Date   
Re: 184 Time mark Gen. Needs filter caps

Chuck Harris
 

They used the 2x40uf cap because it was cheap, very common,
and they very likely already bought them in large quantities.

My general philosophy is that any old 60Hz full wave bridge
filtering capacitor can be replaced with just about any new
electrolytic capacitor of similar capacitance and voltage.
It is not usually a very stressful application for an
electrolytic capacitor.

Twist lock capacitors were not anything special. They were
85C, middle of the road ESR capacitors. They often fail
from the rubber plug that holds in the goo deteriorating
and cracking... letting the moisture in the electrolyte
evaporate. Other times, the electrolyte gets to the junction
between the aluminum ribbon that makes the connection to the
capacitor elements, and the solderable terminal. Electrolysis
happens, and the ribbon gets eaten away... capacitor open.

-Chuck Harris

david via Groups.Io wrote:

I have no idea what the specs are on these old caps, The serial no. on this unit is 000287, date on PCB is 1965. The schematic shows 125V RMS @ 0.125A across secondary winding of transformer, and 175V measured across 2x40uF Cap. I don't have the knowledge to calculate the ripple current. I don't know what it could be. I think any 82uf x 250V cap is o.k. What is the reason they used a 2x40uF cap?



Re: 184 Time mark Gen. Needs filter caps

Eric
 

Wow 287 is an early one. I have a 189 on the bench if I need to open it up
and get some values. When I adjusted mine the crystal was not stable. It
was bouncing about + and - 15Hz around the center frequancy. I was able to
adjust it but I remember it was a very fiddly adjustment. And needs a 2
hour warmup.

On Fri, Mar 6, 2020, 4:54 PM david via Groups.Io <davide_us=
yahoo.com@groups.io> wrote:

I have no idea what the specs are on these old caps, The serial no. on
this unit is 000287, date on PCB is 1965. The schematic shows 125V RMS @
0.125A across secondary winding of transformer, and 175V measured across
2x40uF Cap. I don't have the knowledge to calculate the ripple current. I
don't know what it could be. I think any 82uf x 250V cap is o.k. What is
the reason they used a 2x40uF cap?



Re: 184 Time mark Gen. Needs filter caps

david
 

I have no idea what the specs are on these old caps, The serial no. on this unit is 000287, date on PCB is 1965. The schematic shows 125V RMS @ 0.125A across secondary winding of transformer, and 175V measured across 2x40uF Cap. I don't have the knowledge to calculate the ripple current. I don't know what it could be. I think any 82uf x 250V cap is o.k. What is the reason they used a 2x40uF cap?

Re: Calibration Moonlighters

Eric
 

It does but I am hoping to get it in one case not 4. It needs dc ac
resistance and the amplifier for ac. Because of the 1000v ac. I don't have
THAT much room in the lab laughs

On Fri, Mar 6, 2020, 1:37 PM David Kuhn <Daveyk021@...> wrote:

" Hopefully you guys will be happy to hear that I am *not* old, and just
picked up a TG501 and a PG506 in hopes that I can become one of these
completely inexperienced calibrators you are referring to! :)"

LOL, sorry, I must assume you do not work for one of those sticker changing
calibration calibration labs.

I know one of the "techs" that works for one of them. He couldn't do it
without a computer program stepping him through step by step, but he's
boots on road and goes on calibration runs away from home for a week or two
at a time and is willing to do that. That, in and of itself, is hard to
get a good real tech to be willing to do. Of course, now that I am on my
own, I am doing that more than I did with my old job. lol

Dave

On Fri, Mar 6, 2020 at 12:02 PM Magic_Smoke <@magicsmoke> wrote:

Hopefully you guys will be happy to hear that I am *not* old, and just
picked up a TG501 and a PG506 in hopes that I can become one of these
completely inexperienced calibrators you are referring to! :)





Re: 184 Time mark Gen. Needs filter caps

 

In principle no but, does the ripple current specs of the proposed cap meet/exceed those of the original ?

