Date   
Re: SG505 Output voltage too high

Rick
 
Edited

I think I had heard of that before. Thanks for clarifying.

Re: SG505 Output voltage too high

Bruce Griffiths
 

Linear systems (including mismatched transmission lines) don't generate distortion with sinusoidal signals.

Bruce.


On 24 December 2017 at 16:03 Rick <rpbale@...> wrote:

Okay, I certainly am causing a wild goose chase. I read up on the forum on how to properly setup my AA501A with the bnc shield grounded and the 80khz filter on. Here's the SG505 readings:

10hz @ .0018% thd
20hz @ .0010% thd
1khz @ .0008% thd
20khz @ .0007% thd
50khz @ .0006% thd
100khz @ .0006% thd

This indicates no problem from the 60hz signal on the power rail of the SG505. All these readings are at 1.73V rms, the lowest without using it's attenuator. I also noticed that unless I set the DC504A to x5 attenuation it introduces distortion on the line. Is that an indication that I don't have the correct impedance on the line.

I have another AA501 I want to clean up and calibrate once I'm sure the SG505 is working correctly.


Re: SG505 Output voltage too high

Rick
 

Okay, I certainly am causing a wild goose chase. I read up on the forum on how to properly setup my AA501A with the bnc shield grounded and the 80khz filter on. Here's the SG505 readings:

10hz @ .0018% thd
20hz @ .0010% thd
1khz @ .0008% thd
20khz @ .0007% thd
50khz @ .0006% thd
100khz @ .0006% thd

This indicates no problem from the 60hz signal on the power rail of the SG505. All these readings are at 1.73V rms, the lowest without using it's attenuator. I also noticed that unless I set the DC504A to x5 attenuation it introduces distortion on the line. Is that an indication that I don't have the correct impedance on the line.

I have another AA501 I want to clean up and calibrate once I'm sure the SG505 is working correctly.

Files, photos, searching, Arc groups...

Michael Dunn
 

BTW, I’ve now copied all files & photos from our two old Arc(hive) groups to the new groups.io. We are free of Yahoo.

File searching seems to work well, and even searches on content. Some filename searches do confuse the system (e.g., “_”-delimited substrings), and I’ve submitted a bug report.

There’s no search for photo names/descriptions. I’ve requested it. Unlike Yahoo, such requests and bug reports may actually be answered!

Michael

Re: SG505 Output voltage too high

Harvey White
 

On Sat, 23 Dec 2017 17:34:28 -0800, you wrote:

Thanks Harvey. C1101 is a tant in the power supply circuit. I can check that. I haven't noticed that anything is running hot, temperature wise. My reference to hot is meant to be too high of output voltage, my bad.
Ah, now that makes a difference.

First thing I'd check is to see if the voltage to the output
attenuator (I am guessing there's one, don't remember) is too high.

Now, something does occur to me. If the output voltage is too high,
then perhaps it's going into more of a non-linear region because the
output is too high. So I'd look at the output level adjustment and
suspect that the too high output voltage is also causing the too high
distortion.

Feedback circuit, effectively an AVC (Automatic Volume Control)
circuit. Wonder where it is?

I've got an SG502 and an SG503, nothing else in that line.

Harvey



After a little more reading on the forum I see that my SG505's distortion isn't nearly as low as the original specs. Should be .0018% (-95dB) THD. I'm at 0.018%.


Re: 7D15 Not Working or Cockpit Error?

 

CORRECTION: The 7D10 does not use a XTAL Oscillator (but there is a place
for one and for a considerable amount of additional support circuitry). The
reason for this is because the PC Board (670-2150-xx) is common to the 7D10
and the 7D11. The 7D11 does have the XTAL Oscillator installed.

Dennis Tillman W7PF

-----Original Message-----
From: Dennis Tillman [mailto:@Dennis_Tillman_W7pF]
Sent: Saturday, December 23, 2017 3:51 PM
To: 'TekScopes@groups.io' <TekScopes@groups.io>
Subject: RE: [TekScopes] 7D15 Not Working or Cockpit Error?

