Date   
Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

 

Hi :
I did use " PDF Creator " and Cute PDF writer , both cannot save a single parts in file , it was error happen .

RegardTony CheungAPR 1 2020

On Tuesday, March 31, 2020, 11:25:51 PM GMT+8, Michael A. Terrell <@michaelaterrell> wrote:

Can you print a single transformer to a new PDF, or is that still disabled?
I would like to do that for the used Tektronix transformers that I have.

On Tue, Nov 12, 2019 at 12:41 PM Dave Brown <davebr@...>
wrote:

Both files have been updated with 25 new scans. I received some of the
missing scans from another individual with microfiche and incorporated them
into the files. The links are the same. - Dave



Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

Dave Brown
 

We have never knowingly disabled printing so it should work from any of the files we've uploaded. I just tried it on this latest and it worked for me.
vintageTEK

Re: New 2465 Seimens brushless motor

Chuck Harris
 

The leads must be some weird alloy, as even plain steel
would tin with zinc chloride. Stainless steel behaves very
much like you are describing, and will solder with HCl, but
not ZnCl.

HCl it is.

-Chuck Harris

victor.silva via Groups.Io wrote:

I tried Zinc Chloride paste and the solder balls up like Mercury on glass.
I was able to get a few fragments to adhere but was very much overheating the terminals causing the motor plastic end caps to start to melt.

--Victor



Re: 2400 series Test 4 Fail 3,13, 2

Chuck Harris
 

That's great news Craig. I've seen this one before, with the
same capacitor. Of course, logic tells us that other such caps
on the board are likely bad in the same way, only we don't notice
them because they are mains powered.

Remember, the RAM chip doesn't save data unless it is plugged into
the battery. So, if you remove the chip from the socket, it will
be wiped of all data.

-Chuck Harris

Craig Cramb wrote:

Thanks again Chuck for the help troubleshooting issue. I worked my way thru the circuits trying to locate the voltage drain by breaking them down into smaller circuits. Finally came upon the problem. It was caused by a small cap on the volt input connection to the U2460 ram. During the process I removed the U2460 and installed a socket base for it. Decided to put a new chip in the socket. So now boot up error to Test 04 Fail 13. Will go thru another entire cal procedure and hope for a good result.


Craig



On Mar 31, 2020, at 12:34 PM, Chuck Harris <cfharris@...> wrote:

R2770's purpose is to allow you to measure the current
being drawn from the battery.

To use it, you hook a high impedance voltmeter across the
10K resistor, and the voltage reading is the current flowing
out of the battery in tenths of a milliamp.

2.6V across the 10K resistor shows that something is drawing
.26ma from the battery, which is not a good thing!

The voltage reading across the 10K resistor should be less
than 0.1V... more usually it will read as zero.

You can't expect an ohmmeter to work when it is measuring
a resistor that has current passing through it from other
sources.

-Chuck Harris



Craig Cramb wrote:
Thank you Chuck for your input.
I have gone thru the U2460 ram trace test and the checkout of the associated transistors. All seem ok. I did find something strange is circuit of the - of the battery the R2770 10K, is reading open in circuit I remove it and reading is 10K . I replaced it and same as with old resistor. Again no continuity and there is a voltage drop across it of 2.6vdc. These readings are no power applied to the scope.
I review this same circuit on another A5 card of same part number. Reading in circuit is 9.98 ohm with no voltage drop across R2770. This is definitely got me baffled.

Craig


On Mar 31, 2020, at 8:51 AM, Chuck Harris <cfharris@...> wrote:
Hi Craig,

If the scope was not showing the "11" code, through several
power cycles, and then suddenly it did, the obvious conclusion
is that something in the RAM unexpectedly changed.

This could be a bad RAM, but I really doubt it.

It could be a bad/intermittent connection to the RAM, which is
quite likely. I have seen some customer replaced NVRAM modules
(later scopes), where the customer cut through traces while doing
the desoldering operation... (eg. got too rough).

It could be a flaw in the cutover between battery and mains power.

It is important that the RAM not get written to while the data
lines are in an indeterminate state while 5V is coming on, and cutting
off.

