Date   

Re: Challenging 2465 PS repair

Tom Gardner
 

Since a *switching* PSU will attempt to deliver a constant output
power, a low input voltage means a high input current flowing through
transistors, diodes and some capacitors.

An abnormally high current might cause damage.

On 03/05/2021, Milan Trcka <milan.v.trcka@gmail.com> wrote:

In an attempt to keep in as much smoke as possible when powering up suspect
or failed PS, I use an adjustable transformer (Variac) to slowly bring up
mains voltage while monitoring for vital signs. Use isolation transformer or
battery powered isolated scope when monitoring waveforms.

M






Re: Challenging 2465 PS repair

Milan Trcka
 

In an attempt to keep in as much smoke as possible when powering up suspect or failed PS, I use an adjustable transformer (Variac) to slowly bring up mains voltage while monitoring for vital signs. Use isolation transformer or battery powered isolated scope when monitoring waveforms.

M


Tek 465 - help is needed...

Dr. Manfred K. Zeller
 

Channel 1 Beam with the Beam Finder cannot regulated down over the whole screen with the position knob - it is only on the upper side of the screen.
Only a little - two or three scales.

Result: no Beam in channel 1

Channel 2 is working.

Voltage: ok
Manual: there

Thanks!
Regards
Manfred


Re: Transporting a 500-Series Scope without Breaking the CRT

Greg Muir
 

Inspectors have a tendency to come out of the woodwork when the insurance value equals several months or more of a mid-level managers income.

Greg


Re: Transporting a 500-Series Scope without Breaking the CRT

-
 

Greg,

I'm surprised to hear you say that UPS even sent an inspector out to look
at the item. I've never even heard of a UPS inspector and UPS has never
sent anyone to look at any of my damaged packages. They just automatically
say that the package wasn't packed properly.

UPS inspectors probably sub as Tooth Fairies or Unicorns when they're
not busy (sarcasm intended) inspecting packages for UPS.

On Mon, May 3, 2021 at 10:56 AM Greg Muir via groups.io <big_sky_explorer=
yahoo.com@groups.io> wrote:

Back in the late 90’s I had a small piece of equipment that was captured
in a military shipping container consisting of 2” closed cell stiff foam
shock absorbers around each corner of the unit faced with an aluminum layer
on each one. The transit container consisted of .062” aluminum walls both
inside and outside with a 3/8” layer of plywood sandwiched in between the
aluminum. The unit itself weighed around 20 pounds with the container
coming in a close second.

When received from UPS Ground the knobs (or at least the parts of them
with the control shafts) were sticking out through the exterior aluminum.
Needless to say the unit was toast. The UPS inspector tried to tell me
that the unit was “inadequately packed.” I told him that my impression
was that the container must have been dropped from at least a 10 foot
height onto a concrete floor.

UPS begrudgingly reimbursed the cost of the unit but would not refund the
shipping charges.

Greg






Re: Transporting a 500-Series Scope without Breaking the CRT

Greg Muir
 

Back in the late 90’s I had a small piece of equipment that was captured in a military shipping container consisting of 2” closed cell stiff foam shock absorbers around each corner of the unit faced with an aluminum layer on each one. The transit container consisted of .062” aluminum walls both inside and outside with a 3/8” layer of plywood sandwiched in between the aluminum. The unit itself weighed around 20 pounds with the container coming in a close second.

When received from UPS Ground the knobs (or at least the parts of them with the control shafts) were sticking out through the exterior aluminum. Needless to say the unit was toast. The UPS inspector tried to tell me that the unit was “inadequately packed.” I told him that my impression was that the container must have been dropped from at least a 10 foot height onto a concrete floor.

UPS begrudgingly reimbursed the cost of the unit but would not refund the shipping charges.

Greg


Re: PG506 Repair - I had a Great Day today/

tek_547
 

Thanks Albert and Michael for the information. Looks like T130 in my PG506 is a bit warmer then yours Albert, so maybe something is consuming extra current somewhere...
And next days I investigate the 4N27 and the 7400 Michael, so when I know more I report it here.
Rene


Re: Challenging 2465 PS repair

satbeginner
 

Hi all,

I am determined to repair this PS, so I removed all broken, damaged or suspicious parts and ordered new ones.
For the time being, I removed all the burned fiberglas parts of the PCB, leaving me with a nice, clean 8mm hole in the PCB and many open spaces were new parts will be placed.

