Date   

Re: Tek 7854 Doesn't Come On After EPROM ROM Replacement

 

On Tue, 14 Jan 2014 05:19:19 -0500, you wrote:

On 01/13/2014 12:43 PM, David wrote:
Thanks for that. So, basically, those thin traces are carrying low
voltage, low current signals, where the thicker traces tend to be higher
power carriers.

Mark
That is generally how it works and in this case, the power and ground traces
connected at the left and right sides of the edge connector are even thicker
than the thick signal traces which do not run between pins.

As an alternative to adding an inductor and/or resistor, sometimes power traces
have a deliberately thin section with decoupling at the ends to serve as a low
pass filter for controlling noise.
That would be presuming the noise is a low power component?

Mark
Usually this is done to remove switching noise such as that which would come
from a switching power supply or digital logic. What makes it effective versus
using an LC or RC filter is that the frequency content is high. In many cases,
an LC filter may have too much capacitive coupling from input to output to be
effective at high frequencies so in demanding applications, an LC filter is
followed by a printed circuit board filter which is less expensive than using a
lossy ferrite bead as a filter.

As a practical matter, adding a printed circuit board decoupling filter can mean
the difference between 50mV peak to peak of switching noise and 5mV peak to peak
of switching noise. A lossy ferrite bead would also work well.


Re: C50 'scope camera manual needed.

Don Black <donald_black@...>
 

Thanks Tom,
I'm happy either way. I should be able to receive email attachments up to at least 20 MBytes (I did a test a few days ago for another reason. I'd prefer it to be reasonably sharp.

Cheers, Don.

On 15-Jan-14 1:04 AM, Tom Jobe wrote:
Hi Don,
I have just scanned all of the normal size pages of this C-50, etc. manual,
and I will get the few large size pages scanned in a few hours time.
Let's see how small I can make the file size for emailing, or failing that I
will put it up somewhere as well as post it to KO4BB later today.
tom jobe...



----- Original Message -----
From: "Don Black" <donald_black@bigpond.com>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 5:38 AM
Subject: Re: [TekScopes] C50 'scope camera manual needed.


Thanks Tom, I'd like a copy too please. Can you let us all know when
it's posted.

Don Black.

On 15-Jan-14 12:19 AM, Tom Jobe wrote:
Hi Tim,
I have an original manual that I would give you if you lived close enough
to
pay the postage cost.
But since you are half a world away, how about if I scan it for you?
The manual covers the C-50, C-51, C-52 and C-53 cameras and their
accessories, so it would be a good one to put online.
I will try to get it scanned today and post it to KO4BB's manual site.
tom jobe...


----- Original Message -----
From: "Tim Phillips" <tim@timexucl.orangehome.co.uk>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 2:39 AM
Subject: [TekScopes] C50 'scope camera manual needed.


from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it?
Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim



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Re: C50 'scope camera manual needed.

Tom Jobe <tomjobe@...>
 

Hi Don,
I have just scanned all of the normal size pages of this C-50, etc. manual, and I will get the few large size pages scanned in a few hours time.
Let's see how small I can make the file size for emailing, or failing that I will put it up somewhere as well as post it to KO4BB later today.
tom jobe...

----- Original Message -----
From: "Don Black" <donald_black@bigpond.com>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 5:38 AM
Subject: Re: [TekScopes] C50 'scope camera manual needed.


Thanks Tom, I'd like a copy too please. Can you let us all know when
it's posted.

Don Black.

On 15-Jan-14 12:19 AM, Tom Jobe wrote:
Hi Tim,
I have an original manual that I would give you if you lived close enough to
pay the postage cost.
But since you are half a world away, how about if I scan it for you?
The manual covers the C-50, C-51, C-52 and C-53 cameras and their
accessories, so it would be a good one to put online.
I will try to get it scanned today and post it to KO4BB's manual site.
tom jobe...


