开云体育

A big "Thank You" to Jim Popwell for helping this person get his 465B
running... AND for the excellent tip about using an NPN transistor's EB
junction as a zener!
The first 2N2222 transistor I tried had a starting zener point of 7.4
volts and a very square knee on a curve tracer.
Many zeners do not have a trace that nice!
tom jobe...






On 12/5/2014 8:27 PM, Jim Popwell jpopwell@... [TekScopes] wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point and the
emitter connected where the anode is of the original zener…. this will
give a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>> wrote:

there should be 6.2v difference across VR4341…. measure both sides of
R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿…. a

lot of zeners from these years have it…. usually diodes from

Motorola and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@...

<mailto:TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each of the

leads. Not

sure if that is normal, but to the untrained eye, it looks like

it might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...>>>
wrote:

find vr4341, a zener diode. measure both sides of it please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@...

<mailto:TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>> wrote:

Hi Jim. The symptoms do still exist when I press the 10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@... <mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>> <mailto:

jpopwell@... <mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...>>

<mailto:TekScopes@...

<mailto:TekScopes@...> <mailto:TekScopes@...
<mailto:TekScopes@...>>>>

wrote:

one other thought…. push in the X10 mag button and see if your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@...

<mailto:TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>> wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm still not

sure the

best

way

to

do so. I also checked the wires to the deflector plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria. Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test points

86, 89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM, aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>> <mailto:

aodiversen@... <mailto:aodiversen@...>

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@...

<mailto:TekScopes@...> <mailto:TekScopes@...
<mailto:TekScopes@...>>

<mailto:TekScopes@...

<mailto:TekScopes@...> <mailto:TekScopes@...
<mailto:TekScopes@...>>>>

wrote:

Yes simply set both channels to GND and defocus the

spot. That

way

you

won't burn-in the screen.
Albert


---In TekScopes@...

<mailto:TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal, say

from a

small

signal generator that outputs a dirty square wave, or

can I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test points?




[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

On 12/06/2014 08:17 AM, Kevin Crossett kcrossett@... [TekScopes] wrote:

Am I missing something
or is that backwards?

No time to look up schematic. 2n3904 is NPN. Base to emiiter is
a diode in forward direction. To act like a zener, it needs to
be in the circuit reverse biased so current flows into E, out of B.

That won't happen until a good bit above 0.7 Volts.
Zeners work in reverse breakdown mode.

Guys,
Pls trim your replies, some of you have a very long tail, which makes threads very hard to follow.
Tnx.
?HankC, Boston
WA1HOS


[Non-text portions of this message have been removed]

Thanks everyone for the support on this problem. I have one final question.
When I placed the 2n3904 transistor as Jim suggested with the base at the
cathode end, the circuit did not work. When I turned it around, basically
because I thought maybe I hooked it up wrong, it worked fine. In other
words, the Base of the transistor is connected to the 27 kohm resistor in
the circuit. If the base is the cathode, isn't that wrong. I believe I have
a standard transistor with the EBC configuration when looking at the flat
side of the TO-92 package. The B is connected to the same side as the
resistor and the E is connected to the other point. Am I missing something
or is that backwards?

On Sat, Dec 6, 2014 at 4:22 AM, raymonddf@... [TekScopes] <
TekScopes@...> wrote:

Congrats Kevin, I'm sure you'll enjoy your "new" 'scope. Don't forget:
You'll need at least two!


Raymond

Assuming you installed it correctly i.e. entered the correct parameters in the setup software and you start the
program with the created bat-file it should work.

I run these adjustment softwares in a DOS window on a Win98 PC and it works fine.
I use the NI DOS drivers for other applications however these actually don't need any GPIB drivers and the
scope doesn't have to be set to address 1.

Here's how my setup is:

Card: PC2A
Base I/O: 02E1
No DMA
No IRQ
The set commands in the created bat file say: GPIB0=PC2A 0 7 0 and GPIB1=PC2A 0 7 0

/H?kan

Congrats Kevin,

Well done. Looking forward to pics of the Frankenstein repair. Next thing you know you'll be scouting eBay for scopes listed "for parts or repair", just for the thrill of repairing them :).


