peak-to-Peak Detector Photos

Jared Cabot

Do you remember how the signal passed through from the cavity to the PCB?
It appears there is a feed-through capacitor for each diode maybe? Do you remember if the 50ohm resistor had this too or if it was just passing through a simple hole?


On Fri, Feb 12, 2021 at 12:00 PM, Kerry Burns wrote:

As far as I can remember it was fairly simple – as per the third photo in
the album (the one with the red tape). The 50ohm resistor is soldered directly
to the centre pin of the GR-874 and the two diodes to the ground.  Despite
the warnings in the manual about disturbing this RF cavity, my peak detector
seemed to test ok after the repair.  I had no choice anyway as the 50 ohm
resistor was broken in half.  I was just careful to select the new resistor
to measure as close as possible to the correct value.


Re: Hey this isn't even on Tekwiki!


Thanks 🙏

Hey this isn't even on Tekwiki!

snapdiode <snapdiode@...>

Also an interesting "salvage" stamp from Tek itself all over the thing.

Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603


Hi everyone,
I reassembled the TR503, connected it to 7L13 (SA) and I have the signal on the screen of the SA.
With the MAX span / div the trace drops a bit from 1 GHz to 1.8 GHz but it is in the 2 dB, so I think acceptable, with 50 MHz of span / div the trace on the screen is a straight line. I can get a decent adjustment of the TRACKING ADJUST on the TR503 with the resolution at 300 Hz on the 7L13, but at 30 Hz the adjustment is not enough, maybe some calibration needs to be revised.

I also have two doubts: when I redid the calibration procedure of the BPF four cavity filter, I got the curve centered, but very narrow, from the manual it seemed about 20 MHz wide while to me it is around 2 MHz and I was unable to widen it acting on the BPF filter settings. The other question is about the 7L13: is the PHASE LOCK active with the selector positioned up or down?
When I place it high below a white dot appears.

Thanks for your help

Re: Stan Griffiths estate sale

Lawrance A. Schneider

How many of us are there in this group? Is there any possibility of 'grouping' and buying all of this? Storing it where? The time line is absurd. Living in Maine, I'll never see any of it. I see the laments of those that have seen this. Does anyone know where the 'slip-sticks' are being presented?


Re: Waking a slumbering 475

Weathers, W

On Thu, Feb 11, 2021 at 01:24 PM, Roy Thistle wrote:

On Wed, Feb 10, 2021 at 07:36 AM, Torch wrote:

Before giving it to me, the owner plugged it in and turned it on
That's usually what inexperienced sellers do with these old Tek scopes (unless
you can catch them before they do it.)
I'd say, if you got one (buyer or seller)... don't plug it in, until you check
it out.
This is interesting. So what is the right way to have it checked out if it should not be plugged in and powered up?

If the tantalum caps fail short, should they be measured prior to running?

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