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Blowing line fuses in a 475

 

Hi David:

I use a variac with an AC ammeter in the load side. Temporarily replace the 475 fuse with a 4 amp one and adjust the AC voltage until about 2-4 amps flow into the scope and wait about 15 minutes. Remove power and immediately feel all the bridge rectifiers, filter caps and the power transformer for excessive heat. The transformer should be warm but if any rectifiers or caps are warm that is the problem. If all the rectifiers and caps are cold and the transformer is warm you might have a bad transformer or a short on the main board. Above all, do nor try to remove the main board, it is a terrible job. An alternate method would be to use the variac but measure the current flowing in each secondary wire going to the main board using a clamp on ammeter. I do not use this method as there is little room for my clamp on ammeter. To remove a defective bridge rectifier bend it back and forth until the leads break. Then solder in a new one.

Good luck

Reed Dickinson
Re: Tektronix 545D

Chuck Miles
 

Reed,

I'd love to see the picture of your "545D".,... I have a "B" version.

Thanks

Chuck
Junction City, OR

----- Original Message -----
From: "Reed Dickinson" <reed-d@...>
To: <TekScopes@...>
Cc: "Reed Dickinson" <reed-d@...>
Sent: Thursday, January 03, 2002 11:38 AM
Subject: [TekScopes] Tektronix 545D


I saw the note from Dean and it brought back memories. I worked for IBM
in
1957 to 1959 as bench technician. I used a 541 then a 545. I really
fell
in love with the 545 and wanted a scope for home use so, I managed to buy
a
DuMont 304, it was not up to par with the 545. Being spoiled for a 545
but
not having the cash available to purchase one and, having access to all
the
parts, I decided to make one. From 1957 to 1959 I constructed a 541. In
1966 I came across a delay board for the scope and added it, it then
became
a 545, I call mine a 545D. It has all the features of the 545 with the
addition of a running time meter. I wound the original delay line on wood
dowels with costume beads for the taps. I later added a factory made
delay
line. The home made CA and K plug in's are mounted in the upper right
rather than the lower left. The mercury pulser plug in got lost during a
move. Someday, when I drive up the coast, it is going to Stan Griffiths
for
his museum.

If anyone wants a picture, drop me a line as it is in my garage and still
works great.

Reed Dickinson
S. CA.

reed-d@...




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Re: Help on 485 power supply problems

 

Sounds like you have a short past the PS. Try to get a manual if you
don't have one before you pull off any connectors. If you do get
brave and pull them mark them first. If the ticking stops after you
pull some of them then you'll have a general idea of where it's at.
If it still ticks the problem is with the PS on the secondary of the
power transformer. Could be feedback to primary too but not likely.
Good luck with it.

Pat




--- In TekScopes@y..., Willard G Wood <willardgw@j...> wrote:
Any one that can help with my problem on a 485 oscilloscope, I would
appreciate it.
SYMPTOMS
1)-----Pwr "On" Ticking sound from switching power supply
2)-----Some of the Ne-2's light on various power modules
3)-----Removing ground wire from voltage multiplier, did not help!
4)-----RF type voltage at the -295 voltage check point
5)-----Rectifier filter caps have around 160 volts
6)-----Rear fan will "kick" turn some times
7)-----If I remove the voltage multiplier, entirely will the
switching
power supply still run, I know removing the coax drive cable to the
transformer stops everything.
8)-----Any ideas on this model will help....Thanks!
Re: Lavoie LA-265?

JOSE V. GAVILA (EB5AGV/EC5AAU)
 

Hmmmm... I was offered locally (I am in Spain and it is really difficult to
locate good Tektronix gear so Lavoie is yet more difficult to find) a
Lavoie LA-265A for about $110, along a CA plug-in. I refused to buy it,
because I thought a clone was not worth so much. I wonder if I was wrong,
due to scarcity of them. BTW, seller told me it worked fine and was in top
condition. Perhaps it has the HV transformer already changed ;-)!

Happy 2002 to all!

JOSE
----------------------------------------------------------------------
73 EB5AGV / EC5AAU - JOSE V. GAVILA
La Canyada - Valencia (SPAIN)

EB5AGV Vintage Radio Site:

European Boatanchors List:

Re: Lavoie LA-265?

