|
I just picked up a 465B off Craigslist. Came with 10x probe.
the ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
Nice guy...engineer...just did not want to deal with it.
He mentioned electrical burning smell when turning on.
I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
It is in excellent shape otherwise, calibration stickers all over it.
I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
Phil
|
Nice find, and nothing is sweeter than fixing free stuff :-)
toggle quoted message
Show quoted text
--- In TekScopes@..., "pdxareaid" <public_email@...> wrote:
I just picked up a 465B off Craigslist. Came with 10x probe.
the ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
Nice guy...engineer...just did not want to deal with it.
He mentioned electrical burning smell when turning on.
I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
It is in excellent shape otherwise, calibration stickers all over it.
I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
Phil
|
Hi Phil,
A free 465B is a wonderful thing!
From my own experiences and reading the Tekscopes group for
years, maybe consider starting?by checking the resistance to ground at each
power supply test point, then go looking for some of those pesky tantalums in
the 10uF to 47uF range on the shorted supply(s).
The tantalums make the bad smells when they die, more so than
the electrolytics.
Maybe someone has a list of expected resistances for the
voltage test points on?a 465B ?
tom jobe...
?
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Sunday, September 23, 2012 1:42
PM
Subject: [TekScopes] WooHoo! 465B
?
I just picked up a 465B off Craigslist. Came with 10x probe.
the
ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on
recently, it died. There's a beam, but no sweep. It worked well before that. I
was hoping someone would want to fix it and put it to good use.
Free."
Nice guy...engineer...just did not want to deal with it.
He
mentioned electrical burning smell when turning on.
I got it home and
spent 10 minutes with it...opened it up and turned it on. Burning smell coming
from PS section I think. Whole screen glows off and on, no trace to speak
of.
It is in excellent shape otherwise, calibration stickers all over
it.
I am thinking PS filter caps to start, then tantalum and
electrolytic search after that.
Phil
|
thanks for the tip. i did not know tantalums smelled.
i'll probably hit big filter caps anyway...i had a bad experience with them in a 465M among other PS components. i have the service manual etc. need to read up and start checking things in and around ps. afraid to leave it on and have failures cascade. quick voltage measurements to start.
i understand failed tants are pretty easy to spot. they fail shorted usually? is that right?
phil
toggle quoted message
Show quoted text
--- In TekScopes@..., "Tom Jobe" <tomjobe@...> wrote:
Hi Phil,
A free 465B is a wonderful thing!
From my own experiences and reading the Tekscopes group for years, maybe consider starting by checking the resistance to ground at each power supply test point, then go looking for some of those pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
The tantalums make the bad smells when they die, more so than the electrolytics.
Maybe someone has a list of expected resistances for the voltage test points on a 465B ?
tom jobe...
----- Original Message -----
From: pdxareaid
To: TekScopes@...
Sent: Sunday, September 23, 2012 1:42 PM
Subject: [TekScopes] WooHoo! 465B
I just picked up a 465B off Craigslist. Came with 10x probe.
the ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
Nice guy...engineer...just did not want to deal with it.
He mentioned electrical burning smell when turning on.
I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
It is in excellent shape otherwise, calibration stickers all over it.
I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
Phil
|
yeah, not likely to be grumbling i paid too much for it while working on it :-) though it did cost me a gallon or 2 of gas.
phil
toggle quoted message
Show quoted text
--- In TekScopes@..., "dreadlk" <dreadlk@...> wrote:
Nice find, and nothing is sweeter than fixing free stuff :-)
--- In TekScopes@..., "pdxareaid" <public_email@> wrote:
I just picked up a 465B off Craigslist. Came with 10x probe.
the ad:
"Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
Nice guy...engineer...just did not want to deal with it.
He mentioned electrical burning smell when turning on.
I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
It is in excellent shape otherwise, calibration stickers all over it.
