开云体育

I was going to attach screenshots from my 11801/SD-32 comparing one of Leo Bodnar's new LBE-1322 pulsers to the calibrator in the 11801.

Seems I'm not allowed to do that. Don't know why or care. I'll simply state the result.

My 11801 calibrator output has a 15 ps rise time averaged over >4096 measurements. I measured 19 ps for my LBE-1322. The calibrator signal proves that the head is faster than the DUT.

If you have an 11801 family instrument which either has a failed or the slow revised model calibrator, this is a superb instrument. You want it!

Have Fun!
Reg

Just to make sure it is Ch2 and not the trigger path showing up on screen for some reason, if you change trigger source to Ch1/Ch2 does anything change?
****When I change the trigger from CH1 to CH2 it does change. If in CH2 the Sine Wave becomes synchronized as it should. If I switch the trigger to CH1 it shows the CH2 Sine Wave but it is NOT synchronized.
****Nothing changes when switching between CH1 and CH2.
Are collector voltages of Q1455 and Q1555 same as before after delay line fix?
****Here is what they are now...
****CH 1 Selected
Q1455 E=-0.680 B=-0.047 C=0.649
Q1555 E=-0.680 B=0.000 C=1.160
****CH 2 Selected
Q1455 E=-0.681 B= 0.277 C=0.366
Q1555 E=-0.681 B=0.000 C=1.047
I assume pin 3 voltage of the hybrids will be different now, any change to pins 3,4,5,16,17 on CH2 hybrid after delay line fix?
****CH 1 Selected
Pin 3=+2.718
Pin 4=+2.754
Pin 5=+1.722
Pin16=-0.844
Pin17=-0.841
****CH 2 Selected
Pin 3=+2.721
Pin 4=+2.721
Pin 5=+1.722
Pin16=-0.846
Pin17=-0.838
It is possible Ch1 is visible but it is off the screen and bouncing off the CRT wall giving you ghost image.
****I don't think so. I have a square wave on CH1 and a Sine wave on Channel 2.
Does moving Ch1 Y offset knob change anything?
****There is a slight jitter in the trace when CH1 position is 100% fully clockwise. The jitter goes away at 99% fully clockwise.
What are the voltages of pin 16 and pin 17 (gives an idea about channel DC level) on Ch1 hybrid? Pins 3,4,5 are shared with Hybrid 2 so they will be the same as Hybrid 2 voltages.
****CH1 Hybrid with CH 1 Selected
Pin16=-0.871
Pin17=-0.805
****CH1 Hybrid with CH 2 Selected
Pin16=-0.871
Pin17=-0.805

Checked and doubled checked. Seems like the voltages varies a bit during each test cycle.

Thanks for looking at this. I am learning a lot, but a ways to go

Barry

Just to make sure it is Ch2 and not the trigger path showing up on screen for some reason, if you change trigger source to Ch1/Ch2 does anything change?
****Nothing changes when switching between CH1 and CH2.
Are collector voltages of Q1455 and Q1555 same as before after delay line fix?
****Here is what they are now...
****CH 1 Selected
Q1455 E=-0.680 B=-0.047 C=0.649
Q1555 E=-0.680 B=0.000 C=1.160
****CH 2 Selected
Q1455 E=-0.681 B= 0.277 C=0.366
Q1555 E=-0.681 B=0.000 C=1.047
I assume pin 3 voltage of the hybrids will be different now, any change to pins 3,4,5,16,17 on CH2 hybrid after delay line fix?
****CH 1 Selected
Pin 3=+2.718
Pin 4=+2.754
Pin 5=+1.722
Pin16=-0.844
Pin17=-0.841
****CH 2 Selected
Pin 3=+2.721
Pin 4=+2.721
Pin 5=+1.722
Pin16=-0.846
Pin17=-0.838
It is possible Ch1 is visible but it is off the screen and bouncing off the CRT wall giving you ghost image.
****I don't think so. I have a square wave on CH1 and a Sine wave on Channel 2.
Does moving Ch1 Y offset knob change anything?
****There is a slight jitter in the trace when CH1 position is 100% fully clockwise. The jitter goes away at 99% fully clockwise.
What are the voltages of pin 16 and pin 17 (gives an idea about channel DC level) on Ch1 hybrid? Pins 3,4,5 are shared with Hybrid 2 so they will be the same as Hybrid 2 voltages.
****CH1 Hybrid with CH 1 Selected
Pin16=-0.871
Pin17=-0.805
****CH1 Hybrid with CH 2 Selected
Pin16=-0.871
Pin17=-0.805

Checked and doubled checked. Seems like the voltages varies a bit during each test cycle.

Thanks for looking at this. I am learning a lot, but a ways to go

Barry

Hi Barry,
Nice find with delay line.

