Date   

Re: CRT's

 

Hi Bill,
Wrong Bill. It came from Bill Higdon, not you.
Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Bill Riches via groups.io
Sent: Thursday, April 29, 2021 6:54 AM
To: tekscopes@groups.io; TekScopes@groups.io
Subject: Re: [TekScopes] CRT's

To All - I did not post that link. Dont know where that came from. i have not posted anythin to this list for a few months.
73,
Bill WA2DVU
On Wednesday, April 28, 2021, 07:57:25 PM EDT, Dennis Tillman W7pF <dennis@ridesoft.com> wrote:


Hi Bill,
If you are going to post a suspicious link please be sure to say what it is for.
I can confirm (for Bill) that it is not suspicious after I checked it out.
It is a box of CRTs in the Portland area. At least one or two of them look like TV CRTs. The others are hard to tell. They appear to be old.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Bill Higdon via groups.io
Sent: Wednesday, April 28, 2021 12:40 PM
To: TekScopes@groups.io
Subject: [TekScopes] CRT's

Say this earlier
https://www.facebook.com/marketplace/item/474427257313173/?ref=browse_tab&referral_code=marketplace_top_picks&referral_story_type=top_picks&tracking=%7B%22qid%22%3A%226956294634982177454%22%2C%22mf_story_key%22%3A%22242743473124665662%22%2C%22commerce_rank_obj%22%3A%22%7B%5C%22target_id%5C%22%3A242743473124665662%2C%5C%22target_type%5C%22%3A6%2C%5C%22primary_position%5C%22%3A0%2C%5C%22ranking_signature%5C%22%3A7850170962535251968%2C%5C%22commerce_channel%5C%22%3A501%2C%5C%22value%5C%22%3A0%2C%5C%22upsell_type%5C%22%3A21%2C%5C%22grouping_info%5C%22%3Anull%7D%22%7D







--
Dennis Tillman W7pF
TekScopes Moderator












--
Dennis Tillman W7pF
TekScopes Moderator


TDS 380 Attenuator Resistor Replacement Specs

Richard Peterson
 

Hi Folks. New member, first post . . . I recently picked up a couple of new to me Tektronix scopes to replace my Hitachi V212. The 2236 is up an running beautifully after some cleaning, but the TDS380 has a (hopefully) small issue: No input on CH1. I've traced the problem down to what looks like a burned 50 ohm thick film resistor on the input of the attenuator board between the BNC and one of the capacitors on the board. (not quite sure how to post photos here yet but hopefully this link works: https://groups.io/g/TekScopes/photo/263498/3215960?p=Created,,,20,2,0,0)

I'm thinking I can simply solder a 50 ohm resistor between the BNC connector and the SMD capacitor that the original resistor links (the larger capacitor at the end of the first relay in the photo) . Any thoughts about doing this and what power rating the resistor should be?

Thanks.

Rich


Re: OT! OT! --- E-bay fee change -- OT! OT! Cross posted with HP group.

 

Amazon in Europe has the ability to link your account as the only
payment method, and it works perfectly well for variable,
non-recurring payments of all sorts of amounts.

On Thu, Apr 29, 2021 at 9:02 AM Szabolcs Szigeti
<szigiszabolcs@gmail.com> wrote:

Hi,

Interesting, that is definitely not going to work in a lot of places
outside the US. At least here, for example (Hungary, but I think true for
most of Europe) it is virtually impossible to pull money off an account
without explicit authorization. You can set up recurring variable amount
payments, like utilities bill, etc., but those can have limits and other
controls. There isn't any easy way for someone to just get money out of an
account without the approval of the owner. So I don't think this would be
the purpose for eBay.
As far as I know, with PayPal you only have to link an account if you are
selling and want to take the money out. At least I have never linked
anything to my PP account (other than a credit card (a virtual one, with
hard limits) and I was still able to buy and sell. I just used the amount
from the sale to buy other stuff (a lot of Tek stuff, to stay on topic),
never removed it from my PP account.

Szabolcs


Harvey White <madyn@dragonworks.info> ezt írta (időpont: 2021. ápr. 28.,
Sze, 21:51):

One thing to note is that credit cards may be easily disputed, thus not
guaranteeing EBAY their money immediately. Bank accounts may be harder
to dispute and more difficult to correct.

