Author Topic: Tektronix 317 classic scope - repair and restoration.  (Read 8912 times)

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Offline SeanB

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #75 on: December 16, 2017, 04:34:48 am »
Lokking at that fan I would suggest going out and looking for the cheapest nastieast standing fan ( the white OHL ones are the ones to look for) in the skip, and grab the bushes from the motor from that. Those are sintered steel, and they generally are the right diameter to replace the oilite bushes that are worn. Just take the new bushes and heat up with a soldering iron barrel till at soldering tamperature, then drop into a small cup of engine oil. this will first burn out the nasty tiny amount of oil they originally had in them, and will suck in the new oil as well. Use the 2 felt washers that were also in the fan, but soak them in the oil as well, they generally are not done in the factory. Should fit the fan perfectly.
 

Offline Martin.M

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #76 on: September 06, 2018, 04:19:34 pm »
late Answer.

This Tek Fans have sometimes a mechanical problem with the axial position in the field.
When you can move the rotor more then 1/10" forward or backward this can be the problem, the magnetic field from the stator sucks the rotor in a wrong position and it get slowly..
good help is a simply ring made from Teflon (PTFE Polytetrafluorethylene) so the rotor can°t leave the magnetic zone axial.
added some oil and that must go 8). Excuse the late answer, I am restorating a radio transmitter, so very busy the most time  :)
greetings
Martin
« Last Edit: September 06, 2018, 04:22:13 pm by Martin.M »
 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #77 on: September 20, 2018, 08:20:48 pm »
Hi Martin !

Wow, thanks for your reply, sheds new light on this fan problem, and also brings new hope as well, great ! :-D
Haven't worked on that scope for 9 months now, busy with other stuff, but I am planning on getting back to that little 317 pretty soon, at last !  :)

I am planning to move house by the end of the year, and would like to have finished/ put this scope back together by then... to make it easier to move around, and also avoid losing bits of it !  I don't even know if I will remember how all the parts and screws go together, been so long ! LOL

Sorry for being late myself as well, 2 weeks it appears but... believe it or not, I somehow did NOT receive an e-mail notification telling me you posted here !
If I saw your post it's just out of luck, because I just happened to refresh this page in my web browser today, truly out of the blue, out of compulsiveness ! LOL

Glad I did !

Thanks again for your input / help !  :-+
« Last Edit: September 20, 2018, 08:45:28 pm by Vince »
 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #78 on: October 21, 2018, 04:46:15 pm »
This Tek Fans have sometimes a mechanical problem with the axial position in the field.
When you can move the rotor more then 1/10" forward or backward this can be the problem, the magnetic field from the stator sucks the rotor in a wrong position and it get slowly..

Hi Martin,

I just took a video clip of the axial play of the rotor of my fan motor... are we talking of the same thing here ?



I measured the play with a depth gauge...  you say that 1/16" is getting troublesome... so that's 1.6mm.

Well I measured like 2,85mm, 75% more  !  :o

If we are talking about the same thing... then it means there is hope, if I apply your Teflon washer  fix !  :D
Will try and do that... However which side of the rotor do you put the washer on ? On the fan blade side, or at the back , where the two wires exit ??

Thanks in advance for your input...

 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #79 on: October 21, 2018, 11:53:43 pm »
OK.... after literally a year doing nothing on this scope... I have finally managed to finish its restoration, or almost, 99 % ! A few pics below as always  ;D

As of this evening, It's all back together again, working like a champ and all clean, almost as good as new, quite happy with the result, I am in love with this thing, really am !  :)

Last year I did the trouble shooting to fix the many issues it had. And after a year at idle, with the thing completely in bits all over the lab... it became urgent to put it all back together because... well I will be moving house in a month or two, so there was no way I was going to move this scope in a million bit, surely it some vital little part would get lost in the process...  Anyway, it motivated me to move my butt and finish this restoration so I can put it all back together again and transport it easily and safely.

