Date   

Re: 7603 Readout Diagnosing Help Please

Fabio Trevisan
 

Hello DC902,
I don't know if the horizontal compression is still happening or if it comes and goes, if it is, try to set a slower sweep speed and find out if the sweep is running backwards,
If it's running backwards, then you're probably looking at the exact same problem as I just had with my 7623A.
See the threads:
Tek 7623A - Inverted and compressed Horizontal only from TB (was 7623A + 7A26 + 7B53)
https://groups.io/g/TekScopes/message/145359

Tek 7623A - Inverted and compressed Horizontal only from TB (SOLVED)
https://groups.io/g/TekScopes/message/145419

While it may sound good for you that someone else (me) would have had the same problem and possibly the solution, as you will see looking at the first message of thread #145359 above, the problem disappeared while I was troubleshooting, checking and re-seating the Hor. Signal cable, between the Interface board and the Hor. Amp. board.
Most likely explanation was that one of the sides had a false contact (maybe caused by thickened contact lubricant).

I don't have a problem with my readout, but I would like to rephrase / resubmit the question of Roger... When you press Identify... Are you getting 8 small vertical lines (one for each character) in place where the readout should be displaying the word? or are you getting one vertical line for each the whole word identify?


Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Ok, that is good to know. We were talking about the 2465, not the A or B versions.


Regards

-----Original Message-----
From: machineguy59 via Groups.Io <machineguy59=yahoo.com@groups.io>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:38 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Not on my schematic.
I checked three schematics, a 2465, a 2465A and a 2465B. Only the 2465A had the capacitor incorrectly inverted, with the negative pole connected to the junction of CR1131 and CR1132. The 2465 and 2465B schematics had it correct, with the POSITIVE pole of C1130 connected to the junction of cR1131 and cR1132. I am guessing the PCB layout has it correct since we haven't had a rash of failing C1030s.

But the schematic has C1130 drawn inverted.
Not sure what you mean here.


It was just a comment copied from the original message.


Re: Tek 7623A - Inverted and compressed Horizontal only from TB (SOLVED)

Fabio Trevisan
 

Thanks Jeff,
thanks for the heads up...
Well. I concur with you in that a problem which got solved by itself is a
problem ready to happen again and, moreover, while I exhausted all possible
explanations and having find none, I`m forced to let it be and, if the
problem ever recurs, I`ll have a chance to investigate more carefully (not
touching anything and just probing around) and eventually find the real
culprit.
I have been working on other details of the scope the whole weekend, and
not a single time this problem happened again, between many, many power
cycles and removal and insertion of plug-ins...
It remains a mystery.
Good look with the 561... Tube stuff is completely out of my comfort zone.
rgrds,
Fabio


2018-03-09 13:58 GMT-03:00 Jeff Urban <@JURB>:

Actually I don't like it when it happens. It could recur at any time.

if it does I would look to the mode selection, which is what switches the
IC's gain and who knows what else for the on screen display. While it
doesn't seem logical the sweep would be compressed if it was stuck in that
mode, the input could have been out of range.

I could be off base here, this is my first post and I have to admit to not
reading the whole thread.

But I got my feet wet. Soon I will be ready to start a thread maybe the
old timers might like - a 561. Has troubles in the vertical section after
an arcing transformer threw the DC from the negative bias into the
vertical. I have much information to put together so it probably won't be
today. Honestly, some of it will come from my posts on Usenet.

Be well all. See ya.




Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Nevermind. Can't post pictures.

-----Original Message-----
From: tmillermdems <tmiller11147@...>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 2:11 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!


Here is what my schematic shows.






-----Original Message-----
From: tmillermdems <tmiller11147@...>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:10 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Not on my schematic. It is shown correctly with the positive pole connected to the junction of CR1131 and CR1132. It will have about 40 volts across it and of the correct polarity. Pay attention to the diodes and re-analyze the circuit.














But the schematic has C1130 drawn inverted.