Hi David,
I have three 7D15s and while I like them in general they have two weaknesses
- the XTAL Oscillator Tek used is not very accurate (~10^-6) so the two
least significant digits jump all over the place. Tek used the same XTAL
Oscillator in the 7D10, 7D11, and 7D14. I don't NEED 8 digits of accuracy
BUT I feel that if you are going to display 8 digits, which both the 7D14
and 7D15 does, then they should all be stable.

My solution to this personal pet peeve was to replace the XTAL Oscillators
with a simple drop in replacement I designed that was based on a 10MHz DIP
size OCXO. It ran on different voltages so I had a regulator on the drop-in
PC board, and a divide by 2 flip flop to lower the frequency to 5MHz. I
bought 10 of the OCXOs on Ebay for about $8 each at the time. The small <2"
square PC Boards cost almost nothing at all. Now all my 7D10, 7D11, 7D14,
and 7D15 plugins are good to ~10^-8 after a few minutes of warmup.

Because Tek combined the plugin and scope together with the ability to
display several different waveforms related to the signal being counted this
universal counter/timer has some unique capabilities not found in other
universal counter/timers.

Unfortunately the restricted front panel space meant compromises had to be
made on functionality. I use the 7D15 a lot but I have always found it to be
one of the most difficult ones set up. I'm sure many people don't realize
some capabilities depend on whether it is in a vertical or horizontal slot.
One clue for me that there is a problem with the triggering is I find that I
spend more time than I should getting it to count the waveform I want to
measure. I always feel like it shouldn't take so long to get it setup
properly.

Dennis Tillman W7PF

-----Original Message-----
Sent: Saturday, December 23, 2017 12:16 AM
Subject: Re: [TekScopes] 7D15 Not Working or Cockpit Error?

Once I learned how to use my 7D15 and recalibrated the trigger adjustments,
I found that the trigger was not finicky at all as long as I got the trigger
source configured correctly.

Besides calibration, I had to clean and lubricate the switches on mine, fix
some cracked solder joints on the trigger daughter boards, and repair one of
the attenuator modules.

On Mon, 18 Dec 2017 20:34:33 -0800, you wrote:

...

The 7D15 is also notoriously finicky about how the trigger level is set. If
you set it wrong you probably won't know it except your frequency/period
readings will be off by a factor of 2 or they will be entirely random.

...



--
Dennis Tillman W7PF
TekScopes Moderator

Re: SG505 Output voltage too high

Rick
 

Thanks Harvey. C1101 is a tant in the power supply circuit. I can check that. I haven't noticed that anything is running hot, temperature wise. My reference to hot is meant to be too high of output voltage, my bad.

After a little more reading on the forum I see that my SG505's distortion isn't nearly as low as the original specs. Should be .0018% (-95dB) THD. I'm at 0.018%.

Re: SG505 Output voltage too high

Harvey White
 

On Sat, 23 Dec 2017 16:28:25 -0800, you wrote:

While I'm waiting for a new multiplier to arrive for my 5440 scope I thought I'd look into why my SG505 (has no IM option) has about 1.6 V rms signal at zero attenuation. I couldn't lower it with R1423 to 0dbm (0.775 V rms). The lowest setting only got it down to 1.3 V rms. So I thought maybe the power supply is too high. It's not. The +-15 is sitting at about +-10 V max and the transformer is receiving a 25VAC signal. Also these two rails have about a 800 mVpp 60 hz hum on them. So I replaced the filter caps C1211, C1212, C1201 & C1210 thinking maybe they're leaking. Of course they all checked fine on the LCR meter and replacing didn't help filter out the 60 hz a bit. The oscillator output is as clean as it gets with about .018% distortion.

Could the low and humming power rail even be related to the overly hot output? Seems like it might be a separate problem. I though this was going to be easy one but it's a complicated circuit. Any direction or more theory would be great. Thanks, Rick
The first (and oft neglected) rule is that if the power supply is
wrong, how does it happen that the circuit works properly?

low and humming power rail? I'd wonder how much current is being
drawn. Linear regulators are basically voltage dividers with the
(typically) top element being a transistor. If there's too much
current draw, then the top element needs to supply all that current
and can likely be quite warm. If the bulk supply has hum, then the
regulator has to regulate that out of existance. That doesn't always
happen.