I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
Phil
|
"pdxareaid" <public_email@...> wrote: Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting? Sounds like you may have a trace, just offscreen. See if the beamfinder shows it too you. -ls-
|
My 465 had no trace, 8v rectifier and 1 chip was fried, replaced then I saw a dot. Sent on the TELUS Mobility network with BlackBerry
From: larrys@...
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 17:09:26 -0400 (EDT) To: <TekScopes@...> ReplyTo: TekScopes@...
Subject: Re: [TekScopes] WooHoo! 465B
?
"pdxareaid" <public_email@...> wrote:
> Whole screen glows off and on, no trace to speak of.
Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
sweep rate does not seem to affect anything.
beamfinder:
I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
the burning smell was making me nervous so i shut it down.
are these useful clues?
toggle quoted message
Show quoted text
--- In TekScopes@..., larrys@... wrote:
"pdxareaid" <public_email@...> wrote:
Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
thanks, i'll be checking over all ps components once i dig into it.
toggle quoted message
Show quoted text
--- In TekScopes@..., "Brad King" <cpgixxer@...> wrote:
My 465 had no trace, 8v rectifier and 1 chip was fried, replaced then I saw a dot.
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: larrys@...
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 17:09:26
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: Re: [TekScopes] WooHoo! 465B
"pdxareaid" <public_email@...> wrote:
Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
The glow is because the trace isn't centered, could be a bad resistor or transistor in the vertical. Does it move h or v with the adjustment? Did you try pressing the trigger view button? Sent on the TELUS Mobility network with BlackBerry
From: "pdxareaid" <public_email@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:25:55 -0000 To: <TekScopes@...> ReplyTo: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
?
ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
sweep rate does not seem to affect anything.
beamfinder:
I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
the burning smell was making me nervous so i shut it down.
are these useful clues?
--- In TekScopes@..., larrys@... wrote:
>
> "pdxareaid" <public_email@...> wrote:
> > Whole screen glows off and on, no trace to speak of.
>
> Does the rate of the on / off vary with the sweep speed setting?
> Sounds like you may have a trace, just offscreen. See if the
> beamfinder shows it too you.
>
> -ls-
>
|
I do believe that the tantalums often fail shorted, at least
when they don't blow up.
Maybe one of the more knowledgeable?members will weigh in
on this question.
?
Flip the scope over on its back and look for the few dipped
tantalums that have multiple colors on them. One of the problem
tantalums?is along the back edge of the mainboard near the high voltage
shield. I think there is another one or two under that HV shield as well as one
out in the middle of the mainboard. The tantalums that are all one color seem to
be more reliable. Some of the problem tantalums are rated for 20 volts on a 15
volt supply, so go up on the voltage rating?if you replace any of
them.
tom jobe...
?
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Sunday, September 23, 2012 2:04
PM
Subject: [TekScopes] Re: WooHoo!
465B
?
thanks for the tip. i did not know tantalums smelled.
i'll probably hit
big filter caps anyway...i had a bad experience with them in a 465M among
other PS components. i have the service manual etc. need to read up and start
checking things in and around ps. afraid to leave it on and have failures
cascade. quick voltage measurements to start.
i understand failed tants are
pretty easy to spot. they fail shorted usually? is that
right?
phil
--- In TekScopes@..., "Tom
Jobe" >
> Hi Phil,
> A free 465B
is a wonderful thing!
> From my own experiences and reading the
Tekscopes group for years, maybe consider starting by checking the resistance
to ground at each power supply test point, then go looking for some of those
pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
>
The tantalums make the bad smells when they die, more so than the
electrolytics.
> Maybe someone has a list of expected resistances for
the voltage test points on a 465B ?
> tom jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject: [TekScopes]
WooHoo! 465B
>
>
>
> I just picked up a 465B off
Craigslist. Came with 10x probe.
>
> the ad:
> "Unit was
working, then stored for 3 or 4 years. When I turned it on recently, it died.
