547 HV Transformer: Bill Schell rewind failed


widgethunter
 

My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd

-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris


Chuck Harris <cfharris@...>
 

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on. Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:

My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris










Eric
 

Chuck,

Are you in need of bees wax? I might be able to get some in bulk. I happen
to know a couple of bee keepers. I would also like to learn more about the
transformer winder when the time is right.

Eric

On Thu, Mar 4, 2021, 7:45 PM Chuck Harris <cfharris@erols.com> wrote:

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on. Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to
have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for
me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool. The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell
rewinds.It has been a looong time, but I think I'd remember if he'd said
anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound. It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer. The
naked winding is right there for you to see.

-Chuck Harris














fiftythreebuick
 

Hi Dave-

I'm sorry to hear that you're having trouble with that HV XFMR....

I did a lot of testing and evaluation for Bill Schell over the years and I don't remember him every testing a transformer with any epoxy in it at all. He and I both felt that we oughta get as far away from that as possible. He first wound them without sealing them and I have never had one of those fail. Then when he started treating them with beeswax and a vacuum chamber, it seemed like he had found quite a good process. So far, I have never had one of his fail, of any description.

Just saw your later post and I'm glad that yours is improving! A friend of mine has restored an original xfmr by putting it in a vacuum chamber and keeping it in a deep vacuum for a while. Don't remember how long he left it in there.

I hope yours comes out alright. It really does seem like the moisture is the major factor.

Tom


Chuck Harris <cfharris@...>
 

Hi Eric,

Beeswax is an easy commodity. I get the highly purified white
variety that candle makers use. Smells like honey, but is
free of bee parts, and pollen granules, that exist otherwise.

It takes very little to impregnate hundreds of coils. I am still
working off of a 10lb block I bought 10 years ago.

Should we change the subject on this post? I don't like seeing
Bill Schell's name associated with failed. He did an amazing
thing for the tektronix community back before most any of us
even knew there was a problem.

-Chuck Harris

Eric wrote:

Chuck,

Are you in need of bees wax? I might be able to get some in bulk. I happen
to know a couple of bee keepers. I would also like to learn more about the
transformer winder when the time is right.

Eric
On Thu, Mar 4, 2021, 7:45 PM Chuck Harris <cfharris@erols.com> wrote:

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on. Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to
have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for
me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool. The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell
rewinds.It has been a looong time, but I think I'd remember if he'd said
anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound. It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer. The
naked winding is right there for you to see.

-Chuck Harris


















Chuck Harris <cfharris@...>
 

Hi Tom,

Moisture is definitely a factor, but the problem is not
really reversible.

Yes, you can gain an improvement by cooking, or vacuum
drying, a tektronix epoxy transformer, but it will return
to its failed condition in a much shorter time than it did
originally.

My guess is the brownish/red coloration to the epoxy is
because tektronix added a fire retardant to the epoxy...
most everyone did back then, resulting in a lot of failures
over the years. One place you hear quite a lot about it is
in red doorknob style epoxy molded HV capacitors.

Time has showed that the bromine, and other fire retardants,
have failed in a variety of ways everywhere industry used
them.

Fire retardant plywood loses its structural integrity after
about 10 years, causing roofs to collapse. Fire retardant
added to plastic computer and monitor enclosures caused
them to turn brown over time... and let's not forget about
tris added to kid's pajamas!

-Chuck Harris



fiftythreebuick wrote:

Hi Dave-

I'm sorry to hear that you're having trouble with that HV XFMR....

I did a lot of testing and evaluation for Bill Schell over the years and I don't remember him every testing a transformer with any epoxy in it at all. He and I both felt that we oughta get as far away from that as possible. He first wound them without sealing them and I have never had one of those fail. Then when he started treating them with beeswax and a vacuum chamber, it seemed like he had found quite a good process. So far, I have never had one of his fail, of any description.

Just saw your later post and I'm glad that yours is improving! A friend of mine has restored an original xfmr by putting it in a vacuum chamber and keeping it in a deep vacuum for a while. Don't remember how long he left it in there.

I hope yours comes out alright. It really does seem like the moisture is the major factor.

Tom






widgethunter
 

Chuck;Am pleased to see that your ambitious undertaking is coming to fruition.I know that many Tek owners, who weren't so fortunate as to be able to keep their scopes working, are eagerly awaiting the day.We talked about this in terms of a side business, initially.If you are able to rewind other models, as well, you may be busy enough to get there, after all these years.Bernd

-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:45 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on.  Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris










Chuck Harris <cfharris@...>
 

Hi Bernd,

Since the winding pattern is entirely under computer
control, I can wind anything that goes on the cardboard
former that tektronix used.

The only other issues with models other than the 547/545B,
is termination. Small wires are easy, lugs or pins are
harder.

My highest priorities are 545B/547, 647A/B, and 576.