Generally, hot something, especially in a power circuit, indicates too
much power drawn. In most older Tek equipment, while the bulk
capacitors can be bad (and introduce hum), the bypass capacitors tend
to short out or go leaky. Too much current causes overheating and the
regulator to drop out of limits.

Typical debugging techniques are to either isolate (unplug) sections
and look for current drain, or to look at dropping resistors and look
for too much drop across them. Gumdrop tantalums are often suspect.

Harvey

SG505 Output voltage too high

Rick
 

While I'm waiting for a new multiplier to arrive for my 5440 scope I thought I'd look into why my SG505 (has no IM option) has about 1.6 V rms signal at zero attenuation. I couldn't lower it with R1423 to 0dbm (0.775 V rms). The lowest setting only got it down to 1.3 V rms. So I thought maybe the power supply is too high. It's not. The +-15 is sitting at about +-10 V max and the transformer is receiving a 25VAC signal. Also these two rails have about a 800 mVpp 60 hz hum on them. So I replaced the filter caps C1211, C1212, C1201 & C1210 thinking maybe they're leaking. Of course they all checked fine on the LCR meter and replacing didn't help filter out the 60 hz a bit. The oscillator output is as clean as it gets with about .018% distortion.

Could the low and humming power rail even be related to the overly hot output? Seems like it might be a separate problem. I though this was going to be easy one but it's a complicated circuit. Any direction or more theory would be great. Thanks, Rick

Re: 7D15 Not Working or Cockpit Error?

 

Hi David,
I have three 7D15s and while I like them in general they have two weaknesses
- the XTAL Oscillator Tek used is not very accurate (~10^-6) so the two
least significant digits jump all over the place. Tek used the same XTAL
Oscillator in the 7D10, 7D11, and 7D14. I don't NEED 8 digits of accuracy
BUT I feel that if you are going to display 8 digits, which both the 7D14
and 7D15 does, then they should all be stable.

My solution to this personal pet peeve was to replace the XTAL Oscillators
with a simple drop in replacement I designed that was based on a 10MHz DIP
size OCXO. It ran on different voltages so I had a regulator on the drop-in
PC board, and a divide by 2 flip flop to lower the frequency to 5MHz. I
bought 10 of the OCXOs on Ebay for about $8 each at the time. The small <2"
square PC Boards cost almost nothing at all. Now all my 7D10, 7D11, 7D14,
and 7D15 plugins are good to ~10^-8 after a few minutes of warmup.

Because Tek combined the plugin and scope together with the ability to
display several different waveforms related to the signal being counted this
universal counter/timer has some unique capabilities not found in other
universal counter/timers.

Unfortunately the restricted front panel space meant compromises had to be
made on functionality. I use the 7D15 a lot but I have always found it to be
one of the most difficult ones set up. I'm sure many people don't realize
some capabilities depend on whether it is in a vertical or horizontal slot.
One clue for me that there is a problem with the triggering is I find that I
spend more time than I should getting it to count the waveform I want to
measure. I always feel like it shouldn't take so long to get it setup
properly.

Dennis Tillman W7PF

-----Original Message-----
Sent: Saturday, December 23, 2017 12:16 AM
Subject: Re: [TekScopes] 7D15 Not Working or Cockpit Error?

Once I learned how to use my 7D15 and recalibrated the trigger adjustments,
I found that the trigger was not finicky at all as long as I got the trigger
source configured correctly.

Besides calibration, I had to clean and lubricate the switches on mine, fix
some cracked solder joints on the trigger daughter boards, and repair one of
the attenuator modules.

On Mon, 18 Dec 2017 20:34:33 -0800, you wrote:

...

The 7D15 is also notoriously finicky about how the trigger level is set. If
you set it wrong you probably won't know it except your frequency/period
readings will be off by a factor of 2 or they will be entirely random.

...



