Date   

Re: How I transform a 5A20N to work in a TM500 mainframe

Mark Wendt <mark.wendt@...>
 

I'm with Dennis. Those are some really nice products. Well done.

Google Translate sorta worked. I'm still trying to find the strawberries google translate says are in the design. ;-)

Mark

On 12/08/2013 08:23 PM, Dennis Tillman wrote:


Hi Philippe,

All three projects at your web page are FABULOUS.

It is always great to see some new ideas turned into professional finished products that anyone at Tek would have been proud to have designed.

Keep up the great work,

Dennis Tillman W7PF

PS Google will automatically translate French to English so language is no problem.

*From:*nixie@free.fr <mailto:nixie@free.fr>, *Sent:* Sunday, December 08, 2013 2:17 PM

Hi everybody,

I am a Tek fan and may be some of you may be interesed by my last plugin works.
Normally the AM50X sï¿œrie for TM500 stops at AM503, I have made a AM504 from a 5A20N vertical oscilloscope amplifier to continue the serie....

I have put all the description on my personal WebSite, so clic on the link to see the item :_http://philippe.demerliac.free.fr/TekLab.htm#AM504

_Sorry, my site is in French. My english is not perfect but if you have any question, you can post a reply or send me an email and I'll reply to you.

Enjoy it and have a good day....




Re: How I transform a 5A20N to work in a TM500 mainframe

 

Hi,

 

No sorry, once again it's a bad translation. I used to write my website using a lot of joke and funny expressions that automatic transaltor transform in some strange ways... This sentence just said that the both transistors are monted on the heatsink, even if i added decopling capacitor nearest to the amp  :-)


Re: How I transform a 5A20N to work in a TM500 mainframe

 

It looks very nice.

I was going to ask if you had a schematic showing how you did the differential
to single ended conversion but you described it.

My solution so far has been to use the vertical output of a 7000 series
mainframe with a 7A13 or 7A22.

On 08 Dec 2013 14:16:45 -0800, you wrote:

Hi everybody,

I am a Tek fan and may be some of you may be interesed by my last plugin works.
Normally the AM50X série for TM500 stops at AM503, I have made a AM504 from a 5A20N vertical oscilloscope amplifier to continue the serie....

I have put all the description on my personal WebSite, so clic on the link to see the item : http://philippe.demerliac.free.fr/TekLab.htm#AM504 http://philippe.demerliac.free.fr/TekLab.htm#AM504

Sorry, my site is in French. My english is not perfect but if you have any question, you can post a reply or send me an email and I'll reply to you.

Enjoy it and have a good day....


Re: How I transform a 5A20N to work in a TM500 mainframe

 

"I ride 2 Huskies on a radiator attached to the plate. "

From now on decoupling capacitors will be called huskies. At least I think they
are decoupling capacitors.

On Sun, 8 Dec 2013 20:39:51 -0500, you wrote:

Very nice projects.

Translations get interesting. I'm still not sure what Google meant by "bagpipes"
which turned up a couple times in the translation.

Paul


Re: How I transform a 5A20N to work in a TM500 mainframe

 

Thanks a lot for your nice comments.I have a litle problem on my website so the link show only one page. youn can see all at www;cyrob.org


Re: How I transform a 5A20N to work in a TM500 mainframe

 

Hello

Biniou, which is translated by BagPipe ;is a kind of slang expression.

It just to Speak about the prototype. :)


Re: Service manual for CFG280

Stan & Patricia Griffiths
 

I DO have a couple  of other CFG280 documents that you might be interested in.  Tek did write an Adjustment Procedure telling how to do all the adjustments.  They also wrote a Performance Check Procedure that tells how to check out the CFG280 to make sure it meets all the parameters it should.

 

Personally, I find it WAY more convenient to have ONE procedure that combines the Performance Check and Adjustment procedures and go through the CFG280 just one time checking AND adjusting as you go.  I wrote my own to accomplish that.

 

Stan

 

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Reed Dickinson
Sent: Saturday, December 17, 2011 9:07 PM
To: TekScopes@...
Subject: [TekScopes] Service manual for CFG280

 

 

I am seeking a service manual for a Tek CFG280 Function Generator.  If you have one on a scan I would be delighted to download it,  If you have one for sale please drop me a note.

Reed Dickinson
reed714@...


Re: 545 HV won't oscillate 100% of the time.

Chuck Harris <cfharris@...>
 

It is not PCB. Once you have smelled PCB, you will never forget
the odor. It is just mineral oil.

-Chuck Harris

Daniel Koller wrote:

Good question. But in any case, I treated it as if it was PCB - wiped it up
before handling, and washed my hands frequently.

Dan




On Sunday, December 8, 2013 6:44 PM, Don Black <donald_black@bigpond.com> wrote:


Does anyone know if the leaking oil is PCB?

Don Black.


Re: How I transform a 5A20N to work in a TM500 mainframe

alexeisenhut@...
 

Mais c'est quoi un "biniou"?


Re: 545 HV won't oscillate 100% of the time.

Daniel Koller
 

Good question.  But in any case, I treated it as if it was PCB - wiped it up before handling, and washed my hands frequently.

Dan



On Sunday, December 8, 2013 6:44 PM, Don Black wrote:
 
Does anyone know if the leaking oil is PCB?

Don Black.