Stan or Patricia Griffiths
 

I have one of those things in my collection and it will be interesting to see
what I find wrong with it when (and if) I ever get around to it. I also have
two clones made by Hickok and I have looked at both of them and they both
have HV problems that I believe to be the transformers. In one of them, I
got it to work well by transplanting an entire Tek HV assembly into it. I'll
bet there is not a stock one still running anywhere in the world . . .

Stan
w7ni@...

deanhuster wrote:

During my time in the U.S. Navy at USNAVSECGRUACT Sabana Seca, Puerto
Rico in the test equipment cal shop, I got to use the Lavoie "faux-
clone" of the Tek 545 every day for two years. I finally got tired
of its (and every one of them that I'd seen) problem: bright trace
that gradually dims over an hour or two to no trace at all. I
finally figured out that it must be the HV transformer so decided to
pull a fast one on the Navy and order a Tek replacement rather than
the Lavoie part number. Lo and behold, when the mil-packed Tek
transformer came it, enclosed was a sheet telling how to install the
Tek part in a Lavoie scope! Obviously, this was the premier problem
with this "design". We had two of those danged mainframes at the
operational site and they both had the same problem. I fixed the
second one within a month. Then I saw another one at another duty
station and told the techs how to take care of the problem.

I remember that the Lavoie scope had a little box filled with a
gillion neon lamps, all in series used as a voltage regulator as I
recall. And the ceramic strips were little metal clips in ceramic
notches rather than the fired silver-on-ceramic that real Tek's had.

Once I fixed the scope up, I didn't really have any complaints about
its operation but it always bugged me that it was obvious copyright
and patent infringement. Later, after I went to work for Tek, we'd
gotten the message that the lawsuit against the government, Lavoie,
Hickock, et. al. had been "won" by Tek.

Dean


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Lavoie LA-265?

deanhuster
 

During my time in the U.S. Navy at USNAVSECGRUACT Sabana Seca, Puerto
Rico in the test equipment cal shop, I got to use the Lavoie "faux-
clone" of the Tek 545 every day for two years. I finally got tired
of its (and every one of them that I'd seen) problem: bright trace
that gradually dims over an hour or two to no trace at all. I
finally figured out that it must be the HV transformer so decided to
pull a fast one on the Navy and order a Tek replacement rather than
the Lavoie part number. Lo and behold, when the mil-packed Tek
transformer came it, enclosed was a sheet telling how to install the
Tek part in a Lavoie scope! Obviously, this was the premier problem
with this "design". We had two of those danged mainframes at the
operational site and they both had the same problem. I fixed the
second one within a month. Then I saw another one at another duty
station and told the techs how to take care of the problem.

I remember that the Lavoie scope had a little box filled with a
gillion neon lamps, all in series used as a voltage regulator as I
recall. And the ceramic strips were little metal clips in ceramic
notches rather than the fired silver-on-ceramic that real Tek's had.

Once I fixed the scope up, I didn't really have any complaints about
its operation but it always bugged me that it was obvious copyright
and patent infringement. Later, after I went to work for Tek, we'd
gotten the message that the lawsuit against the government, Lavoie,
Hickock, et. al. had been "won" by Tek.

Dean
Re: X01 Overlay: The 1Word (tm) text editor XTPRO

deanhuster
 

Are you the antique radio Marc Ellis, Marc? Let me know:
dhuster@...

Dean
WTD: Manual for C1002 Camera

w1ksz
 

I picked up this TEK Video Camera (mounts on Scope face).
Does anyone have a manual I can buy or copy ? Or have any info on
this camera ?

Thanks, Dick, W1KSZ
Just missed an eBay bargain

Craig Sawyers
 

Hi list

There has just been a Tek P6156 probe gone on eBay - brand new - for a
BuyItNow price of $5. Have a look at item number 1685282338.

It sold in about a nanosecond. A 10x, 3.5GHz, 50 ohm passive probe with all
accessories in the Tek box - for five bucks.

Just kicking myself that I was watching the television instead of eBay!

Craig
Re: Way off topic: Radio antennas

John Miles
 

The new scanner may be more vulnerable to overloading caused by too much
signal from a nearby transmitter. For many years now, the trend in all
types of receivers -- not just scanners -- has been toward untuned front
ends, and not all of the manufacturers have responded by using the better
preamps, mixers, and synthesizers you need when you don't have any
meaningful preselection. It's not uncommon for older receivers to perform
better in the presence of strong signals than newer ones do.