Note: in the US, debit cards, while they are convenient in maintaining
control over an account balance, do not have (or have not had) the legal
protections that credit cards do. May be the same with a bank withdraw.

Harvey


On 4/28/2021 2:21 PM, Martin wrote:
Hi Dave,

OK, I don't actually know Paypal, never subscribed to it as I have
learned about all these experiences before.

Still I do not understand why Ebay needs any agreement at all with their
new payment methods.
They already could dip into my account via the credit card, so what else
do they need?

cheers
Martin













Re: OT! OT! --- E-bay fee change -- OT! OT! Cross posted with HP group.

Heinz Breuer
 

I guess it is different in every country. In Germany you can order your bank within 6 weeks to cancel any direct debit.
vy 73 Heinz DH2FA, KM5VT

Von meinem iPhone gesendet


Re: OT! OT! --- E-bay fee change -- OT! OT! Cross posted with HP group.

 

Hi Jeff,

On 28. Apr 2021, at 22:28, Jeff Dutky <jeff.dutky@gmail.com> wrote:
There may also be a difference in the transaction fees that eBay needs to pay...
thats the most likely explanation I heard so far as to why they want to stop going via a credit card. The credit card company charge for their services... So for Ebay this is essentially a move to save money.

But also, as has Harvey pointed out, you can dispute the amount taken on your credit card and then Ebay would have to prove something. Thats also a cost factor, but authorising Ebay to withdraw whatever sum they like from my bank account is going too far IMHO. I had my phone provider authorised many years ago, when one day they charged 10x too much due to some mistake in their accounting system. Although they did correct it quickly, for me that was the trigger to ban all services from my account where the amount is not fixed.

I wonder why banks don't offer something like a pre-authorization, where you authorise once but get a message you have to confirm before the transfer is actually carried out. That way it would still be quite comfortable as you do not have to remember, but you can withhold the transfer if deemed incorrect.

cheers
Martin


Re: Recapping Tektronix 2465

iv3ddm
 

I received the material from Mouser, for those interested I report the list of what I found available and I ordered:
https://groups.io/g/TekScopes/files/mouser%20TEK2465.xlsx

More or less everything corresponds to what was found on this group, except the 7 ohm NTC, I found one that should be fine with code 995-SL157R005-L. However I did not use it because the 2 original NTCs measured with the ohmmeter, report the correct resistance.

For those like me who are not familiar with the Mouser catalog, I think I can say that, for example, the codes 647-UHE1E101MED, 647-UHE1E101MED1TA, 647-UHE1E101MED1TD correspond to the same component but in bulk, or taped etc.

I started working with the A2-A3 boards and I have some questions, if anyone would like to answer:

- I found R1016 swollen, then unsoldering it broke, what to replace it with? A common metal or ceramic film?

- I followed the method of searching for the shielded outer end of non-polarized capacitors with the oscilloscope but for several specimens I don't get any difference, or uncertain differences by inverting the connections on the pins. Yet the test clearly works by trying some old capacitors found in my drawers. Does this mean an error on my part, or that for those components the direction of insertion is indifferent?

- Still speaking of non-polarized capacitors, in the wiring diagram does the shielded outer end correspond to the curved line of the capacitor symbol?

Thank you for any information already received and in the future and I apologize for any errors but I'm using google translate....

Gio


Tek DSA8200 help wanted

demianm_1
 

I have a Tek DSA8200 w/ 2 TDR modules. It was retired from service qualifying HDMI cables. The HDMI standards changed and now you need a 4 port VNA to test HDMI cables. In any case when I contacted Tek about getting the 80SJNB package they told me it was obsolete and I needed to get a DSA8300. The software would not work on the DSA8200 any more??? Once they figured out there was no unlimited checkbook at hand they moved on.

At this point I would like to explore how to get the 80SJNB software package on this unit if its possible. Anyone with experiece dealing with this could probably give me some insights. Also about the Iconnect package which again was not available. How does software become no longer made??? To be sure I'm not ready to spend $$$ to get this all running on my obsolete hardware.

Any advice? Or maybe I'll just sell it.


