Date   

non tek info

Jerry Barr
 

any of u with the iwatsu (ss5711)- mine--scopes have any contact info for parts ,my broken
time select switch has a 50 k pot(the variable time pot switch) that is broken and unrepairable/the coupling makes it rather specialized/ and the schematic has no part list with manf. numbers etc/ any idea wud be agreat help
thanks jerry kj6ntl


Re: Mailing lists for non-Tek equipment?

Artekmedia <manuals@...>
 

D.

HP GROUP: hp_agilent_equipment@...
fLUKE: Fluke_DMM@...
Bruel& Kajer: Unknown


Dave
ArtekManuals.com

On 4/27/2013 1:44 PM, cheater00 . wrote:
 

Hi guys,
I was wondering whether there are other lists for measurement
equipment that are not specifically Tektronix. I have recently
purchased a lot of cool gear and some of it needs servicing. There's
an HP 652A oscillator, Fluke 893A differential VM, Brüel & Kjaer 2423
electronics destroyer (megohmmeter), a fairly obscure differential
impedance bridge from the eastern bloc (model E316), Philips PM 5134
Function Generator, and some more fun stuff. For one thing my Fluke
893A has a high-pitched whine while it's on and it's driving me crazy
:-) On another note the B&K is missing any sort of calibration
procedures or even a manual.. and I'd really love to get this thing to
working order!

Cheers,
D.


-- 
Dave Henderson
Manuals@...
www.Artekmanuals.com
PO Box 175
Welch,MN 55089
651-269-4265


Mailing lists for non-Tek equipment?

 

Hi guys,
I was wondering whether there are other lists for measurement
equipment that are not specifically Tektronix. I have recently
purchased a lot of cool gear and some of it needs servicing. There's
an HP 652A oscillator, Fluke 893A differential VM, Brüel & Kjaer 2423
electronics destroyer (megohmmeter), a fairly obscure differential
impedance bridge from the eastern bloc (model E316), Philips PM 5134
Function Generator, and some more fun stuff. For one thing my Fluke
893A has a high-pitched whine while it's on and it's driving me crazy
:-) On another note the B&K is missing any sort of calibration
procedures or even a manual.. and I'd really love to get this thing to
working order!

Cheers,
D.


Reputable Seller of 2445/2465 Scopes

Terry Wagoner <wagstw46@...>
 

Been looking at 2445 and 2465 scopes on Ebay.

Thinking about upgrading from my 475.

Anyone recommend a reputable seller or one to stay away from?

OK to contact me off list. wagstw46@aol.com.

Thanks
Terry K9TW


Re: easy crt question?

empr1o
 

Thanks---Can you describe a 'severe geometry problem' for me?

What about weird noises! A kind of squeak from the tube---I'm ready to believe it is the storage, but it looked and sounded lie something was pretty screwed up.

--- In TekScopes@yahoogroups.com, David <davidwhess@...> wrote:

In non-store mode it should look like any other oscilloscope CRT
except maybe with a little more grain or fuzzier.

If there was physical CRT damage, I would expect severe geometry
problems. I think it more likely the storage circuits are
malfunctioning.

On Sat, 27 Apr 2013 15:31:48 -0000, "empr1o" <emailproblem1@...>
wrote:

Even when in non-store mode?

(thanks!)

--- In TekScopes@yahoogroups.com, larrys@ wrote:

Misadjusted or malfunctioning storage circuitry can look like that
as well.
-ls-


"empr1o" <emailproblem1@> wrote:
Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the
illumination) or a blotchy moon-map looking pattern or a slimy slowly
changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about
the name of this problem so I'm not sure how to search for it.


Re: 2465B

Sergey Kubushyn
 

On Sat, 27 Apr 2013, Steve wrote:

It is B010xxx, not _8_010xxx :)

Yes, it is low number so you don't have to worry about those 4 SMD caps on
A5 board. You should definitely check power supply. Even simple smell check
will tell you if some capacitors failed -- they produce a very distinct odor
that sticks forever.

Valentin,

Thank you for that advice. My scope is in the 8010xxx range of serial
numbers. Is that considered a low serial number?

