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I've seen that happen too.

When there is a Screw AND a Nut...

Well, let's just say and unexperienced person can cause a lot of damage.

Ross

As a member of the unwashed, I ask: What is a waveform library?

Thanking anyone that answers, larry

Luca,

I offer Complete Overhaul Parts Kits for the entire 24x5 series, with a solid discount for Tekscopes members.

If you want to save yourself a whole bunch of work researching and sourcing all the correct parts, then write me off forum

yachadmATgmailD^Tcom

Menahem Yachad
www.condoraudio.com

I replaced the original blower with a small fan, because the fan collet had broken by someone over-tightening the nut. Those collets must be made of un-obtainium.
It's a shame because the original fan motor worked perfectly, and is now taking up residence in my box of Tek parts.

On Thu, Apr 28, 2022 at 06:00 AM, Martin Hodge wrote:

If I ever get my hands on it I will be sure to upload it here. I've since
acquired an AWG610 so I'm also looking for any disks/software not available
from Teks website for that.
-MH

I have recently uploaded the 4 disks originally supplied with the AWG610 to Tekwiki, simply unzip the files and drop them straight to the root directory of 1.44Mb floppy disks.



If you find any more disks or firmware/software etc, I can update it in Tekwiki too.

Regards,
Jared

If I ever get my hands on it I will be sure to upload it here. I've since acquired an AWG610 so I'm also looking for any disks/software not available from Teks website for that.
-MH

To reiterate my distress: the manual says that the instrument should have come with "calibration data providing measured frequency correction factors at 10 points" for frequencies between 30 MHz and 250 MHz, and that correction factors above 250 MHz were available at additional cost. Unsurprisingly, no such calibration data was provided with this instrument. Further, once I have replaced the batteries I must verify the input impedance with a DC resistance bridge (I expect that I can buy or build one of those), and then verify the input VSWR with a "slotted line, VSWR bridge, or reflectometer" which I have doubts about my ability to obtain or operate.

It's a good thing that I didn't spend a huge amount of money on this instrument, because I think I'm really out of my depth.

Can I use a nanoVNA for the VSWR check?
Can I use one of the many, inexpensive "antenna analyzers" for sale on eBay and Amazon to check the VSWR?
Can I just use a DMM to check the input impedance?
Can I reasonably build a DC resistance bridge? (is it just a Wheatstone bridge?)
What would be involved in recreating the frequency correction factors? (I see the doc on the TekWiki, but it requires that I already possess a "Standard" 067-0625-00 characterized at Tektronix primary electrical standards lab using procedure #1225, which is something of a catch-22)

-- Jeff Dutky

Hello John

I need 4 2N4122's and 2 2N4275's. I first changed Q834 as that is where the signal ended as the !n4148 D861 made no difference. I then tried swapping Q814 and Q824 and the 7 volts followed instead of .7 volts and got a trace about 1/4 on the CRT. Then I went ahead and swapped Q863 and Q873 and the trace went to the other side of the CRT. That is why I want to try them if you have any to spare? I will be glad to pay you for them. Also would be glad to send any good ones back to you when finished. I thought of trying them in a transistor checker but don't want to bend up the leads just yet.

Thank you
Pat

On Sat, Aug 8, 2020 at 07:41 AM, Martin Hodge wrote:

063-2171-XX

Any luck finding the 063-2171-XX? I need it.

My brain went in circles several times before I thought I understood the circuit.

With 1.2V P-P, both the + and the - outputs will both be zero. If the input increases to 1.4V P-P, the + output would be 0.1V and the - output would be -0.1V. Looked at differentially, the scope would see +0.1 -(-0.1) =0.2V. The voltmeter would just see the voltage difference between the + and - terminal, which would be 0.2V

John KK6IL

On Tue, Apr 26, 2022 at 06:07 PM, Jeff Dutky wrote:
Jeff

This says to me that the + and - output of the detector responds as a
differential output.