There's a beam, but no sweep. It worked well before that. I was hoping someone
would want to fix it and put it to good use. Free."
>
> Nice
guy...engineer...just did not want to deal with it.
> He mentioned
electrical burning smell when turning on.
>
> I got it home and
spent 10 minutes with it...opened it up and turned it on. Burning smell coming
from PS section I think. Whole screen glows off and on, no trace to speak
of.
> It is in excellent shape otherwise, calibration stickers all over
it.
>
> I am thinking PS filter caps to start, then tantalum and
electrolytic search after that.
> Phil
>
|
lol..i have not had time to do much of anything with it yet (only had it a couple of hours) but i can't resist dropping everything and running out to poke it with these tips rolling in...
when the screen is glowing, none of the controls seems to affect it and it generally lights up the whole screen.
using the beamfinder, i get a bright dot that jumps around and in and out of what looks like it might be trying to show me a reasonable beamfinder display, but severely shift off screen to the right.
the position controls seem to affect it but not in a consistent way...but there is some effect.
all of the beamfinder action appears to be on the right half of the screen.
phil
ps. i'm going to be in trouble if i don't finish some other stuff today...i'll leave poking it again til tomorrow but will check in to soak up the tips for when i do get out there.
thanks for all the help. keep em coming :-)
toggle quoted message
Show quoted text
--- In TekScopes@..., "Brad King" <cpgixxer@...> wrote:
The glow is because the trace isn't centered, could be a bad resistor or transistor in the vertical. Does it move h or v with the adjustment? Did you try pressing the trigger view button?
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: "pdxareaid" <public_email@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:25:55
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
sweep rate does not seem to affect anything.
beamfinder:
I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
the burning smell was making me nervous so i shut it down.
are these useful clues?
--- In TekScopes@..., larrys@ wrote:
"pdxareaid" <public_email@> wrote:
Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
Trigger view as far as I know detaches the vertical pre from the circuit. The service manuals have block diagrams to help segregate the circuit to narrow it down. Sent on the TELUS Mobility network with BlackBerry
From: "pdxareaid" <public_email@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:48:37 -0000 To: <TekScopes@...> ReplyTo: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
?
lol..i have not had time to do much of anything with it yet (only had it a couple of hours) but i can't resist dropping everything and running out to poke it with these tips rolling in...
when the screen is glowing, none of the controls seems to affect it and it generally lights up the whole screen.
using the beamfinder, i get a bright dot that jumps around and in and out of what looks like it might be trying to show me a reasonable beamfinder display, but severely shift off screen to the right.
the position controls seem to affect it but not in a consistent way...but there is some effect.
all of the beamfinder action appears to be on the right half of the screen.
phil
ps. i'm going to be in trouble if i don't finish some other stuff today...i'll leave poking it again til tomorrow but will check in to soak up the tips for when i do get out there.
thanks for all the help. keep em coming :-)
--- In TekScopes@..., "Brad King" <cpgixxer@...> wrote:
>
> The glow is because the trace isn't centered, could be a bad resistor or transistor in the vertical. Does it move h or v with the adjustment? Did you try pressing the trigger view button?
> Sent on the TELUS Mobility network with BlackBerry
>
> -----Original Message-----
> From: "pdxareaid" <public_email@...>
> Sender: TekScopes@...
> Date: Sun, 23 Sep 2012 21:25:55
> To: < TekScopes@...>
> Reply-To: TekScopes@...
> Subject: [TekScopes] Re: WooHoo! 465B
>
>
> ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
>
> sweep rate does not seem to affect anything.
>
> beamfinder:
> I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
> curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
> i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
> the burning smell was making me nervous so i shut it down.
>
> are these useful clues?
>
>
> --- In TekScopes@..., larrys@ wrote:
> >
> > "pdxareaid" <public_email@> wrote:
> > > Whole screen glows off and on, no trace to speak of.