Steve

On 4/26/2013 11:04 PM, vdonisa wrote:
Given the age of the equipment and the fact that you were not the single owner, I would think that a visual inspection of the internals couldn't hurt. If there's dust, blow it off, if you notice anything suspicious, take pics and post them here, if there's a funny smell lingering inside then you may want to dig deeper and examine the PSU too.

Add fuses to your list - Pete, the technician with the slotted screwdriver, also used "one size fits all" fuses, he had a stock of slow blow 15A ones, they never needed any further servicing (the breakers in your electrical panel will trip before those would get even warm). IIRC the correct fuse for your scope is a glass 6x32mm AGC2 (fast 2A), check with the manual to make sure.

As for the battery here's a question for the group: my understanding is that the scope will give you a "low battery" alert when it senses that its voltage is below a certain limit? is that correct? if yes, how fast should you act once you've seen that alert? As the datasheet for the Eagle Picher battery used in low serial nr scopes mentions that it has a "flat characteristic" in the sense that it's designed to keep a rather constant voltage at the output then fall abruptly (in time) from there once it gets near its end of life.

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, Steve <steve65@...> wrote:
Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve


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

Yahoo! Groups Links





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

Yahoo! Groups Links


---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************


Re: 2465B

Steve K8JQ
 

You're right Valentin, it does begin with "B" rather than "8". Old eyes got me.

Thanks for the info regarding the low serial number, thereby answering the question regarding the caps on the controller board.

Steve

On 4/27/2013 10:16 AM, vdonisa wrote:
I think it should be B010xxx, yes that's a "low serial" scope. The "high serial" ones are starting with B050xxx.

This is good news - the A5 board (the controller with the battery) is made using through hole technology (easy to service, and there's no danger that the alu caps have leaked); the battery is separated from the RAM. To replace it you would need just to apply temporary power to the board from external source while replacing the lithium battery.

I've planned to do it to my 2467B which uses same board, I'll post pics and comments here once I get to actually doing it.

--- In TekScopes@yahoogroups.com, Steve <steve65@...> wrote:
Valentin,

Thank you for that advice. My scope is in the 8010xxx range of serial
numbers. Is that considered a low serial number?

Steve

On 4/26/2013 11:04 PM, vdonisa wrote:
Given the age of the equipment and the fact that you were not the single owner, I would think that a visual inspection of the internals couldn't hurt. If there's dust, blow it off, if you notice anything suspicious, take pics and post them here, if there's a funny smell lingering inside then you may want to dig deeper and examine the PSU too.

Add fuses to your list - Pete, the technician with the slotted screwdriver, also used "one size fits all" fuses, he had a stock of slow blow 15A ones, they never needed any further servicing (the breakers in your electrical panel will trip before those would get even warm). IIRC the correct fuse for your scope is a glass 6x32mm AGC2 (fast 2A), check with the manual to make sure.

As for the battery here's a question for the group: my understanding is that the scope will give you a "low battery" alert when it senses that its voltage is below a certain limit? is that correct? if yes, how fast should you act once you've seen that alert? As the datasheet for the Eagle Picher battery used in low serial nr scopes mentions that it has a "flat characteristic" in the sense that it's designed to keep a rather constant voltage at the output then fall abruptly (in time) from there once it gets near its end of life.

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, Steve <steve65@> wrote:
Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve

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

Yahoo! Groups Links





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

Yahoo! Groups Links




Re: easy crt question?

 

In non-store mode it should look like any other oscilloscope CRT
except maybe with a little more grain or fuzzier.

If there was physical CRT damage, I would expect severe geometry
problems. I think it more likely the storage circuits are
malfunctioning.

On Sat, 27 Apr 2013 15:31:48 -0000, "empr1o" <emailproblem1@gmail.com>
wrote:

Even when in non-store mode?

(thanks!)

--- In TekScopes@yahoogroups.com, larrys@... wrote:

Misadjusted or malfunctioning storage circuitry can look like that
as well.
-ls-


"empr1o" <emailproblem1@...> wrote:
Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the
illumination) or a blotchy moon-map looking pattern or a slimy slowly
changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about
the name of this problem so I'm not sure how to search for it.


Re: easy crt question?

 

The service manual on page 5-55 mentions adjusting R1658 (variable
persistence operating level) if shaded areas are noticeable. I
remember doing this when I recalibrated my 7834.

