Date   

Re: Help with 7A18 problem

Jim Ford
 

Ok.  I saw the Austin in your email, plus you mentioned East Texas, so I had an idea where you are.  Hopefully tonight I can confirm condition of the 7A18 and get it boxed up. Thanks. JimSent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Bill Carns <wcarns@austin.rr.com> Date: 3/5/19 5:39 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Help with 7A18 problem By the way Jim, I think I forgot to send my location. Bill Carns661 Saddleridge DriveWimberley, TX 78676Many thanks again.-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim FordSent: Saturday, March 02, 2019 8:02 PMTo: TekScopes@groups.ioSubject: Re: [TekScopes] Help with 7A18 problemHi, Bill.I have a 7A18 that I don't need.  IIRC, it works just fine.  You can have it for shipping if you like.  I'm in Southern California.   Where are you located?I will be back home in So Cal early next week, and I will confirm the condition of the 7A18. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone-------- Original message --------From: Bill Carns <wcarns@austin.rr.com> Date: 3/2/19  2:26 PM  (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Help with 7A18 problem I'll have to go put the unit back in the mainframe and investigate but my memory says that most were bad.I have investigated more and remove the upper capacitor cover and, boy are those things hard to get at.  Gonna be real hard to get cleaning paper in there on all the switches.  Some are not bad, others really bad to get to.  One set has an additional little cover over them for some reason.Working on this thing is not for sissies.B-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert OttenSent: Saturday, March 02, 2019 3:53 PMTo: TekScopes@groups.ioSubject: Re: [TekScopes] Help with 7A18 problemOn Sat, Mar  2, 2019 at 07:58 PM, Colin Herbert wrote:>> ---> On the subject of the input attenuators, they are the type which are > operated by cam-switches. They have springy gold-plated contacts that > get moved up-and-down by cams on the controls shaft. The circuit board > that they are on has gold-plating, too, and the board itself is made > of an easily-damaged material. You need to use thin strips of paper > moistened in IPA and trapped between the moving and stationary > contacts, they *gently* pulling the paper strip out. You may have to > do this a few times. Don't use any other solvents or contact-cleaner > as you will probably ruin the board. Of course it may only be one or > two of these contacts that is dirty, as has already been suggested; > there are only four attenuators there - they get switched in-and-out > to get the different VOLTS/DIV settings. In the most sensitive > VOLTS/DIV setting, they are all switched out, so if your 5mV/div > setting shows lousy bandwidth, then it is likely to be caused by some > other problem, not just the attenuators and their switching . Of course, there might be a problem there, too, but it won't be the only one.>Hi Colin, You probably were too quick in your statement about the 5 mV/div setting. In that setting all attenuators are bypassed by means of a series of closed contacts, so any dirty contacts there destroy the signal path.I'm not sure about the 7A18 construction. My impression is that  including AC/DC there are 10 contact pairs above the drum and 10 below the drum. (Each contact pair forming one switch).It would still be nice to hear from Bill which V/div settings are good and which are bad.Albert


Re: 2213A Repaired and other questions

n4buq
 

Very satisfied QService customer here.

Thanks,
Barry - N4BUQ

Hi,

You might want to try QService from Greece, they currently have a pair of
22xx scope BNC connectors listed on ebay for $9 plus a bit of shipping. I
have not purchased from them yet, but word is they are very dependable
supplier and have 100% positive feedback.

https://www.ebay.com/itm/233134953372

Hope that helps.


Re: 2213A Repaired and other questions

tekscopegroup@...
 

Hi,

You might want to try QService from Greece, they currently have a pair of 22xx scope BNC connectors listed on ebay for $9 plus a bit of shipping. I have not purchased from them yet, but word is they are very dependable supplier and have 100% positive feedback.

https://www.ebay.com/itm/233134953372

Hope that helps.


Re: 475 on a K212 cart?

Dave Daniel
 

Did your cart come with the original hold-down straps? I have yet to see a second-hand cart with those unless it came directly from the original owners.

You can probably find something to use for the u-channel. How about a short piece of double-wide track used on track shelving?

DaveD

On 3/5/2019 9:34 AM, bradytmm@embarqmail.com wrote:
Hi Dave,
Thanks for the reply. I spotted a nice K212 on Craigslist and jumped on it. The 475 fits! The U-shaped channel is missing so I will have to come up with a replacement.
Regards,
Tony


Re: 475 on a K212 cart?

bradytmm@...
 