-----Original Message-----
From: machineguy59 via Groups.Io <machineguy59=yahoo.com@groups.io>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:00 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Ed,

You are correct!! C1130 never sees a negative charge so a polarized capacitor capable of high ripple currents (low ESR) will work best. Non-polarized electrolytics have double the ESR of their polarized brethren. So a Voltage double should always use polarized capacitors. But the schematic has C1130 drawn inverted. I plan to refurb a 2465 series PSU in the next week or so and I will check the PCB markings to see if they have the same mistake. The wrong polarity on the schematic for C1130 is not the only error in the Tek documentation for the PSU. The PCB layout has C1115 and C1132 interchanged so many technicians following the PCB layout put a 25 Volt rated capacitor (C1115) in a 90 volt position (C1132).

I personally, would never use a 450 rated capacitor in a 100 volt circuit. My rule of thumb is nothing more than double the rated voltage. But I often violate that rule when working with low voltage circuits (say 15 Volts or less). The reason is low ESR over the lifetime of the capacitor. A high voltage electrolytic starts out with a higher ESR (because the plates are further apart and I believe the electrolyte is less conductive). Worse, a high voltage electrolytic capacitors ESR will rise and its capacitance fall if it is not properly energized. But, realistically, most of these scopes are not likely to be used more than another ten years before being refurbed for other reasons.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Here is what my schematic shows.

-----Original Message-----
From: tmillermdems <tmiller11147@...>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:10 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Not on my schematic. It is shown correctly with the positive pole connected to the junction of CR1131 and CR1132. It will have about 40 volts across it and of the correct polarity. Pay attention to the diodes and re-analyze the circuit.














But the schematic has C1130 drawn inverted.







-----Original Message-----
From: machineguy59 via Groups.Io <machineguy59=yahoo.com@groups.io>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:00 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Ed,

You are correct!! C1130 never sees a negative charge so a polarized capacitor capable of high ripple currents (low ESR) will work best. Non-polarized electrolytics have double the ESR of their polarized brethren. So a Voltage double should always use polarized capacitors. But the schematic has C1130 drawn inverted. I plan to refurb a 2465 series PSU in the next week or so and I will check the PCB markings to see if they have the same mistake. The wrong polarity on the schematic for C1130 is not the only error in the Tek documentation for the PSU. The PCB layout has C1115 and C1132 interchanged so many technicians following the PCB layout put a 25 Volt rated capacitor (C1115) in a 90 volt position (C1132).

I personally, would never use a 450 rated capacitor in a 100 volt circuit. My rule of thumb is nothing more than double the rated voltage. But I often violate that rule when working with low voltage circuits (say 15 Volts or less). The reason is low ESR over the lifetime of the capacitor. A high voltage electrolytic starts out with a higher ESR (because the plates are further apart and I believe the electrolyte is less conductive). Worse, a high voltage electrolytic capacitors ESR will rise and its capacitance fall if it is not properly energized. But, realistically, most of these scopes are not likely to be used more than another ten years before being refurbed for other reasons.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Not on my schematic.
I checked three schematics, a 2465, a 2465A and a 2465B. Only the 2465A had the capacitor incorrectly inverted, with the negative pole connected to the junction of CR1131 and CR1132. The 2465 and 2465B schematics had it correct, with the POSITIVE pole of C1130 connected to the junction of cR1131 and cR1132. I am guessing the PCB layout has it correct since we haven't had a rash of failing C1030s.

But the schematic has C1130 drawn inverted.
Not sure what you mean here.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Not on my schematic. It is shown correctly with the positive pole connected to the junction of CR1131 and CR1132. It will have about 40 volts across it and of the correct polarity. Pay attention to the diodes and re-analyze the circuit.




But the schematic has C1130 drawn inverted.

-----Original Message-----
From: machineguy59 via Groups.Io <machineguy59=yahoo.com@groups.io>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Mar 12, 2018 1:00 pm
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

Ed,

You are correct!! C1130 never sees a negative charge so a polarized capacitor capable of high ripple currents (low ESR) will work best. Non-polarized electrolytics have double the ESR of their polarized brethren. So a Voltage double should always use polarized capacitors. But the schematic has C1130 drawn inverted. I plan to refurb a 2465 series PSU in the next week or so and I will check the PCB markings to see if they have the same mistake. The wrong polarity on the schematic for C1130 is not the only error in the Tek documentation for the PSU. The PCB layout has C1115 and C1132 interchanged so many technicians following the PCB layout put a 25 Volt rated capacitor (C1115) in a 90 volt position (C1132).

