Re: Tektronix 492BP


No it does not goes to band 5? only to 4 upto 21GHz.

Re: 1 Peter Keller Book for Wichita KS held in USPS Seattle Network Distribution Center

Craig Cramb

Received book, guess just have to have extra patience when dealing with the Postal Service. Thank you for all of your extra effort.

Eric, yes we are definitely in the same county. I’m glad to see there are other Tek fans locally. Too bad we don’t have access to local electronic stores as other members in the USA have in their neighborhoods.


Re: 2236 on shopgoodwill


The guy that posted that ad definitively needs glasses, model was described as "233G".

Status Update on Canada bound Peter Keller Books


I got at least one of the Canadian tracking numbers mixed up with another
Canadian tracking number. These are the correct tracking numbers and their
destinations and/or delivery status
LH127124103US Delivered North Vancouver BC
LH127126740US Delivered Edmonton Alberta
LH127128207US Cleared Customs Jan 17; Arrived in Burnaby BC mail facility
Jan 19; In transit to destination BEACONSFIELD, QC Jan 19.

Dennis Tillman W7pF

Re: Peter Keller's books are going VIA AIR MAIL

Thomas S. Knutsen

My copy to Norway was delivered today. Much pleased with the quality of the


ons. 20. jan. 2021 kl. 02:14 skrev momemeca <>:

Hello Dennis,
My signed copy of Peter Keller's excellent book was delivered this morning
(Australian Standard Eastern Time).
It is such a beautiful book in itself only bettered by the technical and
historical contents.
Thank you for your diligent work in bringing this to fruition, despite the
frustrating challenges along the way. All for a good cause and, I am sure,
most appreciated by all who ordered a copy.
I, for one, can say that this book will hold pride of place in my
technical library.
Finally, please pass on my sincere thanks to Peter, firstly, for for his
excellent work and, secondly, for taking the time to autograph my copy.


Rick (RLG - Somerville AUS).

On 8 Jan 2021, at 17:39, Dennis Tillman W7pF <>

One more detail I forgot to mention:

The international orders for Peter's book are all sent via AIR MAIL so
should arrive fairly quickly even though they are going around the world
many cases.

Dennis Tillman

With Best regards, Thomas S. Knutsen.

Please avoid sending me Word or PowerPoint attachments.

Elastomer Switch / HYPCON Contact Cleaning 067-0587-02 Standardizer


Hello all!

I've got a 7000 Series Standardization Plug-In 067-0587-02 that is acting strange. Sometimes the Gain setting on the TEST switch will show a compressed set of lines instead of the correct 1 line per division and the Aux-In is distorting the waveform. I swapped the Aux-In first Hybrid IC U350 for one out of my 7904A and no change was observed. I removed and re-installed the 2nd Hybrid U390 and the waveform was better but still distorted. Due to the low use of the plug-in from the seller I purchased it from I suspect that the contacts in the HYPCON's and the TEST switch contacts may need cleaning. There is a cleaning procedure in the manual I can follow but I was wondering about the application of DeOxit Gold to the contacts?

Thanks in advance!


Ondrej Pavelka

Where is the service hours and power cycle statistic stored? Is it in the Dallas chip?

I am about to buy 2467B which looks in excellent condition and was recently serviced. Since it shows only 4 power cycles I assume the Dallas chip was replaced as a part of the service / calibration?

Re: Tektronix 492BP

Sergey Kubushyn

On Fri, 22 Jan 2021, Mike Yepes wrote:

Does it switch to frequency bands higher than 5? Bands for use with external
mixers start with Band 6.

Hi, can Anyone help how to get higher frequency displayed on this?

* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *

Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Ed Breya

Bruce, regarding your question about compatibility of this tester with TM5000 mainframes, I believe it should work. As I recall, the TM5000 mainframes can run TM500 plug-ins, but the reverse does not work - TM5000 plugs can not run in TM500 frames, and I believe they are mechanically keyed to prevent engagement.

All the pinouts for connections to the DC supplies, AC windings, and pass transistors are the same*. The main functional difference would be interpreting the tester's response to the DC supplies. The TM5000's regulated supplies were designed to provide just above the worst-case bottom of ripple (BOR) of the TM500's rectifier/filter outputs. So, any TM500 plug installed would see only the minimum value of input DC, and run more efficiently. Plugs that make their own supplies from the AC windings would run about the same in either frame type.