After studying the schematic of this power supply, it is vaguely similar to the 22xx power supplies, but with at least one major difference.

Similar is, it has a Primary switcher, and it has a secondary switcher, but, were in the 22xx PS the secondary switcher runs at it's own frequency, in this 246x PS the secondary switcher uses the same frequency as generated by the primary switcher.
This makes it a bit more of a challenge to separate the Primary and the Secondary to test them one at the time.

The good news is, the service Manual has a procedure to do this, but extra dummy loads are needed.
I ordered these parts as well, and when they arrive I will continue this repair.

To be continued, stay safe,

Leo


Re: New Chat: 2430A scope problem #chat-notice

Szabolcs Szigeti
 

Hi,

First of all, get the service manual and do the performance validation
checks and if necessary do the adjustment (calibration) for the 2430A
calibration is fairly simple, you don't really need much special equipment.
Also, check the power supply values and ripple, as the PSU in these units
are prone to cap leaking, and failure. So you can pretty much expect
recapping, and I say this even though I'm very much against indiscriminate
recapping of stuff as a general cure for everything. But so far I had three
24XX DSOs, out of these all three had to be recapped.


Szabolcs


TekScopes@groups.io Notification <noreply@groups.io> ezt írta (időpont:
2021. máj. 2., V, 15:28):

A new chat has been created:
New

I have bought a 2430A tek scope. the rising edge of the waveform is very
wobbly not just plain jittery, even on save mode. Looking for advice on how
to fix it. Also on how to fine tune this scope.
Thanks
kanwal

*By:* kanwal.jawanda@gmail.com

View/Join This Chat <https://groups.io/g/TekScopes/chat/8087>

Do not reply to this message to post to the chat. You can participate in
chats only through the group's website.




Re: Save this 533A from the trash in Arlington Virgina #photo-notice

 

It is sitting in my garage right now, awaiting space in the lab for a full intake inspection. It's a damn nice looking scope, and should be days of fun fixing up.

-- Jeff Dutky


Re: Save this 533A from the trash in Arlington Virgina #photo-notice

Glydeck
 

This is good news!

On May 2, 2021, at 10:18 AM, Reddy via groups.io <wpost2=verizon.net@groups.io> wrote:

Jeff Dutky picked up the scope today (Sunday).





Re: PG506 Repair - I had a Great Day today/

Michael W. Lynch
 

On Sun, May 2, 2021 at 07:44 AM, tek_547 wrote:


If you have the possibility pls check the 5V1 at the collector from Q70, mine
is 4,75V. For TTL logic (U670, 671, 673 & 675) this is the absolute minimum.
Maybe this is the reason of the problem so I am interested in the value from
your PG506.

And also look that if inside your PG506 T130 in the power supply is about
70°C when the STD AMP switch is activated. So almost not possible to you put
your finger on the windings of it. Is this on yours the same?
Thanks so far and hopefully you have some suggestions, Rene
Rene,

I will take another look at mine tomorrow. I will give you as much as I can as far has how mine acts. I will pay special attention to T130, including some temperature measurements. Your U400 measurements that you are describing do not sound correct.

Glad you included your control settings as we always need to standardize our panel settings when making measurements and observations, so that we can be on the same page. I believe that you can check the opto-couplers using a diode test. I had one bad 4N27 on my unit, one side checked as an NPN and the other side checked open, it should have checked as a diode.

One thing that you may find helpful and what helped me diagnose the issue with mine was actually diagramming the inputs, outputs and cross connections on U400. It is an SN74LS00N Quad 2 input Positive NAND gate, so sorting out what goes in and what comes out is important and helpful. This is how I finally isolated and found my problems, since U400 is sort of the "doorkeeper" to the rest of the circuit. .

--
Michael Lynch
Dardanelle, AR


Re: What's a chat.. and why?

Liam Perkins
 

Exactly . . .