Cheers

Robin

On 6 Mar 2020, at 19:16, david via Groups.Io <davide_us=yahoo.com@groups.io> wrote:

Just got a 184 for parts, powers on, oscillator good. Need to replace filter caps in power supply, 12v ripple on +125v supply, +2v ripple on 12v, 4.8v on -30v supply. When I jumper a 1500uF parallel across the -30v filter cap, ripple on all supplies is 180 mV. and Time mark generator is then working. I am going to replace all caps but need opinion on cap C512. It is a 2x40uF, dual cap, but they are wired in parallel. I want to replace it with an 85uF single cap. Anyone have a good reason not to do this?
David


184 Time mark Gen. Needs filter caps

david
 

Just got a 184 for parts, powers on, oscillator good. Need to replace filter caps in power supply, 12v ripple on +125v supply, +2v ripple on 12v, 4.8v on -30v supply. When I jumper a 1500uF parallel across the -30v filter cap, ripple on all supplies is 180 mV. and Time mark generator is then working. I am going to replace all caps but need opinion on cap C512. It is a 2x40uF, dual cap, but they are wired in parallel. I want to replace it with an 85uF single cap. Anyone have a good reason not to do this?
David

Re: Calibration Moonlighters

David Kuhn
 

" Hopefully you guys will be happy to hear that I am *not* old, and just
picked up a TG501 and a PG506 in hopes that I can become one of these
completely inexperienced calibrators you are referring to! :)"

LOL, sorry, I must assume you do not work for one of those sticker changing
calibration calibration labs.

I know one of the "techs" that works for one of them. He couldn't do it
without a computer program stepping him through step by step, but he's
boots on road and goes on calibration runs away from home for a week or two
at a time and is willing to do that. That, in and of itself, is hard to
get a good real tech to be willing to do. Of course, now that I am on my
own, I am doing that more than I did with my old job. lol

Dave

On Fri, Mar 6, 2020 at 12:02 PM Magic_Smoke <@magicsmoke> wrote:

Hopefully you guys will be happy to hear that I am *not* old, and just
picked up a TG501 and a PG506 in hopes that I can become one of these
completely inexperienced calibrators you are referring to! :)



Re: Calibration Moonlighters

Dave Daniel
 

The DM-502 manual should list the gear needed to calibrate one.

DaveD

On 3/6/2020 1:09 PM, Eric wrote:
Magic Smoke you beat me to it. I am also in the young category. I have the lab to the point where I can CAL up to a 7904A and I am close to having everything I need for 576's and 577's I have done a few CALs on some personal gear. 465, 2X 485, 7A18's, 7A15A's, 7A26's, and 3 x 7K mainframes so far. 7603, 7704A, and checked in a 7904A it did not need work very low hour unit. I am one of the "young whipper snappers" that has found grate satisfaction in keeping as much of this excellent gear out of the scrap yards as possible. The learning curve is steep. But after fighting through it I would do it again in a heartbeat.

That being said if anyone knows what I need to calibrate a few DM502As I have a few hitting the bench in a few days that will need a tune up. It is weird but now I am more comfortable sitting in front of an open scope then a DMM. I have been looking at some of the Daytron stuff but I am always open to learning so advice is welcome and appreciated.


Eric

On 3/6/2020 12:02 PM, Magic_Smoke wrote:
Hopefully you guys will be happy to hear that I am *not* old, and just picked up a TG501 and a PG506 in hopes that I can become one of these completely inexperienced calibrators you are referring to! :)


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Re: Calibration Moonlighters

Eric
 

Magic Smoke you beat me to it. I am also in the young category. I have the lab to the point where I can CAL up to a 7904A and I am close to having everything I need for 576's and 577's I have done a few CALs on some personal gear. 465, 2X 485, 7A18's, 7A15A's, 7A26's, and 3 x 7K mainframes so far. 7603, 7704A, and checked in a 7904A it did not need work very low hour unit. I am one of the "young whipper snappers" that has found grate satisfaction in keeping as much of this excellent gear out of the scrap yards as possible. The learning curve is steep. But after fighting through it I would do it again in a heartbeat.

That being said if anyone knows what I need to calibrate a few DM502As I have a few hitting the bench in a few days that will need a tune up. It is weird but now I am more comfortable sitting in front of an open scope then a DMM. I have been looking at some of the Daytron stuff but I am always open to learning so advice is welcome and appreciated.


Eric

On 3/6/2020 12:02 PM, Magic_Smoke wrote:
Hopefully you guys will be happy to hear that I am *not* old, and just picked up a TG501 and a PG506 in hopes that I can become one of these completely inexperienced calibrators you are referring to! :)

Re: Calibration Moonlighters

John Griessen
 

On 3/6/20 11:02 AM, Magic_Smoke wrote:
Hopefully you guys will be happy to hear that I am*not* old
Yes happy -- it's fun to hear youthful enthusiasm for machines that last and last and are repairable.