On 09-Dec-13 9:48 AM, Daniel Koller wrote:
 
Yup - I agree!  I Ended up replacing C800, C803, C805 and C806 - basically all the remaining bumblebees in the primary circuit of my HV power supply.  The two 0.001 uF caps were clearly leaking oil on the photo I posted earlier.  What was less evident, and I didn't notice until I got some better lighting, was the crack lengthwise across the 0.01uF cap, second from the top in: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781

...and the 0.047 uF cap was similarly cracked on the bottom.  Yet ALL tested just fine at low voltage on my new Chinese tester.  But apply any voltage to them whatsoever (~>10V) and they all leaked to different degrees.  They all had effective resistances of ~~10's of Megohms, so at 100V, ~~10  micro amps leakage.  I'm glad I did not get rid of my old Eico 950 tester!

  So, now my HV works, but with a catch.  It turns on by itself about 1 minute after the tubes turn on.  That's about 1 minute after the B+ relay clicks on.  I can occasionally accelerate the turn-on by jostling the intensity knob.  So, it's not 100% fixed, but I am fine with this.  I don't have the patience to troubleshoot further since it is working well when warmed up.  I'm thinking a weak 6AU5 is the culprit here, no?

  In addition I replaced the vertical output capacitor because I measured ~20V DC at the vertical signal out terminal with no vertical deflection on the screen - leakage.  There are a couple oil filled caps left in the power supply that don't appear to be cracked or leaking, and I am just going to have to leave them there for now.   I'll stock up on replacement parts in the meantime.    All voltages are dead on - I'm not touching the power supply.

  Finally, I now understand those extra components in my photo.  The 33K (not 2.2K - it's hard to tell the orange from the red) and the 470 pF cap seem to have been added in some sort of factory refurb.  These are present in the 545A schematic, so it seems my 545 was partly upgraded to a 545A.  That probably also explains the Silicon diodes on that board in the power supply.

  Dan

On Sunday, December 8, 2013 9:35 AM, "bonddaleena@..." wrote:

>I have replaced literally BUCKETS full of BBOD, Bumblebees, wax caps, etc. I have NEVER seen a single one that would pass a leakage test at rated voltage.
>They might 'test' fine for VALUE on my NIST traceable bridge, but they all leak at HV.
>
>As the Prez would say:
>
>"PERIOD!"
>
>ha ha
>
>ron
>N4UE
>
>
>
>
>
>
>
>-----Original Message-----
>From: Don Black
>To: TekScopes
>Sent: Sun, Dec 8, 2013 4:17 am
>Subject: Re: [TekScopes] 545 HV won't oscillate 100% of the time.
>
>

>Oops. I meant eBay bumblebee and black beauty caps, not tubes. Freudian slip??
>
>Don Black.
>
>On 08-Dec-13 8:09 PM, Don Black wrote:
>

>>I hope you get it sorted out Dan but I was being facetious about the eBay tubes advertised as tested good. I wonder what tests were done? I noticed another ad for similar caps saying they were tested OK on a bridge. No mention of leakage or if the bridge had to be adjusted for losses. Maybe I'm just getting cynical in my old age.
>>
>>Don Black,
>>
>>On 08-Dec-13 10:33 AM, Daniel Koller wrote:
>>
>> 
>>>Hi all,
>>>  My caps probably are bad.  When I first got the
                  scope around 1980, I learned about "black beauties"
                  and had to replace them in the power supply, but I
                  think I recall being told that the bumble-bee types
                  were fine, so those stayed in.  Now it looks like I
                  have leakage from them in the HV power supply.  See
                  the attached photo
                  here: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781
>>>The two shiny black 0.001 uF caps stand out because
                  they are coated in oil.  You can't see it on the
                  photo, but there is a film of liquid oil between the
                  middle cap and the 56K resistor below it.  Those two
                  are coming out but being a big fan of "don't mess with
                  it if it ain't broke" I might leave the other caps in
                  unless there is an obvious failure. Mind you, my scope
                  works well when it does turn on.
>>>
>>>But I've had some other modifications it seems.
                   What's that square cap on the left and the 2.2K
                  resistor doing there?  I'll have to trace the circuit
                  to see where they were put in and why.  Maybe that was
                  a long ago patch for the oscillator failure?  Or the
                  cause of it now?
>>>
>>>I see now why I had originally thought my scope was
                  much younger than it is - before I learned from the
                  group here that the "brown" Teks were pre-1954.  There
                  is this circuit board in my scope:
>>>http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1026393052
>>>Someone seems to have made factory improvements circa
                  1967.   What was in its place before this?  Is it
                  possible my additional HV circuit components were
                  placed in the same upgrades/refurbishment?
>>>
>>>Back to the shop.  I've got an hour before guests
                  arrive!
>>>
>>>Dan
>>>
>>>On Saturday, December 7, 2013 10:58 AM, Don Black wrote:
>>>
>>>>I'm not so sure. Yours may be faulty, these are
                  tested good so they must be a rare animal.
>>>>
>>>>Don Black.
>>>>
>>>>On 08-Dec-13 2:31 AM, Daniel Koller wrote:
>>>>
>>>> 
>>>>>I'll check and see what's in there.   And when
                  I take them out, I'll sell them on e-bay to an
                  audiophool!!
>>>>>http://www.ebay.com/itm/4-TUBE-AMP-CAPACITORS-0-1uF-400V-Sprague-Bumblebee/171185528791?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D177%26meid%3D3232141210003616509%26pid%3D100009%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D181276706729%26
>>>>>
>>>>>(No affiliation with the seller!)
>>>>>
>>>>>Dan
>>>>>
>>>>>On Friday, December 6, 2013 11:27 PM, Chuck
                  Harris wrote:
>>>>>
>>>>>>Most of the time with the 545, the problem
                  is the
>>>              black beauty oil/paper
>>>>>>tubular capacitors used for the HV
                  filters.  They
>>>              always go bad, and if
>>>>>>they haven't been replaced, you must
                  replace
>>>              them.  Ceramic is fine.
>>>>>>
>>>>>>There is also a BB cap that is in series
                  with the grid
>>>              feedback winding,
>>>>>>and another in parallel with the plate
                  winding.  Both
>>>              must go.
>>>>>>
>>>>>>-Chuck Harris
>>>>>>
>>>>>>Daniel Koller wrote:
>>>>>>> Howdy,
>>>>>>>
>>>>>>> The recent discussions on HV repairs
                  has me
>>>              thinking I should look into the issues
>>>>>>> in my 545 (not A or B, old style
                  square case).  
>>>              It works very very well, but
>>>>>>> about half of the time, increasingly
                  more, the HV
>>>              circuit will not oscillate.  If
>>>>>>> I pull the plug-in out and drop it
                  back in, it
>>>              will work.  I know this is not a
>>>>>>> recommended option!  Alternatively,
                  if I shut it
>>>              off and wait for it to cool, it
>>>>>>> will work when I turn it on with
                  about the same
>>>              probability, or a little less.
>>>>>>> Once the scope is on it's up to spec.
>>>>>>>
>>>>>>> The 6AU5 is not brand new, but is
                  good.  It was
>>>              replaced recently with no
>>>>>>> improvement.
>>>>>>>
>>>>>>> So, suggestions as to where to start
                  on this
>>>              intermittant problem are welcome.  Is
>>>>>>> there anything I should look for or
                  measure that
>>>              might indicate what is getting
>>>>>>> tired?
>>>>>>>
>>>>>>> Dan
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>>>________________________________
>>>>
>>>>   This email is free from viruses and malware
                  because avast! Antivirus protection is active.  
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>>>>________________________________
>>
>>   This email is free from viruses and malware because avast! Antivirus protection is active.  
>>
>
>
>>________________________________
>
>   This email is free from viruses and malware because avast! Antivirus protection is active.  
>
>
>
>