Siggi

On 12/05/2014 04:54 PM, edbreya@... [TekScopes] wrote:

directly sampled at full speed - 420 Hz, with 12 usec strobe width. I have a 7904 setup on it now, with recently "fixed" 7B80, and
a 7D15 to measure the actual strobing frequency. Next I'll be experimenting with higher LED strobe current.

Looks nice and bright -- suggesting 2 LEDs and 4 usec strobe width...

ROFL! All that hard work, and the bench still shows...

Mark

On 12/5/2014 4:50 PM, magnustoelle@... [TekScopes] wrote:

Ah, bummer- Yahoo's NEO crap still does not like me, and I do not like it either.
My photos disappeared as it seems. I have uploaded a few to

Cheers,

Magnus

Nicely done Magnus!

Mark

On 12/5/2014 4:43 PM, 'Toelle, Magnus' magnustoelle@... [TekScopes] wrote:

Good Day to the group,

Hello Christian Weagle, I hope you are doing well.

As you are probably aware, I am somewhat a fan of Tektronix'
5000/5400-series oscilloscopes - same as you.

I have always referred to your excellent website as
*the* information source about this series of oscilloscopes on the internet.
The "External read-out" alias Option 3 modification for the
5400-mainframes you have made and documented even inspired me- to do
exactly the same on my 5440.
See my other recent posting.

However, your website above seems permanently down, over several weeks
now. I have verified this using


Please, may you allow me to kindly ask you to put your website back into
operation? I would much like to see all that information to become
available again.
I would be willing to spend some reasonable amount of $$$ to support the
operation of the website, if funding is an issue.

Thank you in anticipation.

Cheers,

Magnus

Magnus,

Seems to be up and running fine this morning at 8:10 AM Eastern time.

Mark

Congrats Kevin, I'm sure you'll enjoy your "new" 'scope. Don't forget: You'll need at least two!


Raymond

Congratulations Kevin. I'm glad I was sleeping (Europe) while you and Jim were playing detective, I know how difficult it can be to stop when you feel you are nearly there!
Albert

I had that a time or two on the Tek rack scopes..After prying the first one out I found it was one of the bottom (or top) cover screws just a hair too long, effectively locking the plugin into the frame..and..OT(tek) on an HP180 for example, if you put the wrong/longer cover screws into certain locations they will shatter the plastic plugin rail which holds the Vertical Plate slide contacts..Way bad..A Very Nice fellow in the UK actually pulled a parts unit down and sent me the rail, which includes the plate interconnect tranmission line..it looks like it unplugs but don't do it, theres a hair fine conductor involved....Carry on ..:)? Dana
?


[Non-text portions of this message have been removed]

Yeah, I think I will get the right zener. Not sure 9 diodes would fit Hi Hi

Take care Mike
Kevin
KN4M

On Fri, Dec 5, 2014 at 9:24 PM, Mike Patriot121@... [TekScopes] <
TekScopes@...> wrote:

You could string 8 or 9 regular diodes in series to get that voltage ...

.7V X 8 = 5.6V .7V X 9 = 6.3V ...

Just get the right zener and be done with it ...

On 12/05/2014 09:10 PM, Kevin Crossett kcrossett@... [TekScopes]
wrote:

Eureka. That was it. I put a 2n3904 transistor in place of the zener
diode,
and it works.

Now I just need to get a zener diode. I'm guessing that I need one that
meets these specs: .4 w, 6.2 v, 5 %

Sorry for the stupid question, but will I be able to find one at mouser?
Doubt Radio Shack will have one.

A big thank you to everyone who assisted me with this scope. I am a very
happy man tonight.

On Fri, Dec 5, 2014 at 8:35 PM, Jim Popwell jpopwell@...
[TekScopes] <
TekScopes@...> wrote:

YES replacing it…..you can NOT just PARALLEL IT.

make sure all power is off and double check things…… some are very

fragile

so desolder it carefully…. they are not hard to find or expensive

On Dec 5, 2014, at 8:29 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh, and I assumed I'm replacing VR4341?