We like those concepts!

Re: Calibration Moonlighters

Magic_Smoke
 

Hopefully you guys will be happy to hear that I am *not* old, and just picked up a TG501 and a PG506 in hopes that I can become one of these completely inexperienced calibrators you are referring to! :)

Re: Calibration Moonlighters

Jim Ford
 

Yeah, you kids get offa my lawn!Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: David Kuhn <Daveyk021@...> Date: 3/6/20 8:29 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Calibration Moonlighters " pared to what Calibration labs would charge."Dennis,For the most part, and from personal experience, 99% of thecalibration labs are sticker changers,  Their techs have calibrationprograms that they operate the take them step by step through a calibrationprocess and the computer makes any needed, or available adjustments, viasoftware interface.  You would be hard pressed to find a diddle stickanywhere in a calibration lab.  I really do not believe that would"calibrate", or certify, anything older than a TDS3000 series scope(although, Spectrum did my TDS420 a few years ago, but there an't noadjustment pots in that one either.People, do need, old time guys for these old time scopes, and otherequipment.  Yes, you have the manuals that tell you what to do, but themanual does NOT take the place of practical experience.  That old timerknows hat step 10.x really means to do his or that and it is poorly wordedor not practical.  The know how to practically adjust the instrument.   Ican do that for old time industrial UT equipment, but no one uses thoseanymore.  Old men retire and these new gamer kids want all that cooldigital UT equipment. Damn whippersnappers!On Fri, Mar 6, 2020 at 12:09 AM Dennis Tillman W7PF <@Dennis_Tillman_W7pF>wrote:> Chuck is highly regarded by me and a veteran of TekScopes. I'm glad he can> provide this service. I have no doubt he is capable of doing an excellent> job and his prices will be reasonable compared to what Calibration labs> would charge.>> Dennis Tillman W7pF>> -----Original Message-----> From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave> Daniel> Sent: Thursday, March 05, 2020 6:25 PM> To: TekScopes@groups.io> Subject: Re: [TekScopes] Calibration Moonlighters>> Chuck calibrated my 2465 a while back. I was extremely pleased with his> work and his price. I packed the ‘scope in my usual over-the-top packing> and he returned it in same.>> While it is probably bad form on this list to recommend people, I hereby> recommend Chuck’s work.>> Dennis, please feel free to admonish me publicly.>> DaveD>> > On Mar 5, 2020, at 20:59, John Ferguson via Groups.Io <jferg977=> aol.com@groups.io> wrote:> >> > I had Chuck Harris recap and calibrate one of my 2445B's.. I shipped it> to him and he shipped it back. No detectable damage from the shipping> experience.  It's true that LA is a lot farther from Maryland than Delray> Beach, but ...> >> > Maybe your machine is a lot bigger than a 2445b.> >> > john> >> >> On 3/5/20 8:48 PM, Gary Robert Bosworth wrote:> >> Does anyone know the name or names of knowledgeable people in the Los> Angeles area who do moonlight calibration of Tektronix equipment for> reasonable fees?  I don't mind paying good money for quality work, but the> techs must know the equipment to some extent.  You would think that doing> this type of work would be comfortably pleasing to retired techs and> engineers.> >>> >> Gary> >>> >>> >> >> >> >>>>>>> --> Dennis Tillman W7PF> TekScopes Moderator>> >>

Re: Calibration Moonlighters

David Kuhn
 

" pared to what Calibration labs would charge."

Dennis,

For the most part, and from personal experience, 99% of the
calibration labs are sticker changers, Their techs have calibration
programs that they operate the take them step by step through a calibration
process and the computer makes any needed, or available adjustments, via
software interface. You would be hard pressed to find a diddle stick
anywhere in a calibration lab. I really do not believe that would
"calibrate", or certify, anything older than a TDS3000 series scope
(although, Spectrum did my TDS420 a few years ago, but there an't no
adjustment pots in that one either.

People, do need, old time guys for these old time scopes, and other
equipment. Yes, you have the manuals that tell you what to do, but the
manual does NOT take the place of practical experience. That old timer
knows hat step 10.x really means to do his or that and it is poorly worded
or not practical. The know how to practically adjust the instrument. I
can do that for old time industrial UT equipment, but no one uses those
anymore. Old men retire and these new gamer kids want all that cool
digital UT equipment. Damn whippersnappers!