This email is free from viruses and malware because avast! Antivirus protection is active.




Re: How I transform a 5A20N to work in a TM500 mainframe

Paul Amaranth
 

Very nice projects.

Translations get interesting. I'm still not sure what Google meant by "bagpipes"
which turned up a couple times in the translation.

Paul

On Sun, Dec 08, 2013 at 05:23:18PM -0800, Dennis Tillman wrote:
Hi Philippe,



All three projects at your web page are FABULOUS.

It is always great to see some new ideas turned into professional finished products that anyone at Tek would have been proud to have designed.

Keep up the great work,



Dennis Tillman W7PF



PS Google will automatically translate French to English so language is no problem.



From: nixie@free.fr, Sent: Sunday, December 08, 2013 2:17 PM



Hi everybody,

I am a Tek fan and may be some of you may be interesed by my last plugin works.
Normally the AM50X s�rie for TM500 stops at AM503, I have made a AM504 from a 5A20N vertical oscilloscope amplifier to continue the serie....

I have put all the description on my personal WebSite, so clic on the link to see the item : http://philippe.demerliac.free.fr/TekLab.htm#AM504

Sorry, my site is in French. My english is not perfect but if you have any question, you can post a reply or send me an email and I'll reply to you.

Enjoy it and have a good day....
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@AuroraGrp.Com | Unix & Windows


How I transform a 5A20N to work in a TM500 mainframe

 

Hi Philippe,

 

All three projects at your web page are FABULOUS.

It is always great to see some new ideas turned into professional finished products that anyone at Tek would have been proud to have designed.

Keep up the great work,

 

Dennis Tillman W7PF

 

PS Google will automatically translate French to English so language is no problem.

 

From: nixie@..., Sent: Sunday, December 08, 2013 2:17 PM

Hi everybody,

I am a Tek fan and may be some of you may be interesed by my last plugin works.
Normally the AM50X série for TM500 stops at AM503, I have made a AM504 from a 5A20N vertical oscilloscope amplifier to continue the serie....

I have put all the description on my personal WebSite, so clic on the link to see the item : http://philippe.demerliac.free.fr/TekLab.htm#AM504

Sorry, my site is in French. My english is not perfect but if you have any question, you can post a reply or send me an email and I'll reply to you.

Enjoy it and have a good day....


Re: 545 HV won't oscillate 100% of the time.

Don Black <donald_black@...>
 

Does anyone know if the leaking oil is PCB?

Don Black.

On 09-Dec-13 9:48 AM, Daniel Koller wrote:
 

Yup - I agree!  I Ended up replacing C800, C803, C805 and C806 - basically all the remaining bumblebees in the primary circuit of my HV power supply.  The two 0.001 uF caps were clearly leaking oil on the photo I posted earlier.  What was less evident, and I didn't notice until I got some better lighting, was the crack lengthwise across the 0.01uF cap, second from the top in: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781

...and the 0.047 uF cap was similarly cracked on the bottom.  Yet ALL tested just fine at low voltage on my new Chinese tester.  But apply any voltage to them whatsoever (~>10V) and they all leaked to different degrees.  They all had effective resistances of ~~10's of Megohms, so at 100V, ~~10  micro amps leakage.  I'm glad I did not get rid of my old Eico 950 tester!

