Date   

Re: 454A fan question

John
 

I would recommend either lubricating or changing the bearings. The motor is a split-phase capacitor-run induction motor: Tek used several suppliers. Nominal voltage 115v but not too critical. A previous post on here gave the bearing details which I've reproduced below (valid for 453/454/454A)
John
*******************************************
R3ZZ is the NSK number for the bearing under discussion.

Cross references are:

Single shielded
NSK = R3ZZ
NTN = RA3ZZ
Fafnir = 33KDD5
SKF = WY3/16ZZ
KOYO = EE1SZZX
MRC = R3FFM
Dayton = 1ZGC1

Double shielded
NTN = RA3LL/1E
Dayton = 1ZDG1

Dimensions:
Bore = 0.1875"
O. D. = 0.500"
Depth = 0.1960"


Re: germanium diodes in Tek 132 plug-in power supply

Tim Phillips
 

Got it, Kurt; many thanks. I have some OA91 'cat's whisker' diodes which
should do the job.
I don't know whether matching the Forward Voltage drop is necessary but I
will anyway.
Tim

On Thu, 15 Nov 2018 at 17:48, Kurt Rosenfeld <kurt.harlem@gmail.com> wrote:

See page 160 of this document:
http://w140.com/tek_common_design_parts_catalog_transistors_diodes_and_misc_may_1988.pdf




Re: 7834 reduced scan

Roger Evans
 

I haven't checked but I am assuming the 7834 reduced scan is the same as the 7934. It works by doubling the cathode voltage on the CRT so that the deflection sensitivity in X and Y are each reduced by a factor of two. In normal scan you would have had a substantial overscan that you can confirm with the horizontal position control on the timebase. I don't suppose your timebase is in X10 expansion is it?

Roger


Re: 2465 Ch 1 probe not switching to 10x

Roger Evans
 

Each of the four probe rings is connected to -1.25V by a 10k resistor so with the scope powered off you should be able to measure the resistance between each pair of probe rings at not more than 20k. If the pairs involving Ch1 give different results to the other pairs (ie Ch1-Ch2 is different from Ch2-Ch3 etc) then there is probably a break in the wiring of the Ch1 probe ring. There is a three way ribbon cable emerging from the Ch1 attenuator, if you unplug this you should get zero ohms from the probe ring to pin 3, the orange wire.

The next check is resistance from the Ch1 probe ring to pin 1 of the analogue multiplexer chip U2601. This should read 10k, if not measure from pin 1 to either side of R2704. If all the resistance checks prove OK then as a last resort measure the voltage on pin1 of U2601 and see if it changes when you plug the 10X probe to channel 1. To compare with a working channel measure pin 5 of U2601 while plugging the probe into Ch2. If you don't find anything wrong by now you probably have a dead U2601 since everything after this is common to all four probe channels.

Roger


Re: 2465 Ch 1 probe not switching to 10x

Jack
 

Good point.

-----Original Message-----
From: Harvey White
Sent: Friday, November 16, 2018 12:34 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 2465 Ch 1 probe not switching to 10x

On Thu, 15 Nov 2018 14:32:56 -0800, you wrote:

Can anyone point me in the right direction to fix this? The scope recognizes the 10x probe when connected to the other three channels.
Look at the ring on the probe. It's likely connected to some
circuitry that forms part of a voltage divider. The other part of the
divider is the resistor in the probe itself.

Try taking a number of resistors and run them from the ring to ground.
If you get no readout change then the mesure/compare circuit isn't
working, or the feedback from the circuit to the readout circuitry
isn't happy.

Harvey



Thanks!







--
Jack


Re: 2465 Ch 1 probe not switching to 10x

Harvey White
 

On Thu, 15 Nov 2018 14:32:56 -0800, you wrote:

Can anyone point me in the right direction to fix this? The scope recognizes the 10x probe when connected to the other three channels.
Look at the ring on the probe. It's likely connected to some
circuitry that forms part of a voltage divider. The other part of the
divider is the resistor in the probe itself.

Try taking a number of resistors and run them from the ring to ground.
If you get no readout change then the mesure/compare circuit isn't
working, or the feedback from the circuit to the readout circuitry
isn't happy.

Harvey



Thanks!



Re: 464 for parts?

 

Sorry, distractions. (phone, gonna shoot that thing one day)

Now, does he consider Ohio local then, or is it that he doesn't want to ship like to Russia or something ? And I wonder if my offer is any good. If his 464 runs other than delayed sweep I'll probably have to throw in a few bucks.

