Re: How to upgrade a 7854 to opt 2D
Hi David,
On "my" schematic 34 there is no U1620A or U2 and no D181 or U3.
I found the TL 72 OpAmp.
I have a U900 aa vertical D/A converter an a U1010 as horizontal D/A converter.
Gerhard
toggle quoted message
Show quoted text
--- In TekScopes@..., David <davidwhess@...> wrote:
I assume that the character display works correctly even when the
stored signal has no or a low vertical deflection.
I think you will find the problem around U1620A or U2 on schematic 34.
If reseating those ICs or the A40 connections does not resolve the
problem, then you could swap U2 with a different DG181 like U3 to see
if the problem moves to the horizontal axis. I have read about
reliability problems with the DG181 before.
The TL072 used for U1620 has lots of possible replacements including
the TL082 and any number of other FET and MOSFET input operational
amplifiers.
There could be a bad part in the networks surrounding U1620A.
On Mon, 18 Mar 2013 16:44:53 -0000, "g_kupka" <ghm1@...> wrote:
After a warmup time of approx 2 hours the stored signal is displayed in the stored mode but only with an ampltude of 35% of the applied signal.
Gerhard
--- In TekScopes@..., "g_kupka" <ghm1@> wrote:
I swapped the RAM Board and now the 2nd 7854 has the opt 2D.
The 1st 7854 has still the problem, that it doesn't display the stored signal in the store mode, it shows only a horizontal line.
Where can I find the failure?
Many thanks.
Gerhard
--- In TekScopes@..., "David C. Partridge" <david.partridge@> wrote:
Yes
Dave
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of g_kupka
Sent: 17 March 2013 10:22
To: TekScopes@...
Subject: [TekScopes] How to upgrade a 7854 to opt 2D
I have two 7854.
1st one opt 2D(extended memory):
I can store a signal, but it doesn't show the stored signal in the store mode, it shows only a horizontal line.
2nd one opt 78(P11 CRT):
It works well. Can I upgrade this mainframe to opt 2D by swapping the memory board from the 1st one to the 2nd one?
Gerhard
|
Those fragile plastic flex connectors are impossible to find
as far as I know, but I question whether a flex coupler is even needed there.
The VAR shaft from the knob back to that flex connector?is a piece of 1/8"
fiberglass rod which I imagine takes care of the insulation out to the knob, so
maybe a normal aluminum connector would be just fine. The fiberglass
rod?should take care of any misalignment too.
The last 1/8" shaft connectors I bought were from Veronia
Northern but I'm sure you can get them from others.
Part number 376-0029-00 on this page:
These are those connectors with two set screws, that look like
a piece of thick wall aluminum tubing.
tom jobe...
?
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Monday, March 18, 2013 6:04
AM
Subject: [TekScopes] New 466 owner
?
Just picked up a 466 over the weekend. Works fine, but the only
problem
was the Var knob on CH 2 is broken. Opened it up and saw it
was the
coupler that connects the two shafts that's broken. Is there
a source for
the couplers? I might just leave it alone as it looks
like a real pain to
get down to the Ch 2 stuff.
Thanks,
-d
|
Re: How to upgrade a 7854 to opt 2D
I assume that the character display works correctly even when the
stored signal has no or a low vertical deflection.
I think you will find the problem around U1620A or U2 on schematic 34.
If reseating those ICs or the A40 connections does not resolve the
problem, then you could swap U2 with a different DG181 like U3 to see
if the problem moves to the horizontal axis. I have read about
reliability problems with the DG181 before.
The TL072 used for U1620 has lots of possible replacements including
the TL082 and any number of other FET and MOSFET input operational
amplifiers.
There could be a bad part in the networks surrounding U1620A.
toggle quoted message
Show quoted text
On Mon, 18 Mar 2013 16:44:53 -0000, "g_kupka" <ghm1@...> wrote: After a warmup time of approx 2 hours the stored signal is displayed in the stored mode but only with an ampltude of 35% of the applied signal.
Gerhard
--- In TekScopes@..., "g_kupka" <ghm1@...> wrote:
I swapped the RAM Board and now the 2nd 7854 has the opt 2D.
The 1st 7854 has still the problem, that it doesn't display the stored signal in the store mode, it shows only a horizontal line.