  So, now my HV works, but with a catch.  It turns on by itself about 1 minute after the tubes turn on.  That's about 1 minute after the B+ relay clicks on.  I can occasionally accelerate the turn-on by jostling the intensity knob.  So, it's not 100% fixed, but I am fine with this.  I don't have the patience to troubleshoot further since it is working well when warmed up.  I'm thinking a weak 6AU5 is the culprit here, no?

  In addition I replaced the vertical output capacitor because I measured ~20V DC at the vertical signal out terminal with no vertical deflection on the screen - leakage.  There are a couple oil filled caps left in the power supply that don't appear to be cracked or leaking, and I am just going to have to leave them there for now.   I'll stock up on replacement parts in the meantime.    All voltages are dead on - I'm not touching the power supply.

  Finally, I now understand those extra components in my photo.  The 33K (not 2.2K - it's hard to tell the orange from the red) and the 470 pF cap seem to have been added in some sort of factory refurb.  These are present in the 545A schematic, so it seems my 545 was partly upgraded to a 545A.  That probably also explains the Silicon diodes on that board in the power supply.

  Dan

On Sunday, December 8, 2013 9:35 AM, "bonddaleena@..." wrote:

>I have replaced literally BUCKETS full of BBOD, Bumblebees, wax caps, etc. I have NEVER seen a single one that would pass a leakage test at rated voltage.
>They might 'test' fine for VALUE on my NIST traceable bridge, but they all leak at HV.
>
>As the Prez would say:
>
>"PERIOD!"
>
>ha ha
>
>ron
>N4UE
>
>
>
>
>
>
>
>-----Original Message-----
>From: Don Black
>To: TekScopes
>Sent: Sun, Dec 8, 2013 4:17 am
>Subject: Re: [TekScopes] 545 HV won't oscillate 100% of the time.
>
>

>Oops. I meant eBay bumblebee and black beauty caps, not tubes. Freudian slip??
>
>Don Black.
>
>On 08-Dec-13 8:09 PM, Don Black wrote:
>

>>I hope you get it sorted out Dan but I was being facetious about the eBay tubes advertised as tested good. I wonder what tests were done? I noticed another ad for similar caps saying they were tested OK on a bridge. No mention of leakage or if the bridge had to be adjusted for losses. Maybe I'm just getting cynical in my old age.
>>
>>Don Black,
>>
>>On 08-Dec-13 10:33 AM, Daniel Koller wrote:
>>
>> 
>>>Hi all,
>>>  My caps probably are bad.  When I first got the
                  scope around 1980, I learned about "black beauties"
                  and had to replace them in the power supply, but I
                  think I recall being told that the bumble-bee types
                  were fine, so those stayed in.  Now it looks like I
                  have leakage from them in the HV power supply.  See
                  the attached photo
                  here: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781
>>>The two shiny black 0.001 uF caps stand out because
                  they are coated in oil.  You can't see it on the
                  photo, but there is a film of liquid oil between the
                  middle cap and the 56K resistor below it.  Those two
                  are coming out but being a big fan of "don't mess with
                  it if it ain't broke" I might leave the other caps in
                  unless there is an obvious failure. Mind you, my scope
                  works well when it does turn on.
>>>
>>>But I've had some other modifications it seems.
                   What's that square cap on the left and the 2.2K
                  resistor doing there?  I'll have to trace the circuit
                  to see where they were put in and why.  Maybe that was
                  a long ago patch for the oscillator failure?  Or the
                  cause of it now?
>>>
>>>I see now why I had originally thought my scope was
                  much younger than it is - before I learned from the
                  group here that the "brown" Teks were pre-1954.  There
                  is this circuit board in my scope:
>>>http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1026393052
>>>Someone seems to have made factory improvements circa
                  1967.   What was in its place before this?  Is it
                  possible my additional HV circuit components were
                  placed in the same upgrades/refurbishment?
>>>
>>>Back to the shop.  I've got an hour before guests
                  arrive!
>>>
>>>Dan
>>>
>>>On Saturday, December 7, 2013 10:58 AM, Don Black wrote:
>>>
>>>>I'm not so sure. Yours may be faulty, these are
                  tested good so they must be a rare animal.
>>>>
>>>>Don Black.
>>>>
>>>>On 08-Dec-13 2:31 AM, Daniel Koller wrote:
>>>>
>>>> 
>>>>>I'll check and see what's in there.   And when
                  I take them out, I'll sell them on e-bay to an
                  audiophool!!
>>>>>http://www.ebay.com/itm/4-TUBE-AMP-CAPACITORS-0-1uF-400V-Sprague-Bumblebee/171185528791?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D177%26meid%3D3232141210003616509%26pid%3D100009%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D181276706729%26
>>>>>
>>>>>(No affiliation with the seller!)
>>>>>
>>>>>Dan
>>>>>
>>>>>On Friday, December 6, 2013 11:27 PM, Chuck
                  Harris wrote:
>>>>>
>>>>>>Most of the time with the 545, the problem
                  is the
>>>              black beauty oil/paper
>>>>>>tubular capacitors used for the HV
                  filters.  They
>>>              always go bad, and if
>>>>>>they haven't been replaced, you must
                  replace
>>>              them.  Ceramic is fine.
>>>>>>
>>>>>>There is also a BB cap that is in series
                  with the grid
>>>              feedback winding,
>>>>>>and another in parallel with the plate
                  winding.  Both
>>>              must go.
>>>>>>
>>>>>>-Chuck Harris
>>>>>>
>>>>>>Daniel Koller wrote:
>>>>>>> Howdy,
>>>>>>>
>>>>>>> The recent discussions on HV repairs
                  has me
>>>              thinking I should look into the issues
>>>>>>> in my 545 (not A or B, old style
                  square case).  
>>>              It works very very well, but
>>>>>>> about half of the time, increasingly
                  more, the HV
>>>              circuit will not oscillate.  If
>>>>>>> I pull the plug-in out and drop it
                  back in, it
>>>              will work.  I know this is not a
>>>>>>> recommended option!  Alternatively,
                  if I shut it
>>>              off and wait for it to cool, it
>>>>>>> will work when I turn it on with
                  about the same
>>>              probability, or a little less.
>>>>>>> Once the scope is on it's up to spec.
>>>>>>>
>>>>>>> The 6AU5 is not brand new, but is
                  good.  It was
>>>              replaced recently with no
>>>>>>> improvement.
>>>>>>>
>>>>>>> So, suggestions as to where to start
                  on this
>>>              intermittant problem are welcome.  Is
>>>>>>> there anything I should look for or
                  measure that
>>>              might indicate what is getting
>>>>>>> tired?
>>>>>>>
>>>>>>> Dan
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>>>________________________________
>>>>
>>>>   This email is free from viruses and malware
                  because avast! Antivirus protection is active.  
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>>>>________________________________
>>
>>   This email is free from viruses and malware because avast! Antivirus protection is active.  
>>
>
>
>>________________________________
>
>   This email is free from viruses and malware because avast! Antivirus protection is active.  
>
>
>
>