So, after spending some time inspecting the scope to make the list of all the nut and bolt sizes I would have to remove, measuring them best I could with calipers, and trying to figure out what imperial size that might correspond to, then ordering 2 times the scope worth, in countless spanners and bits, some short, some long, and Allen keys... I was ready to tackle the job.


WASHING THE INSIDE

So a weeks ago I finally washed its guts, following advice I read on Martin's topic. I was reluctant to wash this old thing, thinking it could corrode all over the place and I would just ruin it for good... but since Martin did it so many times before with success... and since I read on Tektronix OWN literature of back in the day, how they themselves washed every customer scope that came for any servicing work, in a dedicate booth, detailing how one should do it.... well I why not go for it !
Tek even said they they didn't even REMOVED the tubes from their sockets, they washed the scope with all the tubes still in place !  :o

So,  I removed all the easily removable sub assemblies from the scope : CRT tube assembly ( which I too disassembled to give it a good clean), fan motor, shields on the CRT HV section and also the one on the HV "shelve" that sits underneath the CRT. Removed all the tubes, and placed in a polystyrene foam with the same layout they had in the scope, so that I don't mix tubes and I can put them back in place easily.

Then washed it with hot water and some detergent, but in an effort to spare the scope, I did not flood the scope with the mixture Rather, I plunged q-tips and small tiny  paint brushes into the stuff, then used that to clean the scope. This way I could use the stuff sparingly and more easily avoid or baby the "sensitive" areas, like pots and the HV transformer. Then I rinsed with distilled water to keep the scope from corroding, and immediately took the hot air gun to removed the water as fast as possible, taking care not too over heat it, of course.

Then I let it dry in the lab, a warm and dry room, for 3 weeks, watching for any corrosion that might arise... and crossing fingers that I had not just killed my scope !  :-[





REFURBISHING

3 weeks later, still not a sign of corrosion, feeling somewhat better... and me thought it must be dry by now... so I put it back on the bench, and proceeded to refurbish the thing, so I could then put it back together, at long last.

To be done :

- Replace the 3 neon bulbs indicators on the front panel ('"UNCAL" Vertical and Horizontal, and "X5 MAG" indicator), which are absolutely impossible to get to, because the old ones looked a bit dim to my taste, though wasn't sure how they should look to begin with, I must admit ! ...

- Replace 3 paper caps, the 3 last ones, which I had not done previously because the scope was working/fixed, and they were simply impossible to get to, mostly !

- Replace the 3 UHF coax connectors, which were so crusty.. and one of them was even missing its dielectric piece !


UHF connectors

I decided to start by replacing the UHF connectors... thinking it would be the easiest of the 3 jobs. NOT ! Actually in order to replace those connectors... guess what ? you have to remove the FACE PLATE ?! Seriously, Tektronix ?!   :palm:
Removing the face plate meant dismantling 50% of the scope...
Had to remove the 3 black 4mm binding posts, even though they were just fine. These were impossible to remove because the nuts at their backs were seized and the post was just spinning round and round... eventually manage to find a way to remove them with damaging them... about a second and a half before I was ready to commit suicide, that was close ! LOL

Then removed every pot and control.

Then had to remove power switch, easy.  However removing the pilot light was a PITA ! I did have the correct size spanner to nudo the nut at the back... but the chassis/metal work around the pilot light would not allow for any movement of the spanner, ! I could get the spanner on tot the nut, but that's about it, no way to rotate the spanner after that !  :--

The face plate would then eventually come off...