So, I would look carefully at the circuitry comprised of Q2070, Q2170,
Q2270, Q2370, and Q2470. They are there to make sure that the chip
select pin on the RAM is safely parked away in the unselected condition
while power is unstable.

And, I would look at the traces on the bottom of the board about a
desoldering tip diameter around each of the pins on the RAM chip.
An ohmmeter can help.

-Chuck Harris

Craig Cramb wrote:
This is a pretty long feed that tarted back in January. Lots of good info thur-out this.
I finally got back started again with all the sit at home time. The 2465B s/n B010817 I got a correct replacement for the U2460 and BT2570 and installed the a couple of months ago. Waited until this last week to continue. Monitored the Battery and U2460 input voltage over the last 2 months to verify that the chip wasn't draining the battery as before in this feed. All was ok so this past went thru a complete calibration and all seemed to go well. Put scope aside for a week and then restarted it today. Now I get the Test04 fail 11. Does this seem to be that there is another chip failure or is this just a point in the calibration that wasn't correct?









Re: 2430A Fails Repet

Chuck Harris
 

Noise on an early digital scope trace is perfectly normal.
They are like a DVM with its lowest digit dithering up and
down a count or so. On a scope that shows up as a spiky
looking line, like so:

----^----v-----^^---v------vv-----^----v^----

-Chuck Harris

Rich Frahm wrote:

Thanks again Siggi - it turns out the problem with the trace was my own ignorance! Once I pushed the Acquire button and set the trigger to Auto I got a straight line for a trace. It's got a fair amount of noise on it but I am not going to concern myself with that right now. My biggest concern is that it still fails repet in Ext Cal and I still have the same failures, 9113, 9123, and 9300.

From the reading I've done I think a cold start is initiated any time power is turned on with J156 is removed. Is that right? Or do I need to do something else to initiate a cold start?
Thanks!

Rich



Re: 2782 electrical schematics

 

Hi Bob,

Have you looked at these schematics at ko4bb.com? The site looks very friendly and I was tempted to donate. But the schematics are a different story.

Was this 2782 designed by Tektronix? It looks like the mess of a mixture of digital and low level analog electronics. I concentrated on the board A23 High Voltage Power supply Board.
This design is pure obscurity! What is usually a straight forward simple interface to a CRT, it seems to have been intentionally made more obscure by the introduction of a "module" U10, which, sandwiched between the logic schematic and the CRT, leaves the logic in complete darkness. This HV power supply is at least 10 times more complicated than the one in my 547 lab oscilloscope, (tube driven), and many times more complicated than the one in the 7704 mainframe which, in comparison, is clear like water. But at least this 2782 circuit diagram shows some trimmers to adjust astigmatism and geometry, so maybe evdsp39 may play with them and hopefully obtain a readable display.

Also what does not help is that these schematics, maybe the product of love and care, have such a poor resolution that even with the Acrobat reader in 400% one cannot recognize most of the labels. But you should be thanked for the intention and these schematics are much better than nothing.

Ernesto

Re: 2400 series Test 4 Fail 3,13, 2

Craig Cramb
 

Thanks again Chuck for the help troubleshooting issue. I worked my way thru the circuits trying to locate the voltage drain by breaking them down into smaller circuits. Finally came upon the problem. It was caused by a small cap on the volt input connection to the U2460 ram. During the process I removed the U2460 and installed a socket base for it. Decided to put a new chip in the socket. So now boot up error to Test 04 Fail 13. Will go thru another entire cal procedure and hope for a good result.


Craig

On Mar 31, 2020, at 12:34 PM, Chuck Harris <cfharris@...> wrote:

R2770's purpose is to allow you to measure the current
being drawn from the battery.

To use it, you hook a high impedance voltmeter across the
10K resistor, and the voltage reading is the current flowing
out of the battery in tenths of a milliamp.

2.6V across the 10K resistor shows that something is drawing
.26ma from the battery, which is not a good thing!

The voltage reading across the 10K resistor should be less
than 0.1V... more usually it will read as zero.

You can't expect an ohmmeter to work when it is measuring
a resistor that has current passing through it from other
sources.