Hi Dave,
Thanks for the reply. I spotted a nice K212 on Craigslist and jumped on it. The 475 fits! The U-shaped channel is missing so I will have to come up with a replacement.
Regards,
Tony


Re: 2467 restoration: Battery, cleaning

Chuck Harris <cfharris@...>
 

Soldering could be safer, or it could accidentally short
the voltage to ground and delete the constants.

I figure that a) I calibrate scopes regularly, so the constants
are nothing special to me, and b) if the battery needs replacing,
likely the scope has needed calibrating for many years... so
either way, the constants are nothing special to me...

I was mostly espousing the method for the edification of others,
as there are times when you may need to replace one of these cells,
where the loss of power will mean the loss of something truly
irreplaceable, like a program stored in the battery backed up RAM.

-Chuck Harris

Robert Calk Jr. wrote:

I bought my battery at Mouser a few years ago for my Tek 2465A DV. I also soldered the wires to the battery holder that I used to the board because I was afraid the alligator clips might come loose on me. I wrote an article about it that you can google if you want to.

Robert




Re: PG 506

Chuck Harris <cfharris@...>
 

If by Sprague 300 electrolytics, you mean 30D electrolytics,
there may be a few that are bad. I would guess about 5-10%
of all 30D's out in the field are bad by now.

The worst hit in the 30D family are the low voltage caps, 3V
and 6.3V, where I would guess 100% are bad by now.

I would suggest that rather than wholesale replacement, use
an ESR meter to look for obviously bad capacitors.

When a 30D type cap goes bad, it is very obvious, as it will
usually have dried out, causing its ESR to go from 1 or 2 ohms
to 100-200 ohms.

-Chuck Harris

Jim Olson wrote:

I would like to go back to my original question in my original post about any maint. issues such as changing out the original sprague 300 lytics and also if anyone has any spare parts for one?

jim O

On March 2, 2019 at 9:18 PM Jim Olson <v_12eng@comcast.net mailto:v_12eng@comcast.net > wrote:


Craig, I saw that one it's a bit steep for my budget right now was hoping someone had one for a bit less.

> > On March 2, 2019 at 8:35 PM Craig Cramb <electronixtoolbox@gmail.com mailto:electronixtoolbox@gmail.com mailto:electronixtoolbox@gmail.com mailto:electronixtoolbox@gmail.com > wrote:


eBay item number: 233152652042


>



Re: Help with 7A18 problem

 

On Tue, Mar 5, 2019 at 12:57 PM, Peter H wrote:


I've taken the liberty to add a short write-up based on your post to the
TekWiki pages on 7A18 and 7A26.
Thanks for that, Peter. Concise and clear.

Raymond


Re: Help with 7A18 problem

Bill Carns
 

By the way Jim, I think I forgot to send my location.

Bill Carns
661 Saddleridge Drive
Wimberley, TX 78676

Many thanks again.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim Ford
Sent: Saturday, March 02, 2019 8:02 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Help with 7A18 problem

Hi, Bill.I have a 7A18 that I don't need. IIRC, it works just fine. You can have it for shipping if you like. I'm in Southern California. Where are you located?I will be back home in So Cal early next week, and I will confirm the condition of the 7A18. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Bill Carns <wcarns@austin.rr.com> Date: 3/2/19 2:26 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Help with 7A18 problem I'll have to go put the unit back in the mainframe and investigate but my memory says that most were bad.I have investigated more and remove the upper capacitor cover and, boy are those things hard to get at. Gonna be real hard to get cleaning paper in there on all the switches. Some are not bad, others really bad to get to. One set has an additional little cover over them for some reason.Working on this thing is not for sissies.B-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert OttenSent: Saturday, March 02, 2019 3:53 PMTo: TekScopes@groups.ioSubject: Re: [TekScopes] Help with 7A18 problemOn Sat, Mar 2, 2019 at 07:58 PM, Colin Herbert wrote:>> ---> On the subject of the input attenuators, they are the type which are > operated by cam-switches. They have springy gold-plated contacts that > get moved up-and-down by cams on the controls shaft. The circuit board > that they are on has gold-plating, too, and the board itself is made > of an easily-damaged material. You need to use thin strips of paper > moistened in IPA and trapped between the moving and stationary > contacts, they *gently* pulling the paper strip out. You may have to > do this a few times. Don't use any other solvents or contact-cleaner > as you will probably ruin the board. Of course it may only be one or > two of these contacts that is dirty, as has already been suggested; > there are only four attenuators there - they get switched in-and-out > to get the different VOLTS/DIV settings. In the most sensitive > VOLTS/DIV setting, they are all switched out, so if your 5mV/div > setting shows lousy bandwidth, then it is likely to be caused by some > other problem, not just the attenuators and their switching . Of course, there might be a problem there, too, but it won't be the only one.>Hi Colin, You probably were too quick in your statement about the 5 mV/div setting. In that setting all attenuators are bypassed by means of a series of closed contacts, so any dirty contacts there destroy the signal path.I'm not sure about the 7A18 construction. My impression is that including AC/DC there are 10 contact pairs above the drum and 10 below the drum. (Each contact pair forming one switch).It would still be nice to hear from Bill which V/div settings are good and which are bad.Albert