Sourcing UHF connectors was not as straight forward a one would think. Tek uses  connectors which have only 2 lugs, because that's required in order for them to clear the chassis. These are rare, 99.9% have 4 lugs, a square base. But, I eventually found some which had 2 lugs... but they were unbranded cheap stuff. When I received them, their body was blindingly shiny, almost like chromed, horrible, would would not " blend " with the scope, they would look out of place. Plus, the build quality of these connectors was... how to say... let's stay polite.... ATROCIOUS ! And even that, is an understatement... I don't even understand how people even bother selling such crap. Even for a toy scope I would not use them, so for a Tek scope, no way in hell !  :--

So I looked at what I could get here, and found on Farnell some made by "Tyco ELectronics", aka "TE Connectivity".  I was saved : build quality is fine, and the finish on the body is lees shiny... though still a bit too shiny to my taste. I think the Amphenol connectors look even less shiny, but sadly Farnell only carry them on the USA warehouse, and the import fee is outrageaous, they charge like 18 Euros per 2 Euros connector... so I made do with the Tyco instead...  :-[

Fitting these connectors requires.. patience and dexterity... and my tweezers were mandatory.. to put back these tiny 3/16" nuts  in place. For each nut I had to put in place, I must have dropped/lost it in the chassis, 3 or 4 times... a nightmare.

Anyway, the Tyco (and Amphenol just the same anyway) connectors were 4 lugs, square base. So had to resort to trim/file down two of the lugs. Luckily it turned out not to be as painful and time consuming as I thought it would be...
Looking closely at the old connectors, it's clear that Tektronix just did that with their own connectors ! They did not even bother removing the burr from the trimmed edges, yikes ! At least I did that right, so the scope is now BETTER than new ! LOL

You have to be real careful when you fit the connectors in place, because if they are just slightly misaligned, the face place won't fit, or will look ugly... that happened to m the first tim, yikes.

Oh, and when you fit the connectors... make sure to orient them the correct way : I mean when you then want to solder the wire onto them, you must have the opened half of the terminal facing you, otherwise when you poor solder onto it just runs away instead of filling the terminal and covering the wire.
Spent 10 minutes fitting the connector on the external trigger input, and when finally done, went to solder the wire onto it and ... oh no, I put it upside down, bugger, must remove the connector and do it all over again! ARRRRRRRRRGH !!!!    |O


Paper Caps

There were 3 paper caps still in there, 2 on the trigger switch assembly, and 2 on the sweep switch assembly. All of the m facing inward of the scope, so impossible to get to.

Started with the sweep switch. Removing it looked daunting...however, it looked like I could removed SOME of its wires, without too much drama, which would allow me to move the switch assembly enough so that it would stick out of the scope, and be able to rotate enough to reveal the two paper caps, which I then could replace easily. There is a nut holding the back of the switch to an angle bracket, then a grounding strap/braid soldered to the back of the assembly, then a wire that goes to the "uncal" neon indicator, then there are set of 4 wires that connect to a big blue "can" which contains 3 precision timing caps... but no need to desolder those wires, it's much easier to undo the two screws that hold the cap can to the chassis... and then the sweep switch can be made to stick out of the scope enough to let you replace those dreaded paper caps.

Then the third and last paper cap was located on the trigger switch assembly. This switch is impossible to get out or even move at all : its back is bumping against a ceramic strip ! So, you can't pull it backward at all... at all.  Luckily, with the sweep switch and blue can out of the way, you can about access the cap in question, via an opening in the chassis. Using long tweezers I was just able to remove the old one and solder the new HV film cap, in situ.


Neons Bulbs

With the sweep switch assembly and big blue cap can are out of the way, suddenly the 3 neons bulbs "kinda" look feasible... kinda. Again, impossible to get your hands in there, but using tweezers and some patience/calm... it is actually possible to replace them in situ. A pain in the butt, but doable.

The job was made more difficult by the fact that the replacement bulbs I had ordered, though they were "NE-2" bulbs like stated in the part manual... did NOT actually have the diameter and length as the old ones ! Oh no.... New ones were not as long.. which was not a problem because I could just push them farther into the plastic holder until they were sticking out on the face plate side. The terminal were very long so no problems, plenty of wire still sticking out the holder.
However the diameter was quite smaller than the old ones. The old ones fit snugly into the holder, they did not move. but the new ones were so loose that they would move all over the place in their holder, making soldering a bit of a pain, they just would not stay in place ! :-/
First time I replace/use neon bulbs... I guess something must have escaped me...