> >
> > Does the rate of the on / off vary with the sweep speed setting?
> > Sounds like you may have a trace, just offscreen. See if the
> > beamfinder shows it too you.
> >
> > -ls-
> >
>
|
arggg...i fogot to poke the trigger view. one last trip out there right now.
toggle quoted message
Show quoted text
--- In TekScopes@..., "Brad King" <cpgixxer@...> wrote:
Trigger view as far as I know detaches the vertical pre from the circuit. The service manuals have block diagrams to help segregate the circuit to narrow it down.
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: "pdxareaid" <public_email@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:48:37
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
lol..i have not had time to do much of anything with it yet (only had it a couple of hours) but i can't resist dropping everything and running out to poke it with these tips rolling in...
when the screen is glowing, none of the controls seems to affect it and it generally lights up the whole screen.
using the beamfinder, i get a bright dot that jumps around and in and out of what looks like it might be trying to show me a reasonable beamfinder display, but severely shift off screen to the right.
the position controls seem to affect it but not in a consistent way...but there is some effect.
all of the beamfinder action appears to be on the right half of the screen.
phil
ps. i'm going to be in trouble if i don't finish some other stuff today...i'll leave poking it again til tomorrow but will check in to soak up the tips for when i do get out there.
thanks for all the help. keep em coming :-)
--- In TekScopes@..., "Brad King" <cpgixxer@> wrote:
The glow is because the trace isn't centered, could be a bad resistor or transistor in the vertical. Does it move h or v with the adjustment? Did you try pressing the trigger view button?
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: "pdxareaid" <public_email@>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:25:55
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
sweep rate does not seem to affect anything.
beamfinder:
I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
the burning smell was making me nervous so i shut it down.
are these useful clues?
--- In TekScopes@..., larrys@ wrote:
"pdxareaid" <public_email@> wrote:
Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
I didn't notice if you said the low voltages were good or not,
but until every low voltage is good, you are wasting your time checking anything
else.
Another thing to look for is dead rectifiers. There are a few
of them right where the big PS caps are mounted and they are easy to change
without taking the scope apart. These are those full wave bridges all?in
one big rectangular chip.
The Tekscopes Message archive?has several?methods
people have used successfully to change the rectifiers on the 4XX scopes like
the 465, 465B, 475, 474A, etc, if you don't have your own method.
tom jobe...
?
?
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Sunday, September 23, 2012 2:04
PM
Subject: [TekScopes] Re: WooHoo!
465B
?
thanks for the tip. i did not know tantalums smelled.
i'll probably hit
big filter caps anyway...i had a bad experience with them in a 465M among
other PS components. i have the service manual etc. need to read up and start
checking things in and around ps. afraid to leave it on and have failures
cascade. quick voltage measurements to start.
i understand failed tants are
pretty easy to spot. they fail shorted usually? is that
right?
phil
--- In TekScopes@..., "Tom
Jobe" wrote:
>
> Hi Phil,
> A free 465B
is a wonderful thing!
> From my own experiences and reading the
Tekscopes group for years, maybe consider starting by checking the resistance
to ground at each power supply test point, then go looking for some of those
pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
>
The tantalums make the bad smells when they die, more so than the
electrolytics.
> Maybe someone has a list of expected resistances for
the voltage test points on a 465B ?
> tom jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject: [TekScopes]
WooHoo! 465B
>
>
>
> I just picked up a 465B off
Craigslist. Came with 10x probe.
>
> the ad:
> "Unit was
working, then stored for 3 or 4 years. When I turned it on recently, it died.
There's a beam, but no sweep. It worked well before that. I was hoping someone
would want to fix it and put it to good use. Free."
>
> Nice
guy...engineer...just did not want to deal with it.
> He mentioned
electrical burning smell when turning on.
>
> I got it home and
spent 10 minutes with it...opened it up and turned it on. Burning smell coming
from PS section I think. Whole screen glows off and on, no trace to speak
of.