This email is free from viruses and malware because avast! Antivirus protection is active.



Re: 545 HV won't oscillate 100% of the time.

bonddaleena@...
 

Hi Dan. One thing I collect is test equipment. I have a LOT of cap testers. The battery powered ones work OK for value but not leakage, as you mentioned.....
Even though I have some high $ commercial leakage testers, my go-to cap tester (on my main bench) is an OLD VTVM and a HVPS that increments in 50V steps up to 600VDC.
It was explained to me years ago by Dr. Jerry, the Technical Consultant for the Collins Radio Collector Assn.
Simple, fast and dependable.

ron
N4UE.



-----Original Message-----
From: Daniel Koller
To: TekScopes
Sent: Sun, Dec 8, 2013 5:48 pm
Subject: Re: [TekScopes] 545 HV won't oscillate 100% of the time.

 
Yup - I agree!  I Ended up replacing C800, C803, C805 and C806 - basically all the remaining bumblebees in the primary circuit of my HV power supply.  The two 0.001 uF caps were clearly leaking oil on the photo I posted earlier.  What was less evident, and I didn't notice until I got some better lighting, was the crack lengthwise across the 0.01uF cap, second from the top in: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781

...and the 0.047 uF cap was similarly cracked on the bottom.  Yet ALL tested just fine at low voltage on my new Chinese tester.  But apply any voltage to them whatsoever (~>10V) and they all leaked to different degrees.  They all had effective resistances of ~~10's of Megohms, so at 100V, ~~10  micro amps leakage.  I'm glad I did not get rid of my old Eico 950 tester!

  So, now my HV works, but with a catch.  It turns on by itself about 1 minute after the tubes turn on.  That's about 1 minute after the B+ relay clicks on.  I can occasionally accelerate the turn-on by jostling the intensity knob.  So, it's not 100% fixed, but I am fine with this.  I don't have the patience to troubleshoot further since it is working well when warmed up.  I'm thinking a weak 6AU5 is the culprit here, no?

  In addition I replaced the vertical output capacitor because I measured ~20V DC at the vertical signal out terminal with no vertical deflection on the screen - leakage.  There are a couple oil filled caps left in the power supply that don't appear to be cracked or leaking, and I am just going to have to leave them there for now.   I'll stock up on replacement parts in the meantime.    All voltages are dead on - I'm not touching the power supply.

  Finally, I now understand those extra components in my photo.  The 33K (not 2.2K - it's hard to tell the orange from the red) and the 470 pF cap seem to have been added in some sort of factory refurb.  These are present in the 545A schematic, so it seems my 545 was partly upgraded to a 545A.  That probably also explains the Silicon diodes on that board in the power supply.

  Dan

On Sunday, December 8, 2013 9:35 AM, "bonddaleena@..." <bonddaleena@...> wrote:

>I have replaced literally BUCKETS full of BBOD, Bumblebees, wax caps, etc. I have NEVER seen a single one that would pass a leakage test at rated voltage.
>They might 'test' fine for VALUE on my NIST traceable bridge, but they all leak at HV.
>
>As the Prez would say:
>
>"PERIOD!"
>
>ha ha
>
>ron
>N4UE
>
>
>
>
>
>
>
>-----Original Message-----
>From: Don Black <donald_black@...>
>To: TekScopes <TekScopes@...>
>Sent: Sun, Dec 8, 2013 4:17 am
>Subject: Re: [TekScopes] 545 HV won't oscillate 100% of the time.
>
>

>Oops. I meant eBay bumblebee and black beauty caps, not tubes. Freudian slip??
>
>Don Black.
>
>On 08-Dec-13 8:09 PM, Don Black wrote:
>