PUTTING IT ALL BACK TOGETHER

Basically one job lead to dismantling yet more stuff... overall you can't do one job alone, you just end up dismantling a lot of stuff, replacing all that you need to replace, then put it all back together. This means that unless you have an exceptionally good memory... which is not my case, then you better do all these jobs at once, and put it back together as soon as you have finished replacing everything it was that you wanted to replace. Don't let anyone interrupt you, or you will forget where this wire goes, or what not... I let a phone call interrupt me, and yes too late, I forgot where some of the wires had to go on the sweep switch !  :-/
Luckily I had taken plenty of close-up photographs as usual, to help me with reassembly... saved me bacon !

Then I put back all the bits I had dismantled a year ago... somehow I still remembered how it all went together, and somehow, I had not lost a single not or screw, a miracle in its own right.  The CRT assembly, chassis parts, all the tubes... laying them on a polystyrene foam was indeed a wonderful idea (which I "stole" from Martins thread ! ), refitting was a breeze, a no brainer !  :-+

Still worried about some possible corrosion, even minute, from the distilled water (which is never gonna be 100% pure of course...), I feared some corrosion might eventually develop on the tube socket terminals, over time, leading to problems... So, I sprayed that famous " Deoxit " stuff that's famous in the US (finding the stuff in Europe at a DECENT price, was not so easy, though... it usually retails at around 3 times the US price ! ), on every tube socket, and inserted/pulled each and every tube 3 or 4 times in its socket, to give it a good clean and lubrication.



TESTING


Now time to cross fingers and ... FIRE IT UP !!!

Honestly with the washing, I was expecting all kinds of weird and wonderful things to happen... and was worried about the dreaded CRT HV transformer having soaked humidity and going kaput....

So, took a deep breath, hoping for the best but expecting the worse as the saying goes...1....2.... 2 and half.......... FIRE !!!

Simply could not believe it... the thing worked first time !  And it even worked better than before, would you believe it ?!  :D :D :D :phew:

There were just a couple minor problems I ahd to adress :

- The scale illumination was ineffective even at full throttle.... turned out I had mixed up the graticule and color filter. Putting the graticule closer to the CRT, thinking it was logical in order to reduce parallax error... but no, the color filter comes first, and the graticule is on the "outside". That fixed it.

- The signal trace was slightly rotated (like one small division). When I reassembled the CRT assembly, I aligned the CRT as best I could, by trying to center the anode/PDA electrode in the corresponding opening in the metallic shroud/jacket which houses the CRT. But it's not very accurate.
So... had no choice but power up the scope to display a flat line and rotate the CRT while the scope is power up ! Yes... a bit scary... but if you watch what you are doing, it's actually quite easy and fast.   Power off, remove the CRT bezel, graticule and color filter. Unscrew the clip at the back of the CRT assembly, which holds the CRT neck. then "unstick" the CRT by pushing a bit against the connector at the back. Once the CRT is loosened, power up the scope. Put the graticule in place so you can check the trace alignment. Then it's a bit of trial and error. Push against the CRT connector at the back, using some non conductive "tool"... I used my big plastic desoldering pump.. just because it was there on the bench ! LOL  Gently push the CRT to make it stick out half an inch or so, just enough so you can grab it with your fingers and rotate it a little bit... push it back into place, put the graticule back, check the alignment... repeat as necessary until you are satisfied with the result ! LOL


Played with it for an hour to make sure everything was OK, and that the HV was not dropping after a while.... but no, the scope works really beautifully and is rock solid !