Where can I find the failure?
Many thanks.
Gerhard
--- In TekScopes@..., "David C. Partridge" <david.partridge@> wrote:
Yes
Dave
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of g_kupka
Sent: 17 March 2013 10:22
To: TekScopes@...
Subject: [TekScopes] How to upgrade a 7854 to opt 2D
I have two 7854.
1st one opt 2D(extended memory):
I can store a signal, but it doesn't show the stored signal in the store mode, it shows only a horizontal line.
2nd one opt 78(P11 CRT):
It works well. Can I upgrade this mainframe to opt 2D by swapping the memory board from the 1st one to the 2nd one?
Gerhard
|
Re: How to upgrade a 7854 to opt 2D
After a warmup time of approx 2 hours the stored signal is displayed in the stored mode but only with an ampltude of 35% of the applied signal.
Gerhard
toggle quoted message
Show quoted text
--- In TekScopes@..., "g_kupka" <ghm1@...> wrote:
I swapped the RAM Board and now the 2nd 7854 has the opt 2D.
The 1st 7854 has still the problem, that it doesn't display the stored signal in the store mode, it shows only a horizontal line.
Where can I find the failure?
Many thanks.
Gerhard
--- In TekScopes@..., "David C. Partridge" <david.partridge@> wrote:
Yes
Dave
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of g_kupka
Sent: 17 March 2013 10:22
To: TekScopes@...
Subject: [TekScopes] How to upgrade a 7854 to opt 2D
I have two 7854.
1st one opt 2D(extended memory):
I can store a signal, but it doesn't show the stored signal in the store mode, it shows only a horizontal line.
2nd one opt 78(P11 CRT):
It works well. Can I upgrade this mainframe to opt 2D by swapping the memory board from the 1st one to the 2nd one?
Gerhard
------------------------------------
Yahoo! Groups Links
|
2465 Failures & Serial Numbers
I find references to 2465s within a range of serial numbers having a "higher than normal" IC failure rate, but have been unable to find which serial numbers. Please point me in the right direction.
|
Re: How to upgrade a 7854 to opt 2D
I swapped the RAM Board and now the 2nd 7854 has the opt 2D.
The 1st 7854 has still the problem, that it doesn't display the stored signal in the store mode, it shows only a horizontal line.
Where can I find the failure?
Many thanks.
Gerhard
toggle quoted message
Show quoted text
--- In TekScopes@..., "David C. Partridge" <david.partridge@...> wrote:
Yes
Dave
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of g_kupka
Sent: 17 March 2013 10:22
To: TekScopes@...
Subject: [TekScopes] How to upgrade a 7854 to opt 2D
I have two 7854.
1st one opt 2D(extended memory):
I can store a signal, but it doesn't show the stored signal in the store mode, it shows only a horizontal line.
2nd one opt 78(P11 CRT):
It works well. Can I upgrade this mainframe to opt 2D by swapping the memory board from the 1st one to the 2nd one?
Gerhard
------------------------------------
Yahoo! Groups Links
|
I'm looking for same item
Paul K0UYA
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Monday, March 18, 2013 8:04
AM
Subject: [TekScopes] New 466 owner
?
Just picked up a 466 over the weekend. Works fine, but the only
problem
was the Var knob on CH 2 is broken. Opened it up and saw it
was the
coupler that connects the two shafts that's broken. Is there
a source for
the couplers? I might just leave it alone as it looks
like a real pain to
get down to the Ch 2 stuff.
Thanks,
-d
|
Re: Free: collapsible viewing hood and dust cover for 453/4, Tekcamera C12 adapter
Items gone, thanks for all your responses.
Keith
|
Just picked up a 466 over the weekend. Works fine, but the only problem was the Var knob on CH 2 is broken. Opened it up and saw it was the coupler that connects the two shafts that's broken. Is there a source for the couplers? I might just leave it alone as it looks like a real pain to get down to the Ch 2 stuff.
Thanks,
-d
|
It is the same basic oscilloscope as a 2430, 2430A, 2432, and 2440. They pretty much all only differ in bandwidth and sample rate. The 2431L is a little different being a cost reduced version that lacks the hardware for peak detection, has no delayed time base, and is missing some other features. On Sun, 17 Mar 2013 22:15:17 -0400, Paul Amaranth <paul@...> wrote: I finally tracked down a shorted 2.7uf tant on the timebase board and got that
replaced today. After putting everything together it booted up and passed all
the self tests. I have it hooked up to my SG503 right now and it appears to
be functional (yay).