On Fri, Mar 6, 2020 at 12:09 AM Dennis Tillman W7PF <@Dennis_Tillman_W7pF>
wrote:

Chuck is highly regarded by me and a veteran of TekScopes. I'm glad he can
provide this service. I have no doubt he is capable of doing an excellent
job and his prices will be reasonable compared to what Calibration labs
would charge.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave
Daniel
Sent: Thursday, March 05, 2020 6:25 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Calibration Moonlighters

Chuck calibrated my 2465 a while back. I was extremely pleased with his
work and his price. I packed the ‘scope in my usual over-the-top packing
and he returned it in same.

While it is probably bad form on this list to recommend people, I hereby
recommend Chuck’s work.

Dennis, please feel free to admonish me publicly.

DaveD

On Mar 5, 2020, at 20:59, John Ferguson via Groups.Io <jferg977=
aol.com@groups.io> wrote:

I had Chuck Harris recap and calibrate one of my 2445B's.. I shipped it
to him and he shipped it back. No detectable damage from the shipping
experience. It's true that LA is a lot farther from Maryland than Delray
Beach, but ...

Maybe your machine is a lot bigger than a 2445b.

john

On 3/5/20 8:48 PM, Gary Robert Bosworth wrote:
Does anyone know the name or names of knowledgeable people in the Los
Angeles area who do moonlight calibration of Tektronix equipment for
reasonable fees? I don't mind paying good money for quality work, but the
techs must know the equipment to some extent. You would think that doing
this type of work would be comfortably pleasing to retired techs and
engineers.

Gary







--
Dennis Tillman W7PF
TekScopes Moderator



Re: Noob needs help with a 453 no sweep

Brian Mathews
 

Hi Albert,

I did not intend to sound like I am complaining, I am just very frustrated
with this scope. I do not have the electrical design knowledge that most
of the other members have so I am very appreciative of the help that
has been given and I am trying my best to give helpful feedback. So with
that said, thank you for your reply!!

I made a mistake in my measurement report above, and I am not able to find
a way to edit my posting.
The important change is this sentence: "Right next to that is TP505 which
is also +.030vdc and should be -.046vdc"

The correct sentence should be "Right next to that is TP505 which is
also +.030vdc and should be -.46vdc"
When I test my working scope I have -.5vdc there at TP505 and this seems a
to be a big difference to have either no voltage or +.030 there.

I will check the other areas you mention.

Brian

On Fri, Mar 6, 2020 at 6:46 AM Albert Otten <aodiversen@...> wrote:

Hi Brian,

You "complained " that there were no comments on your measurements:
The only thing that seemed off was the collector of Q524 was +6v when
the schematic has +10.5v but I don't know if that is a project or not.
I am seeing a -.5vdc on the cathode side of D501 but only +.030vdc on
the anode side.
Right next to that is TP505 which is also +.030vdc and should be
-.046vdc.
... is TP504 and I am supposed to have -.3vdc there but have -3.7vdc so
that is also way off.
Let's give it a try. I only have the early 453 manual and a (paper) 454
manual.
First of all the DC voltages in the manual are average values while the
circuits are running in AUTO mode. Your's are most likely true DC in some
kind of rest state. Then together with your other findings my impression is
that the Sweep Reset multivib does not return to its rest state after the
end off the Hold Off period. Your TD voltage is slightly positive,
indicating that the TD is not armed to produce a trigger event; the voltage
should be slightly negative. (In the paper 454 manual this is also visible
in the waveform which shows a slightly positive value during Hold Off and a
slightly negative voltage during the waiting time for the next trigger
arrival.) The TD is likely blocked because Q575 is conducting and Q585 is
cut-off. It should be visa versa at the end of the Hold Off period. This
fault can happen when C550 doesn't get charged (positive) enough to reset
the multivib, so for instance when the switch above R551 is bad. But your
measurements seem to show that Q514 might still conduct somewhat after
end-of-sweep and during Hold Off. Then Q514 prevents the voltage at C550 to
increase far enough. The culprit I think will be in the circuit with Q504,
Q514 and Q524.
When in Single Sweep mode the Hold Off circuit is not active at all.
Pressing the Reset button forces a rest of the multivib with a very strong
positive pulse from Q564.
I suggest you do also measurements at Q514-collector, Q524-base (should be
the indicated value) and TP585 (Normal mode, no signal). TP585 is there to
monitor the state of the multivib. Should be high in rest state and low
after end off trace and during Hold Off.

