Date   

Re: Chaining power supplies together.

Harvey White
 

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: Chaining power supplies together.

-
 

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

Steve Hendrix
 

At 2021-05-01 06:59 PM, Jeff Dutky via groups.io wrote:
So I'll strap it right-side-up in the front seat, next to me.
Better to strap it top-side-up instead of right-side-up <grin>.


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

Harvey White
 

Remember that this was after shipping with Gorillas 'R' Us.

Where if it can't withstand a 7 foot drop off a loading dock (especially if it's labeled fragile) it becomes your problem.

Harvey

On 5/1/2021 8:19 PM, Jeff Dutky wrote:
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





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

-
 

Steven,

Oh, I absolutely agree! I've been going to hamfests for decades and I've
clearly seen the decline in the number of participants (both buyers and
sellers) at hamfests and the amount of goods for sale there, and the
quality of the goods. And I've seen the increase in the size of E bay and
number of buyers and items on E-bay at the same time. Now it's rare for
anyone to bring *good* TE, radios or other items to a hamfest! It's all up
for sale on E-bay! Also a majority of buyers at hamfests over the last
more than 15 years have been people thtat were only looking for bargain
priced items that they could buy and then re-sell on E-bay and that weren't
buying something for their own use. The electronics market has also
shifted. There used to be almost *no* demand for OLD TE, OLD computers, OLD
radios and the like but now some of those items are worth, literally, a
small fortune! Have you seen the price being asked for original Apple
1s??? Even old Commodore 64s are worth a few hundred dollars on E-bay.

And I too have seen a large number of sellers at the hamfests that have
been saying "*Well it is selling for $$$$ on Ebay*". I always point out to
them that this is *not* E-bay and that if they want to get an E-bay price
for for their item then they should sell it on E-bay! AND pay E-bay's and
PayPal's fees and deal with idiot buyers and the scammers, and with boxing
and shipping the item, etc etc. Those sellers are also frequently the same
ones that stand around and compalin about how E-bay *always* sides with the
buyer in the case of a disputed sale!

Most of the hamfests in this area have shut down completely and even the
surviving ones are a small fraction of the size that they were 30 years ago.

On Sat, May 1, 2021 at 8:15 PM stevenhorii <sonodocsch@gmail.com> wrote:

I am not sure if you will agree, but I think eBay had a major impact on
hamfests. For me, they were always a great place to buy and sell
electronics. I did sell a couple of Tek scopes at the Gaithersburg Hamfest
years ago. One I probably let go for too little - a completely working 556
dual beam with 1A4 and 1A1 plug-ins. I also bought Tek stuff - mostly
plug-ins. A couple of the hamfests had a place where you could plug stuff
in to see if it worked. The reputable sellers would let you do this.

I want to ones mostly on the east coast plus a couple in southern
California when I happened to be there when one of the hamfests was
running. Many of my friends with whom I would go to hamfests also think
that eBay cut into hamfest participation. One thing we noticed was that
many of those both selling and purchasing would cite eBay prices; buyers
would say, “Well, I can get it for less on eBay” and sellers, “On eBay
these go for much more.” Of course there were comebacks for these - “So,
I’ll go buy it on eBay instead of from you” - “So, sell it on eBay then.”

Hamfests were another resource for buying and selling electronics. The
large Dayton hamfest (I never got to this one) has gone with virtual
sessions this month, but no fleamarket. Maybe next year - let’s hope.

Steve Horii


On Sat, May 1, 2021 at 11:10 Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Auctions have been around since at least 500 B.C. since they promise to
fetch as high a price as possible for the seller while at the same time
offering to the buyer the prospect of buying items at bargain prices or
perhaps buying items that would be difficult to buy in any other way.

Complaining about the latest changes in eBay's fees, or requirements
etc.,
as many members are doing, is a waste of time. The auctioneer, eBay in
this
case, is entitled to collect a fee for providing the auction venue and
for
running it. The shipping companies all charge virtually the same price
(monopolistic competition) so there is nothing you can do about that fee.

A far more useful way to spend your time is learning how to get what you
want at the lowest price (if you are a buyer) or how to sell it at the
highest price (if you are a seller). Almost everything you need to know
to
be more successful can be found in "Snipers, Shills, & Sharks : eBay and
Human Behavior", by Ken Steiglitz, ISBN-13: 978-0-671-12713-2 and
ISBN-10:
0-691-12713-1, 381.177015193-dc28.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of -
Sent: Friday, April 30, 2021 10:30 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] OT! OT! --- E-bay fee change -- OT! OT! Cross
posted with HP group.

