Date   

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


Re: 575 restoration

Mark Vincent
 

Paul,

Replace the red caps with Sprague Orange Drops, good Panasonic, etc. rated at 600 or 630V. If they are in the main power supply, replace them also. You can increase C811 to a ,1mfd since that is a decoupling cap. It may be as simple as these caps to fix your problem.

Mark


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

Albert Otten
 

Just curious I measured in my PG506, B03xxxx.
+5V1 was 4.75 V, for convenience measured between pins 16 and 8 of U673.
+5V was 5.05 V, measured between pins 10 and 5 of U668.
About 0.3 V saturation voltage of Q70 is normal I think.

Even after 2 hours running with the display on the outside of T130 was not hotter than 50 degrees C, while the TM501 transformer is already almost 40 degrees C (measured with cheap IR thermometer). I don't know how much hotter the winding was.

Albert.

On Sun, May 2, 2021 at 02:44 PM, tek_547 wrote to Michael:


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


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

-
 

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: Transporting a 500-Series Scope without Breaking the CRT

Dave Seiter
 

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: 575 restoration

Paul
 

Resurrecting this old thread since it's exactly the issue I'm having. I'm seeing the same artifact that's described here, and it's due to ripple from the HV oscillator that shows up on the Collector Sweep.
I had to replace the HV caps, C812, 813 & 818, as it wasn't getting anywhere near full voltage with the old disc caps. All of the paper caps test good up to 600V; they're not bumble-bees or black beauties, but newer red ones (dunno what you'd call them).
Are others experiencing the same thing?
thanks,
Paul


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

Reddy
 

Jeff Dutky picked up the scope today (Sunday).


Re: My wife makes it possible for me to do this

kim.herron@sbcglobal.net
 

Hi Bert and James (and the rest of the crew)!!

I too, am in west MI. Coopersville area to be exact. I've
got some Tek gear that's looking for a home James.
You'll find my phone number in my signature line (if it's
working correctly). Being close to others that have stuff
makes it easier to buy and sell thing. I did get a notice
from the Independent repeater association and it LOOKS
like they will be having their annual Hamfest in June in
Hudsonville. There isn't a lot of test gear that shows up
there, but it does happen.





On 1 May 2021 at 21:04, nonIonizing EMF wrote:

On Sat, May 1, 2021 at 07:55 PM, Bert Haskins wrote:


Do we have any list members that are anywhere near West
Michigan?
Hi Bert,

Hope the root cause of your wife's issue is identified and she heals
up.

I'm in West Michigan and other than the winter season growing
seemingly shorter and therefore reducing my time on amateur radio,
electronics and RF engineering projects, I have a home for them and
would like to have a complete test equipment lab capable of
performing in house calibrations and qualifications some day.

Kind Regards,

James




Kim Herron W8ZV
kim.herron@sbcglobal.net
1-616-677-3706



--
Kim Herron
W8ZV
kim dot herron at sbcglobal dot net


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

ChuckA
 

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: Transporting a 500-Series Scope without Breaking the CRT

Leon Robinson
 

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


Re: Chaining power supplies together.

-
 

I had to go look at the model numbers but I have an HP 6111A and a HP
6114A Precision Power Supply siting on my workbench right now. Both date to
about 1972 IIRC but I recently checked them against my HP 3456A meter and
both are still *well* within 0.02% accuracy. I don't use these for
powering circuits in general but I do use them when I need a Precision
supply for simulating reference voltages in TE.

A freind of mine owns a much newer HP (agilent?) HP 66312A Power Source
that I've repaired for him and that I've used briefly and boy is that one
sweet! it's really a power supply but they called it a Power Source
because besides being able provide power, it can also *absorb* power! it's
intended to simulate a rechargeable battery in a circuit so it has to be
able to both source, and sink power, without damage. It's also extremely
accurate in both modes of operation. My friend works in designing and
testing Laser Diode LASERs so he needs that kind of regulation and
precision to drive the diodes as hard as possible without damaging them.

On Sun, May 2, 2021 at 10:55 AM - via groups.io <rrrr6789=
gmail.com@groups.io> wrote:

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: 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













New Chat: 2430A scope problem #chat-notice

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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@...

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

tek_547
 

Hi Michael, this weekend I found the time to check your suggestions from your previous mail. So here are some measurements;
With all the measurements the switch on the front panel is allways on STD AMPL and VAR out.
U400
pin 1, 2 & 3 has a sort of square wave (SW)
pin 4 (+4,3V SW), 5 (-0,4V no SW) & 6 (+4,4V no SW)
pin 8 (+4,3V SW), 9 (+3,7V no SW) & 10 (+5V SW)
pin 11 (+5V SW), 12 (+4,4V SW) & 13 (+2,8V no SW)
pin 7 (0,00V)
pin 14 (+5,49V

As you see several of the pins have no waveforms, so maybe not good.
The remaining 741 opamps are all OK, the uA710 (U470) is replaced by a new one.
The two opto couplers 4N27 I don´t have in my junk box, so these are waiting for replacement
All the transistors are checked on board with a multimeter at "diode test". All transistors have normal b-e junction voltage (0,65V) and no shorts inside Q435 & Q535 are presumably Ok but to be sure they must be desoldered. Better wait as last option.
CR290 & CR291 have a (low) voltage drop of 0,35V (126V at anode CR291 and 125,3V at base Q290) so they must be OK

Q535 b; +6,5V with 50mV square wave on top
Q535 c; VAR at CCW square wave +7Vtt / VAR at middle 0V / VAR at CW 0V

Q560 c; VAR at CCW, at middle and at CW +0,8V no square wave visible
Q565 c; VAR at CCW, at middle and at CW +0,16V no square wave visible
All the diodes on the board I checked with the multimeter on diode test, all looks good

What I see is some strange behaviour around U460 & U470:
U460 pin 6 a triangular wave from +16Vtt with VAR at CCW
U460 pin 6 +16V with VAR at middle (while rotating VAR to CCW increasing to a triangle wave from +15Vtt)
U460 pin 6 +16V with VAR at CW (no triangle)

U470 pin 3 +0,7V with VAR at CCW (with needle pulses to 0V)
U470 pin 3 +0,7V with VAR at CW
U470 pin 7 -0.5V permanent, from CCW to CW with 50mV needle pulses
supply voltage at pin 8 and pin 4 are normal
U460 seems working normal but only the small needle pulses at U470 I can´t explain

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


Re: My wife makes it possible for me to do this

Lawrance A. Schneider
 

Wunderbar!!!!
Be sure to work on range of motion with her.

larry

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