-Chuck Harris



Craig Cramb wrote:
Thank you Chuck for your input.
I have gone thru the U2460 ram trace test and the checkout of the associated transistors. All seem ok. I did find something strange is circuit of the - of the battery the R2770 10K, is reading open in circuit I remove it and reading is 10K . I replaced it and same as with old resistor. Again no continuity and there is a voltage drop across it of 2.6vdc. These readings are no power applied to the scope.
I review this same circuit on another A5 card of same part number. Reading in circuit is 9.98 ohm with no voltage drop across R2770. This is definitely got me baffled.

Craig


On Mar 31, 2020, at 8:51 AM, Chuck Harris <cfharris@...> wrote:
Hi Craig,

If the scope was not showing the "11" code, through several
power cycles, and then suddenly it did, the obvious conclusion
is that something in the RAM unexpectedly changed.

This could be a bad RAM, but I really doubt it.

It could be a bad/intermittent connection to the RAM, which is
quite likely. I have seen some customer replaced NVRAM modules
(later scopes), where the customer cut through traces while doing
the desoldering operation... (eg. got too rough).

It could be a flaw in the cutover between battery and mains power.

It is important that the RAM not get written to while the data
lines are in an indeterminate state while 5V is coming on, and cutting
off.

So, I would look carefully at the circuitry comprised of Q2070, Q2170,
Q2270, Q2370, and Q2470. They are there to make sure that the chip
select pin on the RAM is safely parked away in the unselected condition
while power is unstable.

And, I would look at the traces on the bottom of the board about a
desoldering tip diameter around each of the pins on the RAM chip.
An ohmmeter can help.

-Chuck Harris

Craig Cramb wrote:
This is a pretty long feed that tarted back in January. Lots of good info thur-out this.
I finally got back started again with all the sit at home time. The 2465B s/n B010817 I got a correct replacement for the U2460 and BT2570 and installed the a couple of months ago. Waited until this last week to continue. Monitored the Battery and U2460 input voltage over the last 2 months to verify that the chip wasn't draining the battery as before in this feed. All was ok so this past went thru a complete calibration and all seemed to go well. Put scope aside for a week and then restarted it today. Now I get the Test04 fail 11. Does this seem to be that there is another chip failure or is this just a point in the calibration that wasn't correct?







Re: 2782 electrical schematics

 

Hi Tony,

You have a good realistic viewpoint. I can remember 70 years ago, but let's say, 30 years ago. At that time, people also had realistic views and they stated that everything was being made DISPOSABLE, especially the cars full of plastics, while in the good old days things were repairable. Well, I drive a car that is 25.5 years old, from that time of disposables, and it still runs very well and I maintain it. Like with our bodies, it may depend on how we treat things.
I agree with you that some not-so-old instruments seem to be the work of the devil. I just glanced at this Tektronix 2782 spectrum analyzer, and I think that it is one of these. It looks like a service nightmare.

Ernesto

Re: 2430A Fails Repet

Rich Frahm
 

Thanks again Siggi - it turns out the problem with the trace was my own ignorance! Once I pushed the Acquire button and set the trigger to Auto I got a straight line for a trace. It's got a fair amount of noise on it but I am not going to concern myself with that right now. My biggest concern is that it still fails repet in Ext Cal and I still have the same failures, 9113, 9123, and 9300.

From the reading I've done I think a cold start is initiated any time power is turned on with J156 is removed. Is that right? Or do I need to do something else to initiate a cold start?

Thanks!

Rich

Re: New 2465 Seimens brushless motor

victor.silva
 

Did you replace the rear of the scope - rear cover and metal back to be able to use the 80x80mm, 20mm thick fan?

--Victor

Re: New 2465 Seimens brushless motor

victor.silva
 

I tried Zinc Chloride paste and the solder balls up like Mercury on glass.
I was able to get a few fragments to adhere but was very much overheating the terminals causing the motor plastic end caps to start to melt.