I personally, would never use a 450 rated capacitor in a 100 volt circuit. My rule of thumb is nothing more than double the rated voltage. But I often violate that rule when working with low voltage circuits (say 15 Volts or less). The reason is low ESR over the lifetime of the capacitor. A high voltage electrolytic starts out with a higher ESR (because the plates are further apart and I believe the electrolyte is less conductive). Worse, a high voltage electrolytic capacitors ESR will rise and its capacitance fall if it is not properly energized. But, realistically, most of these scopes are not likely to be used more than another ten years before being refurbed for other reasons.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 

Ed,

You are correct!! C1130 never sees a negative charge so a polarized capacitor capable of high ripple currents (low ESR) will work best. Non-polarized electrolytics have double the ESR of their polarized brethren. So a Voltage double should always use polarized capacitors. But the schematic has C1130 drawn inverted. I plan to refurb a 2465 series PSU in the next week or so and I will check the PCB markings to see if they have the same mistake. The wrong polarity on the schematic for C1130 is not the only error in the Tek documentation for the PSU. The PCB layout has C1115 and C1132 interchanged so many technicians following the PCB layout put a 25 Volt rated capacitor (C1115) in a 90 volt position (C1132).

I personally, would never use a 450 rated capacitor in a 100 volt circuit. My rule of thumb is nothing more than double the rated voltage. But I often violate that rule when working with low voltage circuits (say 15 Volts or less). The reason is low ESR over the lifetime of the capacitor. A high voltage electrolytic starts out with a higher ESR (because the plates are further apart and I believe the electrolyte is less conductive). Worse, a high voltage electrolytic capacitors ESR will rise and its capacitance fall if it is not properly energized. But, realistically, most of these scopes are not likely to be used more than another ten years before being refurbed for other reasons.


Re: Tektronix 2465 capacitors etc. - Going deeper!

k1ggi
 

Oh dear,
The voltage across C1130 does NOT alternate (does not change polarity).
Ed

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of k1ggi
Sent: Monday, March 12, 2018 11:11 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

I'm surprised that some of the regulars haven't weighed in on this.

Much of this discussion seems to have started based on a false premise.

The voltage across C1130 does alternate (does not change polarity).

C1130 is in a half-wave voltage doubler and runs with somewhere between 40
to 50Vdc across it, unipolar.

The curved plate is always positive with respect to the flat plate. It would
have been better if the draftsman had flipped the symbol the other way.

On the half-cycle when T0160 pin 2 is positive with respect to pin 1, the
curved plate of C1130 gets positive charge from the transformer through
CR1123 and CR1131.

On the half-cycle when T0160 pin 1 is positive with respect pin 2, the flat
plate of C1130 gets elevated by the positive transformer voltage appearing
on pin 1, with pin 2 at near ground through CR1121. Thus the voltage at the
curved plate becomes nearly twice the transformer peak voltage above ground.
At this point, in series with the transformer, C1130 delivers some of its
charge to C1132 via current through CR1132 and CR1121. This replenishes the
charge drawn from C1132 by the load current during the cycle. As the charge
transfers, the voltage has to drop somewhat, because C*deltaV=I*deltaT,
where T is the period. As the dropping voltage at the curved plate equalizes
with the rising voltage on C1132, the drain on C1130 thru CR1132 stops.
Nothing drains C1130 completely or reverses its charge. So C1130 has some
ripple on top of dc, as is expected of all reservoir caps in a power supply.


The ~50V across C1130, in series with the ~50V out of the transformer, adds
up to make the doubled voltage, cycle after cycle.

From the parts list, C1130 and C1120 are 10uF/100V electrolytics run at
about 50V. C1132 is 10uF/160V run at about 100V. Good engineering.