Think a non low end beater scope worth a defective Tek ? (w/storage)

I don't really know what these things are worth. The only thing I can go by is eBay on "sold listings" and I am sure you can't really trust that. I don't want to waste my money and stuff but I also don't want to insult anyone with ridiculous lowball offers.


Re: 464 for parts?

 

Jeff,
He signed his name at the end as follows:
Vaclav in Houston

So Vaclav would be in Houston Texas, USA.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jeff
Urban
Sent: Thursday, November 15, 2018 4:14 PM
Subject: Re: [TekScopes] 464 for parts?

Where is local ? I got a Telequipment D54, I am in Cleveland. Also have
a B&K. Low MHz on both but they work.

The D54 focus doesn't work, other than that it's fine, the control is on
the inside. The B&K is fine but suffers cosmetically.

Depending on the condition of you 464 I might have to throw in a few
bucks.

But first, where is locally ?



--
Dennis Tillman W7PF
TekScopes Moderator


2465 Ch 1 probe not switching to 10x

Greg
 

Can anyone point me in the right direction to fix this? The scope recognizes the 10x probe when connected to the other three channels.

Thanks!


7834 reduced scan

Fred S.
 

Hi,
I bought a 7834 which in general is working fine. One strange thing is, when the reduced scan button is activated, vertical works as expected, waveform and readout scale down. On the horizontal axis, the scaling of the waveform changed as expected, but the trace is still full length. Horizontal readout is functioning is re-positioned correctly. My question is, where in the schematics is the shortening of the traces supposed to happen?
--
Best regards,

Fred S.


Re: 464 for parts?

 

Where is local ? I got a Telequipment D54, I am in Cleveland. Also have a B&K. Low MHz on both but they work.

The D54 focus doesn't work, other than that it's fine, the control is on the inside. The B&K is fine but suffers cosmetically.

Depending on the condition of you 464 I might have to throw in a few bucks.

But first, where is locally ?


Re: Type 502 scope : missing air filter, what gives ?!

Jack
 

Hi One chap replied as proposing regulating line voltage to a computer fan. I'm all against that degree of pd....perhaps biased by owning a couple of Drake R-4C's
where (no offence intended) I regard resistor-dropping 150v to say 12v as engineering laziness if not insanity. Use a small transformer and dc filter it. Too expensive?
...well...how many hundreds of thousands have been spent fixing the overheated supply? Oh...well that's after market...ok but spending $2000 or a little more on
'full house' revamping and subsequent alignment of a commercial receiver ..is not a concern to a manufacturer? Obviously not....but the difficulties users find should be
advised over and over to the manufacturers and improvement demanded. That's harder with companies dominantly supplying publicly funded organisations as we are of
little commercial impact...so i'd sign 'taxpayer' and c/c to appropriate spending department.

On Vincent's point 'yeah why not' etc....good comment. Would it not be forever more sensible? for Tektronix to use one or just two fan models being different
apertures, speed controlled to suit the required temperature restrictions. A series or compound wound motor would oblige with restriction(as series wound
motors can increase speed to deI know that splitting design struction) or of course dc. If not enough use two....cases can accommodate them. That's then
an issue over and done for designers, manufacturers and users. "

You just don't get it' Jack ok...ok....ok....I'm fleeing like a startled Meerkat....but (over my shoulder) "that kind of rationalising makes sense to me".

Having been a design draftsman in my earlier Century I'm aware that problems arise when design is splintered to various 'specialists'....so one is given specs
for cooling and filtering and either chooses some catelogue model or designs one to suit, rather than have one or two models to be applied.A great example of
the worst such outcome was the airbus...in which no agreement was made before design and production ..between France and Germany...plugs and sockets
so none of the cables made in Germany fitted the French receptacles.

The bright ones here should (I think) be able to come up with suggested replacement motor-filter packages of an ideal and 'universal type' for all Tektronix 'antiquities'
perhaps even using computer fans...though I don't regard them as particularly reliable and certainly, more as cheap junk...Computer fans are, that notwithstanding
also cheap to replace. To just bang one in, however, 'well it is a fan isn't it?' ... to replace an engineered system, I can't recommend. Can anyone?

My regards

-----Original Message-----
From: Vincent Trouilliez
Sent: Thursday, November 15, 2018 11:39 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type 502 scope : missing air filter, what gives ?!

