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Tek 4654M; No Trace, No +5V, No +95V; Help

Harrison
 

Greetings; I am more of a mechanical guy than electronic guy. That said I am trying to troubleshoot a 465M scope that has no trace, no trace with beam finder, no +5V nor +95V. I was testing for the +95V at the TP on the left side of the A11 Interface board forward of the power supply area and the +5V on the TPs on each side of the A11 board (right side in the rear and left side outboard of the +95V TP.. Unit does power up and CRT illumination is present. I am using a Air Force Service Manual (465M Operation and Maintenance) that I found on line. I have been tracing +5 voltage from the T700 transformer forward. Things seem good before the Q742 transistor. After the transistor I was looking for +4.9V and had -0.121V (basically zero. Q742 is a 2N222 NPN transistor. My thought was to replace it to see if that restored the +5V. My issue with the +95V is I at a loss to determine where the +95V originates. I would really appreciate some "adult supervision and guidance" on both the +5V and the +95V issues and any suggestions, advice and guidance in general. Thank you very much. Stay safe and healthy. Harrison N1FAM


Re: Tek 2430 (Non-A) with Strange Problem

Lawrence Glaister
 

I have had several pieces of gear start to "stink". The cause has been leaking electrolytic caps. These have been from small 100uf/25v to larger power supply caps. One has to look very carefully at the cap for any signs of bulging tops or around the base of the pcb mounted caps for any signs of leakage. The leakage will create havoc with the pcb traces and you may end up have to jumper around damaged PCB traces. The smell could best be described as a bad case of body odour. If you have friends in the lab, everyone will be looking around trying to figure out who forgot to shower a week ago!. Equipment with exhaust fans are very good at filling the room with odour. The problem with using the nose to locate the parts is that it seems after several sniffs to saturate and no longer work as a good detector. This problem affected a lot of equipment from around 2000 including computer motherboards.
Happy hunting!

Lawrence VE7IT
Automation Engineer

On 2020-08-05 4:58 p.m., Harvey White wrote:
Depending on the smell (5$, 10$, 20$.....) it could be the RIFA capacitors on the power input.  Those are known to fail, and especially in 220 volt land.  (NOTE: I had some fail in a 120 volt application, likely same smell).  Nothing will indicate a failure *in* the scope, but you still have a potential problem.
Harvey
On 8/5/2020 6:46 PM, Mike Harmon wrote:
A few days ago, I got a 2430 from my friend at the local electronics emporium.  He said it came up, but smelled bad, so he shut it down. When I got it home, I pulled off the case, turned a fan on the CCDs and fired it up to check the voltage rail test points on the side board.  Every one measured exactly where it was supposed to be.  The Self-Test screen came up for several seconds and then the screen went immediately into a display of the A and B sweep lines.  I was able to move them all around, and when I hooked the probe to the calibrator, I got a nice square wave.

Since I wasn't familiar with the 2430, I went to the other side of the shack to pull up the user guide on the computer.  A few minutes later, I went back to the scope.  The 3 GPIB status LEDs were still lit, but there was nothing on the screen at all.  The fan was also throwing out a LOT of "scorched PCB" smell (hot phenolic).  I shut the scope down and waited a couple of hours, then tried powering it up again. Absolutely nothing on the screen.  The longer I had it powered up the stronger the scorched smell got, so I shut it down.

I spent half of last night removing the boards from the scope and carefully inspecting them for any signs of overheating.  Nothing.  No scorched spots on the boards, no visibly overheated components, no discoloration anywhere.  This morning, I put everything back together and fired it back up with the fan on the CCDs.  Every single voltage test point on the side board showed exactly on spec.  By the time the scope was on long enough to make the measurements, it was really starting to stink again, so I shut it down.

At this point, I am stumped!  I have the complete (original) 070-4917-00 (1-1/2") manual and I'm reasonably experienced at trouble shooting, but I'm sort of at an impasse.  I would have thought that anything that caused that much of a stink ought to show some physical signs of overheating somewhere, but to this point, I haven't been able to find any.

Anyone out there who has experience with a 2430?  Do these symptoms sound familiar to anyone?  The NVRAM battery measures 3.07V, but I wouldn't think that a bad battery would cause the whole screen to go blank (?).

I know the smell was there before I fooled with the scope, because the guy at the store mentioned it, but the scope did work the first time I had it powered up (for a few minutes anyway).

Your sage advice and suggestions are most welcome!
73,
Mike Harmon, WB0LDJ
mharmon at att dot net




Tektronix AWG7052 repair

kevin@...
 