Now it will probably take me a week or so to figure out how to actually use
it, assuming nothing else fails in the meantime.
Anyone else have one of these? I don't recall seeing any mention recently.
Paul
|
Re: Tek 455 horizontal sweep power supply problem
Do you have a copy of the service manual? It has detailed disassembly
instructions in the maintenance section.
?
A good copy is here
?
?
What does the +32 volt unregulated supply look like? It should be up around
+52 volts or so. If not, check C-721, a 1000uF, 75 volt can.
?
HTH,
Tom
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Sunday, March 17, 2013 10:46
PM
Subject: [TekScopes] Tek 455 horizontal
sweep power supply problem
?
Hi,
My 455 that has performed perfectly for 18 years has developed a
problem with the horizontal sweep. It appears to be a bit compressed on both
sides and behaves like there is some oscillation on the left side of the
screen. The +95V power supply is down to 68V so I assume this is the source of
the problem. I am hoping it is not a problem with the HV transformer but just
an electrolytic cap that is failing.
I read some posts about this issue
several years ago but didn't read about a resolution to the problem. Does
anyone have experience with this and know what might be the cause of the power
supply low voltage?
Also, the components for the +95 power supply
appear to be under the CRT. Can anyone offer suggestions about how to
disassemble the scope to get to the main
board?
Thanks,
Ed
|
Tek 455 horizontal sweep power supply problem
Hi,
My 455 that has performed perfectly for 18 years has developed a problem with the horizontal sweep. It appears to be a bit compressed on both sides and behaves like there is some oscillation on the left side of the screen. The +95V power supply is down to 68V so I assume this is the source of the problem. I am hoping it is not a problem with the HV transformer but just an electrolytic cap that is failing.
I read some posts about this issue several years ago but didn't read about a resolution to the problem. Does anyone have experience with this and know what might be the cause of the power supply low voltage?
Also, the components for the +95 power supply appear to be under the CRT. Can anyone offer suggestions about how to disassemble the scope to get to the main board?
Thanks,
Ed
|
I finally tracked down a shorted 2.7uf tant on the timebase board and got that
replaced today. After putting everything together it booted up and passed all
the self tests. I have it hooked up to my SG503 right now and it appears to
be functional (yay).
Now it will probably take me a week or so to figure out how to actually use
it, assuming nothing else fails in the meantime.
Anyone else have one of these? I don't recall seeing any mention recently.
Paul
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
|
Free: collapsible viewing hood and dust cover for 453/4, Tekcamera C12 adapter
I have these items for free for any longtime Tekscope member (you pay shipping):
Part# 016-0083-00 Collapsible viewing hood for Types 453 and 454. One place I see it is on page 443 of the 1970 Tek catalog.
Part# 016-0074-01 Instrument cover for Types 453, 454, 491, also in 1970 catalog page 439.
Part #016-0226-01 Tekcamera adapter for C12, but I don't know for which scope.
All the above in decent condition, but dirty. No tears or other obvious problems.
Please don't respond to list- email me.
Cheers,
Keith Ostertag
|
Re: Replacement to DS1230AB Lithium backed NVRAM
>>>>¡°I cannot understand guys, WHY BOTHER?¡±<<<< ? The key to this one is to understand that¡¡by claiming to save a couple of bucks we can easily justify the repair taking 3 to 5 times as long to implement than is should¡.. thus turning a 1 (maybe 2) beer repair (time wise) into a full six pack minimum. With the added possibility of another 6pack in consultation with an ¡°expert¡± ? Hopefully helpful Rob
(now hopefully I don¡¯t lose my man club card do to letting out some insight) ?
toggle quoted message
Show quoted text
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Sergey Kubushyn
Sent: Sunday, March 17, 2013 5:56 PM
To: TekScopes@...
Subject: Re: [TekScopes] Re: Replacement to DS1230AB Lithium backed NVRAM? ? On Sun, 17 Mar 2013, Gala Dragos wrote:
I can not understand guys, WHY BOTHER?