That was my first in depth restoration of a tube equipment, I am glad it turned out quite well ! Scope looks lovely, a joy to look at and play with, really happy with the result !  :D

Now of course since that was my first restoration, I learned as I went.. and some things I would do differently, or not at all, like :

- The blue painted cabinet panels looked dull/matte to me. I thought that was old age and that using some care paint polish I had laying around, would brighten it up... not only did it not have any effect on the matte  finish... which I now think was original, but worse : once dried out the white powdery residue left by the polish, which on a car is easily removed.. did not go away on the scope, because of the "texture" of the crinkle paint, and the myriad of holes/venting.
Same problem when I tried to use metal polish to freshen up the grounding points on the face plate... left white residue all over, which would not go away with hot soapy water and a stiff brush. This white stuff is there forever... unless someone knows of some chemical able to efficiently dissolve the stuff...

- When removing the face plate... make an accurate "map" of what control uses what type of washer and nut, and where, on what side of the face plate... because upon reassembly, I was left with 3 "extra" large start washers..... ahem... 


CONCLUSION

So this scope is almost finished. I still need to sort out the cooling fan, which drives me nuts. Luckily with Martins input recently, there is some new hope that it might be fixable !   :-+

Also, the leather carry handle is very damaged, beyond repair... it looks a bit out of place now that the scope is otherwise really good looking. I see this type of handle on my other equipment of many manufacturers back in the day.. maybe Tek used an off the shelve unit (need to check the mechanical check part list...) that might still be sold these days, who knows. If not, I will look into getting another leather handle made, using the old one as a template.

Also, I would like to experiment some stuff to a better job with all the knobs : I would like to get some gear so I can use a little polish/budding wheel, to see just how shiny and "smooth" I can get those knobs.  I would also like to try buffing the graticule of the CRT, to see how good I can make it look.

Also, I would like to experiment with redoing the white " dot ", because it looks a bit yellowed. I understand people manage to redo them just by applying a little dot of paint, and wiping the excess, and somehow it looks perfect afterwards... need to ask what type of paint is used exactly.

Also, I forgot about it when refitting all the knobs, but it would have good to put a tiny drop of fine machine oil on the set screws to lubricate them, as they tend to rust slightly, and become sometimes real stiff.

Oh, and I noticed that the scope is missing a part ! Nothing vital, but still ! It's about the tubes. 4 of them have a socket meant to receive a metallic "can"/"condom" that goes over the tube. Not sure what it's purpose is... can't be a heat shield I guess, maybe has to do with EMI, to keep a particular section of the scope "clean"...
There are 4 such tube sockets, and I am missing one of them. It's the one the goes on a tube in the CRT HV section, the oscillator tube I think. It is particularly tall/long, compared to all other tubes that use the same socket size/type.


Gear wise... I would also appreciate a new soldering iron with a longer tip and " thinner " hand piece, so that it's more " agile " when having to replace components in situ, in the inner parts of the scope... like these neon bulbs and paper caps in the trigger switch...

More and better tweezers would be good too, again to more reliably grab those hard to reach components when having to replace them in situ.



A little surprise in the pics below.... no your eyes or brain are not playing tricks on you : YES, I now have THREE of these 317 scopes !  :D
A year after buying the one I just restored... I came across another one in France ! It was cheap at only 40 Euros, and the seller was OK to ship it to me... On the single pic the seller posted on his ad, the scope looked really very sad. Of course, completely untested, "as is", take it or leave it, no question asked etc etc... the seller hardly new what a scope was any way, he was just an antique furniture seller, he got the scope as part of a house clearing I guess... and thought he might get a few bucks for it, so picked it up.
At first I thought I would use it as a donor to help me restore and maintain my first one... but when I received it, it actually didn't look all that bad.. was complete, face plate and buttons were not damaged... so I am toying with the idea of trying to restore that one as well !  :-DD

