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
2²Ô3904¡.³Ù°ù²¹²Ô²õ¾±²õ³Ù´Ç°ù²õ¡..
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
²õ³Ù³Ü´Ú´Ú¡.
a
lot of zeners from these years have it¡. usually diodes from
Motorola
and
¹ó²¹¾±°ù³¦³ó¾±±ô»å¡..
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?
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removed]
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--
Mike KC7NOA
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