Dennis,

I agree with everything that you said. However I think that what
people
truely object to are the *never-ending* price increases from E-bay. PLUS
all of the other charges (PayPal and Global Shipping for example) for
services that they force buyers and sellers to use. Personally, I've
been a
buyer and a seller on Ebay since the first year that they started I've
seen
their fees rise from a FLAT 2% to whatever the combined totals are
today. I
quit sellling on Ebay about 5 years ago after I sold ONE item for $200
and
was charged slightly over $22 for Ebay and PayPal only and shipping not
included. But as you point out Ebay is a private company and isn't
beholden
to it's buyer and sellers so they have decide if they want to use it or
not. However, as far as I'm concerned, E-bay is still the only serious
game in town if you want to sell something for a decent price. And it's
also usually the only place where most individuals can buy the
specialized
test equipment or other items that we desire.

Overall; despite it's constant cost increase, I'm very pleased to have
seen the rise of Ebay. I've made a pile of money selling TE and other
items
that I would never have been able to sell without them and I've also been
able buy books, TE and some other items that I would never been able to
find, or have been able to afford, from the old regular TE suppliers such
as Tucker Electronics.




--
Dennis Tillman W7pF
TekScopes Moderator










Re: Chaining power supplies together.

Harvey White
 

Overvoltage would take a zener, or an SCR/zener trigger (IMHO).

A straight back biased diode (say 3 amps at 100 volts or so) should take care of back biasing the power supply.   (reverse polarity here).  It does not protect against positive current being driven into the supply's outputs.

The problem with charging a battery is that the output is lower than the battery voltage, so current flows the wrong way.  PUtting a series diode between the supply and battery (say 50 to 100 PIV) and rated for more than the PS current, would protect the supply You'd have to figure in that your output voltage is 1 diode drop lower than the supply voltage, except that for batter charging, you *may* be more concerned with the current, not the voltage.

While you may be able to play games with the sense inputs, I have no idea of the internal wiring, and don't know (based on no schematic how the circuit might behave).

This is for trying to constant current charge a battery, though.

Harvey

On 5/1/2021 6:10 PM, Dave Peterson via groups.io wrote:
So by protection diode, you're not talking about over-voltage, you're talking about accidentally driving another source. So a forward biased diode that would prevent current into the power supply.

That much I got. No, don't drive into the PS, either setup in parallel, or attempting to drive some other source. Yeah, I wouldn't do that. (On purpose).

Dave


On Saturday, May 1, 2021, 02:52:35 PM PDT, Harvey White <madyn@dragonworks.info> wrote:
Definitely.  Most power supplies take a very dim (as in permanently off)
view of reverse voltage applied to their terminals.  Most also don't
like to be tied to another power supply in parallel unless designed for it.

If you're going to charge a battery with a Chinese (or many other types)
power supply, put a series diode in so that the supply can't be fed by
the battery.

Harvey


On 5/1/2021 5:38 PM, Ed Breya via groups.io wrote:
Be sure to add an external reverse protection diode across each output, in case there isn't one built in.

Ed













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

Liam Perkins
 

Here' a page on the last of 7 Tek 570s I've owned and sold:


https://www.pearl-hifi.com/07_Facility_Tour/Tek_570_005580/Tek_570_005580.html

and a page on it being crated to go to Japan:


https://www.pearl-hifi.com/07_Facility_Tour/Tek_570_005580/Crating/index.html

Note that the fan is well secured.

I once bought a 575 off eBay that looked and sounded for all the world
like it'd been handled by Ace Ventura in, "The Pet Detective":

https://www.youtube.com/watch?v=xicKEpMJz58

Hearing the UPS truck pull up I went to the front door and heard poor
old Bob my good guy, UPS guy come up the front walk with it and sitting
down on the stoop he was embarrassed.

I said, "Old son, you're havin' a hang while I open this trash, I need
you to see it for the shipping claim I'll be making while you're driving
away."

He said, "For this one I have the rest of the afternoon."

UPS had dropped it on every corner, off every loading dock between Ft.
Lauderdale, FL and Calgary, AB and it was -junk- inside.