> It is in excellent shape otherwise, calibration stickers all over
it.
>
> I am thinking PS filter caps to start, then tantalum and
electrolytic search after that.
> Phil
>
|
I had to undo the power transformer on mine and lift it up to access the other side of the board to get at that 8v rectifier, replaced it with a garden variety nte 8 amp. Sent on the TELUS Mobility network with BlackBerry
From: "Tom Jobe" <tomjobe@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 14:59:34 -0700 To: <TekScopes@...> ReplyTo: TekScopes@...
Subject: Re: [TekScopes] Re: WooHoo! 465B
?
I didn't notice if you said the low voltages were good or not,
but until every low voltage is good, you are wasting your time checking anything
else.
Another thing to look for is dead rectifiers. There are a few
of them right where the big PS caps are mounted and they are easy to change
without taking the scope apart. These are those full wave bridges all?in
one big rectangular chip.
The Tekscopes Message archive?has several?methods
people have used successfully to change the rectifiers on the 4XX scopes like
the 465, 465B, 475, 474A, etc, if you don't have your own method.
tom jobe...
?
?
?
?
----- Original Message -----
Sent: Sunday, September 23, 2012 2:04
PM
Subject: [TekScopes] Re: WooHoo!
465B
?
thanks for the tip. i did not know tantalums smelled.
i'll probably hit
big filter caps anyway...i had a bad experience with them in a 465M among
other PS components. i have the service manual etc. need to read up and start
checking things in and around ps. afraid to leave it on and have failures
cascade. quick voltage measurements to start.
i understand failed tants are
pretty easy to spot. they fail shorted usually? is that
right?
phil
--- In TekScopes@..., "Tom
Jobe" <tomjobe@...> wrote:
>
> Hi Phil,
> A free 465B
is a wonderful thing!
> From my own experiences and reading the
Tekscopes group for years, maybe consider starting by checking the resistance
to ground at each power supply test point, then go looking for some of those
pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
>
The tantalums make the bad smells when they die, more so than the
electrolytics.
> Maybe someone has a list of expected resistances for
the voltage test points on a 465B ?
> tom jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject: [TekScopes]
WooHoo! 465B
>
>
>
> I just picked up a 465B off
Craigslist. Came with 10x probe.
>
> the ad:
> "Unit was
working, then stored for 3 or 4 years. When I turned it on recently, it died.
There's a beam, but no sweep. It worked well before that. I was hoping someone
would want to fix it and put it to good use. Free."
>
> Nice
guy...engineer...just did not want to deal with it.
> He mentioned
electrical burning smell when turning on.
>
> I got it home and
spent 10 minutes with it...opened it up and turned it on. Burning smell coming
from PS section I think. Whole screen glows off and on, no trace to speak
of.
> It is in excellent shape otherwise, calibration stickers all over
it.
>
> I am thinking PS filter caps to start, then tantalum and
electrolytic search after that.
> Phil
>
|
trigger view did nothing.
but i had it on long enough that i noticed a smoking tantalum. and it was even moaning! ikyn it was making noise when it started to smoke. it was in a cluster of 3 tants on the large rightmost board (viewed from the front) towards the rear...i don't even know what board that is yet but i will as soon as i can get to look at the service manual.
phil
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--- In TekScopes@..., "pdxareaid" <public_email@...> wrote:
arggg...i fogot to poke the trigger view. one last trip out there right now.
--- In TekScopes@..., "Brad King" <cpgixxer@> wrote:
Trigger view as far as I know detaches the vertical pre from the circuit. The service manuals have block diagrams to help segregate the circuit to narrow it down.