Re: 475 on a K212 cart?

Dave Daniel
 

I've never actually tried a 465 or 475 on a K212 cart, but it should work. The K212 is wider than the older carts used for the 475 et al and it has the u-shaped channel in the front to receive the 'scope's front feet.

DaveD

On 3/3/2019 10:17 PM, bradytmm@embarqmail.com wrote:
Hello to all,
I was wondering if the K212 cart is okay for use with a 475 scope. TekWiki says the cart is primarily for 2000 series scopes, but it looks like the 475 would fit.
Thanks,
Tony.


Re: TM5xx extenders

dnmeeks
 

Hello Bill -
I saw your message about extenders. I need to see how many parts I have, but I am pretty sure I have everything. I'll check today some time and let you know. Do you want one extender or two (for double-wides)?
Dan


Re: 475 with no Display and no HV

SuddenLink
 

Hi Reed,

Yes sir working at the Radio Museum is a lot of fun and hard work at the same time but now that I am retired it is a great place to volunteer a few days a week.

Between the NTE539 and NTE538 which one would you recommend for the Tektronix 475?

Ripley

The words are mine but this iPad does what it will with them.

On Mar 5, 2019, at 12:08 AM, Reed Dickinson <reed714@sbcglobal.net> wrote:

Hi Ripley:
Wiring in a NTE538 is a little different than wiring in an NTE539. When you get your 3Xer write ma back and I will detail how to do it.
Your antique radio setup sounds most interesting. I would probably be helping you out at that facility if it were on the left coast.
Reed
On Monday, March 4, 2019, 4:43:02 PM PST, SuddenLink <bob.ripley@suddenlink.net> wrote:

Hello Reed,

You just have been reading my mind. I was wondering how to handle the HV lead out to the CRT. What about the Focus Tap on the module. I am guessing that is left unterminated and highly insulated from anything around it.

Our plan is to repair the scope so that we can sell it. The Museum of Radio and Technology is a nonprofit all volunteer organization. We don’t charge for admission so our revenue sources are from cash donations, sales from our gift shop , small grants, and the three swap meet/auctions that we host every year.

https://www.mrtwv.org/

I will keep everyone posted as I bring this repair to completion.

Ripley

Sent from Mail for Windows 10

From: Reed Dickinson
Sent: Monday, March 4, 2019 4:59 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hi Ripley:
Good show, a new 3X voltage multiplier will get your 475 back on the air. If you elect to get an ECG or NTS 538 or 539 you will have to splice the HV lead leaving the new tripler. I very carefully slip a piece of thick wall plastic tubing over where the splice will be, carefully solder the joint leaving NO sharp points, coat the entire joint with silicone and slip the tubing over the joint. I put a small tie wrap over each end to keep moisture out. The 538 or 539 will fit in the space the present tripler is in, you will need to drill two mounting holes for the retainer screws.
Reed Dickinson
On Monday, March 4, 2019, 1:40:15 PM PST, SuddenLink <bob.ripley@suddenlink.net> wrote:

Hi Reed,

Per your suggestion I disconnected the wire from the secondary of T1320 to the voltage tripler and powered up the scope. The waveform at TP1318 immediately snapped to 32 volts p-p at about 70Khz without any persuasion via the 1K resistor trick. I also checked the oscillator over at the junction of CR1329 an C1326. It measures 320 volts p-p so it looks like I need to order a voltage tripler module.