The world class coup de grace however was that the fan had broken free
of its 60yo mounts to flail around inside like a Morning Star in a Medieval
horror flick, like so:

https://www.youtube.com/watch?v=xicKEpMJz58

Even the CRT was smashed. I called the seller asking, in short, "WTF ?"

They immediately refunded saying, "Keep the scrap, maybe there's
something useful left." which I did and which there was.

Best,
Liam

On Sat, May 1, 2021 at 4:35 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

Any advice on what to check before transporting a 500-series scope? I know
that there's some kind of clamp or brace for the CRT on these old scopes
that can deteriorate with time. I'm planning to takes some closed-cell foam
sheets tto brace the CRT if necessary, but I haven't found any pictures of
how the CRT is mounted and would like some advanced warning.

I'll be picking the scope up tomorrow (Sunday, May 2nd), so quicker
answers would be appreciated.

Thanks.

-- Jeff Dutky






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

Dave Seiter
 

It should be fine as long as you don't pretend you work for UPS and toss it onto your porch or over a fence!
-Dave
--------------------
Short of removing the CRT, and transporting it separately, I'm not sure
there's much else you can do - beyond being careful - of course.

David

On Sat, May 1, 2021 at 8:19 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

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






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

Dave Seiter
 

The only swap meet I've ever been to was the Foothill/DeAnza/Fry's monthly meet.  It used to be huge, but got so small that I've only been a few times in the past 5 years.  For a long time it was swamped with computer stuff, and recently a lot of general flea market junk. Now that Fry's is gone, Who knows when/were it will reappear?  (I know I could look it up; I just haven't had enough interest yet.
-Dave

On Saturday, May 1, 2021, 05:15:18 PM PDT, stevenhorii <sonodocsch@gmail.com> wrote:

I am not sure if you will agree, but I think eBay had a major impact on
hamfests. For me, they were always a great place to buy and sell
electronics. I did sell a couple of Tek scopes at the Gaithersburg Hamfest
years ago. One I probably let go for too little - a completely working 556
dual beam with 1A4 and 1A1 plug-ins. I also bought Tek stuff - mostly
plug-ins. A couple of the hamfests had a place where you could plug stuff
in to see if it worked. The reputable sellers would let you do this.

I want to ones mostly on the east coast plus a couple in southern
California when I happened to be there when one of the hamfests was
running. Many of my friends with whom I would go to hamfests also think
that eBay cut into hamfest participation. One thing we noticed was that
many of those both selling and purchasing would cite eBay prices; buyers
would say, “Well, I can get it for less on eBay” and sellers, “On eBay
these go for much more.” Of course there were comebacks for these - “So,
I’ll go buy it on eBay instead of from you” - “So, sell it on eBay then.”

Hamfests were another resource for buying and selling electronics. The
large Dayton hamfest (I never got to this one) has gone with virtual
sessions this month, but no fleamarket. Maybe next year - let’s hope.

Steve Horii


On Sat, May 1, 2021 at 11:10 Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Auctions have been around since at least 500 B.C. since they promise to
fetch as high a price as possible for the seller while at the same time
offering to the buyer the prospect of buying items at bargain prices or
perhaps buying items that would be difficult to buy in any other way.

Complaining about the latest changes in eBay's fees, or requirements etc.,
as many members are doing, is a waste of time. The auctioneer, eBay in this
case, is entitled to collect a fee for providing the auction venue and for
running it. The shipping companies all charge virtually the same price
(monopolistic competition) so there is nothing you can do about that fee.

A far more useful way to spend your time is learning how to get what you
want at the lowest price (if you are a buyer) or how to sell it at the
highest price (if you are a seller). Almost everything you need to know to
be more successful can be found in "Snipers, Shills, & Sharks : eBay and
Human Behavior", by Ken Steiglitz, ISBN-13: 978-0-671-12713-2 and ISBN-10:
0-691-12713-1, 381.177015193-dc28.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of -
Sent: Friday, April 30, 2021 10:30 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] OT! OT! --- E-bay fee change -- OT! OT! Cross
posted with HP group.