So, if the tester is looking for the higher average DC voltages of TM500, it may report that it's too low in a TM5000, while in reality, it's just right.

*TM5000 has an additional signal indicating valid power on state, on a pin that was unused in TM500.


Re: Tektronix 492BP


Hi, can Anyone help how to get higher frequency displayed on this?


Re: Tek 4041 GPIB Controller

Monty McGraw


Sorry to hear that - I thought you had your DDU repaired and that you booted from your DDU instead of the tape drive.

I don't suspect the 4041 tape drive, although I would recommend using isopropyl alcohol on a swab to clean the head, and try the tapes again.

It appears the plastibands are only a temporary drive belt solution in the tape cartridge - and they will stretch as the drive rewinds the tape to the beginning before it can find any file.

This is the Amazon link I used to get 4.25 inch plastibands:

It is pretty easy to open the tape cartridge and replace the plastiband - the 4041 operators manual page 5-6 describes tape cartridge respooling with photos on page 5.7.

You don't need to respool the tape to replace the plastiband - just lift the plastiband off the white belt wheels and capstan and put the new plastiband on starting with the capstan and finishing by pulling the plastiband over the white belt wheels. Then I use a bamboo chopstick to pull the belt away from the takeup reel with the least tape and tighten the tape by rotating that reel with a finger, then release the belt onto that reel. I then pull the cover back where the tape head touches the tape and push gently with the chopstick to check the tape tension - the tape should deflect 1/10 of an inch or so, but not 1/4 of an inch.

Then put the cartridge cover back on and fasten the screws and the tape should now work.

Re: [dead tek 485] Can i fix it ? (newbie here)


I've moved the trace on X axes in order to show you this also the weird
vertical trace at the beginning of sweep.

Hope to ear from you.
At the back of the scope there is a BNC marked as A-gate. While applying your sine wave to channel 1, triggering on channel 1, connect A-gate to channel 2. Pick "chop". Move X-axis to see the beginning of waveforms. You should not see the rising edge of the A-gate. Similarly if you look at A-sweep (available at the BNC back of the scope), you should see a linear ramp starting from the beginning of the trace. If you can see some portion of the A-gate while it is low or rising, blanking may have a problem. If A-gate is OK but ramp looks strange then could be something with the ramp.

I have a 485 and tried this, I can send you the screen shots.

Jittery waveform needs to be debugged separately. If you have another scope look at A-gate and the input signal at the same time to see if A sweep always starts at the same point of waveform. You should also try external trigger (BNC at the right bottom) feeding same signal to both Ch1 and "Ext Trig" and choosing Ext (start with Ext/10 if you are applying 5Vpp).

Re: TEK465 Horizontal trace

wes Bolin

Thanks for all of your help. I have spent way more time and I'm out of my
element and another O'scope for around $100 looks real attractive. At
least this one is a
parts source. I'm returning it to my friend who is still looking for a
working O'scope.
I'll keep monitoring the Group. Best Regards,
Texarkana, AR

Re: 2236 Manuals

Michael W. Lynch


Were you wanting a "SERVICE" Manual? Because this is an "OPERATORS" Manual. These are not typically used for repairs and do not always contain detailed repair information, at least not in any of the Operators manuals that I have for my scopes.

Michael Lynch
Dardanelle, AR

2236 Manuals

Dave Peterson

Is Shawn (KJ7MX) on here?

I'm asking in reference to the eBay listing for printings of the 2236 manual:

Seems the original Tek manuals for 2236 are a bit difficult to come by, so I'm considering purchasing the above.

I'm curious which version of the manual it is. There are several listed on the Tek Wiki. My SN is 017799 so I think relatively early. I would prefer having the correct manual for this SN.


Re: Tek 4041 GPIB Controller

Gary Robert Bosworth

Monty: If only the engineers at Tektronix had created a boot ROM that was
not erasable with age. My system is completely dead if I cannot run the
AUTOLD from the tapes. None of my 3 tapes will work with my system. I am
going to try to dig up my other 2 tape drives this weekend and do some
swapping to try and get this 4041 thing up and running. When I built up my
2 Heathkit H8's back in 1977, I never had the slightest difficulty in using
them to the fullest. At my old age, I am losing interest in all of this
technical trouble. I need to be at peace.