You can get DS1230 from Mouser for something like $15 (I purchased one a
week ago to replace DS1225Y in my 2467B scope.) You will get a real thing
that you can just swap in and forget for the next 10 years. And you can
transfer the original chip content to the new one easily so you won't have
to recalibrate.
What are you trying to save here? A buck? Whopping two bucks? Is it worth a
trouble and all that work involved?
> You could add extra logic and a counter to switch between fram chips and increase the mtbf time, or even better make your own NVRAM.
> Oh, and if you keep the fram at 25?degrees?Celsius?you will probably get 10 times more write cycles.
>
> --- On Sun, 3/17/13, bravovb <vbingei@...> wrote:
>
> From: bravovb <vbingei@...>
> Subject: [TekScopes] Re: Replacement to DS1230AB Lithium backed NVRAM
> To: TekScopes@...
> Date: Sunday, March 17, 2013, 8:54 AM
>
> Mr. Silva,
>
> Its been a while. How is the 2465B going with FRAM ?
>
> --- In TekScopes@..., "Victor Silva" <daejon1@...> wrote:
>
>> I have found that the FRAM devices are not a viable option in the
>> 243X/40. Sadly I must report that what looked like a very promising
>> alternative to the DALLAS RAM/Lithium cell combo has turned out to be
>> a dead end.
>
>> I have been testing for over one month now on a 2430A, 2440 and 2465B
>> and everything seemed fine. My last test was to actually determine
>> the read/write frequency to the device.
>
>> It turn out a 2430A writes to the battery-backed devices as often as
>> once every microsecond. Since the FRAM device as a maximum of 10^10
>> read/write cycles (before it loses its NV capability) a quick
>> calculation reveals that the 2430A scope will render the FRAM device
>> a volatile device in one to three months.
>
>> For now I can only recommend the DALLAS (or other vendors)
>> RAM/Lithium cell combo pack device for use in Tek scopes.
>
>> Sorry for getting everyone's hopes up for a more inexpensive
>> replacement for NVRAM.
>
>> --Victor Silva
---
*
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
*
|
Re: Replacement to DS1230AB Lithium backed NVRAM
On Sun, 17 Mar 2013, Gala Dragos wrote: I can not understand guys, WHY BOTHER? You can get DS1230 from Mouser for something like $15 (I purchased one a week ago to replace DS1225Y in my 2467B scope.) You will get a real thing that you can just swap in and forget for the next 10 years. And you can transfer the original chip content to the new one easily so you won't have to recalibrate. What are you trying to save here? A buck? Whopping two bucks? Is it worth a trouble and all that work involved? You could add extra logic and a counter to switch between fram chips and increase the mtbf time, or even better make your own NVRAM.
Oh, and if you keep the fram at 25?degrees?Celsius?you will probably get 10 times more write cycles.
--- On Sun, 3/17/13, bravovb <vbingei@...> wrote:
From: bravovb <vbingei@...>
Subject: [TekScopes] Re: Replacement to DS1230AB Lithium backed NVRAM
To: TekScopes@...
Date: Sunday, March 17, 2013, 8:54 AM
Mr. Silva,
Its been a while. How is the 2465B going with FRAM ?
--- In TekScopes@..., "Victor Silva" <daejon1@...> wrote:
I have found that the FRAM devices are not a viable option in the
243X/40. Sadly I must report that what looked like a very promising
alternative to the DALLAS RAM/Lithium cell combo has turned out to be
a dead end. I have been testing for over one month now on a 2430A, 2440 and 2465B
and everything seemed fine. My last test was to actually determine
the read/write frequency to the device. It turn out a 2430A writes to the battery-backed devices as often as
once every microsecond. Since the FRAM device as a maximum of 10^10
read/write cycles (before it loses its NV capability) a quick
calculation reveals that the 2430A scope will render the FRAM device
a volatile device in one to three months. For now I can only recommend the DALLAS (or other vendors)
RAM/Lithium cell combo pack device for use in Tek scopes. Sorry for getting everyone's hopes up for a more inexpensive
replacement for NVRAM. --Victor Silva --- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *
|
Re: Tektronix 221 Portable Oscilloscope AS IS $59.99
Who got that?