>>I hope you get it sorted out Dan but I was being facetious about the eBay tubes advertised as tested good. I wonder what tests were done? I noticed another ad for similar caps saying they were tested OK on a bridge. No mention of leakage or if the bridge had to be adjusted for losses. Maybe I'm just getting cynical in my old age.
>>
>>Don Black,
>>
>>On 08-Dec-13 10:33 AM, Daniel Koller wrote:
>>
>> 
>>>Hi all,
>>>  My caps probably are bad.  When I first got the
                  scope around 1980, I learned about "black beauties"
                  and had to replace them in the power supply, but I
                  think I recall being told that the bumble-bee types
                  were fine, so those stayed in.  Now it looks like I
                  have leakage from them in the HV power supply.  See
                  the attached photo
                  here: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781
>>>The two shiny black 0.001 uF caps stand out because
                  they are coated in oil.  You can't see it on the
                  photo, but there is a film of liquid oil between the
                  middle cap and the 56K resistor below it.  Those two
                  are coming out but being a big fan of "don't mess with
                  it if it ain't broke" I might leave the other caps in
                  unless there is an obvious failure. Mind you, my scope
                  works well when it does turn on.
>>>
>>>But I've had some other modifications it seems.
                   What's that square cap on the left and the 2.2K
                  resistor doing there?  I'll have to trace the circuit
                  to see where they were put in and why.  Maybe that was
                  a long ago patch for the oscillator failure?  Or the
                  cause of it now?
>>>
>>>I see now why I had originally thought my scope was
                  much younger than it is - before I learned from the
                  group here that the "brown" Teks were pre-1954.  There
                  is this circuit board in my scope:
>>>http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1026393052
>>>Someone seems to have made factory improvements circa
                  1967.   What was in its place before this?  Is it
                  possible my additional HV circuit components were
                  placed in the same upgrades/refurbishment?
>>>
>>>Back to the shop.  I've got an hour before guests
                  arrive!
>>>
>>>Dan
>>>
>>>On Saturday, December 7, 2013 10:58 AM, Don Black <donald_black@...> wrote:
>>>
>>>>I'm not so sure. Yours may be faulty, these are
                  tested good so they must be a rare animal.
>>>>
>>>>Don Black.
>>>>
>>>>On 08-Dec-13 2:31 AM, Daniel Koller wrote:
>>>>
>>>> 
>>>>>I'll check and see what's in there.   And when
                  I take them out, I'll sell them on e-bay to an
                  audiophool!!
>>>>>http://www.ebay.com/itm/4-TUBE-AMP-CAPACITORS-0-1uF-400V-Sprague-Bumblebee/171185528791?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D177%26meid%3D3232141210003616509%26pid%3D100009%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D181276706729%26
>>>>>
>>>>>(No affiliation with the seller!)
>>>>>
>>>>>Dan
>>>>>
>>>>>On Friday, December 6, 2013 11:27 PM, Chuck
                  Harris <cfharris@...> wrote:
>>>>>
>>>>>>Most of the time with the 545, the problem
                  is the
>>>              black beauty oil/paper
>>>>>>tubular capacitors used for the HV
                  filters.  They
>>>              always go bad, and if
>>>>>>they haven't been replaced, you must
                  replace
>>>              them.  Ceramic is fine.
>>>>>>
>>>>>>There is also a BB cap that is in series
                  with the grid
>>>              feedback winding,
>>>>>>and another in parallel with the plate
                  winding.  Both
>>>              must go.
>>>>>>
>>>>>>-Chuck Harris
>>>>>>
>>>>>>Daniel Koller wrote:
>>>>>>> Howdy,
>>>>>>>
>>>>>>> The recent discussions on HV repairs
                  has me
>>>              thinking I should look into the issues
>>>>>>> in my 545 (not A or B, old style
                  square case).  
>>>              It works very very well, but
>>>>>>> about half of the time, increasingly
                  more, the HV
>>>              circuit will not oscillate.  If
>>>>>>> I pull the plug-in out and drop it
                  back in, it
>>>              will work.  I know this is not a
>>>>>>> recommended option!  Alternatively,
                  if I shut it
>>>              off and wait for it to cool, it
>>>>>>> will work when I turn it on with
                  about the same
>>>              probability, or a little less.
>>>>>>> Once the scope is on it's up to spec.
>>>>>>>
>>>>>>> The 6AU5 is not brand new, but is
                  good.  It was
>>>              replaced recently with no
>>>>>>> improvement.
>>>>>>>
>>>>>>> So, suggestions as to where to start
                  on this
>>>              intermittant problem are welcome.  Is
>>>>>>> there anything I should look for or
                  measure that
>>>              might indicate what is getting
>>>>>>> tired?
>>>>>>>
>>>>>>> Dan
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>>>________________________________
>>>>
>>>>   This email is free from viruses and malware
                  because avast! Antivirus protection is active.  
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>>>>________________________________
>>
>>   This email is free from viruses and malware because avast! Antivirus protection is active.  
>>
>
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>>________________________________
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>   This email is free from viruses and malware because avast! Antivirus protection is active.  
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Re: 545 HV won't oscillate 100% of the time.

Daniel Koller
 

Yup - I agree!  I Ended up replacing C800, C803, C805 and C806 - basically all the remaining bumblebees in the primary circuit of my HV power supply.  The two 0.001 uF caps were clearly leaking oil on the photo I posted earlier.  What was less evident, and I didn't notice until I got some better lighting, was the crack lengthwise across the 0.01uF cap, second from the top in: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781

...and the 0.047 uF cap was similarly cracked on the bottom.  Yet ALL tested just fine at low voltage on my new Chinese tester.  But apply any voltage to them whatsoever (~>10V) and they all leaked to different degrees.  They all had effective resistances of ~~10's of Megohms, so at 100V, ~~10  micro amps leakage.  I'm glad I did not get rid of my old Eico 950 tester!