Just to make sure it is Ch2 and not the trigger path showing up on screen for some reason, if you change trigger source to Ch1/Ch2 does anything change?

Are collector voltages of Q1455 and Q1555 same as before after delay line fix?
I assume pin 3 voltage of the hybrids will be different now, any change to pins 3,4,5,16,17 on CH2 hybrid after delay line fix?

It is possible Ch1 is visible but it is off the screen and bouncing off the CRT wall giving you ghost image. Does moving Ch1 Y offset knob change anything? What are the voltages of pin 16 and pin 17 (gives an idea about channel DC level) on Ch1 hybrid? Pins 3,4,5 are shared with Hybrid 2 so they will be the same as Hybrid 2 voltages.

Ozan

Ozan,

Select CH1 OR CH2 and trace shows CH2. I currently have a square wave going to CH1 AND A sine wave going to CH2. Regardless of the switch position CH2 is displayed. (Except when CH1-CH2 is selected.

The trace reflection is there all the time to some extent. Decreases with intensity.

Thanks!

Barry

Greetings!

I made a little progress. One of the delay lines was open. Perhaps that was my interment problem. I fixed that and got CH2 displaying. The problem is (as before I lost both traces) that CH2 is displayed when CH2 is selected(correct) AND when CH1 is selected(incorrect).

Barry

Ozan,

J1350 is correctly positioned.

Q4660B and Q1462B are +0.672
Q1460E = -0.42
Q1462E = -0.42

Q3237E 4.2
Q3237B = 3.525
Q3237C = 0.184

Q3236E = 4.288
Q3236B = 3.623
Q3236C = 0.151

Thank You!

Barry

Both scopes have found a new home now. Thanks to all who showed an interest.

My comments are inline.
Ozan


On Sun, Feb 9, 2025 at 03:20 PM, Barry Breaux wrote:

..... If I short out the delay
line from the F&I board the traces come to the center of the display.
Therefore the problem is before the delay line. What I don't understand is
why shorting out the delay line from the Main board doesn't produce a trace.

Most likely the delay line is made of a lossy coax (there is an explanation in Tektronix technical series) and it has some resistance from end to end. Shorting at the F&I board side or at the attenuator presents a different resistance to the next amp.

Pin, Ch1 Select, Ch2 Select
1, -0.65, -0.35

This reading shows an issue, according to schematic should be either 1V or 2V but this could be because of pin 5 below.

3, -0.03, -0.03
4, 1.37, 1.37
5, -0.01, -0.01

It looks these are also wrong. My guess is common mode (pin 5) has an issue, more about it later.

16, -0.57, -0.57
17, -0.05, -0.05

Is the Y position knob at one of the extremes? This can also be the result of pin5 so for now it is OK. We expect 16 and 17 to be similar and independent of channel switch in normal operation. They will deviate with position knob or input signal. However, no need to think about them for now.

19, 4.99, 4.99

This is good.

I took all these measuements today, but I suspect warmup was not sufficient.

The voltages are quite a bit off, warm up is not an issue.

Pin5 at 0V doesn't sound right, it may also be yanking pin3 and also setting pin4 ~0V. Most likely Q1462+Q1460 is pulling too much current. There could be several possibilities:
- Is J1350/P1350 connected properly? They dump current to emitters of Q1462 and Q1460. Without this current Q1462/Q1460 will pull extra current from pin 5
- It is unlikely extra current is because of bad Q1462/Q1460

I recommend:
- Look at voltages at base and emitters of Q1462 and Q1460
- Look at B/E/C voltages of Q3237 and Q3236. They are sourcing current to emitters of Q1462 and Q1460. Without them extra current is pulled from pin5 of the hybrid.

Ozan

The condition of t; his SC504 has changed. I am currently unable to see a trace from either Ch1 or Ch2. From the beginning I have been seeing an intermittent problem of not seeing either channel. If I short out the delay line from the F&I board the traces come to the center of the display. Therefore the problem is before the delay line. What I don't understand is why shorting out the delay line from the Main board doesn't produce a trace.

OZAN, pin 1 isn't ~1V OR ~2V.

CR1457 Anode: CH1=-0.645, CH2=-0.360
Q155 CH1 Select E=-0.676V B=-0.000V C=+0.708V
Q155 CH1 Select E=-0.679V B=-0.000V C=+0.688V

OZAN, these are the pins you questioned.

Pin, Ch1 Select, Ch2 Select
1, -0.65, -0.35
3, -0.03, -0.03
4, 1.37, 1.37
5, -0.01, -0.01
16, -0.57, -0.57
17, -0.05, -0.05
19, 4.99, 4.99

I took all these measuements today, but I suspect warmup was not sufficient.