On Fri, Dec 5, 2014 at 8:28 PM, Kevin Crossett <kcrossett@...

<mailto:kcrossett@...>> wrote:

I'll do it now. It might take a few minutes.

On Fri, Dec 5, 2014 at 8:27 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point

and the

emitter connected where the anode is of the original zener…. this

will give

a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>>

wrote:

there should be 6.2v difference across VR4341…. measure both

sides of

R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿….

a

lot of zeners from these years have it…. usually diodes from

Motorola

and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each

of the

leads. Not

sure if that is normal, but to the untrained eye, it

looks like

it

might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

find vr4341, a zener diode. measure both sides of it

please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

Hi Jim. The symptoms do still exist when I press the

10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>>

<mailto:

jpopwell@... <mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@...

<mailto:TekScopes@...

<mailto:TekScopes@...

<mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

one other thought…. push in the X10 mag button and

see if

your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm

still not

sure

the

best

way

to

do so. I also checked the wires to the deflector

plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria.

Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test

points

86,

89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM,

aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>>

<mailto:

aodiversen@... <mailto:aodiversen@...

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@...

<mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

Yes simply set both channels to GND and defocus

the

spot.

That

way

you

won't burn-in the screen.
Albert


---In TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal,

say

from a

small

signal generator that outputs a dirty square

wave, or

can

I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test

points?

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

--
Mike KC7NOA

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

Calibration will be the next project:)

On Dec 6, 2014, at 00:16, Jim Popwell jpopwell@... [TekScopes] <TekScopes@...> wrote:

the scope is now UNCALIBRATED because this probably changed the gain of the final stages…. after replacement with a good 6.2 you should be very close to original specs….
Glad things worked out…enjoy….
jim

On Dec 5, 2014, at 9:10 PM, Kevin Crossett kcrossett@... [TekScopes] <TekScopes@...> wrote:

Eureka. That was it. I put a 2n3904 transistor in place of the zener diode,
and it works.

Now I just need to get a zener diode. I'm guessing that I need one that
meets these specs: .4 w, 6.2 v, 5 %

Sorry for the stupid question, but will I be able to find one at mouser?
Doubt Radio Shack will have one.

A big thank you to everyone who assisted me with this scope. I am a very
happy man tonight.

On Fri, Dec 5, 2014 at 8:35 PM, Jim Popwell jpopwell@... <mailto:jpopwell@...> [TekScopes] <
TekScopes@... <mailto:TekScopes@...>> wrote:

YES replacing it…..you can NOT just PARALLEL IT.

make sure all power is off and double check things…… some are very fragile
so desolder it carefully…. they are not hard to find or expensive

On Dec 5, 2014, at 8:29 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh, and I assumed I'm replacing VR4341?

On Fri, Dec 5, 2014 at 8:28 PM, Kevin Crossett <kcrossett@...

<mailto:kcrossett@...>> wrote:

I'll do it now. It might take a few minutes.

On Fri, Dec 5, 2014 at 8:27 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point and the
emitter connected where the anode is of the original zener…. this

will give

a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>>

wrote:

there should be 6.2v difference across VR4341…. measure both

sides of

R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿….

a

lot of zeners from these years have it…. usually diodes from

Motorola

and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each of the

leads. Not

sure if that is normal, but to the untrained eye, it looks like

it

might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

find vr4341, a zener diode. measure both sides of it please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>>

wrote:

Hi Jim. The symptoms do still exist when I press the 10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>> <mailto:

jpopwell@... <mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...

<mailto:TekScopes@... <mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

one other thought…. push in the X10 mag button and see if

your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>>

wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm still not

sure

the

best

way

to

do so. I also checked the wires to the deflector plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria.

Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test points

86,

89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM, aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>> <mailto:

aodiversen@... <mailto:aodiversen@...>

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

Yes simply set both channels to GND and defocus the

spot.