Anyway, thanks. I do not need another project. I do not need
another project ...
toggle quoted message
Show quoted text
On Sun, Mar 17, 2013 at 10:28:11PM -0000, jayw_comark wrote: Ebay 121082875612
no affiliation
Jay
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
|
Re: Replacement to DS1230AB Lithium backed NVRAM
The solution I used for my 2440 which I have discussed here a couple of times was to use the SRAM and EEPROM based NVRAMs from Cypress which as far as I have been able to tell in this case, can be used as direct replacements for the Dallas/Maxim SRAM based NVRAMs. They are not really any less expensive though than new Dallas/Maxim NVRAMs. They only save the SRAM contents to the EEPROM when power is removed or if specifically asked which is not going to happen without a firmware change so continuous writes are not a problem. I also considered reverting my 2440 to the earlier design where an external lithium cell was used. On Sun, 17 Mar 2013 15:21:13 -0700 (PDT), Gala Dragos <gala_dragos@...> wrote: You could add extra logic and a counter to switch between fram chips and increase the mtbf time, or even better make your own NVRAM.
Oh, and if you keep the fram at 25?degrees?Celsius?you will probably get 10 times more write cycles.
--- On Sun, 3/17/13, bravovb <vbingei@...> wrote:
From: bravovb <vbingei@...>
Subject: [TekScopes] Re: Replacement to DS1230AB Lithium backed NVRAM
To: TekScopes@...
Date: Sunday, March 17, 2013, 8:54 AM
Mr. Silva,
Its been a while. How is the 2465B going with FRAM ?
--- In TekScopes@..., "Victor Silva" <daejon1@...> wrote:
I have found that the FRAM devices are not a viable option in the
243X/40. Sadly I must report that what looked like a very promising
alternative to the DALLAS RAM/Lithium cell combo has turned out to be
a dead end.
I have been testing for over one month now on a 2430A, 2440 and 2465B
and everything seemed fine. My last test was to actually determine
the read/write frequency to the device.
It turn out a 2430A writes to the battery-backed devices as often as
once every microsecond. Since the FRAM device as a maximum of 10^10
read/write cycles (before it loses its NV capability) a quick
calculation reveals that the 2430A scope will render the FRAM device
a volatile device in one to three months.
For now I can only recommend the DALLAS (or other vendors)
RAM/Lithium cell combo pack device for use in Tek scopes.
Sorry for getting everyone's hopes up for a more inexpensive
replacement for NVRAM.
--Victor Silva
|
Tektronix 221 Portable Oscilloscope AS IS $59.99
Ebay 121082875612
no affiliation
Jay
|
Re: Replacement to DS1230AB Lithium backed NVRAM
| You could add extra logic and a counter to switch between fram chips and increase the mtbf time, or even better make your own NVRAM.
Oh, and if you keep the fram at 25?degrees?Celsius?you will probably get 10 times more write cycles.
|
--- On Sun, 3/17/13, bravovb wrote:
From: bravovb
Subject: [TekScopes] Re: Replacement to DS1230AB Lithium
backed NVRAM
To: TekScopes@...
Date: Sunday, March 17, 2013, 8:54 AM
?
Mr. Silva,
Its been a while. How is the 2465B going with FRAM ?
--- In TekScopes@..., "Victor Silva" wrote:
>
> I have found that the FRAM devices are not a viable option in the
> 243X/40. Sadly I must report that what looked like a very promising
> alternative to the DALLAS RAM/Lithium cell combo has turned out to be
> a dead end.
>
> I have been testing for over one month now on a 2430A, 2440 and 2465B
> and everything seemed fine. My last test was to actually determine
> the read/write frequency to the device.
>
> It turn out a 2430A writes to the battery-backed devices as often as
> once every microsecond. Since the FRAM device as a maximum of 10^10
> read/write cycles (before it loses its NV capability) a quick
> calculation reveals that the 2430A scope will render the FRAM device
> a volatile device in one to three months.
>
> For now I can only recommend the DALLAS (or other vendors)
> RAM/Lithium cell combo pack device for use in Tek scopes.
>
> Sorry for getting everyone's hopes up for a more inexpensive
> replacement for NVRAM.
>
> --Victor Silva
>
|
David Hess
Sergey Kubushyn