Re: 465M

Ananda
 

Here is an update:
I checked the tube socket and it is clean as a whistle! The U550 in this scope failed a while back in that, the tripler section started blowing the fuse. Since this is not available anymore, I created my own U550. I did it in a way that the tripler is removable from the rest of it. That contraption of mine worked for almost a year or more till it blew the fuse last week. It only blows if the anode is connected. Assuming that my tripler has gone bad, for whatever it is worth, I rigged another 3 diode/3 cap tripler and made sure the 10kV is there and then connected the anode. The fuse blew again. It tells me that my original tripler is still good. The next thing was to make sure the rest of the U550 is not gone bad. So, I hooked up the original TEK U550 (without the EHT connection) and hooked up the external tripler. Again the 10kV is good but no sooner the anode is plugged in, the fuse blows. This made me think the tube might have gone bad and is drawing too much current. Luckily for me, I have another spare tube. So, I hooked that up. Well, it is the same result! So, now I am lost. It is clearly too much current in the anode circuit but what is causing it? I read through the HV section in the service manual and can't say it is pointing me to anything in particular. I have checked the transistors in the HV regulator and HV oscillator etc. But did not find any issue. There still could be a diode that breaks down on load while showing good on the meter. The only major item I cannot check by replacing is the HV transformer as I don't have one. But if that was bad, wouldn't it blow the fuse even if the anode is not connected? Also, it does generate the 10kV. Unless, it is shorting under load, what else can go bad?


Re: Tektronix HC100 plotter on eBay

-
 

The shipping has now gone up. It's now $59.70. I used to want one of
these printers and they were difficult to find but I think I'm over that
now so I'll pass. But FWIW it appears to have both a Centronics and an
HP-IB interface.

On Thu, Apr 29, 2021 at 6:31 PM Keith <coolblueglow@gmail.com> wrote:

Not sure how popular these HC100 still are - but the price is right...
$15.00 plus shipping at $45.

Here:
https://www.ebay.com/itm/254637159546?hash=item3b498eb47a:g:CFYAAOSwd59e1~JH

Not me by the way - just reporting it in case anyone is looking for one.

Cheers,

Keith






Re: Tektronix HC100 plotter on eBay

toby@...
 

On 2021-04-29 6:31 p.m., Keith wrote:
Not sure how popular these HC100 still are - but the price is right... $15.00 plus shipping at $45.

Here: https://www.ebay.com/itm/254637159546?hash=item3b498eb47a:g:CFYAAOSwd59e1~JH

Not me by the way - just reporting it in case anyone is looking for one.
I'm looking for the GPIB interface board to one. Can swap for the RS232.

Getting pens for these is pretty challenging, they're special for this
plotter and the way it's designed you can't really use anything else.

--Toby

Cheers,

Keith





Re: 7A16A with an unknown modification MOD515D

greenboxmaven
 

For many years test equipment had minimal safety requirements. Newer equipment often has "sacrificial" resistors in parts of the circuit that also function as fuses. They often run hot and fail without reason. Usually the prints will have a label on them, calling them a "Critical Safety Component". Could the resistor you see overheating be one of these?

  Bruce Gentry  KA2IVY

On 4/29/21 17:05, Mark Vincent wrote:
Mark,

Obviously this resistor is underrated in wattage. Something like 1 ow 2W would be better. If a resistor looks like this, it should be a higher wattage. I have seen this problem of a overstressed resistor go up in value or open causing the same problem you have/had. An easy way to get the power needed is to parallel or series resistors, when possible. Sometimes getting the precision resistor in the wattage needed cannot be done with one resistor. You can use an 82 ohm 1 or 2W resistor in parallel with a 4700 ohm. That will give you 80,5938.,. ohms. Well within the 1% tolerance. This is provided you use 1% resistors or measured ones. Your plug-in is worth getting right because it is a rare piece. It looks in excellent condition.

Mark




Tektronix HC100 plotter on eBay

Keith
 

Not sure how popular these HC100 still are - but the price is right... $15.00 plus shipping at $45.

Here: https://www.ebay.com/itm/254637159546?hash=item3b498eb47a:g:CFYAAOSwd59e1~JH

Not me by the way - just reporting it in case anyone is looking for one.