Hello

Have an AWG7052 with the error below,

Analog State

Channel 1 FAIL (C200110001)
Channel 2 FAIL (C200200015)

It seems that the internal loop back signal is not being detected correctly. This is a standard test that is run anytime the unit is to be used for signal output. Also, on power up there was an alert displayed stating that the calibration factors were not in memory. This could possibly be a defective memory backup battery.

Looking for recommendations for an individual or company that may be able to repair


Re: Message to satbeginner and Saroj Pradhan re: Tektronix 2230

btorgerson@...
 

Hello,
I personally own a Tek 2235A so I like lurking and reading about these specific scopes.

-Brandon


465M: No trace, No +5V, No +95V

Harrison
 

Am using an Air Force Service Manual (Operation and Maintenance) that I found on line as my reference. When powered up the +5V TP reads -.742 (basically zero) and the +95 TP reads +5.71V. I thought I had an issue with transistor Q742 ((Figure FO-10, PS and Interface board) and zener diode CR582 (Figure FO-9 CRT and Z Axis). Replaced both of them with no positive results. Still struggling to figure out where to go from here. Any guidance, advice or suggestion will be most appreciated.
Second question; In the power supply area (Figure FO-9 CRT and Z Axis) there are two Glow Lamps DS563 and DX564. What is the purpose of these lamps? They seem to be across pins 4 & 9 of the HV Multiplier. Do they function like a fuse? If so can they be tested like a fuse? Thank you.


Tektronix 475

Simon
 

I have a Tektronix 475 oscilloscope with no display. All voltages test correctly including the -2450V supply. On pressing the beam finder I see a very faint vertical stripe which can be moved from side to side by the horizontal deflection knob. I suspect a fault in the high voltage multiplier. I am wondering if there is a way of testing it without extensive disassembly. I was thinking of sticking a hypodermic needle through the HT insulation and connecting it to a neon bulb through a large resistor. Is this dangerous or is there an easier way?
Many thanks
Simon


Want to buy: Tektronix 213 DMM oscilloscope

László Császár
 

Dear group members,

I would like to buy a Tek 213 DMM Oscilloscope, even in broken or
incomplete condition. I need it for restoration of a faulty unit (i.e.
make 1 good from 2 faulty). EU seller preferred.

Thanks,

Laszlo


Re: Tektronix 2230

chipbee40
 

Hi Saroj,
I've followed this thread for a while and looked at where you have replaced components. You are focused on the preregulator, you might want to look at the inverter components. There is a number of threads covering excessive heating in these scopes (2235,2236) caused by Q944 Q947 Q946 T944 C944 etc.
Q946/7 are on the same heatsink as the FET so it might not be heat from the FET you are measuring.
Like I mentioned earlier, if the bridge diodes fail it does a real trash job on the power supply especially if you run 220V mains, all components are suspect.
https://groups.io/g/TekScopes/topic/7651908#98430
https://groups.io/g/TekScopes/topic/7651657#91605
Nice job rebuilding the transformer.
JC


Tektronix TDS3PRT Printer

 

I recently bought a TDS3PRT plug-in thermal printer for use in my TDS3000-series scope. I thought the price was reasonable; however, looking online for a manual for this printer, or the 016-1907-00 print rolls, nothing is to be found. These were discontinued at some point by Tektronix, but I assumed they were still usable. However from the sheer scarcity of information available about this printer's faults or otherwise, I am wondering if Tek lawyers didn't order marketing to make every trace evaporate. Have I made a mistake in buying this unit? Are the print rolls a standard type that can be obtained more economically elsewhere?

Bruce, KG6OJI


Fuzzy Trace that Auto-Corrects Itself

n4buq
 

I have a Hameg scope and if this question/thread needs to be deleted, then may the moderator please intervene; however, I think it may be generic enough for this list and I've run out of other sources so I'll try here.

When first powered on and the CRT starts displaying a trace, it is very fuzzy and wide - approximatrly 1.5 cm. Given about two minutes, the trace gradually becomes very sharp, focuses where it should, and stays that way for as long as the scope is powered up.

During that "warm up" time, the trace gradually becomes focusable near one extreme of the focus control and then gradually is focusable at/near center of the knob rotation and stays that way.

If I increase the intensity to fully bright as soon as the display becomes visible, the fuzziness disappears much faster but still doesn't settle out fully until about two minutes after power on.

I have replaced the HV resistors in the chain that makes up the focus voltage divider as well as a couple of other HV resistors in the intensity circuit but the problem persists.

There are a few 0.1uf 1kV film caps that are part of that focus circuit and I am thinking it could be one or more of those but not sure.

Anyone have any ideas as to what's going wrong and what to look for?