On Sun, May 2, 2021 at 5:27 PM Roy Thistle <roy.thistle@mail.utoronto.ca>
wrote:

Hi:
I saw the post on the 2430A was as a chat?
Do we do that on TekScopes?
And why would someone want to? ... What's the advantage of that over
starting/participating in a thread?
It appears that chats are in the sub-basement of TekScopes.
--
Roy Thistle






Re: Transporting a 500-Series Scope without Breaking the CRT

Dave Seiter
 

These days it really doesn't matter who you ship through- they're all the same.  Everyone uses robots/conveyors for sorting, and UPS/USPS share some facilities.  A few months ago I shipped a (well packed) delicate item via Fedex, and asked them to put a fragile sticker on it.  The guy did, but warned me that it only applied to human handlers; the robots don't care and will still toss them around.   If you want careful shipping, it's got to be on a pallet with shockwatch, etc.  At least then you'll know it if was dropped and/or tipped over.
Of course it's not just shippers- one of my 7104s was hit by a forklift at Telogy.  It just kissed the left front of the unit, but that was all it needed, the CRT was toast.
-Dave

On Sunday, May 2, 2021, 12:48:19 PM PDT, - <rrrr6789@gmail.com> wrote:

  The biggest problem is that most shippers don't use common sense!
Especially UPS! I just shipped a well packed 575 from Maryland to Florida
via FedEx and it arrived fine.  Many years ago I used to ship stuff via UPS
but I went into their shipping center one day and watched them throwing and
kicking boxes around and I said to myself "never again!".  I briefly worked
for another company that also ships a LOT of TE via UPS and I've seen UPS
actually drive one of the forks on a forklift THROUGH packages and then
deny paying the insurance claim and claiming that the box wasn't properly
packed!  No, Never Again! If I buy something and the seller only has an
account with UPS, as many of them do, I send them my FedEx account number
and tell them to drop the package off at FedEx and give them my account
number and FedEx takes it from there.  I've only had one claim with FedEx
and they paid it quickly and with no difficulty.  OTOH UPS has damaged
dozens of packages and has never paid a claim.  Never Again!

On Sun, May 2, 2021 at 2:47 PM Dave Seiter <d.seiter@att.net> wrote:

  They can be pretty rugged.  I bought a RM502 years ago and when it
arrived there was almost no packing material in the box, and one corner of
the front panel had breached the cardboard a little and was bent (not
badly, but based on the listing photos, it was new damage).  After hearing
so many tragic stories, I feared the worst, but the CRT was fine, and it
worked great.
-Dave
    On Sunday, May 2, 2021, 09:07:11 AM PDT, ChuckA <chuck@myvintagetv.com>
wrote:

  I've been reading this thread and am wondering what 500 scope are you
moving and how far?

I've moved many of them in the back of my truck just wrapped in a moving
blanket and secured so they can't slide around with no problems. This
includes three 555's, shortest trip was about 40 miles the longest was
400 miles. I never opened them up when picked up, just wrap them up.
I've either been really lucky or they are much more rugged then most
people realize.

I do follow common sense, don't throw them in the truck and don't drop
them.

  Chuck



On 5/2/2021 11:23 AM, Leon Robinson wrote:
Jeff

Take a screwdriver to remove the cover & a handfull of 8 or 11 inch
tyraps just in case there is something wrong you can then secure it.


Leon Robinson  K5JLR

-------- Original message --------
From: Jeff Dutky <jeff.dutky@gmail.com>
Date: 05/01/2021  7:19 PM  (GMT-06:00)
To: TekScopes@groups.io
Subject: Re: [TekScopes] Transporting a 500-Series Scope without
Breaking the CRT

Paul,

I used to haul large CRTs (21" computer displays) this way, which are
admittedly less finicky than an old tek scope, at least they never seemed
to care about orientation, and I would seatbelt them in. They were all deep
enough that the seatbelt was near its limit, so they were held in pretty
securely that way. For this, however, I will try to pick up some bungie
cords or something, to get a good strap around the seat back. I was going
to bring some larger blocks of closed cell foam to give it some cushioning
in case I had to put it in back, but I can use the same foam to wedge
against the dash in front.