----- Original Message -----
From: "Tim Phillips" <tim@timexucl.orangehome.co.uk>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 2:39 AM
Subject: [TekScopes] C50 'scope camera manual needed.


from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it?
Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim



------------------------------------

Yahoo Groups Links



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---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com



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Re: C50 'scope camera manual needed.

Don Black <donald_black@...>
 

Thanks Tom, I'd like a copy too please. Can you let us all know when it's posted.

Don Black.

On 15-Jan-14 12:19 AM, Tom Jobe wrote:
Hi Tim,
I have an original manual that I would give you if you lived close enough to
pay the postage cost.
But since you are half a world away, how about if I scan it for you?
The manual covers the C-50, C-51, C-52 and C-53 cameras and their
accessories, so it would be a good one to put online.
I will try to get it scanned today and post it to KO4BB's manual site.
tom jobe...


----- Original Message -----
From: "Tim Phillips" <tim@timexucl.orangehome.co.uk>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 2:39 AM
Subject: [TekScopes] C50 'scope camera manual needed.


from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it?
Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim



------------------------------------

Yahoo Groups Links



------------------------------------

Yahoo Groups Links





---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com


Re: C50 'scope camera manual needed.

Tom Jobe <tomjobe@...>
 

Hi Tim,
I have an original manual that I would give you if you lived close enough to pay the postage cost.
But since you are half a world away, how about if I scan it for you?
The manual covers the C-50, C-51, C-52 and C-53 cameras and their accessories, so it would be a good one to put online.
I will try to get it scanned today and post it to KO4BB's manual site.
tom jobe...

----- Original Message -----
From: "Tim Phillips" <tim@timexucl.orangehome.co.uk>
To: <TekScopes@yahoogroups.com>
Sent: Tuesday, January 14, 2014 2:39 AM
Subject: [TekScopes] C50 'scope camera manual needed.


from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it?
Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim



------------------------------------

Yahoo Groups Links



Re: C50 'scope camera manual needed.

 

Hi Tim,

On Tue, Jan 14, 2014 at 11:39 AM, Tim Phillips
<tim@timexucl.orangehome.co.uk> wrote:
from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it?
Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim
Have you tried Artek?

Cheers,
D.


Re: A small request

 

On Tue, Jan 14, 2014 at 12:54 AM, <n6otq@yahoo.com> wrote:

When replying to messages, whether on the group of by email,

PLEASE TRIM DOWN THE REPLIED-TO TEXT!!!

You should retain enough to keep your reply in context with the thread.

Why should you do this?

Some folks get message in email via the digest, and it's worse than an annoyance to scroll through endlessly quoted text, especially when a thread is active and nobody's editing.

If anybody thinks I complain too much, I'll happily show you what this looks like from my end... :)
I don't use digest, and it annoys me too, somewhat. However, to be
fair, you should be using a client which blends out quotes by default.
If yours doesn't support that in digest mode, get or write a better
one.

Cheers,
D.


C50 'scope camera manual needed.

Tim Phillips <tim@...>
 

from Tim P (UK)
I have acqured a C50 camera - anyone know where to find a manual for it? Nothing on BAMA or TekWiki AFAICS
many thanks.
Tim


Re: Soldering Thermocouple Wires

Mark Wendt <mark.wendt@...>
 

On 01/13/2014 07:30 PM, David wrote:
The thermocouple voltage is proportional to the temperature difference along the
length of the wire. The voltage across the junction itself is small because the
temperature difference across the junction itself is small. Any error caused by
a junction with more than one dissimilar metal will be greater only because it
allows for a greater temperature difference along the junction itself.

This is why extension grade thermocouple wire can be less expensive. Since it
is only used where the temperature difference between the ends is small, it does
not have to be as precise as far as alloy or purity.

Man. We get off on some really, really good tangents here. ;-)

Mark


Re: A small request

 

>If anybody thinks I complain too much, I'll happily show you what this looks like from >my end... :)


I don't think you complain too much, I wish people would do this as well. Even the web interface gets quite messy... The convention on Usenet is to trim your quotes as well.


My 2 cents.