C1130 should have been drawn with the flat plate to the right, and with a +
sign. I would hope the silkscreen on the board is marked appropriately, but
I don't have a 2465 to check.

Ed, k1ggi

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of woody
wilson
Sent: Monday, March 12, 2018 4:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

There is an alternating voltage across the capacitor and a corresponding
alternating current that is passing through the capacitor. You may find that
some high voltage capacitors actually have a lower esr than low voltage
capacitors, the electrolyte has a direct correlation in regards to the
dissipation factor of the capacitor. I will explain, the higher the voltage
the capacitor, the greater the electrode spacing and depending on the type
of electrolyte the high voltage capacitor needs a greater electrode area for
the same capacitance as lower voltage capacitor, thus high voltage
capacitors do have lower esr.
At the end of the day, a capacitor was open circuit more or less, 1.8nf
measured on a 10uf device pretty well tells me it is dead. I will recap this
2465 with a variety of 450wv and 100wv caps and C1130 will get two 25uf
capacitors connected in series with their positives connected together to
make a long lasting non polarised capacitor.


Re: Tektronix 2465 capacitors etc. - Going deeper!

k1ggi
 

I'm surprised that some of the regulars haven't weighed in on this.

Much of this discussion seems to have started based on a false premise.

The voltage across C1130 does alternate (does not change polarity).

C1130 is in a half-wave voltage doubler and runs with somewhere between 40
to 50Vdc across it, unipolar.

The curved plate is always positive with respect to the flat plate. It would
have been better if the draftsman had flipped the symbol the other way.

On the half-cycle when T0160 pin 2 is positive with respect to pin 1, the
curved plate of C1130 gets positive charge from the transformer through
CR1123 and CR1131.

On the half-cycle when T0160 pin 1 is positive with respect pin 2, the flat
plate of C1130 gets elevated by the positive transformer voltage appearing
on pin 1, with pin 2 at near ground through CR1121. Thus the voltage at the
curved plate becomes nearly twice the transformer peak voltage above ground.
At this point, in series with the transformer, C1130 delivers some of its
charge to C1132 via current through CR1132 and CR1121. This replenishes the
charge drawn from C1132 by the load current during the cycle. As the charge
transfers, the voltage has to drop somewhat, because C*deltaV=I*deltaT,
where T is the period. As the dropping voltage at the curved plate equalizes
with the rising voltage on C1132, the drain on C1130 thru CR1132 stops.
Nothing drains C1130 completely or reverses its charge. So C1130 has some
ripple on top of dc, as is expected of all reservoir caps in a power supply.


The ~50V across C1130, in series with the ~50V out of the transformer, adds
up to make the doubled voltage, cycle after cycle.

From the parts list, C1130 and C1120 are 10uF/100V electrolytics run at
about 50V. C1132 is 10uF/160V run at about 100V. Good engineering.

C1130 should have been drawn with the flat plate to the right, and with a +
sign. I would hope the silkscreen on the board is marked appropriately, but
I don't have a 2465 to check.

Ed, k1ggi

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of woody
wilson
Sent: Monday, March 12, 2018 4:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix 2465 capacitors etc. - Going deeper!

There is an alternating voltage across the capacitor and a corresponding
alternating current that is passing through the capacitor. You may find that
some high voltage capacitors actually have a lower esr than low voltage
capacitors, the electrolyte has a direct correlation in regards to the
dissipation factor of the capacitor. I will explain, the higher the voltage
the capacitor, the greater the electrode spacing and depending on the type
of electrolyte the high voltage capacitor needs a greater electrode area for
the same capacitance as lower voltage capacitor, thus high voltage
capacitors do have lower esr.
At the end of the day, a capacitor was open circuit more or less, 1.8nf
measured on a 10uf device pretty well tells me it is dead. I will recap this
2465 with a variety of 450wv and 100wv caps and C1130 will get two 25uf
capacitors connected in series with their positives connected together to
make a long lasting non polarised capacitor.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 
Edited

1. Adrian

"as if you are saying that an electrolytic capacitor will not function correctly "

A capacitor will operate OPTIMALLY (you used the words 'not function correctly') when the voltage across the cap is close to the cap's rated voltage.
That does NOT mean or imply in any form, that the cap will "NOT function correctly", etc, etc, as you wrote.
Whether the cap will or will not function correctly, depends ENTIRELY on its function in the circuit and what it's being asked to do.