Thank you so much for your help. Obviously, you know your way around these scopes.

Ripley

Sent from Mail for Windows 10

From: SuddenLink
Sent: Sunday, March 3, 2019 8:27 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hello Again,

I went back to the circuit around Q1306 and Q1308 this evening. The resistors are all within specs. C1305 was pulled and checked. It is also fine. C1304 is good and so is C1302.
By the way I am checking the capacitors with a DE-5000 LCR meter. It was never let me down yet.

The only component that I have not replaced or substituted is Q1306. It checks fine on my little Chinse component tester. For whatever that is worth.

Enough for today.

Ripley

Sent from Mail for Windows 10

From: Steph L
Sent: Sunday, March 3, 2019 7:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hi Ripley,
How about C1305 0.1uF.
If open, gain of Q1306 (and whole oscillator loop) will be lower and perhaps not enough to maintain oscillation? (Great suggestion from Don re 1K pull up touch on Q1318 base.)
Steph

PS. Still nubie here and unsure which "Reply" button to click on. I clicked on Ripley's "what the heck?" message "reply" button and see it has been inserted a few messages prior! That is really confusing. I'm in Melbourne Oz GMT +10 hrs. Is this the reason (i mean time difference guys and not quirky)




















Re: Help with 7A18 problem

Peter H
 

Raymond, thanks for the reminder. I've taken the liberty to add a short write-up based on your post to the TekWiki pages on 7A18 and 7A26.

Best
Peter


Re: Help with 7A18 problem

Peter H
 

Thanks for the kudos, it's from one of my own 7A18s.
BTW, the contacts under the board on the other side of the cam switch are for the readout circuits. It's no big deal to remove the board for cleaning but usually not required.

For "tricky" cam switch arrangements see the photos at http://w140.com/tekwiki/wiki/Cam_switch ...

Best
Peter


Re: 7L13, more exact frequency readout

Miguel Work
 

https://groups.io/g/TekScopes/album?id=86278


-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Gudjon Gudjonsson
Enviado el: domingo, 19 de agosto de 2018 21:28
Para: TekScopes
Asunto: Re: [TekScopes] 7L13, more exact frequency readout

Hi again

Now I have done quite a few measurements with my 7L13. I just used a know frequency source to tune it into the frequency I am searching for and then I do the measurement. This works well enough for my zero span measurements with resolution of 300kHz.

I did buy a frequency meter for up to 5.8GHz and tried to correlate the frequency of the YIG oscillator with the voltage between pin 6 of
U2110 and ground with a more precise voltage measurement than the frequency readout contains.

Regarding phase locking of LO1. According to the manual, the span is done in the following way:
= 5MHz/div: Main coil of the YIG
2MHz/div to 100kHz/div: FM-coil
<=50kHz/div: The phase lock loop of LO2, and then the LO1 can be phase locked.

I found out that the plugin need through calibration since the center frequency moves quite a lot with changing span.

But the nice thing is that I think I have solved the EMC problem the setup was supposed to help solving and my 7L13 is very helpful in my EMC precompliance toolset.

Regards
Gudjon


Re: 2467 restoration: Battery, cleaning

Robert Calk Jr.
 

I bought my battery at Mouser a few years ago for my Tek 2465A DV. I also soldered the wires to the battery holder that I used to the board because I was afraid the alligator clips might come loose on me. I wrote an article about it that you can google if you want to.

Robert


Re: TM5xx extenders

Peter Mulvey
 

Sorry, that email address got truncated I see - the last part is JUNOdotCOM

Pete.


Re: TM5xx extenders

Peter Mulvey
 

I've just ordered a set on eBay from John Nery, currently awaiting delivery. These are in kit form so some soldering will be required. He makes custom boards to order using a CNC milling process. I have no affiliation, just passing on the information.

https://www.ebay.co.uk/itm/Tektronix-TM500-TM506-SC-504-Oscilloscope-RTM506-TM5003-Extenders-KIT-FORM/223294199322?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

He also included the following note if you want to contact him directly:

"In the future please feel free to contact me directly by this e-mail address (WA1ESO@JUNO.COM) for any item you may need and receive a discounted price."