Although if what you're hearing is genuine "static," that sounds like a bad
connection somewhere in the antenna system. Why it would affect the new
scanner but not the old one is anyone's guess... you will probably just have
to take the whole antenna system apart for a careful inspection.

-- jm

----- Original Message -----
From: "james89es" <james89es@...>
To: <TekScopes@...>
Sent: Wednesday, January 02, 2002 7:49 AM
Subject: [TekScopes] Re: Way off topic: Radio antennas


Could you explain what "front-end overloading" would indicate?
Radio's fault or antenna's fault?
Re: Way off topic: Radio antennas

Don Black
 

I wonder if the aerial connection could be inducing hash from a switchmode
power supply (if it has one). Is there any difference in earthing between the
two sets?
Don Black.

james89es wrote:

Could you explain what "front-end overloading" would indicate?
Radio's fault or antenna's fault?

--- In TekScopes@y..., "John Miles" <jmiles@p...> wrote:
Might be a symptom of front-end overloading. What does the "static"
sound
like -- AM-style random static, or distortion of a tonal (pager
transmitter?) signal?

-- jm


----- Original Message -----
From: "james89es" <james89es@y...>
To: <TekScopes@y...>
Sent: Tuesday, January 01, 2002 8:20 PM
Subject: [TekScopes] Way off topic: Radio antennas


I know this has nothing to do with Tek-scopes (I do own a RM547,
so I
do belong "in the club") but I know many of you are also into HAM
radio.

Here's the story:

I bought my mother a new police scanner (from Rasio Shack) for x-
mas. She has had scanners for 25+ years. Her old Uniden was 15
years old. The outside antenna is about 20 years old.

Problem:

When we plug the outside antenna into the new scanner, it CAUSES
static and reduces signal strength!! I ruled out the plug on the
radio itself by connecting a short piece of cable, and touching
the
bare wire with my finger. In this scenario the signal is stronger
and there's less static when I touch the wire, as I would expect.
Once I plug in the outside antenna, however, more static and less
strength ... even if I leave the little inside antenna on.

They replaced the coax just in case, they used the recommended
50ohm
cable - a run of about 30 feet.

What would explain this?? Keep in mind that the old Uniden still
works fine with the outside antenna.

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Re: Way off topic: Radio antennas

james89es
 

Could you explain what "front-end overloading" would indicate?
Radio's fault or antenna's fault?


--- In TekScopes@y..., "John Miles" <jmiles@p...> wrote:
Might be a symptom of front-end overloading. What does the "static"
sound
like -- AM-style random static, or distortion of a tonal (pager
transmitter?) signal?

-- jm


----- Original Message -----
From: "james89es" <james89es@y...>
To: <TekScopes@y...>
Sent: Tuesday, January 01, 2002 8:20 PM
Subject: [TekScopes] Way off topic: Radio antennas


I know this has nothing to do with Tek-scopes (I do own a RM547,
so I
do belong "in the club") but I know many of you are also into HAM
radio.

Here's the story:

I bought my mother a new police scanner (from Rasio Shack) for x-
mas. She has had scanners for 25+ years. Her old Uniden was 15
years old. The outside antenna is about 20 years old.

Problem:

When we plug the outside antenna into the new scanner, it CAUSES
static and reduces signal strength!! I ruled out the plug on the
radio itself by connecting a short piece of cable, and touching
the
bare wire with my finger. In this scenario the signal is stronger
and there's less static when I touch the wire, as I would expect.
Once I plug in the outside antenna, however, more static and less
strength ... even if I leave the little inside antenna on.

They replaced the coax just in case, they used the recommended
50ohm
cable - a run of about 30 feet.

What would explain this?? Keep in mind that the old Uniden still
works fine with the outside antenna.
Re: Way off topic: Radio antennas

Michael
 

Hi,

Maybe - just maybe, there is a problem with the outside antenna. Perhaps
the centre conductor is open circuit at the actual antenna, and the signal
you're getting from it is being picked up and fed to the scanner via the
shield...

Depending on the individual configuration of the two scanners' input
circuitry, the Uniden may have been happy with this, the new one may not be.
Especially if the new scanner has a ground connection, and grounds the
antenna shield...