Then 3 months later, what were the odds... a THIRD one shows up ! Very similar story to the second one : seller is clueless, and picked up the scope the day before at a flea market ! Again, untested, no questions asked, as is etc etc... and again I was lucky the seller was ok to ship it to me. Got that one for even cheaper, only 35 Euros !  :)   As you can see it looks real sorry : it covered with CEMENT all over the cabinet and face plate ! Still, upon reception... it actually does NOT look hopeless ! Again there is zero physical damage to the cabinet or fce plate or knobs... it's all there in good nick. Just need to remove all that cement in a soft way... without damaging the paint work or face plate finish. will see how that turns out...
so again, I can help but want to try to restore this one as well ! LOL

There is a big BUT though.... Both these scopes were packed really... really badly. There was simply no packing material what-so-ever !!!  both sellers somehow found a box that just about fit the scope, and shoe horned into it ! Somehow the cabinet panels and face plate/knobs escaped intact... but that does not mean that the scopes were not dropped at least once in their journey to me... if so, then I guess it's possible that the CRTs suffered from internal damage to their electrodes.. if so, CRT is toast and so is the scope as a result !

So... until I get time to start working on these scopes, it's still too early to say if they will get restored or used a parts chassis...


OK that was a long post, but considering the restoration is finished and that it lasted over a year... if you average it over 12 months, it's actually not all that long !  :P


 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #80 on: October 21, 2018, 11:58:58 pm »
Pics of the inside after cleaning, CRT assembly and tubes are back in place.


 
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Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #81 on: October 22, 2018, 12:00:38 am »
Pics of the front of the scope.

 
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Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #82 on: October 22, 2018, 12:02:50 am »
Pïcs of the restored 317 next to the two new 317 I just got recently, in a very sad state but not hopeless I think !  ;D

 
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Online SilverSolder

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #83 on: October 22, 2018, 01:08:04 am »
Beautiful restoration work Vince. 

 

Online xrunner

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #84 on: October 22, 2018, 01:17:02 am »
Beautiful restoration work Vince.

Wow amazing job Vince!  :clap:
I am a Test Equipment Addict (TEA) - by virtue of this forum signature, I have now faced my addiction
 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #85 on: October 24, 2018, 01:29:08 am »
Thank you guys !  :)

Looking forward to having some time to start working on the other two puppies !  :)

Hopefully in 3 or 4 months, the time to complete the house move and tidy things up a bit...

 

Offline cnqhdszq

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #86 on: October 24, 2018, 03:34:17 am »
I saw an old CRT monitor pertaining to an old computer . :)   Vintage computer !
 

Offline 6PTsocket

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #87 on: October 25, 2018, 03:48:50 pm »
Yep no worries, I will replace them all, I started looking into it that last night, hoping to place an order tonight.

The ones which are going to be a nightmare to replace are the 4 caps in the time base switch, the "hold off" capacitors. The 4 papers caps are impossible to replace in situ, access is too bad./.. so I must remove the entire rotary switch assembly so I can work on it outside of the scope. It looks a little bit involved...  my spanners can't even remove the necessary nuts : looks like I will have to buy a set of small wrenches .. Imperial sizes !  :-\    That's US gear for you...

Yesterday I came across this site, interesting... I wish I had seen it sooner... they clearly tell you that these black caps are molded paper and need to be replaced no matter what.

https://antiqueradio.org/recap.htm


While I am at, and to correct myself : in my previous message I said I turned on the x10 time base magnification.... actually I looked at the manual and double checked on the scope front panel... on this scope the magnification is not the usual x10.. it's only x5.

Still, the trace is really bright indeed...
On a site called TEKwiki. They said the aim of the 317 was  to supply a very bright screen where needed so the acceleration voltage was vastly increased over the dimmer 316. They also said that later models of the 317 went to BNC connectors. It also said the fan is DC. Is your slow start possibly a power supply issue or is it thermally controlled? The scope is from 1959. Nice little 10mhz scope.

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Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #88 on: October 25, 2018, 07:50:09 pm »
On a site called TEKwiki.

Yep, I sure konw of TekWiki, it's THE bible for any technical information on old Tek scopes !  :)

There is also the "TekScope" forum/mailing list , both places go hand in hand.