Again, if this is too far OT, then please let me know and I will not continue the thread.

Thanks,
Barry - N4BUQ


Re: 2465 Fan Collet Thingy

 

Hi Li,

would it be possible to add a guidance hole for the insert? Like some 2mm diameter and 5mm deep...

It seems crucial the hole is drilled in the very middle of the piece for the fan not to wobble around. Without guidance that seems rather difficult to obtain.

cheers
Martin


FS: Tek 11301A with 4 Chan & Diff Comparator Plug-ins

Bill Perkins
 

I have a Tek 11301A mainframe ser. no. B010135, an 11A34 4-chan plug-in ser. no. B010219 and an 11A33 diff comparator plug-in ser. no. B020129 for sale.

Everything had been sitting unused and owed to me for the last three years and finally arrived in beautifully packed, excellent condition from Toronto last week.

I bought an Artek Op manual copy for it, have spent a couple of hours with it and everything seems to work as expected. All controls respond, the touch screen areas all respond, everything drawn on the screen is sharp and clear with no trace of screen burn.

Cosmetically the mainframe is excellent, not a mark of the front or rear panels or controls and only a small-ish dig on the blue vinyl (?) covering on the removable top cover. The 4-chan plugin is unmarked while the diff comparator took a hit and has a chunk cracked out of its plastic front panel overlay, otherwise it's fine.

The cal' stickers are intact on both plug-ins although no cal' date is to be seen, leading me to think they might be the factory originals.

The keep alive batteries measure 3V as they should and it holds its settings thru a restart.

The shipping container is excellent, with at least 2" of fitted foam on all six sides. It rode 3,000 miles to Calgary from Toronto by UPS Ground and arrived unmarked and in such condition that it's reusable for reshipment.

$US550.00 all-up but shipping costs which are on the buyer's dime.

I also have a little cute little HP 3476A Digital Multimeter for $US50.00, a Wavetek 182A 4MHz Function Gen for $US75.00, and two of the 182A's exact predecessor from 'ED Engineering Co. Ltd.' in Japan, their model FG-1881, for $US75.00 for both. One is fine, the other produces no output.

Wavetek 182A Op_Serv is here:

https://www.pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/38_Wavetek/Wavetek_182A.pdf


Hit me off-list pls.

Best,
Bill Perkins
PEARL, Inc.
3020a Erlton St. SW
Calgary, AB
T2S 2Y6

+ 403 244 4434 Office fwds to cell' on 4th ring
+ 587 578 4434 Cell' and text

https://www.pearl-hifi.com


Re: 475 With a bowed display. . . .Ideas?

Michael W. Lynch
 

I am going to post some pictures of the phenomenon later today. I am also going to follow up on all the suggestion or ideas presented in the preceding conversations. I have plenty to check off the list for now.

If the Astigmatism, Geometry and Y Axis Align voltages and component values check out, then I will proceed with a CRT substitution. That will definitely help to isolate the issue to either the CRT or the Instrument circuitry.

I wish that I was better at using the proper terms to describe what I am seeing. I feel like I lead people astray when I use the wrong terms or otherwise poor wording to describe the issue. For example, my using the term "loading" when this was not a case of low voltage due to an overload in the circuit.



Thanks again for all the help!

--
Michael Lynch
Dardanelle, AR


Re: 7834 Missing Trace

Colin Herbert
 

To remove a plug-in with a broken pull-tab:

If you can grasp some of the pull-tab with long-nosed pliers, do so once you have put something to act as a pull-handle onto one of the BNCs (it doesn't matter which, but don't obscure the pull-tab too much and don't use a BNC Tee-piece; they simply pull apart. Something like a Normalizer is perfect). Pull the plug-in forward gently without pulling the whole scope off the bench and then give the pull-tab a pull with the long-nosed pliers while keeping pulling gently at the plug-in. You might hear a click as the retainer disengages and the plug-in start to move out. Once you have got the plug-in out of the scope, don't put it back into that or any other scope until you have sourced a spare pull-tab or disabled the retaining ability of the broken one, otherwise you are back at square one.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of sdferg7@...
Sent: 08 August 2020 17:08
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7834 Missing Trace

The trace only gets fuzzy when I have the calibrator signal plugged in, and only the top half. The issue still comes and goes, usually after I change a setting, e.g. the vertical channel. With no signal the only time the trace flickers from moving up and down is when it goes through the trigger.

Unfortunately the scope only came with 1 vertical plugin, in the right slot, and the pull tab is missing. Is there an easy way to get it out without much disassembly? In the manual it seems the only way to get the black follower tracks out is to have their respective plugin removed to access the screws. When I select the empty left vertical plugin slot I get a flat trace slightly tilted clockwise, maybe 1 or 2 degrees.