On Thu, Jan 21, 2021 at 5:30 PM Monty McGraw <> wrote:

I have spent the last couple of weeks with the EZ-TEST Generator (Volume
1) and Translator (Volume 2) programs and can confirm the files I posted
are complete and work fine.

The EZ-TEST Generator program does require a Tektronix 4105 / 4107 color
graphics terminal - but I found a VersaTerm Pro emulator program for the
68K Mac that runs in a Mac emulator called Basilisk II on Windows.
VersaTerm Pro emulates DEC VT and Tektronix graphics terminals including
the 4105.

EZ-TEST Generator programs must be loaded and run with the Generator, but
the Translator can create a standalone 4041 program from an EZ-TEST program
that runs with a regular serial console and is faster than the EZ-TEST

My 4041 forum photo album has photos of EZ-TEST running on the VersaTerm
Pro emulator:,,,20,2,0,0

I created a simple two-step EZ-TEST program with the Generator, then used
the Translator to convert it to a BASIC program. I was then able to edit
that BASIC program to add commands that I didn't find in Generator menus.

I just posted info on!!&p=652071#post652071
on my first EZ-TEST program, which runs some tests on my Tektronix MI5010
and six interface cards: ADC (analog to digital converter), DAC (digital to
analog converter), DIO (digital I/O), RSC (relay switches) and a MEMORY
card that can DMA digital data from the other cards into buffer memory,
faster than GPIB transfers.

Gary Robert Bosworth
Tel: 310-317-2247

Re: [dead tek 485] Can i fix it ? (newbie here)



it looks like the beam is being unblanked before the sweep starts. Maybe the Z-axis amplifier has a problem? Or maybe the trigger circuits? Maybe some interaction between the two?

That vertical bar you see on the left is the input signal without a sweep signal. That should be hidden by the Z-axis amp squashing the beam intensity during the retrace and before the trigger arms and triggers, but clearly it's not working correctly in your scope.

-- Jeff Dutky

KiCAD 6 is coming shortly


A big milestone is coming this spring for KiCAD (schematic/PCB software).
this new version is a very powerful tool, and 6 adds microwave/RF layout features and a lot
of other goodies. For everybody that has groaned over the initial cost and ongoing support cost
of other eCAD tools this can be important news.

If you are unable to afford the big seat cost of altium/Orcad, you may really want to look at this open-source tool.
it is multi-platform (MacOS/Win/Linux) and free, with huge library support from Digikey and Mouser.
CERN is the driving and coordinating group for this in europe, and is well funded long-term.
The software is already 30 years old.

Here's the latest 6 update info:

Just passing it along, as coupled with the huge security and cost benefits of an OS like Ubuntu,
it can really help you deploy a lot of capability and reliability for virtually no cost, whether you are a home user or company.
I have used most eCAD tools (including KiCAD), and the new changes really make this look appealing to me.
If as a Windows user, you really miss the once free eCAD tools that used to be available, here's a chance to get
a truly professional grade tool in an affordable way. If you add in LTspice, you have a great engineering suite for free.

the home KiCAD site is here:

all for today, hope everybody there is well and safe,
walter2 -at-
sphere research corp.

Tektronix 7L12


Have just obtained a new to me 7l12--it seems to work somehow--if filters-video span etc works--but dc feedthrough 150Mhz off--when tested with 50Mhz cal signal --it is located 150 off and span seems to be okay.
Level seems also to be off.
Any idea welcome.

Re: 2235 Horizontal Calibration Issue


On Mon, Jan 18, 2021 at 10:51 AM, Ozan wrote:

Hi Stephen,
Before I derailed the thread (Tom opened a new one for those of us who can
talk about two transistors for hours) I gave some suggestions to debug in

Take a look at B sweep to rule out nonlinearity in A sweep generator.

When I suggested to check the voltages I meant to check the voltages shown in
the schematic sheet <6> (Probe Adjust, XY Amplifier, Horizontal Output). In
particular voltages at the base of Q780 and Q770, and voltage at the cathode
of VR764. You need to put the scope in a setup shown in "Control Settings"
section prior to the schematic. Voltages could be slightly off but pay special
attention to the difference, i.e. if everyone is up/down by 100mV could be OK.
Report back here if any voltages are off.

Base of Q770 reads +6.090 VDC, while the base of Q780 reads +6.081 VDC
However, the cathode of VR764 reads high a +5.135 VDC....

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