--Victor

Re: 2430A Fails Repet

victor.silva
 

CCD hybrids in the 2430A with version earlier than -04 are problematic. Especially if they are -02 or -01, it's a lost cause trying to even use those.
If you have version -04 or preferably -05 then you may have a workable scope.

--Victor

Re: Off topic - Electronics Book Club from the 70s and 80s

Richard in Edenton NC
 

Thanks Dave. The 103 projects book sounds interesting. I'll check it out on Alibris.

Also I accidentally ran across a site called Worldcat. Which is a worldwide library book look up site. I think I might try looking on there for electronics related books. They might not have any of the older books though.

https://www.worldcat.org/

73 Richard W4MCD

Re: Tek 222/224 Battery Replacement

Jeff Davis
 

Hi Rick,

I'd be happy to work with my doppelgänger (the "other Jeff") to see if this design could be adapted to the Tek 422.

Jeff (Davis) / N0DY

________________________________
From: hydrogen Ger <@garp66>
Sent: Tuesday, March 31, 2020 11:42 AM
To: Jeff Davis <n0dyjeff@...>
Subject: Re: [TekScopes] Tek 222/224 Battery Replacement

hi Jeff,

Ah, different "Jeff" , sorry I thought it was you who was familiar with the older Tek 422 portable scope battery issues.

Instead, it was a Jeff Urban:

https://groups.io/g/TekScopes/topic/16763633#146390<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Ftopic%2F16763633%23146390&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374002895&sdata=ARFxp6tJ%2BmF4Yl8YulYkIZ5EUQgg6riKwF%2FKdG6%2BYio%3D&reserved=0>

I am not certain if the Tek 422 scope charging circuit is at all like your Tek 222 scope.
rick


On Tue, Mar 31, 2020 at 2:24 PM Jeff Davis <n0dyjeff@...<mailto:n0dyjeff@...>> wrote:
Hi Rick,

I did a little bit of research on the Tek 422, but in the limited amount I time I gave it, I didn't come across what voltage is supplied by the battery or much information on the charging circuit in that scope.

Being unfamiliar with the Tek 422, can you tell me a little bit more about what would be needed? In the case of the 222/224, the battery is expected to supply 8V, and the scope disconnects if the battery voltage drops below 7.5V. That never happens with this design as the converter supplies 8V regardless of the battery discharge condition, over-discharge cutout is handled by the charge circuitry on board. When plugged it, the scope supplies charging current at 9.5V. The only interface to the scope is the battery power connector - +8V (nom) and ground.

Regards,
Jeff

________________________________
From: hydrogen Ger <@garp66<mailto:@garp66>>
Sent: Monday, March 30, 2020 11:21 AM
To: Jeff Davis <n0dyjeff@...<mailto:n0dyjeff@...>>
Subject: Re: [TekScopes] Tek 222/224 Battery Replacement

hi Jeff,

Could this pcb design be used in the older Tek 422 scope ?

thank you,
rick

On Mon, Mar 30, 2020 at 1:21 PM Jeff Davis <n0dyjeff@...<mailto:n0dyjeff@...>> wrote:
All,

Update on the group purchase. As of this morning, we have deposits for 7 kits, plus I'm planning to order 2 for my own use, making 9 total.

To avoid spamming the list with daily status updates, I've created a web page where I'll keep the current order status<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.n0dy.com%2F2020%2F03%2F29%2Ftek-222-224-charger-order-status%2F&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374002895&sdata=lszpmn3k5jicHmKq4j2g9FVYWodXxLXMn9mzxuIUmlg%3D&reserved=0> updated. The URL is https://www.n0dy.com/2020/03/29/tek-222-224-charger-order-status/<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.n0dy.com%2F2020%2F03%2F29%2Ftek-222-224-charger-order-status%2F&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374022886&sdata=eNLlvlvQbFc9lix4p1NJxw0mh%2BkZJ6qZGv2UF1d4Fjc%3D&reserved=0>.