Jay


Re: Tek 7854 Doesn't Come On After EPROM ROM Replacement

Mark Wendt <mark.wendt@...>
 

On 01/13/2014 12:43 PM, David wrote:
Thanks for that. So, basically, those thin traces are carrying low
voltage, low current signals, where the thicker traces tend to be higher
power carriers.

Mark
That is generally how it works and in this case, the power and ground traces
connected at the left and right sides of the edge connector are even thicker
than the thick signal traces which do not run between pins.

As an alternative to adding an inductor and/or resistor, sometimes power traces
have a deliberately thin section with decoupling at the ends to serve as a low
pass filter for controlling noise.
That would be presuming the noise is a low power component?

Mark


Re: Soldering Thermocouple Wires

stefan_trethan
 

The extra junctions do not matter as long as they are at equal temperature on both ends.
The solder joint on the thermocouple tip is compact and conducts heat well, so it will be very close, well within typical instrument precision of 1 or 2 degrees. It does not matter if the reference junction is also soldered because it directly compensates at the tip. The voltage generated into the solder and out of the solder is equal and opposite, so only the difference of the thermopair remains no matter how many metals you add.

I too had exactly the same beliefs as you about TCs.  But then, like with Robert, someone came along and told me what is good enough for government work, so to speak. Since then I have soldered hundreds of junctions and confirmed many times this is no problem.

Attachment is a far greater source of error, since the wires conduct heat away you need to avoid local cooling of the material you measure and ensure a good thermal contact. Often I solder the thermocouple directly to the material if it is solderable metal and not at high voltage.

Besides, if TCs could not be soldered then the cold junction inside the instrument could not be soldered either. They all are - clamps or sockets soldered to a PCB. The only thing that matters is that both joints are equal in temperature. Much harder to do on this end because they are not shorted together like on the tip. Major problem and source of error for designs, such as temp. reading multimeters, where you need high voltage insulation at the same input terminals.

ST


On Mon, Jan 13, 2014 at 10:17 PM, <ditter2@...> wrote:


Your boss was wrong.  You will create extra junctions as the solder would be on different metals.  This would be compensated if the reference junction was also soldered.

As other have pointed out, many of the metals used in thermocouples can not be soldered, as solder does not wet them when it melts.  They need to be welded.

Steve


Re: [hp_agilent_equipment] GPIBUSB Adapter rev3 - Galvant Industries

jvanderwall1941
 

Won't the handshake signal simply forbid data transmission if the buffer is full?


Can someone please tell me what serial numbers correspond to early and late 7854s?


TIA and regards,


Jonathan


Re: Soldering Thermocouple Wires

John Griessen
 

On 01/13/2014 04:08 PM, Dennis Tillman wrote:
If whatever you do to one wire of the thermocouple you do to the other wire, the net result is differential summing to zero – at
least for first order effects.
That's the case when screws, solder balls, welds are all close together so the temperature of each is close.


Re: Soldering Thermocouple Wires

Robin Whittle
 

My understanding of thermocouples is that it doesn't matter what
intermediate metals, if any, there are at the hot or cold junctions.

Wiring multiple thermocouples together in series would work in a
particular way: the total voltage generated would be proportional to the
temperature difference between the hot ends (on average, if they are at
different temperatures) and the cold ends, where these solder joints
were made, in a junction box where each joint is presumably at the same
temperature. So if that junction box got hot, the high temperature
warning system would be activated at a correspondingly higher temperature.

- Robin http://www.firstpr.com.au/tequip/


Re: Soldering Thermocouple Wires

 

The thermocouple voltage is proportional to the temperature difference along the
length of the wire. The voltage across the junction itself is small because the
temperature difference across the junction itself is small. Any error caused by
a junction with more than one dissimilar metal will be greater only because it
allows for a greater temperature difference along the junction itself.

This is why extension grade thermocouple wire can be less expensive. Since it
is only used where the temperature difference between the ends is small, it does
not have to be as precise as far as alloy or purity.