On Sat, 27 Apr 2013 09:18:58 -0400 (EDT), larrys@teamlarry.com wrote:

Misadjusted or malfunctioning storage circuitry can look like that
as well.
-ls-

"empr1o" <emailproblem1@gmail.com> wrote:
Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the
illumination) or a blotchy moon-map looking pattern or a slimy slowly
changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about
the name of this problem so I'm not sure how to search for it.


Re: easy crt question?

empr1o
 

Even when in non-store mode?

(thanks!)

--- In TekScopes@yahoogroups.com, larrys@... wrote:

Misadjusted or malfunctioning storage circuitry can look like that
as well.
-ls-


"empr1o" <emailproblem1@...> wrote:
Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the
illumination) or a blotchy moon-map looking pattern or a slimy slowly
changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about
the name of this problem so I'm not sure how to search for it.



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

Yahoo! Groups Links



Re: 2465B

vdonisa
 

I think it should be B010xxx, yes that's a "low serial" scope. The "high serial" ones are starting with B050xxx.

This is good news - the A5 board (the controller with the battery) is made using through hole technology (easy to service, and there's no danger that the alu caps have leaked); the battery is separated from the RAM. To replace it you would need just to apply temporary power to the board from external source while replacing the lithium battery.

I've planned to do it to my 2467B which uses same board, I'll post pics and comments here once I get to actually doing it.

--- In TekScopes@yahoogroups.com, Steve <steve65@...> wrote:

Valentin,

Thank you for that advice. My scope is in the 8010xxx range of serial
numbers. Is that considered a low serial number?

Steve

On 4/26/2013 11:04 PM, vdonisa wrote:
Given the age of the equipment and the fact that you were not the single owner, I would think that a visual inspection of the internals couldn't hurt. If there's dust, blow it off, if you notice anything suspicious, take pics and post them here, if there's a funny smell lingering inside then you may want to dig deeper and examine the PSU too.

Add fuses to your list - Pete, the technician with the slotted screwdriver, also used "one size fits all" fuses, he had a stock of slow blow 15A ones, they never needed any further servicing (the breakers in your electrical panel will trip before those would get even warm). IIRC the correct fuse for your scope is a glass 6x32mm AGC2 (fast 2A), check with the manual to make sure.

As for the battery here's a question for the group: my understanding is that the scope will give you a "low battery" alert when it senses that its voltage is below a certain limit? is that correct? if yes, how fast should you act once you've seen that alert? As the datasheet for the Eagle Picher battery used in low serial nr scopes mentions that it has a "flat characteristic" in the sense that it's designed to keep a rather constant voltage at the output then fall abruptly (in time) from there once it gets near its end of life.

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, Steve <steve65@> wrote:
Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve


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

Yahoo! Groups Links




Re: 2465B

Steve K8JQ
 

Valentin,

Thank you for that advice. My scope is in the 8010xxx range of serial numbers. Is that considered a low serial number?

Steve

On 4/26/2013 11:04 PM, vdonisa wrote:
Given the age of the equipment and the fact that you were not the single owner, I would think that a visual inspection of the internals couldn't hurt. If there's dust, blow it off, if you notice anything suspicious, take pics and post them here, if there's a funny smell lingering inside then you may want to dig deeper and examine the PSU too.

Add fuses to your list - Pete, the technician with the slotted screwdriver, also used "one size fits all" fuses, he had a stock of slow blow 15A ones, they never needed any further servicing (the breakers in your electrical panel will trip before those would get even warm). IIRC the correct fuse for your scope is a glass 6x32mm AGC2 (fast 2A), check with the manual to make sure.

As for the battery here's a question for the group: my understanding is that the scope will give you a "low battery" alert when it senses that its voltage is below a certain limit? is that correct? if yes, how fast should you act once you've seen that alert? As the datasheet for the Eagle Picher battery used in low serial nr scopes mentions that it has a "flat characteristic" in the sense that it's designed to keep a rather constant voltage at the output then fall abruptly (in time) from there once it gets near its end of life.

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, Steve <steve65@...> wrote:
Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve


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

Yahoo! Groups Links




Re: 2465B

Steve K8JQ
 

Thank you Tom.