I also discovered I was mistaken about the 2 dots, they actually appear to be the minimum and maximum of the right horizontal plugin from the calibrator signal I had plugged in. If I select chop with no signal I get 1 brighter dot from the right plugin, still nothing from the left.

I also did more testing on the scope's calibration. Last night after the scope was pretty warm I tried measuring a 1.6V battery at 1V/div which showed on the scope as about 3/4 of a division. This morning I tried the same with the scope cold and it came to almost exactly 1 division. This seems to follow my previous experience with the scope reading lower as it gets warm. The scope also seems to read slightly off on the frequency of the calibrator signal, each period shows as slightly less than 1ms. Of course that could be an issue with the calibrator.

Shane


Re: 475 With a bowed display. . . .Ideas?

Michael W. Lynch
 

On Sat, Aug 8, 2020 at 10:34 AM, Raymond Domp Frank wrote:


I'd think that's way out of range for the electrical Geometry adjustments that
you mentioned earlier, so probably something is wrong of the sort that Chuck
describes. It may be worthwhile to quickly check if the Geometry adjustment
pot's range reaches the intended 0 to +110V. It's GND-related, so not
dangerous to measure, unlike grid- and focus- voltage levels.
I was thinking of checking the Geometry Pot, just to mark it off the list of possibilities. If this pot is somehow defective, this might affect the range of Geometry adjustment.

Re. the "fisheye" appearance: Is the distortion mostly (radially) symmetrical?
In that case, I wouldn't think it could be just a moved magnet.
The marker peaks and lines are straight (more or less) but simply tilted in at the top. The tops of markers to the left of center lean in toward the center and those to the right do the same. The markers are a mirror image of one another, with the centerline being the mirror point. If that makes any sense.

Trying another CRT seems to make sense. Not too much hassle with a 465/475.
Just the usual care with the lingering anode voltage.
Yes! I will discharge before handling or removing, I have shocked myself before. One does not quickly forget a multi kV shock.
.
BTW, re. the first post, Michael wrote:

"Problem was C1442 was bad. High resistance and almost no capacitance, loading
the +15V supply."

The high resistance and low capacitance resulted in your meter showing that
the average or RMS voltage was too low so good regulation wasn't possible.
C1442 wasn't loading the +15V supply ("high resistance") but loading the 15V
supply wasn't possible, since the regulation circuit received practically
unbuffered rectified AC. It's probably what you meant.
Actually, I used the term "loading", as that was a typical cause of low DC voltage which I was familiar with, especially when "Bad" capacitors are concerned. I "assumed" loading, but after reading your comment, I realized that actual cause of the problem was that the regulation circuit simply could not cope with the unbuffered rectified AC. I knew there was a problem, but did not know the proper term to use to describe it.

One important lesson that I learned early on, was that all the power supplies need to be within specs before trying to make anything else work. This is the one thing that seems to be overlooked by novices like myself,

After isolating the +15V supply from the instrument and still having problems, there were a very limited number of parts that could be the cause. So my diagnosis was a process of elimination of the individual components and the bulk capacitors lke C1442 are the most likely and well know failure point.

I did not attempt to test the capacitor "in circuit". As a confirmation of the failure, I tested C1442 after I had removed it. The ESR showed about 1000 ohms and the capacitance at 196pF.

As always, I appreciate the education that I receive from everyone who has replied!

Sincerely,
--
Michael Lynch
Dardanelle, AR


Re: 2465 Fan Collet Thingy

Li Gangyi
 

Completely forgot the link, here it is.

https://www.thingiverse.com/thing:4564817

On Sun, Aug 9, 2020 at 1:24 AM Gangyi Li <li.gangyi@...> wrote:

Very quickly drew up a STL for people who wanna try 3D printing the
plastic bit, I believe the original part has a metal stud for the nut to
thread onto, you're gonna have to drill and tap the center for a stud.
Do let me know if you've tested it out and if it works good.

I have access to a small lathe, however I'm not equipped to do slits as of
yet, if there is interest I might get around to adding that capability.

On Sun, Aug 9, 2020 at 12:45 AM Chuck Harris <cfharris@...> wrote:

Log onto your groups.io account. It should open with your "my groups"
screen.
Click on "Tekscopes".

On the left side of the messages screen there is a list of areas
associated
with tekscopes. One of them is marked "FILES".