I'm still a little worried about the CRT mounting in the case. I can't
seem to find the thread now (and maybe it wasn't in this group; maybe it
was in a Facebook group I also belong to) where someone had moved a
500-series scope but some part of the CRT mounting hardware had failed and
the neck had shattered. I'd really like to avoid that sort of tragedy if at
all possible.

-- Jeff Dutky









--
See Early TV at:

www.myvintagetv.com












Re: Tek DSA8200 help wanted

guy_ellis_1964
 

Hi again,

I checked the CD I have at work, its the same Version (2.5.4) as the download on the Tek website...
https://www.tek.com/oscilloscope/csa8000b-software/80sjnb-jitter-noise-and-ber-analysis-v254-including-80sjarb-v114

According to the INI file on the CD, Windows 95,98, 2k and XP are all supported.

Regards,
- Guy


Re: Transporting a 500-Series Scope without Breaking the CRT

ChuckA
 

Jeff

Most of the scopes I've picked up have been in storage for many years and lots of dust. I usually just do cleaning with a compressor for dust and loose dirt and lots of elbow grease for stubborn dirt.

Never tried to clean a complete one with a hose. I have used the dishwasher for cleaning plugins with good results.

Chuck

On 5/2/2021 7:38 PM, Jeff Dutky wrote:
Chuck,

I was picking up a 533A, and moving it about 15-20 miles, about half of that "highway" travel (this being the DC area, the highway travel averaged less they 40 mph).

I got the scope home without incident. I need to put some work into it before I can power it up, but it looks like it's in good condition. It's been in storage for something like 45 years, and it's a low serial number (003969) so it's easily 60 years old. The caps are likely dry as a bone. Some of the pots and switches could use some exercise and DeOxit.

It's a bit dusty (though I've seen much, much worse), and I'm working up my courage to clean it using Stan Griffiths' method. Of course I don't have an oven to bake it in afterwards (I could tent it with a dehumidifier, though, and let the DC summer provide the heat), so maybe the hose isn't the best idea.

I'm excited to get it working and experience a 500-series scope. My grandfather had one (I think) but it never worked in my lifetime, something about a bad transformer (maybe it was a 547?). I was also having an itch to try working on some vacuum tube equipment.

-- Jeff Dutky





--
See Early TV at:

www.myvintagetv.com


Re: Transporting a 500-Series Scope without Breaking the CRT

 

Chuck,

I was picking up a 533A, and moving it about 15-20 miles, about half of that "highway" travel (this being the DC area, the highway travel averaged less they 40 mph).

I got the scope home without incident. I need to put some work into it before I can power it up, but it looks like it's in good condition. It's been in storage for something like 45 years, and it's a low serial number (003969) so it's easily 60 years old. The caps are likely dry as a bone. Some of the pots and switches could use some exercise and DeOxit.

It's a bit dusty (though I've seen much, much worse), and I'm working up my courage to clean it using Stan Griffiths' method. Of course I don't have an oven to bake it in afterwards (I could tent it with a dehumidifier, though, and let the DC summer provide the heat), so maybe the hose isn't the best idea.

I'm excited to get it working and experience a 500-series scope. My grandfather had one (I think) but it never worked in my lifetime, something about a bad transformer (maybe it was a 547?). I was also having an itch to try working on some vacuum tube equipment.

-- Jeff Dutky


What's a chat.. and why?

Roy Thistle
 

Hi:
I saw the post on the 2430A was as a chat?
Do we do that on TekScopes?
And why would someone want to? ... What's the advantage of that over starting/participating in a thread?
It appears that chats are in the sub-basement of TekScopes.
--
Roy Thistle


Re: Chaining power supplies together.

Jim Ford
 

A technician at Lockheed back in 1993-1995 when I worked there told me that he'd seen lots of HP and other power supplies go out for repair but never in 30 years had he seen a Trygon need repair. I understand Trygon had something to do with Systron Donner. I have a Trygon triple supply and an HP 6111A thumbwheel PS, along with another no-name one that was given to me. Aside from some scratchy pots, all work just fine.

Also had a Lambda 5 V, 35 A boat anchor that I got for something like $5 at the TRW swap meet in the early 1990's. I put a power cable on it and installed some Pomona Electronics heavy-duty banana jacks/binding posts. But I never used it and sold it on eBay for around $50. Nice supply and built like a tank!