--
Dennis Tillman W7PF
TekScopes Moderator

Re: 7603 with noise in traces

Phillip Potter
 

Thanks, David for your feedback.

It is good to know that what I am seeing is (more or less) standard operating for my scope.

I do intend to get into the power supply, but I find that I am having too much fun just using the thing to even consider tearing into it, for a while. I do intend to get into the 7A18, as it has dirty switches and one of the V/D knobs has cracked and fallen apart, again.  I suppose it's time to try the soldering iron melt idea... I also want to lubricate the detents to try and relieve the pressure on the knobs.

Thanks, again.  MERRY CHRISTMAS TO YOU ALL!

 Phil-in-CA

On 12/23/2017 12:33 AM, David Hess wrote:
On Mon, 18 Dec 2017 20:43:24 -0800, you wrote:

I have a 7603 with a 7A18, 7a18A, and a7B53A. I am just starting to use this scope and I've noticed a few things that I think need addressing, but would like some feedback before I do anything. I am new to this group, and if there is a wiki or file in the groups repository that you think I should read, I would appreciate the suggestion. Also, since I am new here, I suspect that this type of problem post has come up before I got here... If there is, just give me a link to that thread and I will go read up, first.

With both amplifiers installed, there is noise (moving black vertical lines) in all four of the traces with sweep speeds of 1ms, .5 ms, and .1ms, and slower but not higher. With just one amp installed, the trace isn't so much noisy at .1ms, but rather rippled but they become noisy with slower sweeps, again, down to 1ms.
Like Chris says, the blank spots in the traces are caused by the
readout multiplexing. If this is objectionable, then the readout
intensity control can shut off the readout or the slide switch on the
readout board inside the mainframe may be used to configure the
readout to "gated" mode so that the readout is written between sweeps.
But this also results in no readout when no sweep is present.

I think the traces are not completely sharp, no matter how the focus control is adjusted, and the READOUT and the trace(s) get sharper at different settings of the focus control! They are not sharpest at the same adjustment. Also, the whole image (readout and traces) seem to be jumping just a tiny bit.
The readout may shift depending on what the sweep is doing but usually
the sweep is stable. It may be worth checking the low voltage power
supply outputs for level and ripple. I need to change the input
capacitors on my 7603.

If the readout focus is not tracking the trace focus, then the
automatic focus may need to be calibrated.

If the 7603 has been in storage for a long time, then the CRT
sharpness may improve after a few days of operation. If you do this,
only leave it on while supervised and set the trace intensity to a low
but visible level; do not turn the intensity off.

When I look at the cal outputs, the vertical trace lines are nonexistent.
Trace brightness at any one point depends on the writing speed and at
a slow sweep speed, the vertical parts of the calibration waveform are
moving much faster than the horizontal parts.


Re: Tektronix 5111A storage doesn't work

magnustoelle
 

Good Day,
I would try the following simple trick: Turn unit off. Apply a very small amount of contact cleaner to the Erase and Upper/Lower front panel buttons. Let it sit overnight, and actuate all buttons at least 50 times still turned off. Turn it on and evaluate the storage function acc. to the manual.
This has helped me with my NOS 5111A many moons ago. Good luck!
Merry Christmas,
Magnus 


If the normal analog mode works and the whole screen brightens in
storage mode, then there must be something wrong with the storage mode
circuits and not the CRT.  The whole screen brightening is caused by
the storage flood gun.

Do the pushbutton switches on the mainframe seem to work cleanly? They
may need to be cleaned and lubricated to make good contact.

There is a scan of the manual here:

http://w140.com/tekwiki/wiki/5111

On Fri, 22 Dec 2017 05:07:56 -0800, you wrote:

Hi everyone,

This is my first post here. So let me introduce myself.
I'm basically a software guy doing analog electronics for fun/hobby, mainly audio.

I've a few 500 series modules already. Very cheap for the value they offer.
And I've recently acquired a Tektronix 5111A scope along with 3 modules.
I don't own an analog scope and this was a cheap opportunity.
Plus there are a few useful modules: 5ct1n curve tracer and 5l4n spectrum analyzer that I would be interested to purchase.