  Dennis,

    I agree with everything that you said. However I think that what people
truely object to are the *never-ending* price increases from E-bay. PLUS
all of the other charges (PayPal and Global Shipping for example) for
services that they force buyers and sellers to use. Personally, I've been a
buyer and a seller on Ebay since the first year that they started I've seen
their fees rise from a FLAT 2% to whatever the combined totals are today. I
quit sellling on Ebay about 5 years ago after I sold ONE item for $200 and
was charged slightly over $22 for Ebay and PayPal only and shipping not
included. But as you point out Ebay is a private company and isn't beholden
to it's buyer and sellers so they have decide if they want to use it or
not. However, as far as I'm concerned,  E-bay is still the only serious
game in town if you want to sell something for a decent price. And it's
also usually the only place where most individuals can buy the specialized
test equipment or other items that we desire.

    Overall; despite it's constant cost increase, I'm very pleased to have
seen the rise of Ebay. I've made a pile of money selling TE and other items
that I would never have been able to sell without them and I've also been
able buy books, TE and some other items that I would never been able to
find, or have been able to afford, from the old regular TE suppliers such
as Tucker Electronics.




--
Dennis Tillman W7pF
TekScopes Moderator






Re: Chaining power supplies together.

Bill
 

Be worth obtaining an adjustable power supply if you plan on doing many board repairs. Why risk damaging boards?

Bill


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

David Holland
 

The rotator ring mechanism in the 575, and perhaps other scopes of that era
was made of nylon. The nylon splits, and the back end of the tube can
flop around a bit. Not alot mind you, it's still in a metal shield.

As Ed said, if you take care, don't drop it, don't knock it about, you
should be fine - at least till you can get it down on the bench and see
what state the mounting hardware is in.

I do agree to keep it off its face. If there's any loose bits of glass in
the tube, they'll for certain mark the phosphorus, but if that's the case,
the CRT will be suspect anyways.

Short of removing the CRT, and transporting it separately, I'm not sure
there's much else you can do - beyond being careful - of course.

David

On Sat, May 1, 2021 at 8:19 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

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






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

Greg Muir
 

I'd be more worried abut my dashboard if the item weren't strapped in the seat.

As for hauling it in your seat, if you have a nice vehicle grab a couple of fluffy bath towels and throw them on the seat beforehand by placing one under the item and one between it and the seat back. That way you won't end up with permanent crush marks in your upholstery if it is that (to use the term of a Detroit car CEO) "mouse hair" style of fabric.

I frequently haul equipment in my vehicle by placing it in the rider's seat. The towels have saved the seat plus have prevented it from becoming dirty. And the seat belt works well for capturing big items.

Greg


Re: 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


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

stevenhorii
 

I am not sure if you will agree, but I think eBay had a major impact on
hamfests. For me, they were always a great place to buy and sell
electronics. I did sell a couple of Tek scopes at the Gaithersburg Hamfest
years ago. One I probably let go for too little - a completely working 556
dual beam with 1A4 and 1A1 plug-ins. I also bought Tek stuff - mostly
plug-ins. A couple of the hamfests had a place where you could plug stuff
in to see if it worked. The reputable sellers would let you do this.

I want to ones mostly on the east coast plus a couple in southern
California when I happened to be there when one of the hamfests was
running. Many of my friends with whom I would go to hamfests also think
that eBay cut into hamfest participation. One thing we noticed was that
many of those both selling and purchasing would cite eBay prices; buyers
would say, “Well, I can get it for less on eBay” and sellers, “On eBay
these go for much more.” Of course there were comebacks for these - “So,
I’ll go buy it on eBay instead of from you” - “So, sell it on eBay then.”

Hamfests were another resource for buying and selling electronics. The
large Dayton hamfest (I never got to this one) has gone with virtual
sessions this month, but no fleamarket. Maybe next year - let’s hope.

Steve Horii


On Sat, May 1, 2021 at 11:10 Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Auctions have been around since at least 500 B.C. since they promise to
fetch as high a price as possible for the seller while at the same time
offering to the buyer the prospect of buying items at bargain prices or
perhaps buying items that would be difficult to buy in any other way.

Complaining about the latest changes in eBay's fees, or requirements etc.,
as many members are doing, is a waste of time. The auctioneer, eBay in this
case, is entitled to collect a fee for providing the auction venue and for
running it. The shipping companies all charge virtually the same price
(monopolistic competition) so there is nothing you can do about that fee.