Anything that uses the same mounting as the 545B/547/647A/B
transformers should come essentially for free.

-Chuck Harris

widgethunter via groups.io wrote:

Chuck;Am pleased to see that your ambitious undertaking is coming to fruition.I know that many Tek owners, who weren't so fortunate as to be able to keep their scopes working, are eagerly awaiting the day.We talked about this in terms of a side business, initially.If you are able to rewind other models, as well, you may be busy enough to get there, after all these years.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:45 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on.  Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris



















 

Does that include the 561B? I need one, once you start winding again :)


Chuck Harris <cfharris@...>
 

Hi Charles,

I would imagine so, but I don't have anything that shows
what the 561B transformer looked like, nor how it mounted.

The 561A is the old style as was used in the 545 etal before
epoxy was used. It has micarta boards that fit into the
core window to insulate the filament winding from the core.

One of the family used a similar transformer, but stuffed it
into a drawn aluminum can with clear silicone RTV to insulate.

That might be more of a challenge, due to the wires all coming
out through the can's opening... High voltage, low voltage all
mingled together.

-Chuck Harris


Charles wrote:

Does that include the 561B? I need one, once you start winding again :)






David Holland
 

I directly emailed Chuck a picture of the 561B HV Transformer from my
B19xxx. (I hope he didn't mind.)

But I'll also freely admit it is a fairly late SN'd 561B.

David

On Fri, Mar 5, 2021 at 2:50 PM Chuck Harris <cfharris@erols.com> wrote:

Hi Charles,

I would imagine so, but I don't have anything that shows
what the 561B transformer looked like, nor how it mounted.

The 561A is the old style as was used in the 545 etal before
epoxy was used. It has micarta boards that fit into the
core window to insulate the filament winding from the core.

One of the family used a similar transformer, but stuffed it
into a drawn aluminum can with clear silicone RTV to insulate.

That might be more of a challenge, due to the wires all coming
out through the can's opening... High voltage, low voltage all
mingled together.

-Chuck Harris


Charles wrote:
Does that include the 561B? I need one, once you start winding again :)










Chuck Harris <cfharris@...>
 

Hi David,

Thank you for the picture.

The 561B tranny shown is in black epoxy, which isn't usually
a problem, and has turret posts, which adds to my expense.

I will probably keep the tranny open frame, and use an FR4
terminal board to handle either eyelets, or turrets... likely
eyelets.

-Chuck Harris

David Holland wrote:

I directly emailed Chuck a picture of the 561B HV Transformer from my
B19xxx. (I hope he didn't mind.)

But I'll also freely admit it is a fairly late SN'd 561B.

David

On Fri, Mar 5, 2021 at 2:50 PM Chuck Harris <cfharris@erols.com> wrote:


David Holland
 

Hi,

Yeah, it looks like you're correct there were brown epoxy impregnated
transformers in the 561B series. The manual I have (from Shannon Hill's
collection) lists 3 different revisions of the transformer in the 561B.
RPR & Transformer Diagrams show 4 different versions of the 120-0466-xx
transformer.

I did a little research against the transformer diagrams and what they were
coated/impregnated with.

120-0466-00 ( to B099999 ) Epoxy 252-0089-00 (Un-curiously this is the
same epoxy used on the 547 transformer 120-308.)
120-0466-01 ( to B159999 ) Silicone Varnish 252-0169-00, Silicone
Resin 252-0198-00
120-0466-02 ( and up ) Silicone Resin 252-0213-00 & 252-0214-00
120-0466-03 ( ??? ) Epoxy 255-0479-00

The same 120-0466-00 was used in the 564B, and the 568, per the RPR.

I found a couple of pictures of the -00 version in this EEVBlog thread:
https://www.eevblog.com/forum/repair/repairrestoration-of-a-tek-type-561b/50/

Looks brown to me... As Chuck said, mine, serial # B19xxx, is a -02, and
Black. I can't speak further to -01, and -03, but definitely there were
quite a pile of 561B/564B/568's made with now known bad epoxy.

The 567 was mentioned at one point in the transformer discussions recently,
per the transformer diagrams, the 567 transformer ( 120-292 ) was
impregnated with wax 256-508 (neither epoxy, nor silicone). My RM567 is
not in a position for me to look and confirm.

That's my contribution to the thread.... Cheers!

David

On Fri, Mar 5, 2021 at 5:04 PM Chuck Harris <cfharris@erols.com> wrote:

Hi David,

Thank you for the picture.

The 561B tranny shown is in black epoxy, which isn't usually
a problem, and has turret posts, which adds to my expense.

I will probably keep the tranny open frame, and use an FR4
terminal board to handle either eyelets, or turrets... likely
eyelets.

-Chuck Harris

David Holland wrote:
I directly emailed Chuck a picture of the 561B HV Transformer from my
B19xxx. (I hope he didn't mind.)