So the issue is -
Do you want a circuit to "work", OR
Do you want the circuit to work OPTIMALLY, with lowest possible stress, and longest user reliability?

That's the question I ask myself when I design or repair a given circuit.
Generally, the Chinese consumer products are designed according to only the first paradigm.

Many times in TV PSU's, I have seen failed Chinese caps with too-high voltage ratings with ridiculously high ESR, rendering them useless in the relevant PSU circuit.
I have asked myself - why would an engineer put a 50V cap in a position where only a 10V cap is required?

And after some investigation, I discovered that the cheapo "Ching-wing" cap has stupidly LOW ripple capability.
So, to meet the ripple requirements, a 50V cap was installed in production, instead of a 10V cap. The 50V cap was never energized properly, causing stress in the surrounding circuits, and subsequent cascade failure.

If a good quality cap had been used, such as Nichicon PW (which I use as a replacement), I can achieve the required ripple current capability with a 10V or 16V rated cap. And everything works MUCH better.

To me, just because a given component is factory-installed does NOT imply, by any stretch of the imagination, that I should use the same or a similar-rated component.

So yes, I absolutely stand by my position, that even if a given PCB had a 50V cap installed at the factory, I am 100% correct and professional to replace it with a higher-quality 10V or 16V lower-ESR cap (taking into account the ripple and other requirements), and so the machine functions far better, and longer!


2. Woody,
I must take issue with your statement.
You are presenting only a partial view, not the entire picture, "thus high voltage capacitors do have lower esr."
Not so!
You are using 100V and 450V caps, so I am going to be absolutely specific and relate to those.

For an example, please take the datasheet for the Panasonic FC and EE capacitors, which to me, provide an excellent combination for use from 6.3V all the way up to 450V.

Looking at these two types as a "family", when specifying ESR vs Voltage rating, we see an inverted bell curve.

A given FC cap, say 100uF, will have high ESR at a 6.3V rating (0.80 ohm), and that ESR will decrease with increased voltage, to 0.15 ohm at 100V rating.
So far, clear enough, and that's in line with your statement. But only so far.

But why are there no Panasonic FC caps rated for 200V, 450V, etc?
Simply because the FC Electrolytic is not stable at high voltages, THEREFORE another type of electrolytic is required.

Let's have a look at Panasonic EE, which has an electrolytic which is stable at High Voltages, and unuseable at Low Voltages.
100uF 160V = 0.15 ohm - good enough - we're at the bottom of the bell curve.
100uF 350V = 0.20 ohm - starting to rise.
100uF 400V = 0.24 ohm - rising - that's the upswing in the bell curve.

So, Woody, using too high a voltage rating is going to cost you a penalty in ESR and therefore circuit efficiency.

And if you're not using a high-quality cap (in my world, that's Panasonic, Nichicon, Vishay, UCC), but a generic Chinese unit, then the ESR numbers are FAR worse.
No matter your good intentions, your scope PSU is NOT going to go the distance.

It's your lab, your choice - I'm just pointing out that there are better choices and more informed choices, than the default easy-picks.


Re: Tektronix 2465 capacitors etc. - Going deeper!

woody wilson <optushome@...>
 

There is an alternating voltage across the capacitor and a corresponding alternating current that is passing through the capacitor. You may find that some high voltage capacitors actually have a lower esr than low voltage capacitors, the electrolyte has a direct correlation in regards to the dissipation factor of the capacitor. I will explain, the higher the voltage the capacitor, the greater the electrode spacing and depending on the type of electrolyte the high voltage capacitor needs a greater electrode area for the same capacitance as lower voltage capacitor, thus high voltage capacitors do have lower esr.
At the end of the day, a capacitor was open circuit more or less, 1.8nf measured on a 10uf device pretty well tells me it is dead. I will recap this 2465 with a variety of 450wv and 100wv caps and C1130 will get two 25uf capacitors connected in series with their positives connected together to make a long lasting non polarised capacitor.