Can the presence of the SMT controller board be determined by serial number? Or perhaps by some type of external physical characteristic? Or is it necessary to remove the scope from the case?

Steve

On 4/26/2013 9:38 PM, Tom Miller wrote:


Does it have the SMT version of the A5 controller board and if so, have the four aluminum SMT electrolytics been replaced?
That would be the first thing I would check as continued use will extend damage to the board.
The additional items can be as needed and subject to testing. Check the voltages and ripple at the J119 test socket.
If you open it up, then blowing out any accumulated dust would be a good idea.
Regards,
Tom

----- Original Message -----
*From:* Steve <mailto:steve65@suddenlink.net>
*To:* TekScopes@yahoogroups.com <mailto:TekScopes@yahoogroups.com>
*Sent:* Friday, April 26, 2013 9:26 PM
*Subject:* [TekScopes] 2465B

Hi all,

I have been reading this list for several years. Last year I
acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps,
controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a
lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve




Re: easy crt question?

teamlarryohio
 

Misadjusted or malfunctioning storage circuitry can look like that
as well.
-ls-


"empr1o" <emailproblem1@gmail.com> wrote:

Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the
illumination) or a blotchy moon-map looking pattern or a slimy slowly
changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about
the name of this problem so I'm not sure how to search for it.



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

Yahoo! Groups Links



easy crt question?

empr1o
 

Hi all,

I'm starting from scratch salvaging some 7623As.

I want to confirm my suspicions about CRT failures.

I believe that a crt flooded with green light shapes (not just the illumination) or a blotchy moon-map looking pattern or a slimy slowly changing shape is a sign of failure.

I wasn't completely lazy before posting this, but I'm not sure about the name of this problem so I'm not sure how to search for it.


Re: 7623A: Let there be dot

Don Black <donald_black@...>
 

Use all your senses. Look and smell and try to see where the smoke came from. It might not be as bad as you fear.

Don Black.

On 26-Apr-13 9:32 PM, empr1o wrote:
 


Oh Ed, I wish I could implement your recommendation, but I fear the worst.

Last night I was in a state of joy with beams tracing for all four channels. I tried to deal with the back shield and managed to blow a fuse and then when I replaced with another fuse I had on hand from another scope something went dreadfully wrong and a terrible smoke rose from the area around the HV I think---I'm not really sure what failed or where, so I can't say for sure.

The fact is, I think I blew it.

I have another scope that powered up with a blown CRT...back to the drawing board I guess. Hopefully my next patient doesn't die on the table...

