Tektronix 465 Scope

John Miles wrote in news: snipped-for-privacy@news-central.giganews.com:

I worked for TEK for 21.5 years as a service tech in 2 of their field offices;repaired and cal'd a lot of scopes and other TEK products.

Considering how longlasting and popular the 465 is,that's not a very smart sentence.The same HF and LF cam switches were also used in the high- performance 7000 series lab scopes.

Same here.

--
Jim Yanik
jyanik-at-kua.net

Tek won't fix the 2012 either :(

Yes, this unit could indeed have had some non-Tek semiconductors in it. I got the HF ocsillation to stop by putting a few gimmick capacitors, less that 1 pF, at the output of the Ch 1 vertical amp. Didn't affect the frequency response any, but the vertical output amp had a few extra time constants visible on a leading edge that none of the adjustments would control.

It was a real learning experience, but the patient died. One thing I DID learn was that gold-plated sockets don't mean a thing if they mate with tinned leads. When I first got that scope almost nothing worked, and major recovery was effected by removing and replacing all the socketed connectiions, which in that scope included virtually all of the semiconductors. I also suspected that that scope was not a "complete" instrument; seems to me that the versions and serial numbers didn't really agree, as if someone tried to make one good scope out of parts from other ones that were of varying vintages.

Anyway, I decided that I am out of the scope-fixing business. It's kind of like changing the engine in a car, the first couple dozen are fun, and after that its just plain work.

True enough in the case of the 465. That model in particular seems to have been very robust. You don't see many owners asking about how to clean 465 switches.

485 switches, though, are another thing entirely. It's very rare to see a 485 whose vertical attenuator switches aren't noisy. Perhaps gold-pad abrasion has caught up to the instruments over time; however, I'm personally aware of at least two anecdotal cases of noisy 485 switches being fixed (at least for the time being) with contact cleaner.

It's possible there's more than one cause of switch degradation at work in the 485 and other notorious "problem children." Either way, though, the original designers were clearly not omniscient in all cases, or the problems with certain models wouldn't be as widespread as they are. I wish there were a sure-fire way to fix the 485's front-end switches; it was my favorite Tek scope of the bunch otherwise.

-- jm

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Note: My E-mail address has been altered to avoid spam

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"BFoelsch" wrote in news: snipped-for-privacy@giganews.com:

Trying to support a TEK product without the Tek selected transistors and other specialized components is extremely difficult. One of the first things I did when getting a unit that someone else had tried to repair was to find and remove all the non-Tek xstrs,and replace with the proper TEK parts.They were often causes of oscillations and bad HF responses.Some scopes may have had ferrite beads used in some places lost or not installed with the new transistors.One other common problem was a black silver oxide growing on the tiny HF trimmer caps,especially on the bottom of them,acting as an insulator and making the cap open and ineffective.

IMO,the HF cam contacts used in the attenuators should be failing and no longer repairable due to the plastic part that holds the gold contact to the spring metal degrading and coming apart,or loss of spring tension. That's a problem with using plastic parts,they outgass and eventually degrade and lose strength.Some of the atten intermittents can be due to the outgassing making a film on the contacts and pads.

--
Jim Yanik
jyanik-at-kua.net

Bob Stephens wrote in news:1lew3waxlb6mj$.gqna0v1rc06l$. snipped-for-privacy@40tude.net:

TEK has a Long Term Product Support(LTPS) policy,where the item will be serviceable by TEK X number of years after it's last sold in their catalog. They have a list of whats supported and for how long on their website,IIRC. "X" used to be 9 years,then got cut to 6,then some items are only ONE year. That's why you have to check the list. Also,repair prices climb in the last couple of years of "support",to encourage you to buy a new unit.

AFTER the LTPS period is over,the item is no longer supported at all. No exchange modules,and no parts support unless the part is used in a current product.

--
Jim Yanik
jyanik-at-kua.net

Banned? Perhaps from use as a general solvent in assembly areas, but if you walk into most hardware stores (such as Ace), you can buy it in gallons in their paint sections... Pretty cheap too!

It's at least a bit amazing that one industry may ban an item, yet another still provides it... It seems that you can't purchase lacquer paint for an automobile anywhere at this point, yet can still buy gallons of lacquer thinner (and lacquer based paints for wood) at the local hardware store... sigh...