For those of you not familiar with the project, here's a brief summary:

The kit allows the use of readily available 18650 rechargeable lithium batteries to replace the now unavailable sealed lead acid battery originally sold with the Tektronix 222/224 oscilloscope. No modifications to the scope are required other than removal of the original sealed lead acid battery. Charging and protection circuitry is provided, allowing the use of unprotected 18650 cells. The kit will consist of one assembled and tested battery charger circuit board, one 3D printed case, and at my option some miscellaneous parts such as light pipes to bring the LED indicators to the front of the case and a jumper cable to attach to the scope’s battery connector. Kit does not include rechargeable 18650 lithium batteries (required for operation).

Circuit board design based upon the work of Kitsune-Denshi<https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fkitsune-denshi.net%2Fprojects%3Atek222bat&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374032880&sdata=6up4Tcwys0kvx%2FtqXtjXCiBdI4%2FxsipPNke4xjPXj9Y%3D&reserved=0>. licensed under the Creative Commons Attribution-ShareAlike License.

Case design based upon the work of NearFarMedia on Thingiverse<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.thingiverse.com%2Fthing%3A3623622&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374042877&sdata=ZFJEBEHRSWLxKwKANDL6Dygpj5HJvYKmUP2MPXlNkSs%3D&reserved=0> licensed under the Creative Commons Attribution License.

Thanks,
Jeff / N0DY

________________________________
From: TekScopes@groups.io<mailto:TekScopes@groups.io> <TekScopes@groups.io<mailto:TekScopes@groups.io>> on behalf of Jeff Davis <n0dyjeff@...<mailto:n0dyjeff@...>>
Sent: Saturday, March 28, 2020 5:51 PM
To: TekScopes <TekScopes@groups.io<mailto:TekScopes@groups.io>>
Cc: Dave Voorhis <voorhis@...<mailto:voorhis@...>>; Miguel Work <harrimansat@...<mailto:harrimansat@...>>; benx618(g) <benx618@...<mailto:benx618@...>>; @rubbrdux<mailto:@rubbrdux> <@rubbrdux<mailto:@rubbrdux>>; g m <saphill7@...<mailto:saphill7@...>>; Dave Holigan <dave@...<mailto:dave@...>>; Byron Hayes, Jr. <bhayes@...<mailto:bhayes@...>>; SuddenLink <bob.ripley@...<mailto:bob.ripley@...>>; satbeginner <@satbeginner<mailto:@satbeginner>>; garp66 <@garp66<mailto:@garp66>>
Subject: Re: [TekScopes] Tek 222/224 Battery Replacement

All,

Here's an update on the Tek 222/224 Battery Replacement project. After a few go rounds, I was able to create a BOM that the fab house could source. Unfortunately, the parts that had been pending turned out to be somewhat expensive. The cost in low quantities went from $60 each to about $93. Given the minimum order of 10 pieces is committing nearly $1,000 upfront, I need to ask for deposits from people who are interested in purchasing to reduce my financial exposure. If you're interested in participating in the group buy (and hopefully helping us get a better quantity discount), the link is https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.n0dy.com%2Fproduct%2Ftek-222-224-battery-charger-deposit%2F&amp;data=02%7C01%7C%7C9ddf3c8d9e9e4bcff63a08d7d37b624d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637210399184673953&amp;sdata=3HOf5aZem%2FQ5BeQFzLbq36xJ0uORMH4PVjQeOLFVMU0%3D&amp;reserved=0<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.n0dy.com%2Fproduct%2Ftek-222-224-battery-charger-deposit%2F&data=02%7C01%7C%7Ca0f717762c9d43bea9c908d7d5a33c79%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637212769374052871&sdata=UWq%2Bzy%2Bs%2FuZq87fkArGkjgXpZyfgAm09suh1kWGhfzE%3D&reserved=0>. There you'll find not only details on the deposit and possible volume discounts, there are also links to technical sites for more information on the project.

While I'm not doing this project entirely out of the goodness of my heart, I'm making this first buy available at just slightly over my cost, plus shipping, both as a way of paying back the value I've gotten from the list over the years, and as an encouragement to get the quantities up so we can all get a volume discount. Any volume discounts would be passed along as explained on the deposit web page.

Thanks for the bandwidth.