--- In TekScopes@..., "Ed Breya" wrote:
>
> Once you figure out the gross failures, I'd recommend swapping the boards associated with the storage function so that those that went with the good CRT are kept. As I recall, there are a number of adjustments for storage mesh bias and flood gun settings, that are specific to the CRT. This may save some grief later, or maybe eliminate doing a lot of adjustments after it's working again.
>
> Ed
>
> --- In TekScopes@..., larrys@ wrote:
> >
> > You should have easily reachable power supply test points on the
> > vertical output board. They are helpful. Far as the shield issue
> > goes, make sure you aren't using 4-40 screws that are too long.
> > The shield goes over the LV regulator board. It often has solder
> > joint issues with the TO-3 series pass transistors. Stressing it
> > can make a supply (or more) go away. You will want a 7Axx in one
> > of the two left slots and a 7BXX in the right. Do you have the
> > manual?
> >
> > -ls-
> >
> >
> >
> >
> > "empr1o" wrote:
> > > Thanks guys. After I posted this I started to question my sanity and
> > > went to check if this was really what was happening. For the record,
> > > I realize that I took the shield off just because it was smashed
> > > up---probably what broke the crt to begin with.
> > >
> > > It really is something like making the last edge that puts the crt
> > > out---it isn't even just the dot, but the whole display--you know, the
> > > identify or <5V or whatever.
> > >
> > > It also can't be any kind of contact with the elements on the board.
> > > I've got bigger fish to fry, like figuring out if anything else is
> > > broken. I'm going to fix it in a spot that is safe and will work and
> > > make my way through the manual to see where I end up.
> > >
> > > Thanks all. This list is great.
> > >
> > >
> > >
> > > --- In TekScopes@..., "Rob" wrote:
> > > >
> > > > The following are best guesses from my experience with 7000 series
> > > scopes in general. I have not however worked on a 7623A..
> > > >
> > > >
> > > >
> > > > 7000 series in general do not sweep w/o plug-ins. Normally the
> > > “dot” is biased to not be visible so w/o plug-ins you don’t see
> > > anything (this can sometimes be overcome by getting the screen to
> > > flash somewhat with the beam finder w/o plug-ins).
> > > >
> > > >
> > > >
> > > > Anyway, I suspect changing the shielding is changing the bias and
> > > hence the dot appears and goes away when it is replaced.. I would
> > > replace the shielding and put a plug-in in and see what happens. If
> > > no-joy start troubleshooting with flow chart in the manual it is very
> > > good for other models.
> > > >
> > > >
> > > >
> > > > Anyway, my best guess. Hopefully helpful
> > > >
> > > > Rob
> > > >
> > > >
> > > >
> > > > From: TekScopes@... [mailto:TekScopes@...]
> > > On Behalf Of bonddaleena@
> > > > Sent: Thursday, April 25, 2013 7:38 PM
> > > > To: TekScopes@...
> > > > Subject: Re: [TekScopes] 7623A: Let there be dot
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Good question. I have several 7623As. I have a mint one thatd did
> > > this:
> > > > I took the aluminum cover off the back because the fan was a little
> > > noisy. Measuring voltages on be board underneath, I heard a 'snap' and
> > > that was that. Never could get it going again. Have a bunch in various
> > > stages of 'repair', but I did get one going.
> > > > BTW, I bought a whole bunch of misc plug ins for this great old
> > > model, for almost nothing on ePay a while back... all good.
> > > >
> > > > ron
> > > > N4UE
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: empr1o
> > > > To: TekScopes <TekScopes@...>
> > > > Sent: Thu, Apr 25, 2013 8:27 pm
> > > > Subject: [TekScopes] 7623A: Let there be dot
> > > >
> > > >
> > > >
> > > > Hi all.
> > > >
> > > > I preface this message with the disclaimer that I know nothing about
> > > scopes. One must start somewhere...
> > > >
> > > > I've come to own a 7623A that powered up but had a smashed crt. So,
> > > I track down another 7623A with a good tube that isn't powering up and
> > > move the good tube to the powering device.
> > > >
> > > > I power up the re-tubed scope and manage to find a dot. I can't
> > > remember if that happened with or without a plugin (I have a 7818,
> > > 7828 and a 7B53---no idea if those work at all either but that's
> > > another front...)
> > > >
> > > > The dot is a morale boost and I'm even more impressed with the
> > > craftsmanship and design of these things. Swapping crts was a cinch.
> > > >
> > > > My question is about the strange thing that happens next. I had to
> > > pull the board and fan on the back side to push the crt out, and after
> > > putting it all back together I didn't replace the perforated shield
> > > when I fired it out to see what gives.
> > > >
> > > > The next morning, I (reasonably I think) set off to close everything
> > > up properly so I can try to figure out how many of the other broken
> > > puzzle pieces I have can be snap together, and the power light doesn't
> > > come on. I shortly thereafter determine that the thing that is keeping
> > > the scope from returning to its signs-of-life status is the perforated
> > > shield on the back end that covers the board behind the fan. I put in
> > > a less bent cover and the light comes on but no dot. The only way I
> > > get the dot is when the shield is off completely.
> > > >
> > > > What is up with that? Is there something about how that metal shield
> > > fits in that is making a bad connection to the chassis? I tried a few
> > > 7623A shields (in various states of bent and straight-looking---yes, I
> > > have a stack of 7623as) and they all seem to make the same thing
> > > happen.
> > > >
> > > > Can someone tell me how to identify what is happening so I can try
> > > to make it right?
> > > >
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Re: CRT replacement for TDS7xx scope

 

Hi Howard,

You can use the LCD in Ebay item 170877360368.

http://www.ebay.com/itm/VGA-AV-signal-Driver-Borad-7inch-800-600-resolution-4-3-A070SN02-tft-lcd-display-/170877360368?ssPageName=ADME:X:AAQ:US:1123

You will need to make a voltage regulator that will use the existing 25V for the CRT into 12V needed by this kit. You will also need to find a way to mount the LCD and controller to the front panel. Yes, you use the existing VGA output. If you buy the kit, make sure you tell the seller that you want the CARTV128.BIN firmware, or you won't be able to line up the video quite right. You can see one that I converted in Ebay item 221203719866.

http://www.ebay.com/itm/221203719866?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

The right hand menu buttons don't quite line up, however...