That

way

you

won't burn-in the screen.
Albert


---In TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal,

say

from a

small

signal generator that outputs a dirty square wave, or

can

I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test points?




[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

You could string 8 or 9 regular diodes in series to get that voltage ...

.7V X 8 = 5.6V .7V X 9 = 6.3V ...

Just get the right zener and be done with it ...


On 12/05/2014 09:10 PM, Kevin Crossett kcrossett@... [TekScopes]
wrote:

Eureka. That was it. I put a 2n3904 transistor in place of the zener
diode,
and it works.

Now I just need to get a zener diode. I'm guessing that I need one that
meets these specs: .4 w, 6.2 v, 5 %

Sorry for the stupid question, but will I be able to find one at mouser?
Doubt Radio Shack will have one.

A big thank you to everyone who assisted me with this scope. I am a very
happy man tonight.

On Fri, Dec 5, 2014 at 8:35 PM, Jim Popwell jpopwell@...
[TekScopes] <
TekScopes@...> wrote:

YES replacing it…..you can NOT just PARALLEL IT.

make sure all power is off and double check things…… some are very

fragile

so desolder it carefully…. they are not hard to find or expensive

On Dec 5, 2014, at 8:29 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh, and I assumed I'm replacing VR4341?

On Fri, Dec 5, 2014 at 8:28 PM, Kevin Crossett <kcrossett@...

<mailto:kcrossett@...>> wrote:

I'll do it now. It might take a few minutes.

On Fri, Dec 5, 2014 at 8:27 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point

and the

emitter connected where the anode is of the original zener…. this

will give

a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>>

wrote:

there should be 6.2v difference across VR4341…. measure both

sides of

R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿….

a

lot of zeners from these years have it…. usually diodes from

Motorola

and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each

of the

leads. Not

sure if that is normal, but to the untrained eye, it

looks like

it

might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

find vr4341, a zener diode. measure both sides of it please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>>

wrote:

Hi Jim. The symptoms do still exist when I press the

10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>>

<mailto:

jpopwell@... <mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@...

<mailto:TekScopes@...

<mailto:TekScopes@...

<mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

one other thought…. push in the X10 mag button and

see if

your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>>

wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm

still not

sure

the

best

way

to

do so. I also checked the wires to the deflector

plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria.

Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test

points

86,

89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM,

aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>>

<mailto:

aodiversen@... <mailto:aodiversen@...>

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@...

<mailto:TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:TekScopes@...

wrote:

Yes simply set both channels to GND and defocus the

spot.

That

way

you

won't burn-in the screen.
Albert


---In TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...>>,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal,

say

from a

small

signal generator that outputs a dirty square

wave, or

can

I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test points?




[Non-text portions of this message have been

removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

--
Mike KC7NOA



[Non-text portions of this message have been removed]

I will post a fix with my little Frankenstein transistor soldered to the
board. Talk about a Maguiver fix.

On Fri, Dec 5, 2014 at 9:18 PM, Jim Popwell jpopwell@... [TekScopes] <
TekScopes@...> wrote:

post a pic of the fix…… you’ve got good one…..

On Dec 5, 2014, at 9:10 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Eureka. That was it. I put a 2n3904 transistor in place of the zener

diode,

and it works.

Now I just need to get a zener diode. I'm guessing that I need one that
meets these specs: .4 w, 6.2 v, 5 %

Sorry for the stupid question, but will I be able to find one at mouser?
Doubt Radio Shack will have one.

A big thank you to everyone who assisted me with this scope. I am a very
happy man tonight.

On Fri, Dec 5, 2014 at 8:35 PM, Jim Popwell jpopwell@... <mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>> wrote:

YES replacing it…..you can NOT just PARALLEL IT.

make sure all power is off and double check things…… some are very

fragile

so desolder it carefully…. they are not hard to find or expensive

On Dec 5, 2014, at 8:29 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh, and I assumed I'm replacing VR4341?

On Fri, Dec 5, 2014 at 8:28 PM, Kevin Crossett <kcrossett@...