Not sure how a DC voltmeter and a differential oscilloscope would act the same. The 067-0625-00 does have 2 outputs, so I assume you would connect both of them to an oscilloscope and then add the 2 channels together. The voltmeter method is just measuring between the two non-ground outputs, like in Jared's video where he calibrates his 067-0625-00.

After more thought, I changed my mind on what you would measure on a no-battery, 2 diode version of the circuit. I think you would measure twice the voltage of the 1 diode version, not 0V as I said before. It would behave like a dual rail power supply that has both positive and negative outputs. The voltage between the + output and - output would be double that of either the + or - single output, assuming the two outputs tracked each other. Maybe I will add to my crude test circuit to verify this.

- Jim

Which transistors do you need, and how many?
John

Yes, that's seems to be the issue. There are several routes into the X amp ahead of the x10 switch, not least the Ext X via the trigger circuits, or the X shift controls. Or just dirty earth / screen connections?

On Tue, Apr 26, 2022 at 03:39 PM, <lylejlarson@...> wrote:

...
I've been pouring over the schematic, trying to understand how it develops
the 'start-up' voltages it needs to run, and the startup processes involved.
I suspect that the circuitry attached to T1020's secondary winding forms an
oscillator condition that pumps the C1025 via CR1022, until it reaches a level

C1025 initially charges from rectified line voltage through R1020. Once C1025 has enough voltage across it U1030 powers up. However, current coming through R1020 is not enough to supply U1030, running switcher needed to keep charging C1025 through CR1022. If the switcher is not starting U1030 will cycle on/off.

Initial pulses will flow through C1072, this current in T1050 charges up C1066. Once switcher starts current in T1050 continues to charge C1066.

If you look at voltage across C1066 wrt "REF", does it initially charge up or stay flat? If there is no voltage building up on C1066, C1072 could be bad, not giving the initial kick. A toasty R1071 could be the result of it too.

A minimum load is needed at +5VD as described in the SM if the PSU is not connected to the scope.

Ozan

Jim,

DISCLAIMER: I don't really know what I'm doing, so take any of my answers with a grain of salt.

My first choice of capacitor value (the pF range cap) was arbitrary and random, based mostly on what I had to hand.

My second choice was based on wanting to put a 1 MΩ resistor across the output, for no particularly good reason (to match the input impedance of a scope?) and the desire to have the peak detector respond to changes in the input relatively quickly (i.e. to have the low pass filter on the output have an fc of ~100 Hz).

The way I envisioned the peak detector operating was exactly as you describe: the output cap may not charge up on the first cycle, but will eventually charge up because the resistance on the output is much higher than that on the input: the leaky bathtub must fill eventually, so long as the faucet pours in more water than is leaking out.

As for the type of capacitor, I was just going to use plain ceramic caps (that I got in a kit from Amazon. They don't get much less specialized than that). Maybe some other type of cap would be better (poly-film?) but this is what I have handy.

As for the + and - outputs, the manual for the calibration fixture says this about how it should be used (skipping the first two steps):

3. Connect a DC voltmeter or differential oscilloscope to detector
output. DC voltmeter must provide approximate 2 M OHM load.
Oscilloscope must have 1 M OHM inputs and be in A minus B mode.

4. Verify that an increase in generator output causes a positive-going
indication on the voltmeter or oscilloscope.

5. Wait approximately 5 minutes for detector and generator to stabilize.
Then set the generator to reference frequency and adjust generator
output for zero detector DC output.

6. Change generator frequency and note detector DC output. The change
in generator output is determined by the following relationship:

? Generator Output/1% = ? Detector Output/10 mV

NOTE: This relationship is valid for peak-to-peak
voltage changes of up to 10%. Because the diode
rectification efficiency is a function of the applied
voltage, large changes will deviate from the above
relationship.

7. After measuring the generator's output at various frequencies, recheck
output at the reference frequency to verify negligible drift.

This says to me that the + and - output of the detector responds as a differential output.