On 13 Jan 2014 13:17:40 -0800, you wrote:

Your boss was wrong. You will create extra junctions as the solder would be on different metals. This would be compensated if the reference junction was also soldered.

As other have pointed out, many of the metals used in thermocouples can not be soldered, as solder does not wet them when it melts. They need to be welded.

Steve


A small request

n6otq@...
 

When replying to messages, whether on the group of by email,

PLEASE TRIM DOWN THE REPLIED-TO TEXT!!!

You should retain enough to keep your reply in context with the thread.

Why should you do this?

Some folks get message in email via the digest, and it's worse than an annoyance to scroll through endlessly quoted text, especially when a thread is active and nobody's editing.

If anybody thinks I complain too much, I'll happily show you what this looks like from my end... :)

73
Jim N6OTQ


Re: 2N3055 redux

 

It is possible that the 2N3055s were not fake. As discussed here earlier, there
were several different processes used to make 2N3055 transistors over time.

The initial single-diffused mesa version took a lot of production time and
yielded a large semiconductor die. It was slow but had large forward biased
safe operating area and was apparently immune to secondary breakdown. The later
epitaxial base version took a lot less time to produce and had a smaller die
size which made the mesa version uneconomical. It had a higher Ft but a smaller
forward biased safe operating area and definitely suffered from secondary
breakdown.

Using the later in a design for the former could definitely cause mysterious
failures and secondary breakdown can be very difficult to confirm.

On Mon, 13 Jan 2014 12:20:20 -0800, you wrote:

In early 80s military had problems with 2N3055 in power supplies. I do
not quite remember which service had problems, but I think it was Navy.
The power supplies were linear and problem was that serial transistors,
2N3055, were dying like flies. Analysis of power supplies showed that
2N3055 was not overstressed so in next step number of transistors were
de-capped and it was found out that in most cases an undersized die, as
usually used in TO5 package, was mounted in TO3 package and sold as
2N3055. Motorola was singled out as the only manufacturer which used
proper size die. As Gordon Moore, of 'Moore Law' fame likes to state
that the cost in semiconductors is in acreage of silicon; he has a
number that he floats, I think it is something like 100 million dollars
per acre, so 2N3055 cheaters saved some bucks by making fake 2N3055. Now
that I said it, it dawned on me that counterfeit parts are not a new
scourge that we are facing today, those thing were happening in the past
but were just small blips.

Miroslav Pokorni


Re: 2N3055 redux

Craig Sawyers <c.sawyers@...>
 

In early 80s military had problems with 2N3055 in power supplies. I do not
quite remember which service had problems, but I think it was Navy. The
power supplies were linear and problem was that serial transistors, 2N3055,
were dying like flies.
============================

I used to have a CERN technical note about a pulsed kicker magnet power
supply back in the 70's that used 7,200 3N3055s in parallel on water cooled
heatsinks filling two seriously tall 19" racks. These were driven by 3,600
drivers. Lent it to someone, and it never got returned.

Craig


Re: Soldering Thermocouple Wires

 

Hi Steve,

 

For a while I was puzzled why the screws on thermocouple connectors were fairly ordinary and why they were both the same. I thought each one had to be made from the same metal as the wire coming to that pin of the connector. As I found out by investigating a little deeper when I was soldering the thermocouples for my friends turboshaft engine that is not the case. If the screws, or solder joints (or by whatever method the contacts are made)  are the same they do not add an additional voltage since the voltages from the screws / solder connections / etc.  are summed differentially.

 

If whatever you do to one wire of the thermocouple you do to the other wire, the net result is differential summing to zero – at least for first order effects.

 

Dennis

 

From: ditter2@..., Sent: Monday, January 13, 2014 1:18 PM

Your boss was wrong.  You will create extra junctions as the solder would be on different metals.  This would be compensated if the reference junction was also soldered.

As other have pointed out, many of the metals used in thermocouples can not be soldered, as solder does not wet them when it melts.  They need to be welded.

Steve

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