Barry

I was asked to clarify, my above email was about Bill/William vel Liam Perkins

On Sat, Feb 8, 2025 at 12:55?AM cheater cheater
<cheater00social@...> wrote:

Hello,
maybe before sending emails to various lists you should send out my
manual I paid for that you promised to send to me by the end of
January and have ignored all emails about since.

All the best

On Fri, Feb 7, 2025 at 8:12?PM Bill Perkins via groups.io
<sales@...> wrote:

This post is OT but possibly of interest to B&K 2012 owners. There's a
slew of info on the 2012 in my site here:



and a lot of info on B&K in general in this directory:

I know this is not the natural place for this request, but perhaps there are like minded people here?
Does anybody here have a copy of the boot code disk for the B&K 2012 analyser?
My unit has lost its memory after some years in storage.
The hardware is in good shape.
Any help would be appreciated.

Please contact me off list

Pete
G4GJL

Bill @ PEARL, Inc. - Canada

Not a list but a good description of how to care for an old 49x analyzer including PSU recapping:

Look for "Service Notes for the Tektronix 49x/275x Spectrum Analyzers (650KB .PDF, 28 pages) "

on KE5FX.com The document also describes a lot of other things that should be checked.
I have followed many of the recommendations in that document.

Cheers

Ulf
SM6GXV

My son has acquired a 494AP marked to have Option 9. This option does not seem to appear in available manuals. Have others encountered this >> option?

Bruce, KG6OJI

Hello Bruce,

The option 9 increases the low frequency display range down to 1 KHz by replacing the included standard cable
with a special one, Tektronix part number 174-1338-000.

Rubens, [NoCallSign]

Keep in mind, of course, that a patent is only a license to sue.? A patent holder would need to be able to prove infringement, have enough wherewithal for lawyers' fees and court costs, and have the stomach to persist for months, years, or even decades to hope to receive compensation for infringement.? For private inventors and small companies, patents almost always make no sense to pursue, unfortunately.? Let the big companies use their armies of lawyers to duke it out against each other.? For example, Broadcom extracting $891 million from rival Qualcomm back when I worked for BRCM (2006 to 2016) to settle all outstanding lawsuits.? HTH.

Jim FordLaguna Hills, California, USA

Confirmed: In the horizontal slot, connecting pin A1 (Gate) to pin A8 (+5V) un-blanks the CRT, and a dot appears near the center of the screen.
Now it is possible to plug in ANY suitable plugin into either of the vertical slots, and get a vertical trace.

Pete

Yep, Bruel & Kjaer for sound and vibration measuring instruments, now part of HBK (Hottinger Bruel & Kjaer), and B&K Precision (ownership changed many times - big surprise!), for power supplies and other general purpose instruments.
I haven't done an exhaustive price comparison, but I would bet Bruel & Kjaer instruments are at least an order of magnitude more expensive that those of B&K Precision.? Come to think of it, who the hell am I to comment on this subject?!? I've never owned any instruments from either company!? Duh!? LOL!
Jim FordLaguna Hills, California, USA

I'd be happy to re-home one, particularly the non-working one. I'm always up for a fun project if it's got Tektronix written on the front! :D

- Scott

On Fri, Feb 7, 2025 at 08:54 AM, Barry Breaux wrote:

Greetings,

What would cause this?

Thank you!

/g/TekScopes/photo/300558/3883505?p=Created%2C%2C%2C20%2C2%2C0%2C0

Scope seems to be in "chop" mode based on the position of "Display" knob. Are you applying the same signal to both channels? You could be seeing Ch1 and Ch2 together, I see that triggering is on Ch2, and Ch1 and Ch2 gains are not the same (Ch2 red knob is also out of cal position).

If you switch coupling to GND for one of the channels, pick trigger and input source for the active channel, do you still see two waveforms?
Ozan

On Sun, Feb 2, 2025 at 07:21 AM, Barry Breaux wrote:

...
The anode of CR1457: CH1=-0.65, CH2=-0.37
The Collector of Q1555: CH1=+1.12, Ch2=+1.01

Anode of CR1457 is the same node as collector of Q1455. Seeing -0.37 to -0.65V doesn't have an easy explanation when collector of Q1555 is ~ 1V. What voltages do you see at Ch2 hybrid, HY1430, pins 1, 3, 4, 5, 16, 17, 19?

Pin1 should be at ~ 1V when channel is disabled, ~ 2V when it is enabled. It is the same node as the collector of Q1455 but perhaps there is a broken trace between them so it is best to measure at the pins of the hybrid.

Ozan

Not only does the Horz plugin in provide the sweep signals it ALSO provides the positioning as well as blanking disable. In the absence of signal the dot is there but it is pulled off the side of the screen. Left side if I remember correctly. The drive signals also provide blanking disable. So the dot might be in the middle of the screen but the blanking circuit is keeping the beam current driven off.

Zen