  So, now my HV works, but with a catch.  It turns on by itself about 1 minute after the tubes turn on.  That's about 1 minute after the B+ relay clicks on.  I can occasionally accelerate the turn-on by jostling the intensity knob.  So, it's not 100% fixed, but I am fine with this.  I don't have the patience to troubleshoot further since it is working well when warmed up.  I'm thinking a weak 6AU5 is the culprit here, no?

  In addition I replaced the vertical output capacitor because I measured ~20V DC at the vertical signal out terminal with no vertical deflection on the screen - leakage.  There are a couple oil filled caps left in the power supply that don't appear to be cracked or leaking, and I am just going to have to leave them there for now.   I'll stock up on replacement parts in the meantime.    All voltages are dead on - I'm not touching the power supply.

  Finally, I now understand those extra components in my photo.  The 33K (not 2.2K - it's hard to tell the orange from the red) and the 470 pF cap seem to have been added in some sort of factory refurb.  These are present in the 545A schematic, so it seems my 545 was partly upgraded to a 545A.  That probably also explains the Silicon diodes on that board in the power supply.

  Dan





On Sunday, December 8, 2013 9:35 AM, "bonddaleena@aol.com" <bonddaleena@aol.com> wrote:


I have replaced literally BUCKETS full of BBOD, Bumblebees, wax caps, etc. I have NEVER seen a single one that would pass a leakage test at rated voltage.
They might 'test' fine for VALUE on my NIST traceable bridge, but they all leak at HV.

As the Prez would say:

"PERIOD!"

ha ha

ron
N4UE







-----Original Message-----
From: Don Black <donald_black@bigpond.com>
To: TekScopes <TekScopes@yahoogroups.com>
Sent: Sun, Dec 8, 2013 4:17 am
Subject: Re: [TekScopes] 545 HV won't oscillate 100% of the time.


 
Oops. I meant eBay bumblebee and black beauty caps, not tubes. Freudian slip??

Don Black.

On 08-Dec-13 8:09 PM, Don Black wrote:

 
I hope you get it sorted out Dan but I was being facetious about the eBay tubes advertised as tested good. I wonder what tests were done? I noticed another ad for similar caps saying they were tested OK on a bridge. No mention of leakage or if the bridge had to be adjusted for losses. Maybe I'm just getting cynical in my old age.

Don Black,

On 08-Dec-13 10:33 AM, Daniel Koller wrote:

 
Hi all,
  My caps probably are bad.  When I first got the
                  scope around 1980, I learned about "black beauties"
                  and had to replace them in the power supply, but I
                  think I recall being told that the bumble-bee types
                  were fine, so those stayed in.  Now it looks like I
                  have leakage from them in the HV power supply.  See
                  the attached photo
                  here: http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1517700781
The two shiny black 0.001 uF caps stand out because
                  they are coated in oil.  You can't see it on the
                  photo, but there is a film of liquid oil between the
                  middle cap and the 56K resistor below it.  Those two
                  are coming out but being a big fan of "don't mess with
                  it if it ain't broke" I might leave the other caps in
                  unless there is an obvious failure. Mind you, my scope
                  works well when it does turn on.

But I've had some other modifications it seems.
                   What's that square cap on the left and the 2.2K
                  resistor doing there?  I'll have to trace the circuit
                  to see where they were put in and why.  Maybe that was
                  a long ago patch for the oscillator failure?  Or the
                  cause of it now?

I see now why I had originally thought my scope was
                  much younger than it is - before I learned from the
                  group here that the "brown" Teks were pre-1954.  There
                  is this circuit board in my scope:
http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/158207078/lightbox/1026393052
Someone seems to have made factory improvements circa
                  1967.   What was in its place before this?  Is it
                  possible my additional HV circuit components were
                  placed in the same upgrades/refurbishment?

Back to the shop.  I've got an hour before guests
                  arrive!

Dan

On Saturday, December 7, 2013 10:58 AM, Don Black <donald_black@bigpond.com> wrote:

I'm not so sure. Yours may be faulty, these are
                  tested good so they must be a rare animal.

Don Black.

On 08-Dec-13 2:31 AM, Daniel Koller wrote:

 
I'll check and see what's in there.   And when
                  I take them out, I'll sell them on e-bay to an
                  audiophool!!
http://www.ebay.com/itm/4-TUBE-AMP-CAPACITORS-0-1uF-400V-Sprague-Bumblebee/171185528791?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D177%26meid%3D3232141210003616509%26pid%3D100009%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D181276706729%26

(No affiliation with the seller!)

Dan

On Friday, December 6, 2013 11:27 PM, Chuck
                  Harris <cfharris@erols.com> wrote:

Most of the time with the 545, the problem
                  is the
              black beauty oil/paper
tubular capacitors used for the HV
                  filters.  They
              always go bad, and if
they haven't been replaced, you must
                  replace
              them.  Ceramic is fine.

There is also a BB cap that is in series
                  with the grid
              feedback winding,
and another in parallel with the plate
                  winding.  Both
              must go.

-Chuck Harris

Daniel Koller wrote:
Howdy,

The recent discussions on HV repairs
                  has me
              thinking I should look into the issues
in my 545 (not A or B, old style
                  square case).  
              It works very very well, but
about half of the time, increasingly
                  more, the HV
              circuit will not oscillate.  If
I pull the plug-in out and drop it
                  back in, it
              will work.  I know this is not a
recommended option!  Alternatively,
                  if I shut it
              off and wait for it to cool, it
will work when I turn it on with
                  about the same
              probability, or a little less.
Once the scope is on it's up to spec.