The scope and the modules work well.
It's just a matter of getting used to it when all your experience is with digital scope (just press "auto set").
However, the storage doesn't seem to work.

Basically, the screen turns greener, but the traces (I used the integrated calibration square ware) are not stored.
I mean if I use the "beam finder" and move it around, I should be able to draw things. But not here.

I asked an "older" colleague (he used analog scope for quite long) to check it.
And it confirmed that it doesn't work.
According to him, the tube should be ok.

Any idea ? Is it the tube which has worn out ? Or may be the erasing circuit is stuck ?

Re: Tek Knob Project - scan and make

Harvey White
 

On Sat, 23 Dec 2017 13:00:37 -0500 (GMT-05:00), you wrote:

Thanks for the reply.

Were you the one who wanted to go to Nightfire Electronics in Ocala?
Yep, school got really busy and I haven't managed to break loose. Even
though I wasn't officially teaching the last two months, life was
still very busy.

I met them at the recent Ocala hamfest. He was too busy to talk very much, but I promised to visit him at his store when I could. I've been out of commission with a UTI, and my truck needed some repairs but I plan on seeing him after the first of the year.
Ouch on both cases.

Some of the nightfire stuff is good, some is not quite so good,
depending. You have to realize which Chinese vendors (for some of it)
he's using, and see if there exists windows drivers.

Right after I find room to unload my truck of TV modulators and video switching equipment. I have 42, 1U modulators and 16 Extron 1U video switches that I bought for their rack mount cases. Thee local county approved electronics recycler went out of business, and I filled the truck for a little over $100.
I would have likely killed for that stuff about 20 years ago. I
wanted enough equipment to be able to subtitle video tapes or at least
edit them well. Yep, got a sony SLV VHS editing deck, but needed the
synch generator. Not even sure where the one I built is. Then the
digital revolution got going, and analog isn't king any more. Have a
vector scope and waveform monitor as well as a TEK 1910 digital signal
generator (which could be a synch generator if I ever needed one).

Oh well....

I've managed to 3D print the latch assemblies from the Tektronix
TM5000 series, right now, I only have black. Nobody seemed too
interested. The TM500 series might be next.

Harvey




-----Original Message-----
From: Harvey White <madyn@...>
Sent: Dec 23, 2017 12:51 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Knob Project - scan and make

On Tue, 19 Dec 2017 23:13:18 -0500 (GMT-05:00), you wrote:

Is anyone in the group near Orlando, Florida? Skycraft used to have bins full of used knobs from the test equipment that they scrapped for gold.
Yes. It's nearby.

They also had some handles and rack mounts for HP equipment. I used to buy up all they had when I went there for parts. I was working in Orlando as a Broadcast Engineer at that time, so I went there and to the other surplus shops quite often.
Not sure about the handles and rack mounts. They may have some, but
unless you know the part, not sure that you'll be able to pick it out.

I haven't been there in over a decade, and I doubt that I'll ever make that long trip just to look for knobs.
You're not likely to find any at this point, I don't remember seeing
any that looked like "tektronix" knobs. Maybe something for older
equipment, but not likely.

Harvey



-----Original Message-----
From: stefan_trethan <stefan_trethan@...>
Sent: Dec 19, 2017 10:51 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Knob Project - scan and make

The following notion might be distressing to some members, reader
discretion is advised:

If all else fails you can just use standard knobs in many cases.
I replaced the upper three knobs on an AM502 with different black ones
and it doesn't look all that bad.
You can even make stacked knobs by drilling through the larger one.

By replacing all three that were a similar design it isn't as obvious
that they are not original.
I can provide a photo, for your amusement.

ST



Michael A. Terrell





Michael A. Terrell


Re: Tek Knob Project - scan and make

Michael A. Terrell
 

Thanks for the reply.