Harvey White wrote:
Perhaps putting it in a timeline may make sense.
Was the 502 the first 5 series scope?
Hardly. since it was introduced in 1958, so plenty of 500 models were already on sale before tje 502 hit the market, and plenty more followed. All had that mesh filter.. except the 502...

Could have been learning process or an engineering trial.
Yeah why not, though you would think tat they would modify all their current line up rather than jut one model ?
Also, one owuld thing that such a changed could be assessed in their R&D lab efficiently, rather than just market it and then cross fingers that it actually works...

Not all scopes have the same ventilation needs (see 7904 vs 7904A).
I know nothing about the 7000 scopes so I believe you ! ^^
Of course all scopes have different air flow requirements, and aperture size, dictated by internal mechanical construction of a particular scope.. but changing the type of material used for the filter ??


Jack wrote:
Some one must know the story....one person who wrote in recently worked for Tektronix...I wonder if they know
or know someone who'll know?....Tektronix may have an archivist who can look at the design notes.

The grey bears at VintageTekMuseum might know ! OR know who to ask... and they are in contact with Tektronix, can't hurt...
At least one person on this TekScope forum, happens to be an active member of the VintageTekMuseum, I remember.. maybe he can submit our question to the other members of the museum..



Vincent Trouilliez





--
Jack


Re: Type 502 scope : missing air filter, what gives ?!

Chuck Harris
 

As far as we are concerned, filters have to be very
free flowing, but not necessarily all that effective
at filtering dust..

An unfiltered automotive engine will seize up in a
sand storm, but if our scopes ever see such an
environmental attack we probably have far bigger
problems.

For us, a little dust, though annoying, really isn't all
that harmful. A little blow down with compressed air,
and it will look like new. The bigger dust, hairballs,
mice and insects are what we have to be careful to filter.

HP for years used pleated aluminum window screen filters with
a little added sticky stuff to enhance their effectiveness.

I think we should aim for that level of performance.

The old style coated aluminum mesh filters were slightly better
than that, and were very free flowing.

There are furnace filters available that are like a coated
horse hair mat. I have used them to good affect to replace
the foam filters on 545B's and 547's... though I still tend
to look for the aluminum mesh variety.

If you choose to use one of the furnace filters, be warned
that not all 500 series scopes have a piece of diamond screen
to protect the fan. Early scopes (585A) with the aluminum mesh
filter may not have that feature. You must be sure it is
there if you are going to use a furnace filter, or your fan
will get stopped.

-Chuck Harris

Jack wrote:

Chuck when 'foam' and 'good filter material though esta-foam' arrived herein the 1960's it was set upon by manufacturers of all types..my father's business was the first on the nth shore to keep it. I had to cut the wretched stuff, up to 6 inches thick . Used widely in multi-carb engine conversions, of which I did quite a few including Buick straight 8's I have never liked it for that purpose. It's still common in lawn mowers but they have a high differential pressure, CRO's don't . So I am biased against it without any CRO experience with it.......I wonder nevertheless ....have you found it to be 'good stuff' or do you prefer
other types and do you see as 'of the essence' meeting rate and volume requirements...and are such requirements stipulated for Tektronix?...or is it 'finger in the air' or temperature rise recording ..or is it regarded as insignificant..if considered at all..? Irrespective of the antiquity of the CRO what filter material would you recommend as 'best choice'..?
My regards
Jack


Re: Type 502 scope : missing air filter, what gives ?!

Richard Knoppow
 

Late in this thread and maybe of no interest. When I worked for Hewlett-Packard a very long time ago many instruments had blowers. The usual filter was the aluminum mesh kind coated with an oily material made for that purpose. I don't remember its name but it came in about pint cans with a push pump sprayer on it. The stuff washed off with hot water. From the crap on the filters it must have been fairly effective.
Foam has to be porous something like acoustical foam. Special foam is made for air filters. Many kinds of plastics disintegrate with time, some turn into nasty mush.
As has been stated by others a filter must allow air to flow. Its always an obstruction but should be a minimum obstruction. There are well established methods for measuring the flow rate but I am unaware of any that are simple other than just feeling the air stream.

On 11/15/2018 2:27 PM, Vincent Trouilliez wrote:
Chuck thans for your input... looks like th sis it then... Tek used both the charcoal foam filter, and the mesh filter, on a given scope.. so it's nothing special to the 502 unlike what I thought ! .. and just "bad" luck that every 502 I saw had a missing filter and every non-502 had a metal mesh filter.
But your memories are vivid, and looking at pictures of the 545/A on Tekwiki, confirms what you say !
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL


Re: Type 502 scope : missing air filter, what gives ?!