-Chuck Harris

Raymond Cote wrote:
And just WHERE IS THE FILES SECTION???
I dont see any link to it. Never have
In matters of style, float with the current. In matters of Principle,
stand like a rock. “. — Thomas Jefferson —

On Aug 8, 2020, at 06:55, Martin <@musaeum> wrote:

On Fri, Aug 7, 2020 at 01:55 PM, DaveC wrote:
Can you please provide a link to he location of these files? I looked
in the group files and there aren’t many. I didn’t see anything relating to
a collet.

Hi Dave,

it was explained somewhere in this thread: go into the files section
and search for "collet".

cheers
Martin







Re: 2465 Fan Collet Thingy

Li Gangyi
 

Very quickly drew up a STL for people who wanna try 3D printing the plastic
bit, I believe the original part has a metal stud for the nut to thread
onto, you're gonna have to drill and tap the center for a stud.
Do let me know if you've tested it out and if it works good.

I have access to a small lathe, however I'm not equipped to do slits as of
yet, if there is interest I might get around to adding that capability.

On Sun, Aug 9, 2020 at 12:45 AM Chuck Harris <cfharris@...> wrote:

Log onto your groups.io account. It should open with your "my groups"
screen.
Click on "Tekscopes".

On the left side of the messages screen there is a list of areas associated
with tekscopes. One of them is marked "FILES".

-Chuck Harris

Raymond Cote wrote:
And just WHERE IS THE FILES SECTION???
I dont see any link to it. Never have
In matters of style, float with the current. In matters of Principle,
stand like a rock. “. — Thomas Jefferson —

On Aug 8, 2020, at 06:55, Martin <@musaeum> wrote:

On Fri, Aug 7, 2020 at 01:55 PM, DaveC wrote:
Can you please provide a link to he location of these files? I looked
in the group files and there aren’t many. I didn’t see anything relating to
a collet.

Hi Dave,

it was explained somewhere in this thread: go into the files section
and search for "collet".

cheers
Martin







Re: Cut wiring harness

Roy Thistle
 

On Fri, Aug 7, 2020 at 09:18 AM, kim.herron@... wrote:


so large that you can't get the loom back in
place. ...stagger your repair splices so that
you can get it back together.
The obstacle that arose was the bulk, created by the accumulation of splices...getting the spliced loom back in position was not possible... staggering helps... also reducing the number of splices by replacing as many runs as convenient (some are usually easy to do... and then running a constructed loom (of those replacements) in parallel... or sometimes rerouting the new loom more conveniently. I've used inline multi-pole connectors... sometimes panel (or chassis mount) plug and socket... and sometimes terminal blocks (or stacked terminal blocks)... or retrofitted in a junction box.
Some insight is to be gleaned from the amazing number of wire T&M guys mannage to squeeze through the approximately 1cm. by 5cm. opening on the plugins for mux and switch plugins. (all the pairs are connected to screw down, or spring loaded, terminal blocks, on the plugin.) Some insight can be gained from pstn guys who used to do splicing, of multicondutor cable runs, all the time.
Signal carrying pairs need attention as to the point to point re-connection (and splicing), according to the wire/cable used (possibly length too, as well as shielding)... and of course routing.
Although you undoubtedly know, the 556 is almost symmetrical... so getting the power supply working first, and then one beam/channel working...before getting the other... might be a reasonable option.


Re: 7834 Missing Trace

Roger Evans
 

Two more thoughts - does the vertical plugin have an 'Invert' button? That would put the noise at the bottom of the screen if the calibrator is the culprit.

Have you tried all the different voltage output from the calibrator? Is the discrepancy the same for each and for any different V/div settings where you can make a meaningful measurement on two adjacent ranges eg 1V/div and 2V/div for the 4V calibrator output?

Roger


Re: 7834 Missing Trace

Roger Evans
 

You should be able to remove the bottom cover from the scope with a few screws. Whether this gives enough access to pull whatever is left of the release tab with a set of pointed pliers I am not sure. You could start a new thread here on 'how do I remove a 7000 plugin with a broken tab?'

What vertical plugin do you have? If it has two channels then I imagine by now you would have checked both. Nearly all vertical plugins have a 'var' setting which gives a continuously variable Volts/div but this should activate the '>' symbol on the readout and make it obvious that the V/div is not calibrated.

You can put a timebase in the vacant left vertical slot and on auto-trigger it should produce a vertical line if you select the empty slot for the horizontal mode. The line should shift up and down with the position control of the timebase and you might see if the top end displayed any noise (not a very convincing test). If you can arrange for both timebases to trigger from the same external input (maybe the cal output but now you are only relying for it for a trigger signal) then you should get some diagonal lines and any noise would be a bit more obvious. This is all dependent on the left vertical slot actually displaying a trace.

The journey is not ended yet!

Roger