Re: 475 with no Display and no HV

Reed Dickinson
 

Hi Ripley:
Wiring in a NTE538 is a little different than wiring in an NTE539.  When you get your 3Xer write ma back and I will detail how to do it.
Your antique radio setup sounds most interesting.  I would probably be helping you out at that facility if it were on the left coast.
Reed

On Monday, March 4, 2019, 4:43:02 PM PST, SuddenLink <bob.ripley@suddenlink.net> wrote:

Hello Reed,

You just have been reading my mind. I was wondering how to handle the HV lead out to the CRT. What about the Focus Tap on the module. I am guessing that is left unterminated and highly insulated from anything around it.

Our plan is to repair the scope so that we can sell it. The Museum of Radio and Technology is a nonprofit all volunteer organization. We don’t charge for admission so our revenue sources are from cash donations, sales from our gift shop , small grants, and the three swap meet/auctions that we host every year.

https://www.mrtwv.org/

I will keep everyone posted as I bring this repair to completion.

Ripley

Sent from Mail for Windows 10

From: Reed Dickinson
Sent: Monday, March 4, 2019 4:59 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hi Ripley:
Good show, a new 3X voltage multiplier will get your 475 back on the air.  If you elect to get an ECG or NTS 538 or 539 you will have to splice the HV lead leaving the new tripler.  I very carefully slip a piece of thick wall plastic tubing over where the splice will be, carefully solder the joint leaving NO sharp points, coat the entire joint with silicone and slip the tubing over the joint.  I put a small tie wrap over each end to keep moisture out.  The 538 or 539 will fit in the space the present tripler is in, you will need to drill two mounting holes for the retainer screws.
Reed Dickinson
    On Monday, March 4, 2019, 1:40:15 PM PST, SuddenLink <bob.ripley@suddenlink.net> wrote:

Hi Reed,

Per your suggestion I disconnected the wire from the secondary of T1320 to the voltage tripler and powered up the scope. The waveform at TP1318 immediately snapped to 32 volts p-p at about 70Khz without any persuasion via the 1K resistor trick. I also checked the oscillator over at the junction of CR1329 an C1326. It measures 320 volts p-p so it looks like I need to order a voltage tripler module.

Thank you so much for your help. Obviously, you know your way around these scopes.

Ripley

Sent from Mail for Windows 10

From: SuddenLink
Sent: Sunday, March 3, 2019 8:27 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hello Again,

I went back to the circuit around Q1306 and Q1308 this evening. The resistors are all within specs. C1305 was pulled and checked. It is also fine. C1304 is good and so is C1302.
By the way I am checking the capacitors with a DE-5000 LCR meter. It was never let me down yet.

The only component that I have not replaced or substituted is Q1306. It checks fine on my little Chinse component tester. For whatever that is worth.

Enough for today.

Ripley

Sent from Mail for Windows 10

From: Steph L
Sent: Sunday, March 3, 2019 7:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hi Ripley,
How about C1305 0.1uF.
If open, gain of Q1306 (and whole oscillator loop) will be lower and perhaps not enough to maintain oscillation? (Great suggestion from Don re 1K pull up touch on Q1318 base.)
Steph

PS. Still nubie here and unsure which "Reply" button to click on. I clicked on Ripley's "what the heck?" message "reply" button and see it has been inserted a few messages prior!  That is really confusing. I'm in Melbourne Oz GMT +10 hrs. Is this the reason (i mean time difference guys and not quirky)


2213A Repaired and other questions

Coll Bay
 

Hello thanks for some of the advice earlier for my problem. Not sure what did it exactly but the issue is gone. I am thinking that short caused a solder joint to crack on a ground some where. Just re did a lot of joints and everything works great.

So thank you guys. My first scope that I bought and repaired works again.

I had a few other questions. I have heard that the capacitors in this thing has to go because they are old. Is there a guide showing the process of which to remove and a list for me to buy replacements?

Also the front BNCs are pretty worn that replacements might be needed. Anyone know of what will work well here? I looked up what I could that led me to this.
https://www.mouser.com/ProductDetail/Souriau/28JR205-2?qs=7LmGHoxvMXD4XqJNSVJVsA%3D%3D

But there is no datasheet or any possible replacement model. Any ideas?

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