Regards,
Jeff / N0DY

Tek 222/224 Battery Replacement - Contract Manufacturer

Jeff Davis
 

Hi all,

For the subject project, I've gotten a quote from Seeed Fusion, a contract manufacturer I have worked with previously, but their quote for assembly is rather high. I am also obtaining a quote from "OceanSmile" (www.cnospcb.com), but I've never worked with them before. I'm looking for a firm that can do the PCB fab, source the parts from the BOM, and stuff the boards. Does anyone on the list have experience with OceanSmile or any other contract manufacturer (onshore or offshore) that they've had good results with and would recommend?

Thanks,
Jeff

Re: 2400 series Test 4 Fail 3,13, 2

Chuck Harris
 

R2770's purpose is to allow you to measure the current
being drawn from the battery.

To use it, you hook a high impedance voltmeter across the
10K resistor, and the voltage reading is the current flowing
out of the battery in tenths of a milliamp.

2.6V across the 10K resistor shows that something is drawing
.26ma from the battery, which is not a good thing!

The voltage reading across the 10K resistor should be less
than 0.1V... more usually it will read as zero.

You can't expect an ohmmeter to work when it is measuring
a resistor that has current passing through it from other
sources.

-Chuck Harris



Craig Cramb wrote:

Thank you Chuck for your input.
I have gone thru the U2460 ram trace test and the checkout of the associated transistors. All seem ok. I did find something strange is circuit of the - of the battery the R2770 10K, is reading open in circuit I remove it and reading is 10K . I replaced it and same as with old resistor. Again no continuity and there is a voltage drop across it of 2.6vdc. These readings are no power applied to the scope.
I review this same circuit on another A5 card of same part number. Reading in circuit is 9.98 ohm with no voltage drop across R2770. This is definitely got me baffled.

Craig


On Mar 31, 2020, at 8:51 AM, Chuck Harris <cfharris@...> wrote:

Hi Craig,

If the scope was not showing the "11" code, through several
power cycles, and then suddenly it did, the obvious conclusion
is that something in the RAM unexpectedly changed.

This could be a bad RAM, but I really doubt it.

It could be a bad/intermittent connection to the RAM, which is
quite likely. I have seen some customer replaced NVRAM modules
(later scopes), where the customer cut through traces while doing
the desoldering operation... (eg. got too rough).

It could be a flaw in the cutover between battery and mains power.

It is important that the RAM not get written to while the data
lines are in an indeterminate state while 5V is coming on, and cutting
off.

So, I would look carefully at the circuitry comprised of Q2070, Q2170,
Q2270, Q2370, and Q2470. They are there to make sure that the chip
select pin on the RAM is safely parked away in the unselected condition
while power is unstable.

And, I would look at the traces on the bottom of the board about a
desoldering tip diameter around each of the pins on the RAM chip.
An ohmmeter can help.

-Chuck Harris

Craig Cramb wrote:
This is a pretty long feed that tarted back in January. Lots of good info thur-out this.
I finally got back started again with all the sit at home time. The 2465B s/n B010817 I got a correct replacement for the U2460 and BT2570 and installed the a couple of months ago. Waited until this last week to continue. Monitored the Battery and U2460 input voltage over the last 2 months to verify that the chip wasn't draining the battery as before in this feed. All was ok so this past went thru a complete calibration and all seemed to go well. Put scope aside for a week and then restarted it today. Now I get the Test04 fail 11. Does this seem to be that there is another chip failure or is this just a point in the calibration that wasn't correct?






Re: 2400 series Test 4 Fail 3,13, 2

Craig Cramb
 

Thank you Chuck for your input.
I have gone thru the U2460 ram trace test and the checkout of the associated transistors. All seem ok. I did find something strange is circuit of the - of the battery the R2770 10K, is reading open in circuit I remove it and reading is 10K . I replaced it and same as with old resistor. Again no continuity and there is a voltage drop across it of 2.6vdc. These readings are no power applied to the scope.
I review this same circuit on another A5 card of same part number. Reading in circuit is 9.98 ohm with no voltage drop across R2770. This is definitely got me baffled.