Good luck!

Jay

--- In TekScopes@yahoogroups.com, "W1WF" <hwashcraft@...> wrote:

I have a 784D that is working quite well--calbrated this January--but has a dim screen. It is barely workable in strong light, ok if the lighting is reduced. I can get by by using an external VGA monitor, would like to develop a more portable solution. What has been the experience with replacing with an LCD or other solutions? I'm assuming that the LCD replacement skips around the existing CRT/Shutter and is just a VGA LCD driven from the source for the back panel VGA output. If anyone has posted a description of a conversion, I would be interested in that, too.

Thanks,

Howard

--- In TekScopes@yahoogroups.com, David Woodhead <david_woodhead@> wrote:

I have a TDS784D that works perfectly except the CRT is dim and the internal adj pot is maxed out. Most likely the CRT is worn out.
 
Norway Labs offers a LCD conversion for $1150. I have looked over the manual for this and it looks like a nice and easy conversion. Since the scope already provides a VGA output, it appears that this is used to drive the LCD. The kit includes a custom PCB to interface the LCD which I beleive it is nothing more than a 640x480 VGA monitor. Does anyone have experience with such a modified unit? Is there any downside to using a LCD display compared to the original CRT/Shutter? I understand viewing angle is an issue with LCD's but newer displays ar emuch better than they used ot be in this regard.
 
$1150 is a bit more than I want to spend; considerably more than I paid for the scope! I have found a company in China that will sell me a high quality 6.4" LCD, back light inverter and a VGA driver board for about $200. I'll need to fabricate my own metalwork to mount it in the scope but that looks fairly easy. I'd be interested in communicating with anyone that might have already done this?

David.






Re: Tek 2230 power supply strange

vdonisa
 

Hi Ted,

Since the inverter is working when powered separately from a different power supply, you probably have one of these issues:

- the inverter presents an excessive/fluctuating/oscillating load that the pre-regulator cannot cope with; some further measurements using the aux power supply and readings of currents / waveforms would shed some light on this

- the pre-reg can't draw sufficient power from mains - an element such as a varistor / resistor / inductor is acting up and not letting full power go through it; check the whole schematic from power plug to the pre-reg

- a component that measures well with DMM is acting up under load / higher voltages only; this will make you run in circles forever unless you decide to replace all components in that area with brand new ones

- there's some subtle issue with the transformer - insulation, core cracks etc

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, "tedgraz1961" <systecma@...> wrote:

Q908 is good also R908.

Test inverter : no power AC , disconected Q9070 , external power +43 volt on TP940 TP950
The scope run all function ; I tested it for 30 min !!
Pre-regulato is failed !!
Now I tested it with lamp bulb 220V serie to main AC power
for pretection fuse and mosfet.
Tomorrow I change C908,Q908,CR908 Q9070,CR907 and also add a ferrite bead to the gate of Q9070.
After I post result.

Bye
--- In TekScopes@yahoogroups.com, Bert Haskins <bhaskins@> wrote:

On 04/26/2013 03:38 PM, tedgraz1961 wrote:

Now, after new check I found oscillation : Tip 31C Toshiba couple
replace with two Tip41C,
Oscillation is missed.
Tekscope 2230 power on but after 5 minute burn fuse.
Check : bad fuse + mosfet Q9070(IRF840) + diode CR907(BYV26E)+
Q947(Tip41C).
Ok re-check inverter with external power.
Burn-in 30 minute : current measure .800mA ca. all function good !!!
Verify U930 pin 10 waveform:normal.
Now connect serial bulb 220V 100W to power cord.
change fuse+mosfet+ diode+tip41C and for security also C907

Power another time :lamp 220V 100W blink also led power!!!