But I'll also freely admit it is a fairly late SN'd 561B.

David

On Fri, Mar 5, 2021 at 2:50 PM Chuck Harris <cfharris@erols.com> wrote:






 

On Fri, Mar 5, 2021 at 05:54 PM, David Holland wrote:
definitely there were quite a pile of 561B/564B/568's made with now known bad epoxy.
And mine is definitely one of them!
Chuck, I can send you a picture if that would help.


Chuck Harris <cfharris@...>
 

It would.

-Chuck Harris

Charles wrote:

On Fri, Mar 5, 2021 at 05:54 PM, David Holland wrote:
definitely there were quite a pile of 561B/564B/568's made with now known bad epoxy.
And mine is definitely one of them!
Chuck, I can send you a picture if that would help.






widgethunter
 

I do hope you are able to add 561/4B, 549 and 556, at some point...B

-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Fri, Mar 5, 2021 11:18 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

Since the winding pattern is entirely under computer
control, I can wind anything that goes on the cardboard
former that tektronix used.

The only other issues with models other than the 547/545B,
is termination.  Small wires are easy, lugs or pins are
harder.

My highest priorities are 545B/547, 647A/B, and 576.

Anything that uses the same mounting as the 545B/547/647A/B
transformers should come essentially for free.

-Chuck Harris

widgethunter via groups.io wrote:
Chuck;Am pleased to see that your ambitious undertaking is coming to fruition.I know that many Tek owners, who weren't so fortunate as to be able to keep their scopes working, are eagerly awaiting the day.We talked about this in terms of a side business, initially.If you are able to rewind other models, as well, you may be busy enough to get there, after all these years.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:45 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on.  Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris



















Chuck Harris <cfharris@...>
 

Hi Bernd,

As I said, anything that fits on the usual ferrite core,
and uses the usual cardboard former for the winding can
be wound with my machine. So, it's all the same to me.

I will make up the recipe's for the 547/545B, 647, and 576
first, and as demand happens, the recipe's for whatever...

The biggest issue is testing. I build a mock up of the
547/545B HV section so I could easily test the transformers
I built before. It will be difficult to do that if I am
winding the whole spectrum of HV transformers that Tek
once wound.

I will probably have to take some of my Kepco BOP supplies,
and use them to drive the primary, and some sort of generic
load for the secondary...

-Chuck Harris

widgethunter via groups.io wrote:

I do hope you are able to add 561/4B, 549 and 556, at some point...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Fri, Mar 5, 2021 11:18 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

Since the winding pattern is entirely under computer
control, I can wind anything that goes on the cardboard
former that tektronix used.

The only other issues with models other than the 547/545B,
is termination.  Small wires are easy, lugs or pins are
harder.

My highest priorities are 545B/547, 647A/B, and 576.

Anything that uses the same mounting as the 545B/547/647A/B
transformers should come essentially for free.

-Chuck Harris

widgethunter via groups.io wrote:
Chuck;Am pleased to see that your ambitious undertaking is coming to fruition.I know that many Tek owners, who weren't so fortunate as to be able to keep their scopes working, are eagerly awaiting the day.We talked about this in terms of a side business, initially.If you are able to rewind other models, as well, you may be busy enough to get there, after all these years.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:45 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

All indications are that my new machine is going to
do an even better job than the best I could do with
the old manual machine.

As an example, I was able to get 2/3 of the way to a
full wind without using the rosin/alcohol mixture that
I developed to enhance the wire's friction...

Using the rosin/alcohol, I am there already.

And, I will be using beeswax.

I'm glad to hear the prototype is still soldiering
on.  Soon, I may be able to get you the winds I promised
oh so long ago...

-Chuck Harris

widgethunter via groups.io wrote:
My memory certainly hasn't improved with age.Not much else seems to have, either...But, the beeswax thing I'd be willing to put money on - fwiw.
Incidentally, I still have not installed the 2nd wax xfrmr you made for me, but the 1st prototype continues to perform flawlessly.Bernd



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Thu, Mar 4, 2021 4:05 pm
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

I guess the biggest indicator of a scatter wind would be
the presence of a spool.  The universal wind doesn't require
any additional support.

In addition to talking to you, I talked to Deane Kidd, and
Deane talked about Bill using beeswax, like tektronix did in
the earlier transformers.

But, like you, it has been a looong time, and I don't think
our memories are getting any better.

-Chuck Harris

widgethunter via groups.io wrote:
Hi Chuck;Assumed scatter because of the larger size of Schell rewinds.It has been a looong time, but I think I'd remember if he'd said anything about epoxy...B



-----Original Message-----
From: Chuck Harris <cfharris@erols.com>
To: TekScopes@groups.io
Sent: Wed, Mar 3, 2021 9:57 am
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound.  It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer.  The
naked winding is right there for you to see.

-Chuck Harris