-- Jeff Dutky

Yeah,

I once received 10 each, 2465s of different flavors from a Company Surplus auction.

All of those Siemens fan motors - 7 of the 10 - the other ones were Boxer Fans - had the same problem.

You are correct, the bushing rides in the plastic front motor cover and it does deform oblong with the weight of the impeller.

All of the 7 had the bushing burned and melted into the plastic front motor cover and had been seized. That cooked the Motor H-Bridge Electronics and the motor windings. Replacement was required. I replaced all of the motors with the spare motors I received in the auction and had some left over that I sold to Fab Exchange.


As far as a fix for it to prevent the problem, I just replaced them because I had new ones.

I guess someone could digitize the front plastic motor cover and 3D Print one. I don't know much about 3D print Materials - whether they can stand the heat or not. I don't remember if the Motor Shaft was at some Voltage Potential that may cause a problem with a 3D Metal Print.

Ross

On Tue, Apr 26, 2022 at 11:53 PM, si_emi_01 wrote:

The failure mode of them is that the heat generated by the shaft turning over
time melts the front plastic bushing and the shaft wobbles.

Never seen that happen and I'd be surprised if that'd ever be the case. In all cases that I encountered, wear of the shaft inside the sintered bronze bushing caused the wobble. Most of the time, the hole in the bushing became oblong vertically because of the horizontal orientation of the motor during most use.

Raymond

I've got a slightly toasted R1071 as well, and a supply that won't come up.
Initially, I could hear a ticking sound, U1030 would come alive, drive
signals were reaching the drivers, and the supply would come on for about
50mS and then stop. I went through the Inverter Troubleshooting Flowchart, and took
the PS503 power supply branch of the flowchart. Using that approach, I determined that
Q1021 and Q1022 weren't passing current, so I changed them out, and and it
started to work, albeit with levels at only about 25% of normal, due to PS503 limitations.
Now I've hooked back up to to normal 120VAC, and now it's not working, at all.

I've been pouring over the schematic, trying to understand how it develops
the 'start-up' voltages it needs to run, and the startup processes involved.
I suspect that the circuitry attached to T1020's secondary winding forms an
oscillator condition that pumps the C1025 via CR1022, until it reaches a level
high enough to turn on the TL475...
But there are 3 main difficulties to deal with:
1) The board layout is a nightmare. Component placement is scattered, and 90%
of the reference designators are missing in the silkscreen. So locating part positions
is so slow and tedious, that by the time I locat the part, I've forgotten why I was looking for it.

2) It's a complex board, conceptually. Easily one of the most challenging that I've dealt with.

3) I'm not as sharp as I once was. Not dull yet, but I'm no razor anymore either.

Swapping out all these caps may not be a shotgun approach, but it sure looks and feels like one
to me, and that might be the most sensible approach, but I'm not quite there yet. If I find something
useful, I'll let you know, and I'll watching here, in case someone has a good theory of operation, or
just a solution that doesn't involve 25 different components.

Thanks,
Lyle

Ross,

Is there a suggested repair for the plastic bushing? Is there some preventative maintenance that can be done?

-- Jeff Dutky

Got the voltage stabilized by replacing the 2N4275's and the 2N4122's with 2N3904's and 2N3906's on the horizontal amp board. Voltages are out of whack however I don't have that out of line voltage I had before (.7 at connector I and 7 at connector G) for now I am scrounging up parts if I can find them. I have a trace now near the center of the CRT but is only about an inch or so wide and triggering. Thanks for the input gentlemen and will resume if I can find the parts. If I can get it stabilized I plan on re capping. I am glad to get rid of the pesky 7 volt's I was getting though. I thought it may have been one of the Q884 and Q894 (2N3119's) but at all seems OK now.

On my original post I was hoping someone could turn on there 453 and tell me where there dot or short line showed up when they hit the trace finder button.

Thanks gents and will post an update if I can locate some transistors. Already been looking up caps on Mouser.

Take care
Pat