How to protect mosfet from this destructive event ???
Have you checked Q908 and CR908?
The purpose of these parts is to drain the gate charge of Q9070
when U930 turns off.
I have found them damaged after a Q9070 short and R908 alone
will not turn off Q9070 fast enough.
I also add a ferrite bead to the gate of Q9070 when I repair these.

FWIW on some IBM SMPSs they have FBs on all three terminals and
they don't even have the wire leads and socket to contend with.

Your reports that the supply did run for 30 minutes makes it sound
like Q9070 is overheating.

Good Luck,
Bert



--- In TekScopes@yahoogroups.com <mailto:TekScopes%40yahoogroups.com>,
David <davidwhess@> wrote:

C906, C925, or C940 could be bad.

I would also check R917 and C917 which control the frequency response
of the regulator.

Did you replace CR920, C907, or CR907? If you know what to look for
in the reverse recovery of the two diodes, that might tell you
something.

Is Q9070 oscillating?

On Tue, 23 Apr 2013 20:02:53 -0000, "tedgraz1961" <systecma@>
wrote:

Hi, friends
are still struggling with power supply Tek 2230
Now after finally start the TL594 (there was a transistor fault)
The inverter has already been tested with external power supply
The pre-regulator is not working properly
On the C940 I found +41.5 volts with 500mV ripple
On the gate of Q9070 found 12volt but with variable duty cycle
continuously
This causes Q9070 to produce a square wave that varies continuously
and I wonder if this is normal?
I also connected to the pre-regulator to external load
disconnecting R949 with parallel 5x220ohmm 10W 50 W = 49 ohmm : same
result.
If I understand the pin 2 of U930 is voltage regulator.
On pin 3 of U930 find a half-wave superimposed on +4 Vdc negative
wave that varies in phase with the variation of the duty cycle of the
U930 ..... this normal??

I ask for help to close this case that is out of my head!


Re: 2465B

vdonisa
 

Given the age of the equipment and the fact that you were not the single owner, I would think that a visual inspection of the internals couldn't hurt. If there's dust, blow it off, if you notice anything suspicious, take pics and post them here, if there's a funny smell lingering inside then you may want to dig deeper and examine the PSU too.

Add fuses to your list - Pete, the technician with the slotted screwdriver, also used "one size fits all" fuses, he had a stock of slow blow 15A ones, they never needed any further servicing (the breakers in your electrical panel will trip before those would get even warm). IIRC the correct fuse for your scope is a glass 6x32mm AGC2 (fast 2A), check with the manual to make sure.

As for the battery here's a question for the group: my understanding is that the scope will give you a "low battery" alert when it senses that its voltage is below a certain limit? is that correct? if yes, how fast should you act once you've seen that alert? As the datasheet for the Eagle Picher battery used in low serial nr scopes mentions that it has a "flat characteristic" in the sense that it's designed to keep a rather constant voltage at the output then fall abruptly (in time) from there once it gets near its end of life.

Cheers,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, Steve <steve65@...> wrote:

Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve


Re: 2465B

 

Does it have the SMT version of the A5 controller board and if so, have the four aluminum SMT electrolytics been replaced?
 
That would be the first thing I would check as continued use will extend damage to the board.
 
The additional items can be as needed and subject to testing. Check the voltages and ripple at the J119 test socket.
 
If you open it up, then blowing out any accumulated dust would be a good idea.
 
Regards,
Tom
 
 

----- Original Message -----
From: Steve
Sent: Friday, April 26, 2013 9:26 PM
Subject: [TekScopes] 2465B

 

Hi all,

I have been reading this list for several years. Last year I acquired a
2465B and have since been more attentive to postings relating to that
model of scope.

I've seen discussions on this list in the recent past relating to
lithium battery, U800 heat sink, switching power supply caps, controller
board caps and fans. Probably other topics as well, but those are the
one that come to mind.

The scope I have seems to work ok. The guy I got it from said he had
not opened it up during the several years he had it.

Given that the scope is working, I'm inclined to not fix what isn't
broken. Is that a wise thing to do? Or should I proactively deal with
the battery? Or the heat sink? The switching power supply caps? The
controller board caps? The fan? Other things?

The postings to this list indicate that some of you guys have a lot of
insight regarding these topics. I would appreciate your advice.

Thank you.

Steve

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