<mailto:kcrossett@...>> wrote:

I'll do it now. It might take a few minutes.

On Fri, Dec 5, 2014 at 8:27 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point and

the

emitter connected where the anode is of the original zener…. this

will give

a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>>

wrote:

there should be 6.2v difference across VR4341…. measure both

sides of

R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿….

a

lot of zeners from these years have it…. usually diodes from

Motorola

and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each of

the

leads. Not

sure if that is normal, but to the untrained eye, it looks

like

it

might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

find vr4341, a zener diode. measure both sides of it

please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

Hi Jim. The symptoms do still exist when I press the

10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>>

<mailto:

jpopwell@... <mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@... <mailto:

TekScopes@...

<mailto:TekScopes@... <mailto:

TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

one other thought…. push in the X10 mag button and

see if

your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm still

not

sure

the

best

way

to

do so. I also checked the wires to the deflector

plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria.

Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test

points

86,

89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM,

aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>>

<mailto:

aodiversen@... <mailto:aodiversen@...

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

Yes simply set both channels to GND and defocus

the

spot.

That

way

you

won't burn-in the screen.
Albert


---In TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal,

say

from a

small

signal generator that outputs a dirty square

wave, or

can

I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test

points?

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

voltage is now 100 and 107.6

I am so pleased. Jim, thank you so much for taking the time to assist
tonight. It's nearly 12:30 est and my 2 year old is going to get me out of
bed awfully early tomorrow, but it is worth it. I didn't want to stop since
you were so kind and willing to help. I'm going to sleep well tonight, and
in the morning after I finish raking the back yard, I'm taking a trip to
Radio Shack.

Siggi, you were right, I am feeling on top of the world right now. I hope
to one day be able to assist newbies like myself in troubleshooting
circuits. Until then, I'll keep on learning from this great group.

Cheers
Kevin

On Fri, Dec 5, 2014 at 9:14 PM, Jim Popwell jpopwell@... [TekScopes] <
TekScopes@...> wrote:

yes mouser or digikey or newark or radio shack…..6.2 is a common value….
5% yes….

I would recommend you not run the scope for a long period of time until
you get the right value zener….

what is the voltage across it now….

jim

On Dec 5, 2014, at 9:10 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Eureka. That was it. I put a 2n3904 transistor in place of the zener

diode,

and it works.

Now I just need to get a zener diode. I'm guessing that I need one that
meets these specs: .4 w, 6.2 v, 5 %

Sorry for the stupid question, but will I be able to find one at mouser?
Doubt Radio Shack will have one.

A big thank you to everyone who assisted me with this scope. I am a very
happy man tonight.

On Fri, Dec 5, 2014 at 8:35 PM, Jim Popwell jpopwell@... <mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>> wrote:

YES replacing it…..you can NOT just PARALLEL IT.

make sure all power is off and double check things…… some are very

fragile

so desolder it carefully…. they are not hard to find or expensive

On Dec 5, 2014, at 8:29 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh, and I assumed I'm replacing VR4341?

On Fri, Dec 5, 2014 at 8:28 PM, Kevin Crossett <kcrossett@...

<mailto:kcrossett@...>> wrote:

I'll do it now. It might take a few minutes.

On Fri, Dec 5, 2014 at 8:27 PM, Jim Popwell jpopwell@...

<mailto:jpopwell@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

do you have any 6.2v zener diodes….or any spare npn 2n2222
2苍3904….迟谤补苍蝉颈蝉迟辞谤蝉…..

you can make a zener out of a spare NPN transistor emitter to base
junction…..the base should be connected to the cathode point and

the

emitter connected where the anode is of the original zener…. this

will give

a “zener of about 6 to 7v to see if it affects the amps gain…..

jim

On Dec 5, 2014, at 8:19 PM, Kevin Crossett kcrossett@...

[TekScopes] <TekScopes@...> wrote:

Oh. Thanks for the education...