Were you the one who wanted to go to Nightfire Electronics in Ocala? I met them at the recent Ocala hamfest. He was too busy to talk very much, but I promised to visit him at his store when I could. I've been out of commission with a UTI, and my truck needed some repairs but I plan on seeing him after the first of the year. Right after I find room to unload my truck of TV modulators and video switching equipment. I have 42, 1U modulators and 16 Extron 1U video switches that I bought for their rack mount cases. Thee local county approved electronics recycler went out of business, and I filled the truck for a little over $100.

-----Original Message-----
From: Harvey White <madyn@...>
Sent: Dec 23, 2017 12:51 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Knob Project - scan and make

On Tue, 19 Dec 2017 23:13:18 -0500 (GMT-05:00), you wrote:

Is anyone in the group near Orlando, Florida? Skycraft used to have bins full of used knobs from the test equipment that they scrapped for gold.
Yes. It's nearby.

They also had some handles and rack mounts for HP equipment. I used to buy up all they had when I went there for parts. I was working in Orlando as a Broadcast Engineer at that time, so I went there and to the other surplus shops quite often.
Not sure about the handles and rack mounts. They may have some, but
unless you know the part, not sure that you'll be able to pick it out.

I haven't been there in over a decade, and I doubt that I'll ever make that long trip just to look for knobs.
You're not likely to find any at this point, I don't remember seeing
any that looked like "tektronix" knobs. Maybe something for older
equipment, but not likely.

Harvey



-----Original Message-----
From: stefan_trethan <stefan_trethan@...>
Sent: Dec 19, 2017 10:51 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Knob Project - scan and make

The following notion might be distressing to some members, reader
discretion is advised:

If all else fails you can just use standard knobs in many cases.
I replaced the upper three knobs on an AM502 with different black ones
and it doesn't look all that bad.
You can even make stacked knobs by drilling through the larger one.

By replacing all three that were a similar design it isn't as obvious
that they are not original.
I can provide a photo, for your amusement.

ST



Michael A. Terrell





Michael A. Terrell

Re: Tek Knob Project - scan and make

Harvey White
 

On Tue, 19 Dec 2017 23:13:18 -0500 (GMT-05:00), you wrote:

Is anyone in the group near Orlando, Florida? Skycraft used to have bins full of used knobs from the test equipment that they scrapped for gold.
Yes. It's nearby.

They also had some handles and rack mounts for HP equipment. I used to buy up all they had when I went there for parts. I was working in Orlando as a Broadcast Engineer at that time, so I went there and to the other surplus shops quite often.
Not sure about the handles and rack mounts. They may have some, but
unless you know the part, not sure that you'll be able to pick it out.

I haven't been there in over a decade, and I doubt that I'll ever make that long trip just to look for knobs.
You're not likely to find any at this point, I don't remember seeing
any that looked like "tektronix" knobs. Maybe something for older
equipment, but not likely.

Harvey



-----Original Message-----
From: stefan_trethan <stefan_trethan@...>
Sent: Dec 19, 2017 10:51 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Knob Project - scan and make

The following notion might be distressing to some members, reader
discretion is advised:

If all else fails you can just use standard knobs in many cases.
I replaced the upper three knobs on an AM502 with different black ones
and it doesn't look all that bad.
You can even make stacked knobs by drilling through the larger one.

By replacing all three that were a similar design it isn't as obvious
that they are not original.
I can provide a photo, for your amusement.

ST



Michael A. Terrell


Re: PG-506 Calibrator and Power Module Compatibility

Adrian
 

Hi David,

Mystery solved I think - it's yer nuts mate!

They are on the wrong side, both my TM501s have the nuts on the underside of the Chassis and the button-head screw (with no washer) directly through the transistor. Now I look closely, as I mate the PG506 I can see the alignment pin just kisses the the button-head screw until the edge connector engages then the rear of the module lifts slightly and it clears.

Hopefully once you change the screw round yours will work the same.

All the best,

Adrian

On 12/23/2017 7:53 AM, David Hess wrote:
So the forum strips attachments. Here is a photograph that I took
which shows the transistors:

https://groups.io/g/TekScopes/photo/13641/1?p=Name,,,100,1,0,0

On Sat, 23 Dec 2017 01:48:21 -0600, you wrote:

The transistors and transistor mounting hardware on my TM501 appear to
be stock so I have assumed that the earlier plug-ins lacked the index
posts.