Cheers,

Keith


Re: 7A16A with an unknown modification MOD515D

Mark
 

Actually the manual says these are 0.125 watt. I'm not familiar enough with TRW resistors but that would indeed be under rated. So interesting to say the least.

The actual power dissipation would be around 1/4 watt so 1/2 watt is safe.


Re: 7A16A with an unknown modification MOD515D

Mark
 

Well a half watt would be good enough.

I don't know the history of this unit. If you look closely you will see that someone was tweaking the pots. Could of been a slip of the probe.


Re: OT: Groups.io bounced me

Jim Strohm
 

True t’ing!!

My Congressional campaign website got blacklisted by spamhaus in 2006 because one website on my provider Texas.net was forwarding SPAM.

I switched to a more reputable provider forthwith. And instead of serving up SPAM they served up large-breasted NASCAR lady drivers.

Hey, here’s some advice. If you ever run for political office and you have a website, you have to park the website and all its aliases until after you die, because it’s a sure bet somebody will pwn the URL and put a XXX pr0n site there.

Have a nice day.

Jim N6OTQ

Sent from my quenched-gap spark transmitter.


Re: 465 Electrolytic Capacitor Replacement

DaveH52
 

The cap cans themselves complete part of the circuits. What I'd do is to get the same value caps that will fit inside the empty cans (or on the bases). The cans can be cut open with a tubing cutter, or just by spreading the crimp at the bottom, then pulling the guts out. And yes you need a good dose of heat to melt the solder. Suck/wick out as much as you can, then go around and heat the tabs individually and work them out by wiggling a little as you go around with the iron.


Re: CRT's

Roy Thistle
 

On Wed, Apr 28, 2021 at 04:57 PM, Dennis Tillman W7pF wrote:


At least one or two of them look like TV CRT
If I were in Portland... I'd pick them up.
At least one of the tubes was made by the Electron Tube Corporation (an early maker... circa 1948... or multi-beam... CRTs and oscilloscopes... some with more than four!) The one CRT I'm thinking of looks to have multiple cathodes.

--
Roy Thistle


Re: 7A16A with an unknown modification MOD515D

Mark Vincent
 

Mark,

Obviously this resistor is underrated in wattage. Something like 1 ow 2W would be better. If a resistor looks like this, it should be a higher wattage. I have seen this problem of a overstressed resistor go up in value or open causing the same problem you have/had. An easy way to get the power needed is to parallel or series resistors, when possible. Sometimes getting the precision resistor in the wattage needed cannot be done with one resistor. You can use an 82 ohm 1 or 2W resistor in parallel with a 4700 ohm. That will give you 80,5938.,. ohms. Well within the 1% tolerance. This is provided you use 1% resistors or measured ones. Your plug-in is worth getting right because it is a rare piece. It looks in excellent condition.

Mark


Lots of Tek mechanical and electro-mechanical parts posted

 

Finally, it's all done, over 100 Tek mechanical and electro-mechanical items all photographed, identified and posted up on the stuff season page. There are some interesting bits there, from the skinny BNC nuts needed on a few scopes to attach the vertical input connectors, current probe housings and switches, case feet and panel latches, power switch tie-rod couplers, curve tracer parts to reed relay coils. You can see it all here:

https://www.sphere.bc.ca/test/stuffday.html#tekfans

No, it's not in numerical order, that's just how it turned out, so you can just go "control-F, then type in the part number you want" in your browser, and it will find it.

A lot of work, and many items are free (how can I charge for a setscrew?), so I am not sure it was time productively spent, BUT if it clears out these items, then susan will be happier, so that works for me.

all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.


Re: 7A16A with an unknown modification MOD515D

Mark
 

So I confirmed that this amplifier should work normally when in the local mode. I also confirmed that this mod would only work on a 7704A with MOD 515C.

Back to the problem... In general the unit had low gain and when you use the Position control it would simultaneously adjust the gain of the applied signal higher at both extreme ranges of the control.

Solution: R705, bias resistor for the signal splitter amp, was out of spec. Was supposed to be 80.6 ohms but measured about 119 ohms. It was slightly discolored, see my photos... https://groups.io/g/TekScopes/album?id=263432

All in all good entertainment I would say.

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