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: "pdxareaid" <public_email@>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:48:37
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
lol..i have not had time to do much of anything with it yet (only had it a couple of hours) but i can't resist dropping everything and running out to poke it with these tips rolling in...
when the screen is glowing, none of the controls seems to affect it and it generally lights up the whole screen.
using the beamfinder, i get a bright dot that jumps around and in and out of what looks like it might be trying to show me a reasonable beamfinder display, but severely shift off screen to the right.
the position controls seem to affect it but not in a consistent way...but there is some effect.
all of the beamfinder action appears to be on the right half of the screen.
phil
ps. i'm going to be in trouble if i don't finish some other stuff today...i'll leave poking it again til tomorrow but will check in to soak up the tips for when i do get out there.
thanks for all the help. keep em coming :-)
--- In TekScopes@..., "Brad King" <cpgixxer@> wrote:
The glow is because the trace isn't centered, could be a bad resistor or transistor in the vertical. Does it move h or v with the adjustment? Did you try pressing the trigger view button?
Sent on the TELUS Mobility network with BlackBerry
-----Original Message-----
From: "pdxareaid" <public_email@>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 21:25:55
To: <TekScopes@...>
Reply-To: TekScopes@...
Subject: [TekScopes] Re: WooHoo! 465B
ah, the beamfinder...never was very fond of it. now maybe i see why it is there. thanks for the tip.
sweep rate does not seem to affect anything.
beamfinder:
I got the usual bright connected 2 (i assume) point display but severely shifted to the right such that only 1/2 of the expected display is on the screen.
curiously, when i tried that, and released the beamfinder, i got a bright point on the display rather than a full screen glow. then it went back to the glow.
i tried the beamfinder a few more times and it seemed to start bringing something back from the dead. i even saw it flash what looked like it might have been a reasonable trace...but it disappeared very quickly.
the burning smell was making me nervous so i shut it down.
are these useful clues?
--- In TekScopes@..., larrys@ wrote:
"pdxareaid" <public_email@> wrote:
Whole screen glows off and on, no trace to speak of. Does the rate of the on / off vary with the sweep speed setting?
Sounds like you may have a trace, just offscreen. See if the
beamfinder shows it too you.
-ls-
|
i agree, all ps's are first check (except i just found a smoking tantalum).
i have a few big rectifiers left over from a 465M fix. if they are a prob i'll be able to hit em pretty easily. i have not even had a volt meter on it yet. i do have a working scope to debug it.
thanks.
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--- In TekScopes@..., "Tom Jobe" <tomjobe@...> wrote:
I didn't notice if you said the low voltages were good or not, but until every low voltage is good, you are wasting your time checking anything else.
Another thing to look for is dead rectifiers. There are a few of them right where the big PS caps are mounted and they are easy to change without taking the scope apart. These are those full wave bridges all in one big rectangular chip.
The Tekscopes Message archive has several methods people have used successfully to change the rectifiers on the 4XX scopes like the 465, 465B, 475, 474A, etc, if you don't have your own method.
tom jobe...
----- Original Message -----
From: pdxareaid
To: TekScopes@...
Sent: Sunday, September 23, 2012 2:04 PM
Subject: [TekScopes] Re: WooHoo! 465B
thanks for the tip. i did not know tantalums smelled.
i'll probably hit big filter caps anyway...i had a bad experience with them in a 465M among other PS components. i have the service manual etc. need to read up and start checking things in and around ps. afraid to leave it on and have failures cascade. quick voltage measurements to start.
i understand failed tants are pretty easy to spot. they fail shorted usually? is that right?
phil
--- In TekScopes@..., "Tom Jobe" <tomjobe@> wrote:
>
> Hi Phil,
> A free 465B is a wonderful thing!
> From my own experiences and reading the Tekscopes group for years, maybe consider starting by checking the resistance to ground at each power supply test point, then go looking for some of those pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
> The tantalums make the bad smells when they die, more so than the electrolytics.
> Maybe someone has a list of expected resistances for the voltage test points on a 465B ?
> tom jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject: [TekScopes] WooHoo! 465B
>
>
>
> I just picked up a 465B off Craigslist. Came with 10x probe.