Craig

On Mar 31, 2020, at 8:51 AM, Chuck Harris <cfharris@...> wrote:

Hi Craig,

If the scope was not showing the "11" code, through several
power cycles, and then suddenly it did, the obvious conclusion
is that something in the RAM unexpectedly changed.

This could be a bad RAM, but I really doubt it.

It could be a bad/intermittent connection to the RAM, which is
quite likely. I have seen some customer replaced NVRAM modules
(later scopes), where the customer cut through traces while doing
the desoldering operation... (eg. got too rough).

It could be a flaw in the cutover between battery and mains power.

It is important that the RAM not get written to while the data
lines are in an indeterminate state while 5V is coming on, and cutting
off.

So, I would look carefully at the circuitry comprised of Q2070, Q2170,
Q2270, Q2370, and Q2470. They are there to make sure that the chip
select pin on the RAM is safely parked away in the unselected condition
while power is unstable.

And, I would look at the traces on the bottom of the board about a
desoldering tip diameter around each of the pins on the RAM chip.
An ohmmeter can help.

-Chuck Harris

Craig Cramb wrote:
This is a pretty long feed that tarted back in January. Lots of good info thur-out this.
I finally got back started again with all the sit at home time. The 2465B s/n B010817 I got a correct replacement for the U2460 and BT2570 and installed the a couple of months ago. Waited until this last week to continue. Monitored the Battery and U2460 input voltage over the last 2 months to verify that the chip wasn't draining the battery as before in this feed. All was ok so this past went thru a complete calibration and all seemed to go well. Put scope aside for a week and then restarted it today. Now I get the Test04 fail 11. Does this seem to be that there is another chip failure or is this just a point in the calibration that wasn't correct?




Re: 2430A Fails Repet

Siggi
 

On Tue, Mar 31, 2020 at 12:06 PM Rich Frahm <criageek@...> wrote:


https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing
When I connect a probe to channel 1 and connect it to the calibrator
terminal on the front panel it makes no difference.
As in you see a square wave, but chopped up, or you still see a flat line
chopped up? If nothing changes, maybe the scope isn't capturing, or isn't
triggered.
My apologies if this is no news to you, but you need to press the "ACQUIRE"
button on the "STORAGE" panel for the scope to start acquiring. Best thing
is then to put the trigger in "AUTO" or "AUTO LVL" mode, set for A trigger
and then press the INIT@50% button.

So, hook up a probe to the calibrator, and do all of that above. What do
you see?

I remember seeing this kind of square wave-like artifact on my scope on
startup, so this could be WAI, but this could also be coming out of a bad
acquisition system.
You have the service manual where there's a description of the acquisition
system. As I recall the acquisition system runs in two different major
modes. For fast signals the full capacity of the CCD FIFOs is filled up
rapidly, then on trigger read out slowly. For slow signals only a short
section of the CCDs is used, and is digitized in realtime.
It'd be useful to know whether there's a difference in your display
depending on which mode is in effect, but I forget the cut-over horizontal
timing...

Re: 2430A Fails Repet

Rich Frahm
 

I'm not familiar enough with this scope to know for sure I'm setting it properly, but you can see in this photo that channel 1 is set to gnd and I still have the chopped trace: https://drive.google.com/file/d/12VhAL5xLh_o_wLFQbxhwxAq2-Bh4qS_m/view?usp=sharing The intensity is turned down in order to get a decent photo. When turned up you can see the other artifacts like in the previous photo I posted. I've fiddled with all of the controls in the trigger section of the front panel and none make a difference. https://drive.google.com/file/d/1DnL8WGdCWLjQ1aA9dq9oKvmY-p2O8ZOe/view?usp=sharing When I connect a probe to channel 1 and connect it to the calibrator terminal on the front panel it makes no difference.

Thanks for your interest and help!

Rich

Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

Michael A. Terrell
 

Can you print a single transformer to a new PDF, or is that still disabled?
I would like to do that for the used Tektronix transformers that I have.

On Tue, Nov 12, 2019 at 12:41 PM Dave Brown <davebr@...>
wrote:

Both files have been updated with 25 new scans. I received some of the
missing scans from another individual with microfiche and incorporated them
into the files. The links are the same. - Dave