The 6AU5 is not brand new, but is
                  good.  It was
              replaced recently with no
improvement.

So, suggestions as to where to start
                  on this
              intermittant problem are welcome.  Is
there anything I should look for or
                  measure that
              might indicate what is getting
tired?

Dan



________________________________
   This email is free from viruses and malware
                  because avast! Antivirus protection is active.  




________________________________
   This email is free from viruses and malware because avast! Antivirus protection is active.  

________________________________
   This email is free from viruses and malware because avast! Antivirus protection is active.  




How I transform a 5A20N to work in a TM500 mainframe

 

Hi everybody,

I am a Tek fan and may be some of you may be interesed by my last plugin works.
Normally the AM50X série for TM500 stops at AM503, I have made a AM504 from a 5A20N vertical oscilloscope amplifier to continue the serie....

I have put all the description on my personal WebSite, so clic on the link to see the item : http://philippe.demerliac.free.fr/TekLab.htm#AM504

Sorry, my site is in French. My english is not perfect but if you have any question, you can post a reply or send me an email and I'll reply to you.

Enjoy it and have a good day....


Re: HV transformer equalizing loop

Albert Otten
 

and the pictures (I hope...)
Albert


HV transformer equalizing loop

Albert Otten
 

and the pictures...
Albert


HV transformer equalizing loop

Albert Otten
 

Continued from the "647 HV transformer" thread as a new topic.

More surprises...
Since I also have 564s with 2 original 5642 diodes I decided to also measure one of these. I measured and measured again, but all the time I saw no real difference between the two legs. I also saw no equalizing loop. Mysterious. So I digged up the remaining 564, again draw wires trough the holes and (big relief) this time the empty leg showed much higher induction voltage than the heater leg.
I opened the first 564 again for comparison and yes, there *was* an equalizer loop, but quite different from what I expected. Having seen those heavy insulated wires for the heaters I expected something similar for such a loop. But no, it's a simple thin copper wire, see attached pictures, and why not.
All transformers have the same number -275. The one with loop is in the most recent 'scope. In my opinion all are beeswax types.

The heater side voltage for the transformers without loop was 0.86-0.88 V, against 1.10 V for the one with loop. A considerable difference, and both well below the nominal 1.25 V. (All HV voltages have been calibrated in recent years but I didn't check again.)
Following Chuck I wonder whether the designers were aware of this, though it is hard to believe they were not. Maybe the low voltage was intended to be low to increase life time?

Albert

===
Intriguing thing those equalizing "8" windings. Chuck (private mail) suggested that these would perhaps first of all serve to equalize the heater voltages. I happens that one of my 564's has one 5642 and one semiconductor diode (done by previous owner), without equalizing loop. I guided additional wires through both holes of the EI-core and did waveform and rms voltage measurement at these.
heater side leg: 0.9 V
empty leg: 1.4 V
The heater current tries to prevent flux changes, so to some extend these prefer the empty leg and hence the induced voltage is higher there.
With a 6.8 Ohm load at the empty leg side wire the heater side voltage increased to 1.0 V.
The 'scope works normally with calibrated HV IIRC. So the low 0.9 V (rounded up from 0.88 V) heater voltage seems sufficient for normal emission of the 5642.

Albert

===
Further evidence of this is the flux equalizing loop that got
added for the 545B/547/647... later transformers. Most (all?) of
the scopes had an odd number of 5642 rectifiers, and as such an
odd number of filament windings. Because they were using the EHT
to source the filament voltage, they put the windings on the outer
legs of the transformer core, 3 on one leg, and 2 on the other.
That causes a flux imbalance in the core, ...
(---)
To compensate for this imbalance, they added a single shorted
turn to link the two outer legs of the core. The turn was
arranged so that if one side was more heavily loaded than the
other, it would steal some extra current from the lightly loaded
side to even up the balance.
(---)
-Chuck Harris


Re: 155-0012-00 datasheet

 

I am just pointing out that high speed design techniques should be used to
prevent oscillation and achieve the IC's rated performance. It can be clocked
as slowly as you like but there may be maximum rise and fall times which should
be observed for the digital inputs and operating them in their active region may
cause oscillation. Treat it like slow ECL or a video operational amplifier.

On Sun, 08 Dec 2013 11:50:39 +0000, you wrote:

There is a really good explanation (including basic truth table) of just
how this part works in the 7834 Manual. It is much more detailed than
the 7844 manual that I have been using.

As to the speed issue, I agree the chip is built for speed, but it looks
as though it can be clocked slowly using the A Gate input from a slow
running TB and all other inputs, except the intensity current sink input
on pin 16 and current sink output to the Z Axis Amp on pin 8, held
statically HI or LO as required. Or am I too simple here?
Chris HJ
On 06/12/2013 17:00, David wrote:

The 155-0012-00 operates in the 100+ MHz range (250 MHz?) so lead
length and
decoupling can be critical.

The current sink output from pin 8 is usually going to operate into
the emitter
of a cascode transistor at the input of the z-axis amplifier which is
the case
with the 7844. The low emitter resistance, about 5 ohms, plus the 47
ohm series
resistor is only going to allow very small voltage changes at pin 8.

The voltages at the three inputs, pins 1, 2, and 16, will behave the
same way
with their voltages reflecting the logic control signals from pins 15
and 5
instead of their input currents.

91241 - 91260 of 193042