--Rick AH7H

I read in sci.electronics.design that budgie wrote (in ) about 'Tektronix 465 Scope', on Thu, 23 Dec 2004:

Toluene is one of the aromatics that is NOT carcinogenic. From the ATSDR web site:

QUOTE Studies in workers and animals exposed to toluene generally indicate that toluene does not cause cancer. The International Agency for Research on Cancer (IARC) and the Department of Health and Human Services (DHHS) have not classified toluene for carcinogenic effects. The EPA has determined that toluene is not classifiable as to its human carcinogenicity. ENDQUOTE

Toluene is available in small quantities as a solvent for contact adhesive. It DOES attack some plastics, and those it attacks slowly can exhibit surface dulling and crazing.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

of

telephone

it

It might have been carbon tet (tetracloride or however it is spelled). I think it was taken off the market because of either liver or kidney failure if the user had been drinking .

(snip)

May well have been toluene. It was often used as a cleaner in all sorts of areas, some as pedestrian as the T/R/S plugs on old lamp-signalling telephone switchboards. Unfortunately proved to be a carcinogen and was banned, but it WAS used to clean a myriad of hardware in a myriad of situations.

Other than speed, is there any difference between a 465B and a 475/475A that I should know about? I am looking for a replacement but I want all or nearly all of the knobs to be the same.

When carbon tet was removed from telephone offices there was a story about a technician spilling some on a operator. The operator lost here hair and finger nails. Don't know if that is true but we had to remove all carbon tet from the cleaning supplies.

Bill K7NOM

Yeah, that's the stoopid guv'mint for ya! If they was just as smart as we was, they wouldn't ban all this neat stuff.

According to a hazmat data sheet I have, carbon tet (which can be absorbed by breathing, skin contact, or ingestion) causes damage to the liver, kidneys, heart, adrenal glands, and nervous system, and is particularly dangerous to people who have recently consumed alcohol, are exceedingly fleshy or are undernourished, or have other problems like hypertension. You can smell it at a concentration of 70 ppm; toxicity is known at concentrations of 5 ppm.

I used the stuff quite a bit when I was a kid, and I'm just fine (I think) so that's obvious proof that it's all a bunch of hogwash and a government conspiracy.

Personally, I favor allowing anyone to buy and sell any kind of hazardous chemical or object. By banning them, we've interfered with natural selection, which seems to be resulting in a less and less intelligent population. A sort of "unintelligent design" as it were.

Roy Lewallen, W7EL

John Miles wrote in news: snipped-for-privacy@news-central.giganews.com:

Both 465 and 485 use the same HF cam switch contacts.

TEK used to have a repair kit that included both contacts,drill bits to remove the securing rivets,and tiny nuts and bolts to secure the new contacts.

They also had a repair kit for the LF contacts used in the timing switch,with an alignment guide to get them straight.

Both are no longer available.

--
Jim Yanik
jyanik-at-kua.net

Guy Macon wrote in news: snipped-for-privacy@corp.supernews.com:

Different input sensitivities on the vertical channels(knobs will not be same as 465,IIRC),and 475 and /A have higher bandwidth.

IIRC,465 had 5mv V/div reading,and 475 had 2mv V/div

--
Jim Yanik
jyanik-at-kua.net

___________________________________________________________

Carbon tet was used in the dry cleaning industry in the early 20th century. People worked over open vats, breathing the fumes all day long, and it took about 20 years of exposure for harm to be done. It is an excellent solvent for general purpose cleaning. I'm sorry it was banned.

I used in the TV service business back in the olden days and I'm perfectly n..n..n..normal, just like Roy.

On the other hand, some people would say this explains a lot. :-)

--
Bill, W6WRT

Hm, the Center for Disease Control must have accumulated faulty data over all those years (See

Of course, it's a government agency, so they probably just made all that up as part of a liberal-pinko plot to control our minds and our precious bodily fluids. I'm sure we can get much more reliable information from those folks on AM talk radio, who don't have any agenda but just want to get the truth out. Those of us who breathed carbon tet in our formative years can see through all those guvmint plots!

Roy Lewallen, W7EL

Bill Turner wrote:

walk

paint

Different countries, different strokes.

(snip)

That was the reason used when it was banned here, merit notwithstanding.