Hmm, let's see what happens to picture attachments with this new forum
...

Re: 7D15 Not Working or Cockpit Error?

 

Make a suggestion to the groups.io folks, they are looking for suggestions
for improvement.

Dave

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
Hess
Sent: 23 December 2017 08:16
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7D15 Not Working or Cockpit Error?

Once I learned how to use my 7D15 and recalibrated the trigger adjustments,
I found that the trigger was not finicky at all as long as I got the trigger
source configured correctly.

Besides calibration, I had to clean and lubricate the switches on mine, fix
some cracked solder joints on the trigger daughter boards, and repair one of
the attenuator modules.

On Mon, 18 Dec 2017 20:34:33 -0800, you wrote:

...

The 7D15 is also notoriously finicky about how the trigger level is set. If
you set it wrong you probably won't know it except your frequency/period
readings will be off by a factor of 2 or they will be entirely random.

...

Re: 7603 with noise in traces

 

On Mon, 18 Dec 2017 20:43:24 -0800, you wrote:

I have a 7603 with a 7A18, 7a18A, and a7B53A. I am just starting to use this scope and I've noticed a few things that I think need addressing, but would like some feedback before I do anything. I am new to this group, and if there is a wiki or file in the groups repository that you think I should read, I would appreciate the suggestion. Also, since I am new here, I suspect that this type of problem post has come up before I got here... If there is, just give me a link to that thread and I will go read up, first.

With both amplifiers installed, there is noise (moving black vertical lines) in all four of the traces with sweep speeds of 1ms, .5 ms, and .1ms, and slower but not higher. With just one amp installed, the trace isn't so much noisy at .1ms, but rather rippled but they become noisy with slower sweeps, again, down to 1ms.
Like Chris says, the blank spots in the traces are caused by the
readout multiplexing. If this is objectionable, then the readout
intensity control can shut off the readout or the slide switch on the
readout board inside the mainframe may be used to configure the
readout to "gated" mode so that the readout is written between sweeps.
But this also results in no readout when no sweep is present.

I think the traces are not completely sharp, no matter how the focus control is adjusted, and the READOUT and the trace(s) get sharper at different settings of the focus control! They are not sharpest at the same adjustment. Also, the whole image (readout and traces) seem to be jumping just a tiny bit.
The readout may shift depending on what the sweep is doing but usually
the sweep is stable. It may be worth checking the low voltage power
supply outputs for level and ripple. I need to change the input
capacitors on my 7603.

If the readout focus is not tracking the trace focus, then the
automatic focus may need to be calibrated.

If the 7603 has been in storage for a long time, then the CRT
sharpness may improve after a few days of operation. If you do this,
only leave it on while supervised and set the trace intensity to a low
but visible level; do not turn the intensity off.

When I look at the cal outputs, the vertical trace lines are nonexistent.
Trace brightness at any one point depends on the writing speed and at
a slow sweep speed, the vertical parts of the calibration waveform are
moving much faster than the horizontal parts.

Re: 7D15 Not Working or Cockpit Error?

 

Once I learned how to use my 7D15 and recalibrated the trigger
adjustments, I found that the trigger was not finicky at all as long
as I got the trigger source configured correctly.

Besides calibration, I had to clean and lubricate the switches on
mine, fix some cracked solder joints on the trigger daughter boards,
and repair one of the attenuator modules.

On Mon, 18 Dec 2017 20:34:33 -0800, you wrote:

...

The 7D15 is also notoriously finicky about how the trigger level is set. If you set it wrong you probably won’t know it except your frequency/period readings will be off by a factor of 2 or they will be entirely random.

...

Re: Searching Photo Albums

 

I also could not find a way to list just my own files, photographs, or
my folders.

On Tue, 19 Dec 2017 13:06:21 -0000, you wrote:

Maybe I'm just being a little dense, but I can't find a way to search for a particular photo album.
So if I was looking for all albums which contained, say, 7603?



Craig