On R4344
54.85 vdc
108.5vdc

On Fri, Dec 5, 2014 at 8:14 PM, Jim Popwell jpopwell@...

<mailto:

jpopwell@...> [TekScopes] <

TekScopes@... <mailto:TekScopes@...>>

wrote:

there should be 6.2v difference across VR4341…. measure both

sides of

R4344…. on side should be 55v the other 103.8.

the blackish coating on the leads is silver oxide, not burned

蝉迟耻蹿蹿….

a

lot of zeners from these years have it…. usually diodes from

Motorola

and

贵补颈谤肠丑颈濒诲…..

jim

On Dec 5, 2014, at 8:09 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...>> wrote:

Interesting VR4341 has some blackened materials on each of

the

leads. Not

sure if that is normal, but to the untrained eye, it looks

like

it

might

have been toasted.

VR 4341 measurements
Cathode 110.6
Anode 108.6

On Fri, Dec 5, 2014 at 8:01 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>> [TekScopes] <

TekScopes@... <mailto:TekScopes@...

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

find vr4341, a zener diode. measure both sides of it

please

On Dec 5, 2014, at 7:58 PM, Kevin Crossett

kcrossett@...

<mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

Hi Jim. The symptoms do still exist when I press the

10x mag

button.

On Fri, Dec 5, 2014 at 7:56 PM, Jim Popwell

jpopwell@...

<mailto:jpopwell@...>

<mailto:jpopwell@... <mailto:jpopwell@...>>

<mailto:

jpopwell@... <mailto:jpopwell@...> <mailto:

jpopwell@... <mailto:jpopwell@...>>> [TekScopes] <

TekScopes@... <mailto:

TekScopes@...

<mailto:TekScopes@... <mailto:

TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

one other thought…. push in the X10 mag button and

see if

your

original

symptoms still exist…..
jim

On Dec 5, 2014, at 6:46 PM, Kevin Crossett

kcrossett@... <mailto:kcrossett@...>

<mailto:kcrossett@... <mailto:kcrossett@...>>

[TekScopes] <TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

wrote:

OK. So I made the measurements on the test points as

directed by

Albert.

I

have not checked the transistors because I'm still

not

sure

the

best

way

to

do so. I also checked the wires to the deflector

plates,

and they

seem to

be secure.

Here are the measurements based on the following

criteria.

Scope

in

XY

and

both channels set to GND. Defocused the beam and

manipulated the

horz

control while reading voltages on the test points as

identified

in

the

manual figure 9-7.

TP VDC
85 1.42 to 3.90
86 2.35 to 4.90
87 -1.46 to -4.19
88 -2.10 to -3.34
89 36.25 to 36.80
90 35.60 to 37.07

These seem a little wonky to me, especially test

points

86,

89

and

90.

Any thoughts?

On Fri, Dec 5, 2014 at 1:11 PM,

aodiversen@...

<mailto:aodiversen@...> <mailto:

aodiversen@... <mailto:aodiversen@...>>

<mailto:

aodiversen@... <mailto:aodiversen@...

<mailto:aodiversen@... <mailto:aodiversen@...>>>

[TekScopes] <

TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...>>

<mailto:TekScopes@... <mailto:

TekScopes@...>

<mailto:TekScopes@... <mailto:

TekScopes@...

wrote:

Yes simply set both channels to GND and defocus

the

spot.

That

way

you

won't burn-in the screen.
Albert


---In TekScopes@... <mailto:

TekScopes@...> <mailto:

TekScopes@... <mailto:TekScopes@...

,

<kcrossett@...> wrote :

Ah. I think I understand. Do I need to inject a

signal,

say

from a

small

signal generator that outputs a dirty square

wave, or

can

I do

it

simply

by
turning on the scope, defocusing the spot and

manipulating the

horz

control
while measuring the voltage on the two test

points?

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been

removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

post a pic of the fix…… you’ve got good one…..

the scope is now UNCALIBRATED because this probably changed the gain of the final stages…. after replacement with a good 6.2 you should be very close to original specs….
Glad things worked out…enjoy….
jim