A far more useful way to spend your time is learning how to get what you
want at the lowest price (if you are a buyer) or how to sell it at the
highest price (if you are a seller). Almost everything you need to know to
be more successful can be found in "Snipers, Shills, & Sharks : eBay and
Human Behavior", by Ken Steiglitz, ISBN-13: 978-0-671-12713-2 and ISBN-10:
0-691-12713-1, 381.177015193-dc28.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of -
Sent: Friday, April 30, 2021 10:30 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] OT! OT! --- E-bay fee change -- OT! OT! Cross
posted with HP group.

Dennis,

I agree with everything that you said. However I think that what people
truely object to are the *never-ending* price increases from E-bay. PLUS
all of the other charges (PayPal and Global Shipping for example) for
services that they force buyers and sellers to use. Personally, I've been a
buyer and a seller on Ebay since the first year that they started I've seen
their fees rise from a FLAT 2% to whatever the combined totals are today. I
quit sellling on Ebay about 5 years ago after I sold ONE item for $200 and
was charged slightly over $22 for Ebay and PayPal only and shipping not
included. But as you point out Ebay is a private company and isn't beholden
to it's buyer and sellers so they have decide if they want to use it or
not. However, as far as I'm concerned, E-bay is still the only serious
game in town if you want to sell something for a decent price. And it's
also usually the only place where most individuals can buy the specialized
test equipment or other items that we desire.

Overall; despite it's constant cost increase, I'm very pleased to have
seen the rise of Ebay. I've made a pile of money selling TE and other items
that I would never have been able to sell without them and I've also been
able buy books, TE and some other items that I would never been able to
find, or have been able to afford, from the old regular TE suppliers such
as Tucker Electronics.




--
Dennis Tillman W7pF
TekScopes Moderator






Re: 465M

Ananda
 

Bill and Dave,
Thanks for the replies. I have an HV probe (Kaise SK-9000: http://www.electronicrepairguide.com/high-voltage-meter.html) and that is how I checked the 10kV at the end of the tripler. It is dead on 10kV without the anode connected. I also tried 2 different tubes as mentioned. So, the issue of corona is not there in my opinion. I know some people have had the HV transformer in old scopes failing and if that is the case here, this is going to be a dead cause. But I have no way of checking the transformer-in case it fails only on load.

Since the original U550 failed and I made my own U550, I wonder if I damaged anything else while it was in use for almost 1 year.


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

Paul Amaranth
 

As long as it's strapped in so it doesn't shift on a panic stop you should be fine.

Paul

On Sat, May 01, 2021 at 03:59:38PM -0700, Jeff Dutky wrote:
Cool. Thanks Ed.

So I'll strap it right-side-up in the front seat, next to me. That should provide enough cushioning for the drive home.

I think there's a scope-mobile cart, as well, but that will fit in the back with room to spare, if the scope is up front.

-- Jeff Dutky







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--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Re: 465M

Bill Riches
 

I have one of the Pomona HV  metered probe that I will lend if someone needs to make a measurement.
73,
Bill , WA2DVUCape May

On Saturday, May 1, 2021, 02:56:14 PM EDT, DaveH52 <ac2gl.dave@gmail.com> wrote:

You can try to find a HV probe like the ones used back when TV sets had CRTs (like I did). The CRT beam current shouldn't be that high so that it presents much of a load. I now recall that I did have an issue with the insulation failing on the HV flying lead. I painted it with super corona dope and mummified it with tape because replacing it seemed to be out of the question.


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

 

Cool. Thanks Ed.

So I'll strap it right-side-up in the front seat, next to me. That should provide enough cushioning for the drive home.

I think there's a scope-mobile cart, as well, but that will fit in the back with room to spare, if the scope is up front.

-- Jeff Dutky


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

Ed Breya
 

If carrying it yourself, it should be just fine if not banged around or dropped. Keep it upright in its normal operating position - never haul with the face down. Ed


Transporting a 500-Series Scope without Breaking the CRT

 

Any advice on what to check before transporting a 500-series scope? I know that there's some kind of clamp or brace for the CRT on these old scopes that can deteriorate with time. I'm planning to takes some closed-cell foam sheets tto brace the CRT if necessary, but I haven't found any pictures of how the CRT is mounted and would like some advanced warning.

I'll be picking the scope up tomorrow (Sunday, May 2nd), so quicker answers would be appreciated.

Thanks.

-- Jeff Dutky

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