Just 2c worth.
:)
Michael
Re: Way off topic: Radio antennas

james89es
 

The static is AM style. What I did was: tune in one of the weather
stations so there was a constant signal. It was fine with the small
inside ant. Then I unplugged the inside ant. and the signal got
weaker and a little static was mixed in. Then I plugged in the
outside ant. and the signal got very weak with much more static.

The same procedure using my finger as the ant. would make the signal
stronger.

(I know what you mean about pager transmitter signals - it wasn't
that).

Note: we are NOT trying to use one ant. in two radios at the same
time. We unplug from one then plug into the other.

Thanks, by the way, for responding so quick.

--- In TekScopes@y..., "John Miles" <jmiles@p...> wrote:
Might be a symptom of front-end overloading. What does the "static"
sound
like -- AM-style random static, or distortion of a tonal (pager
transmitter?) signal?

-- jm


----- Original Message -----
From: "james89es" <james89es@y...>
To: <TekScopes@y...>
Sent: Tuesday, January 01, 2002 8:20 PM
Subject: [TekScopes] Way off topic: Radio antennas


I know this has nothing to do with Tek-scopes (I do own a RM547,
so I
do belong "in the club") but I know many of you are also into HAM
radio.

Here's the story:

I bought my mother a new police scanner (from Rasio Shack) for x-
mas. She has had scanners for 25+ years. Her old Uniden was 15
years old. The outside antenna is about 20 years old.

Problem:

When we plug the outside antenna into the new scanner, it CAUSES
static and reduces signal strength!! I ruled out the plug on the
radio itself by connecting a short piece of cable, and touching
the
bare wire with my finger. In this scenario the signal is stronger
and there's less static when I touch the wire, as I would expect.
Once I plug in the outside antenna, however, more static and less
strength ... even if I leave the little inside antenna on.

They replaced the coax just in case, they used the recommended
50ohm
cable - a run of about 30 feet.

What would explain this?? Keep in mind that the old Uniden still
works fine with the outside antenna.
Re: Way off topic: Radio antennas

John Miles
 

Might be a symptom of front-end overloading. What does the "static" sound
like -- AM-style random static, or distortion of a tonal (pager
transmitter?) signal?

-- jm

----- Original Message -----
From: "james89es" <james89es@...>
To: <TekScopes@...>
Sent: Tuesday, January 01, 2002 8:20 PM
Subject: [TekScopes] Way off topic: Radio antennas


I know this has nothing to do with Tek-scopes (I do own a RM547, so I
do belong "in the club") but I know many of you are also into HAM
radio.

Here's the story:

I bought my mother a new police scanner (from Rasio Shack) for x-
mas. She has had scanners for 25+ years. Her old Uniden was 15
years old. The outside antenna is about 20 years old.

Problem:

When we plug the outside antenna into the new scanner, it CAUSES
static and reduces signal strength!! I ruled out the plug on the
radio itself by connecting a short piece of cable, and touching the
bare wire with my finger. In this scenario the signal is stronger
and there's less static when I touch the wire, as I would expect.
Once I plug in the outside antenna, however, more static and less
strength ... even if I leave the little inside antenna on.

They replaced the coax just in case, they used the recommended 50ohm
cable - a run of about 30 feet.

What would explain this?? Keep in mind that the old Uniden still
works fine with the outside antenna.
Way off topic: Radio antennas

james89es
 

I know this has nothing to do with Tek-scopes (I do own a RM547, so I
do belong "in the club") but I know many of you are also into HAM
radio.

Here's the story:

I bought my mother a new police scanner (from Rasio Shack) for x-
mas. She has had scanners for 25+ years. Her old Uniden was 15
years old. The outside antenna is about 20 years old.

Problem:

When we plug the outside antenna into the new scanner, it CAUSES
static and reduces signal strength!! I ruled out the plug on the
radio itself by connecting a short piece of cable, and touching the
bare wire with my finger. In this scenario the signal is stronger
and there's less static when I touch the wire, as I would expect.
Once I plug in the outside antenna, however, more static and less
strength ... even if I leave the little inside antenna on.

They replaced the coax just in case, they used the recommended 50ohm
cable - a run of about 30 feet.

What would explain this?? Keep in mind that the old Uniden still
works fine with the outside antenna.
Re: Broken YIG oscillator wanted

DEANE KIDD
 

开云体育

Hi Jim:
?? I can provide a set of board extenders.? They are available from Norway Labs, Inc. matt@... for a fair price of about $90.00.? Your set is available at no charge as a friend to friend deal.? You can pick them up on Sat in the early afternoon.? Please call first to make sure that I am awake and available.? I if I don't answer, try again in a few minutes.
Deane
?
?