>
> the ad:
> "Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
>
> Nice guy...engineer...just did not want to deal with it.
> He mentioned electrical burning smell when turning on.
>
> I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
> It is in excellent shape otherwise, calibration stickers all over it.
>
> I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
> Phil
>
|
The Tekscopes archive could have saved you a lot of work
Brad.
Your advice to go up on full wave bridge voltage rating is
excellent!
in my experience, the limiting factor on a replacement bridge
is the diameter of the leads coming out of the bridge, and whether they will fit
into the holes on the mainboard. You need to lay the bridge over on an angle to
get vertical clearance for a taller bridge, as well as to gain access to solder
the new bridge in place.
The larger bridges have the leads on larger centers, but you
can bend the leads inward to fit the hole pattern in the mainboard.
tom jobe...
?
?
?
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Show quoted text
----- Original Message -----
Sent: Sunday, September 23, 2012 3:01
PM
Subject: Re: [TekScopes] Re: WooHoo!
465B
?
I had to undo the power transformer on mine and lift it up to access the
other side of the board to get at that 8v rectifier, replaced it with a garden
variety nte 8 amp.
Sent on the TELUS Mobility network with BlackBerry
Date: Sun, 23 Sep 2012 14:59:34 -0700
To:
ReplyTo: TekScopes@...
Subject: Re: [TekScopes] Re: WooHoo! 465B
?
I didn't notice if you said the low voltages were good or
not, but until every low voltage is good, you are wasting your time checking
anything else.
Another thing to look for is dead rectifiers. There are a
few of them right where the big PS caps are mounted and they are easy to
change without taking the scope apart. These are those full wave bridges
all?in one big rectangular chip.
The Tekscopes Message archive?has several?methods
people have used successfully to change the rectifiers on the 4XX scopes like
the 465, 465B, 475, 474A, etc, if you don't have your own method.
tom jobe...
?
?
?
?
----- Original Message -----
Sent: Sunday, September 23, 2012 2:04
PM
Subject: [TekScopes] Re: WooHoo!
465B
?
thanks for the tip. i did not know tantalums smelled.
i'll probably
hit big filter caps anyway...i had a bad experience with them in a 465M
among other PS components. i have the service manual etc. need to read up
and start checking things in and around ps. afraid to leave it on and have
failures cascade. quick voltage measurements to start.
i understand
failed tants are pretty easy to spot. they fail shorted usually? is that
right?
phil
--- In TekScopes@...,
"Tom Jobe" wrote:
>
> Hi Phil,
> A
free 465B is a wonderful thing!
> From my own experiences and reading
the Tekscopes group for years, maybe consider starting by checking the
resistance to ground at each power supply test point, then go looking for
some of those pesky tantalums in the 10uF to 47uF range on the shorted
supply(s).
> The tantalums make the bad smells when they die, more so
than the electrolytics.
> Maybe someone has a list of expected
resistances for the voltage test points on a 465B ?
> tom
jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject:
[TekScopes] WooHoo! 465B
>
>
>
> I just picked up
a 465B off Craigslist. Came with 10x probe.
>
> the ad:
>
"Unit was working, then stored for 3 or 4 years. When I turned it on
recently, it died. There's a beam, but no sweep. It worked well before that.
I was hoping someone would want to fix it and put it to good use.
Free."
>
> Nice guy...engineer...just did not want to deal with
it.
> He mentioned electrical burning smell when turning on.
>
> I got it home and spent 10 minutes with it...opened it up and
turned it on. Burning smell coming from PS section I think. Whole screen
glows off and on, no trace to speak of.
> It is in excellent shape
otherwise, calibration stickers all over it.
>
> I am thinking
PS filter caps to start, then tantalum and electrolytic search after
that.