Re: Tektronix 2465 capacitors etc. - Going deeper!

Adrian
 

Hi,

I'm puzzled by your comment re capacitor voltage. It reads as if you are saying that an electrolytic capacitor will not function correctly if it is run at less than it's maximum rated voltage? I presume you don't actually mean that.....do you?

On 3/11/2018 2:40 PM, M Yachad wrote:
2.
With only about 87V going through a 450V cap, you'll never have that cap correctly energized.
That's why the cap's original voltage spec is for 100V.

It is not professional to install caps rated for voltages, which are way above the actual voltage passing through the cap.


Re: 453 BUT maybe just Tek Paint related...

Richard Knoppow
 

I have had good luck with black wrinkle and crackle (old General Radio finish) with using boiled linseed oil after cleaning. Rub it into the finish and let it sit for a few minutes, then rub off the excess with cloth. Then let it sit for a couple of days. The finish will have the "wet" look of new paint and keep it. Some will say that the oil collects dust, it does not because it drys to a hard finish in a few hours.
Works best on black but does OK on gray also.

On 3/11/2018 9:04 PM, Daveolla wrote:
As Tek suggests in their document on cleaning (should be in the files section) clean and polish with WD-40
Ive used it on a number of Tek and non Tek cabinets and find it ok when paste furniture wax from hardware stores may not be the ideal choice (just used it on a Heath tube tester textured metal cabinet where paste wax in texture presents polishing difficulties).
Dave
At 03:09 PM 3/11/2018, you wrote:
Hi all,

I now have my recent find running pretty well and I spent the evening, last night, scrubbing (literally!) both top and bottom covers, which were FILTHY. This scope spent many of it's most recent years in a CB shop and from the looks of it, it was out in the diesel truck bay!

Anyway, I hand rubbed the bottom, before I gave up using a piece of bath towel and started using a Scotchbrite scrubbing sponge, which along with some "green" cleaner, was able to cut through the grease and grime.  Now, it looks pretty good, but the combination of wear and my scrubbing has taken away the nice shine that the original Tek paint had.

Is there anyone here who, like me, had to clean a REALLY filthy cover and ended up with dull paint and found a way to shine it up?  I wonder whether  leather wax, car wax, or something like that would work...

Any thoughts?  At this point, it looks pretty good and it sure wouldn't hurt for me to experiment, but thought I'd check the "Tek Brain Trust" first...

Thanks,
Phil

--
Richard Knoppow
dickburk@...
WB6KBL


Re: Tektronix 2465 capacitors etc. - Going deeper!

keantoken
 

A capacitor that is voltage polarized (every electrolytic power supply capacitor ever) should be a polar capacitor, not a bipolar capacitor. A bipolar electrolytic capacitor works in both polarities and is much more rare and expensive.
The 450V cap may have higher ESR than the original 100V specified cap. So it may heat up and/or fail to maintain low ripple.
Describing voltage as something that flows is a bad analogy. I know some people do this because they learned from people who do. Personally I say "the voltage across the cap". That way when I need to talk to an expert, they won't just find a way to end the conversation.
It would be nice if we could all get our engines rebuilt. Just imagine it. No one would ever sell their car. On Monday, March 12, 2018, 12:33:20 AM CDT, M Yachad <@yachadm> wrote:

C1130 - thank you for the explanation.
In that case, a non-polar film capacitor would be most ideal, rather than an electrolytic.

Regarding capacitor voltage - I disagree.
The voltage rating of a capacitor should be higher than, but close to the actual (or peak) voltage flowing inside the cap, subject to other requirements such as ripple capability, dissipation, temperature, and ESR.


Re: Tektronix 2465 capacitors etc. - Going deeper!