----- Original Message -----
Sent: Wednesday, October 07, 2009 6:25 AM
Subject: Re: [TekScopes] Re: Broken YIG oscillator wanted

?

Hi Deane,

I'm Still looking for an extender card set for the 492's.
any luck???
are you doing ok?
i've sent a couple of emails, but I know your busy.
thanks
Jim



On Oct 3, 2009, at 10:58 PM, DEANE KIDD wrote:

?

Hi John:
?? I can provide YIG oscilators as used in the TEK SA/s.? These are all removed from units and may or may not work.? I only would like postage for the YIG's.? I will need your address for mailing.
I have made this offer recently?but? have not had any takers which makes me wonder about my email system.
Deane Kidd;? dektyr@comcast.net
-----
From: snapdiode
Sent: Tuesday, September 08, 2009 10:40 AM
Subject: Original Message ----- [TekScopes] Re: Broken YIG oscillator wanted

?

--- In TekScopes@yahoogroups.com, John Rehwinkel <jrehwin@...> wrote:
>
> It occurred to me that a YIG oscillator would be a dandy example of
> yttrium for my element collection. However, I don't want to break
> working equipment (and I'm cheap). Anybody have a dead YIG oscillator
> module they'd care to sell me? I'm in the United States, in northern
> Virginia.
>
> – Regards,
> John
>
What are the little ceramic pucks in satellite receiver DROs made from?
I've found a few dead antennas like this and enjoyed cracking the LNA open. Probably easier to find for free than a YIG module.




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Re: TDS Schematics

DEANE KIDD
 

开云体育

To all users of Tek scopes:
?? I would like to suggest that it might help if all scope users would use the correct numbers for their scopes.? There is a 544 scope and there is a TDS544 scope and they are two different products with two different manuals.? It makes no sense to omit any of the alpha numeric symbols and it does not make it very easy to know what you really need.?
Deane
?

----- Original Message -----
From: Tom Taylor
Sent: Saturday, May 30, 2009 10:15 PM
Subject: Re: [TekScopes] Re: TDS Schematics

I also own a 544A as well as a 744 and would be very interested in sharing the cost as well.

Tom Taylor

David I. Emery wrote: 

On Sat, Apr 18, 2009 at 02:56:38PM -0700, Al Jamison wrote:
  
Hakan:

I think I would be interested in sharing the cost to have the TDS544A
documentation scanned professionally if it includes the information you
indicated including schematics. I already have the modular level service
manual.
I am very happy with this scope and it's performance.

Please let me know if this is an option and what the cost would be.

Al Jamison
    
	I too own a 544A and desparately want the .pdfs of the real
service docs... I'd chip in too...


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Re: Broken YIG oscillator wanted

DEANE KIDD
 

开云体育

?Hi Pete:
?? I can provide a Yig osc. Need your address.? No charge for the Yig but postage would be nice.
Deane
?
----- Original Message -----
Sent: Tuesday, September 08, 2009 5:28 PM
Subject: [TekScopes] Re: Broken YIG oscillator wanted

?

Is it just the sphere you want ?

-pete

--- In TekScopes@yahoogroups.com, John Rehwinkel > wrote:
>
> It occurred to me that a YIG oscillator would be a dandy example of
> yttrium for my element collection. However, I don't want to break
> working equipment (and I'm cheap). Anybody have a dead YIG oscillator
> module they'd care to sell me? I'm in the United States, in northern
> Virginia.
>
> – Regards,
> John
>


No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.409 / Virus Database: 270.13.83/2352 - Release Date: 09/07/09 18:03:00
Re: unsoldering tricks

 

A de-soldering trick from an old gas passer.

Cutting the leads off the IC works well, you use a pair of dikes with narrow jaws and cut the legs right at the body of the IC. What I do next is turn the board over and heat the pad with a low temperature iron then push the cut-off leg out using a dental explorer. Push the explorer all the way through the hole cleaning the hole out. Then turn the board back over and clip the solder mounds off, insert the new IC and, again using a low temperature iron, carefully solder the new IC back in. Fast, reliable and with minimal board damage!

Reed Dickinson
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