Jim Ford

------ Original Message ------
From: "-" <rrrr6789@gmail.com>
To: TekScopes@groups.io
Sent: 5/2/2021 7:53:51 AM
Subject: Re: [TekScopes] Chaining power supplies together.

Any of the TE grade ones built by HP. Even their economy class small
green plastic cased ones are better than the econo class Chinese meters.
Lambdas are also good but not as EASY to find service info on as just about
ANY of the HP PSs are.. Most of the other US built PSs built by any of the
major TE manufacturing companies are also good but none tops HP in terms of
reliability, durability, and the level of service information available. I
have at least one HP PS built in 1966 that is still running strong and has
never been recapped or had to be repaired. Needless to say that is a linear
supply and there's no digital electronics in it and it's HEAVY but as any
experienced machinist can tell you, HEAVY means that it's built to last.

True story, a few years ago a EE student at a nearby college rented a
room in a house next door to me and we became friends. He was an avid
electronic hobbyist with the arduinos but lacked any reaperience in
electronics in general and he was also poor as most students are. He needed
PSs, meters and other parts for his arduino projects but he couldn't afford
them. He'd never heard of a hamfest so I took him to several of them and he
was like a kid in a candy store! He had never imagined that TE and parts
could be bought so cheaply! I also took him to an electonics scrap yard
that is owned by a friend of mine. He walked out of there with THREE old
HP 54100 color scopes! My friend took pity on him and only charged him what
he thought that the scopes were worth in scrap value, $35. My neighbor
later told me that he got two of the three scopes completely working just
by disassembling and cleaning the tiny mechanical attenuator switchs in
them. But on the way out of the scrap yard, I looked over at one of the
scrap baskets and spotted an old Lambda power suply. I can't tell you what
model it was but it was a heavily built linear supply with dual analog
meters on the front and it had variable voltage and variable current
limiting and went to about 30 VDC. It had been sitting in the scrap yard
for MONTHs and was nasty looking but I pointed it out to him and said
"Here. This is what you need for your projects." He took one look at it and
thought that I was joking and that it would never work.I But I told him
that I was serious and that I would BET that it worked. He carried it home
and later that day he called me and in an amazed voice that "It works!".
He graduated several years ago and moved away but we still talk
occasinonally and just a few months ago he told me that he is STILL using
that PS and that it is still working fine. In my experience, I don't think
that I've ever found or seen a Lambda PS that didn't work!

On Sat, May 1, 2021 at 10:28 PM Harvey White <madyn@dragonworks.info> wrote:

What would you consider good power supplies given what you've said?

Harvey


On 5/1/2021 9:37 PM, - wrote:
> "Be worth obtaining an adjustable power supply if you plan on doing many
> board repairs. Why risk damaging boards?"
>
> Absolutely! And use a PS with an adjustable current limit and set the
> limit only slightly higher than the amount of current that you expect the
> item under test to draw. I used to keep notebooks full of notes about
> various repairs including how much power that model item actually drew
> under various operating conditions. I also STRONGLY suggest using a GOOD
> quality PS like those from HP, Lambda, etc and not one of cheap Chinese
> ones. Many of the cheap PSs contain large filter caps on their output in
> oder to reduce AC ripple but those large caps can provide enough power to
> fry your electronics before their *slow* current limiters can kick in.
> GOOD PSs are expensive when new but used ones are available just about
> anywhere (at least in the US and Canada) and are usually very cheap
(~$20)
>
> On Sat, May 1, 2021 at 8:45 PM Bill via groups.io <ko4nrbs=
> yahoo.com@groups.io> wrote:
>
>> Be worth obtaining an adjustable power supply if you plan on doing many
>> board repairs. Why risk damaging boards?
>>
>> Bill
>>
>>
>>
>>
>>
>>
>
>
>
>
>









Re: 575 restoration

Paul
 

Thanks Mark - As a part of my initial trouble-shooting I did change out C811 with a polyester film cap of the same value and saw no change, but I'll try increasing it's value.
I'm generally stocking 600V axial film caps (CDE or Vishay, usually) for paper cap replacements - would one expect to see any performance difference in using Orange Drops over those in filtering applications?
thanks,
Paul

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