 
Edited

C1130 - thank you for the explanation.
In that case, a non-polar film capacitor would be most ideal, rather than an electrolytic.

Regarding capacitor voltage - I disagree.
The voltage rating of a capacitor should be higher than, but close to the actual (or peak) voltage across the cap, subject to other requirements such as ripple capability, dissipation, temperature, and ESR (which if too high - as the 450V cap certainly is, compared to the 100V cap - will cause the cap to heat up unnecessarily, and fail to maintain specified ripple capability).


Re: 453 BUT maybe just Tek Paint related...

Daveolla
 

As Tek suggests in their document on cleaning (should be in the files section) clean and polish with WD-40
Ive used it on a number of Tek and non Tek cabinets and find it ok when paste furniture wax from hardware stores may not be the ideal choice (just used it on a Heath tube tester textured metal cabinet where paste wax in texture presents polishing difficulties).
Dave

At 03:09 PM 3/11/2018, you wrote:
Hi all,

I now have my recent find running pretty well and I spent the evening, last night, scrubbing (literally!) both top and bottom covers, which were FILTHY. This scope spent many of it's most recent years in a CB shop and from the looks of it, it was out in the diesel truck bay!

Anyway, I hand rubbed the bottom, before I gave up using a piece of bath towel and started using a Scotchbrite scrubbing sponge, which along with some "green" cleaner, was able to cut through the grease and grime. Now, it looks pretty good, but the combination of wear and my scrubbing has taken away the nice shine that the original Tek paint had.

Is there anyone here who, like me, had to clean a REALLY filthy cover and ended up with dull paint and found a way to shine it up? I wonder whether leather wax, car wax, or something like that would work...

Any thoughts? At this point, it looks pretty good and it sure wouldn't hurt for me to experiment, but thought I'd check the "Tek Brain Trust" first...

Thanks,
Phil


Re: Tektronix 2465 capacitors etc. - Going deeper!

woody wilson <optushome@...>
 

C1130 has high frequency alternating voltage flowing through it, thus for long term reliability it should be a non polarised type. As per installing higher voltage rated capacitors, the higher the voltage rating the better. The only difference is size and cost.


Re: 453 BUT maybe just Tek Paint related...

Brendan
 

I'm going to try out that Bahama Sea Krylon spray paint.


Re: Tek 2210 Help needed

tom jobe <tomjobe@...>
 

Hi Walter,
I just got an email from Dave at Artekmanuals and they now have the 2210 service manual in stock!
Hopefully Dave contacted you about this too.
tom jobe...

On 3/11/2018 5:36 PM, tom jobe wrote:
Hi Walter,
I've had a very rough looking 2210 for years and have never found a service manual for it.
When you compare the 2211 service manual to the 2210 circuitry they appear to be close enough to give you some help.
Artek manuals sells the 2211 manual, which is where I got mine.
The internals are quite unlike the internals of the common 2215A, 2235, 2236 family when viewed with the outer cover off.
There is a vertical  aluminum bulkhead in the 2210 that goes side to side and top to bottom about 2/3 of the way back. Then there is an upper circuit board that goes from the front, back to the aluminum bulkhead. The power supply seems to be in the rear 1/3 of the case with a large coil bolted to the inside of the rear bulkhead. The lower circuit board fills up much of the bottom of the frame, but it does not come as close to the front panel as most 22xx's
I will send some photos of the 2210's interior directly to you so you can see what I am trying to describe.
If you look at the mechanical parts section of the 2211 manual you will see how similar the 2210 is to it. Maybe the 2210 is the base model in the series that includes the 2211?
tom jobe...

On 3/11/2018 3:04 PM, walter shawlee wrote:
Any kind of manual for this would be welcome, I can't find one.
It seems to be working well except for one odd thing, when I press Sore/Non-store,
the traces jump one division up.  in addition, inverting ch. 2 causes a half div shift.
is this a DC balance issue, or normal?  hard to know what to look at or adjust
with no manual.  nice lower end digital/analog scope, and the reference trace feature is
quite good..

all help welcome,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.



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