Albert



Re: Noob needs help with a 453 no sweep

Albert Otten
 

Hi Brian,

You "complained " that there were no comments on your measurements:
The only thing that seemed off was the collector of Q524 was +6v when the schematic has +10.5v but I don't know if that is a project or not.
I am seeing a -.5vdc on the cathode side of D501 but only +.030vdc on the anode side.
Right next to that is TP505 which is also +.030vdc and should be -.046vdc.
... is TP504 and I am supposed to have -.3vdc there but have -3.7vdc so that is also way off.
Let's give it a try. I only have the early 453 manual and a (paper) 454 manual.
First of all the DC voltages in the manual are average values while the circuits are running in AUTO mode. Your's are most likely true DC in some kind of rest state. Then together with your other findings my impression is that the Sweep Reset multivib does not return to its rest state after the end off the Hold Off period. Your TD voltage is slightly positive, indicating that the TD is not armed to produce a trigger event; the voltage should be slightly negative. (In the paper 454 manual this is also visible in the waveform which shows a slightly positive value during Hold Off and a slightly negative voltage during the waiting time for the next trigger arrival.) The TD is likely blocked because Q575 is conducting and Q585 is cut-off. It should be visa versa at the end of the Hold Off period. This fault can happen when C550 doesn't get charged (positive) enough to reset the multivib, so for instance when the switch above R551 is bad. But your measurements seem to show that Q514 might still conduct somewhat after end-of-sweep and during Hold Off. Then Q514 prevents the voltage at C550 to increase far enough. The culprit I think will be in the circuit with Q504, Q514 and Q524.
When in Single Sweep mode the Hold Off circuit is not active at all. Pressing the Reset button forces a rest of the multivib with a very strong positive pulse from Q564.
I suggest you do also measurements at Q514-collector, Q524-base (should be the indicated value) and TP585 (Normal mode, no signal). TP585 is there to monitor the state of the multivib. Should be high in rest state and low after end off trace and during Hold Off.

Albert

Re: 2215 cleaning + recap

ridderg@...
 

Just to be sure, I do have a question on HV safety:

The scope has been disconnected from power for a number of weeks now. When starting the recap is it enough to discharge the large power capacitors? Or is there a need to disconnect and discharge the CRT lead as well?

Thanks.

Re: WTB: Switch parts for 2230 scope

greenboxmaven
 

Yes, they are. In the scope I have, all of the switches with the brass springs on top are shown on the front panel as having a latched position. Bruce, KA2IVY

On 3/6/20 12:01 AM, Dave Casey wrote:
Are these supposed to latch? They may be momentary on purpose.

Dave Casey

On Thu, Mar 5, 2020 at 8:54 PM greenboxmaven via Groups.Io <ka2ivy=
verizon.net@groups.io> wrote:





Re: Noob needs help with a 453 no sweep

John
 

Roger:
Re: "My (suspect) memory tells me that someone reported 'no sweep' on a 453 and finally tracked it down to failure of C561 but I now can't find the reference to this."

You're right, and none of us could understand why !
John

Re: Blank needed for 7K frame

stevenhorii
 

Eric,

Sorry for the second message. I checked the part number on TekWiki and it
is the 7000 series blank panel.

Steve

On Thu, Mar 5, 2020 at 14:53 Eric <ericsp@...> wrote:

I have on the way a 7403N series mainframe. I have a use case for it but I
need a blank cover as it will only have 2 plugins. I am wondering if anyone
here has a blank, they are willing to part with. It does not need to be the
experimental board.



Re: Blank needed for 7K frame

stevenhorii
 

Eric,

I have a blank plate - I am fairly sure it is for the 7000 series
mainframes. Tektronix part number 016-0155-00. It has a black plastic plate
on the back that projects back (into the plug-in space) by about 3/4-inch.

You are welcome to it - I will need your mailing address. If it is what you
need, rather than pay me for it you could send me a couple of knobs for Tek
7000 plug-ins if you have spares.

You can contact me off list to give me your address:

Sonodocsch@...

Steve

On Thu, Mar 5, 2020 at 14:53 Eric <ericsp@...> wrote:

I have on the way a 7403N series mainframe. I have a use case for it but I
need a blank cover as it will only have 2 plugins. I am wondering if anyone
here has a blank, they are willing to part with. It does not need to be the
experimental board.