>
Phil
>
|
i did bend and shave to size for the holes on rectifiers for a 465M fix. bigger is better when it comes to rectifiers.
toggle quoted message
Show quoted text
--- In TekScopes@..., "Tom Jobe" <tomjobe@...> wrote:
The Tekscopes archive could have saved you a lot of work Brad.
Your advice to go up on full wave bridge voltage rating is excellent!
in my experience, the limiting factor on a replacement bridge is the diameter of the leads coming out of the bridge, and whether they will fit into the holes on the mainboard. You need to lay the bridge over on an angle to get vertical clearance for a taller bridge, as well as to gain access to solder the new bridge in place.
The larger bridges have the leads on larger centers, but you can bend the leads inward to fit the hole pattern in the mainboard.
tom jobe...
----- Original Message -----
From: Brad King
To: TekScopes@...
Sent: Sunday, September 23, 2012 3:01 PM
Subject: Re: [TekScopes] Re: WooHoo! 465B
I had to undo the power transformer on mine and lift it up to access the other side of the board to get at that 8v rectifier, replaced it with a garden variety nte 8 amp.
Sent on the TELUS Mobility network with BlackBerry
------------------------------------------------------------------------------
From: "Tom Jobe" <tomjobe@...>
Sender: TekScopes@...
Date: Sun, 23 Sep 2012 14:59:34 -0700
To: <TekScopes@...>
ReplyTo: TekScopes@...
Subject: Re: [TekScopes] Re: WooHoo! 465B
I didn't notice if you said the low voltages were good or not, but until every low voltage is good, you are wasting your time checking anything else.
Another thing to look for is dead rectifiers. There are a few of them right where the big PS caps are mounted and they are easy to change without taking the scope apart. These are those full wave bridges all in one big rectangular chip.
The Tekscopes Message archive has several methods people have used successfully to change the rectifiers on the 4XX scopes like the 465, 465B, 475, 474A, etc, if you don't have your own method.
tom jobe...
----- Original Message -----
From: pdxareaid
To: TekScopes@...
Sent: Sunday, September 23, 2012 2:04 PM
Subject: [TekScopes] Re: WooHoo! 465B
thanks for the tip. i did not know tantalums smelled.
i'll probably hit big filter caps anyway...i had a bad experience with them in a 465M among other PS components. i have the service manual etc. need to read up and start checking things in and around ps. afraid to leave it on and have failures cascade. quick voltage measurements to start.
i understand failed tants are pretty easy to spot. they fail shorted usually? is that right?
phil
--- In TekScopes@..., "Tom Jobe" <tomjobe@> wrote:
>
> Hi Phil,
> A free 465B is a wonderful thing!
> From my own experiences and reading the Tekscopes group for years, maybe consider starting by checking the resistance to ground at each power supply test point, then go looking for some of those pesky tantalums in the 10uF to 47uF range on the shorted supply(s).
> The tantalums make the bad smells when they die, more so than the electrolytics.
> Maybe someone has a list of expected resistances for the voltage test points on a 465B ?
> tom jobe...
>
>
>
> ----- Original Message -----
> From: pdxareaid
> To: TekScopes@...
> Sent: Sunday, September 23, 2012 1:42 PM
> Subject: [TekScopes] WooHoo! 465B
>
>
>
> I just picked up a 465B off Craigslist. Came with 10x probe.
>
> the ad:
> "Unit was working, then stored for 3 or 4 years. When I turned it on recently, it died. There's a beam, but no sweep. It worked well before that. I was hoping someone would want to fix it and put it to good use. Free."
>
> Nice guy...engineer...just did not want to deal with it.
> He mentioned electrical burning smell when turning on.
>
> I got it home and spent 10 minutes with it...opened it up and turned it on. Burning smell coming from PS section I think. Whole screen glows off and on, no trace to speak of.
> It is in excellent shape otherwise, calibration stickers all over it.
>
> I am thinking PS filter caps to start, then tantalum and electrolytic search after that.
> Phil
>
|