Jack
 

Chuck when 'foam' and 'good filter material though esta-foam' arrived herein the 1960's it was set upon by manufacturers of all types..my father's business was the first on the nth shore to keep it. I had to cut the wretched stuff, up to 6 inches thick . Used widely in multi-carb engine conversions, of which I did quite a few including Buick straight 8's I have never liked it for that purpose. It's still common in lawn mowers but they have a high differential pressure, CRO's don't . So I am biased against it without any CRO experience with it.......I wonder nevertheless ....have you found it to be 'good stuff' or do you prefer
other types and do you see as 'of the essence' meeting rate and volume requirements...and are such requirements stipulated for Tektronix?...or is it 'finger in the air' or temperature rise recording ..or is it regarded as insignificant..if considered at all..? Irrespective of the antiquity of the CRO what filter material would you recommend as 'best choice'..?
My regards
Jack


Re: Type 502 scope : missing air filter, what gives ?!

Vincent Trouilliez
 

Chuck thans for your input... looks like th sis it then... Tek used both the charcoal foam filter, and the mesh filter, on a given scope.. so it's nothing special to the 502 unlike what I thought ! .. and just "bad" luck that every 502 I saw had a missing filter and every non-502 had a metal mesh filter.

But your memories are vivid, and looking at pictures of the 545/A on Tekwiki, confirms what you say !

- vanilla 545 clearly has a charcoal filter, and was sold until 195P8... which is when the 502 got introdcuced, so that's consistent.
- the revised 545A appeared in 1959 then, and the pictures clearly show it with mesh filter..

So I guess I probably got mislead by the fact that most 500 scopes still "alive"/on the market, are, understandably, the most recent ones, 545 A or B rather than vanilla 545, etc etc...

So clearly now, the 502 being fitted with a foam filter had nothing to do with its specs. Had it been introduced a different year, it might just as well been fitted with the mesh filter...

At last I have my final answer, thank you to all who participated ! ^^


Vincent Trouilliez


464 for parts?

vaclav_sal
 

I am looking for areplacement for my broken 464 scope.

I am open to trade it in forparts for working scope of same or lesser value. 

The only thing wrongwith it - it has mechanical problem with "delayed sweep" and it is currently partially dissembled - the sweep board is out.


I did try to fix the delayed sweep friction switch issue but not sure if it is going to work.

Before that happen it was normally working older 464.

I am NOT interested in buyinganything for more than $100, or non working Hitachi (e-bay) ect. Ilike to trade locally if possible.


Vaclav in Houston


Re: 454A fan question

Jack Rubin <j@...>
 

Nicely done - it does bring new meaning to "surface mount technology"!


Re: 2445/2465 Power Supply Smoking

Chuck Harris
 

The engineers certainly could have designed the 2465's
supply to work without load, but you have to ask yourself
several design manager questions:

1) Is there an OEM market for bare 2465 supplies that we want
to enter?
2) Will the majority of 2465 users, or for that matter, any
2465 users, be impacted by having a supply that burns up
a cheap part if you run it without a load?
3) Will the majority of customers want to pay an extra price
for protecting a supply from conditions it will never see
in actual use?
4) Would it be enough to put a verbal warning in the service
manual to prevent some repair technician from unintentionally
burning up a part?

Back then, protecting the supply from every combination of loaded
and unloaded operation would have cost more parts, and more space.

We are so far down the food chain that we were never considered
in their design decisions.

A 2465 that is still on the bench 35 years later was never considered
in their design decisions.

-Chuck Harris

BryanByTheSea wrote:

R1071 smoking is normal behaviour if you don't load the scope with the required resistances spec'd in the service manual. I learned that the hard way and assume there was issues with the power supply. In hindsight the engineers probably should have designed it different. I believe there is also another component near R1071 that will get hot as well, but I can't remember.




Re: 2445/2465 Power Supply Smoking

BryanByTheSea
 

R1071 smoking is normal behaviour if you don't load the scope with the required resistances spec'd in the service manual. I learned that the hard way and assume there was issues with the power supply. In hindsight the engineers probably should have designed it different. I believe there is also another component near R1071 that will get hot as well, but I can't remember.

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