Quote
They said the aim of the 317 was  to supply a very bright screen where needed so the acceleration voltage was vastly increased over the dimmer 316.

Yes, that's right. The 317 was a service scope meant to be used outside so with direct sunlight... the increased brightness was a big plus/selling point...

Quote
They also said that later models of the 317 went to BNC connectors.

Yes, though it has nothing to do with the 317 specifically. All Tektronix scope models moved to BNC connectors in the early '60's, because BNC was becoming the new standard in the industry.


Quote
It also said the fan is DC.

Yes and no. Early 317 models had the usual AC fan, like the one I just restored. Only late models had DC fans.
If you look at the pictures above, you can see that one of my 317 does ahve BNC connectors, so is a late model, confirmed by its high serial number.
I had a quick peek inside it, and yes, I can see that the fan has a DC motor on it, not the old AC style anymore.


Quote
Is your slow start possibly a power supply issue or is it thermally controlled?

Neither.  Power supply is fine, just 110AC straight from taps on the transformer primary windings, can't go wrong...
There is no thermal anything involved in the fan, it just runs straight from the transformer primary.


Quote
The scope is from 1959. Nice little 10mhz scope.

Yeah I love this little scope. It might a "small" service scope, but 10MHz B/W is just as good as the big 500 scopes of the day, it was not crappy scope at all... only a smaller scope   ;D

« Last Edit: November 01, 2018, 08:35:59 pm by Vince »
 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #89 on: November 01, 2018, 08:50:08 pm »
Hmmm... looks like I was mistaken about this DC fan ... when TekWiki said it corresponded to the " MOD101".... I assumed that this modification was an improvement /evolution  of later 317 scopes.. thnking well a DC motor must be a more modern thing compared to the ancient looking AC fan, and the DC motor has a much more compact/thinner body/footprint than the AC motor, must help with air flow/cooling I thought.... So it all seemed to add up.

BUT... no. This was not it, at all...

I looked at the 1959 Tektronix catalogu, the year where the 317 introduced, and.. right there, at its very introduction, I see this "MOD101" thing mentioned !

It's not at all an evolution implemented to later models, no. It was an option one could select from day one ! One could chose at will between AC or DC fan.
DC motor was not offered as an "improvement", no. It's purpose was to be able to run the fan motor / scope. on a 400Hz supply !  400Hz is way too much for the AC fan to cope with, so solution was to use a DC fan and must rectify the 400Hz...

You learn a little something new every day !  ;D

Nice to have all these old Tektronix catalog, helps put things in their original context and help you understand things better...

Now the next question : WHAT country on earth runs on a 400Hz power grid, rather than the 50/60 Hz of most countries ?!

I guess none ? Is 400Hz some industry standard to power test gear or other electronic equipment ? What voltage level does is use ? The main transformer being only designed to run on 110V and 220V, it would have to use one or the other... I presume.  Does it still the same power cord standard as well ?

Need to find out more about this 400Hz thing, intrigues me !  :o




 

Offline bd139

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #90 on: November 01, 2018, 08:57:03 pm »
115V 400Hz is aviation / military standard. Smaller transformers, less weight etc etc.

See MIL-STD-704: https://prod.nais.nasa.gov/eps/eps_data/137899-SOL-001-015.pdf
« Last Edit: November 01, 2018, 08:59:03 pm by bd139 »
 

Offline Vince

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #91 on: November 01, 2018, 09:08:01 pm »
Thanks BD139 !  :-+

Makes sense now...  I happen to work in aviation and did work a bit on the A400M military aircraft, though I am specialized in the cell/airframe, not the electrics, so I didn't know about this standard, shame on me  :--

So that means service techs were able take their Tek scope aboard aircraft or military vehicles and be able to power it from within the vehicle, quite practical indeed...
 

Offline Cyberdragon

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Re: Tektronix 317 classic scope - repair and restoration.
« Reply #92 on: November 02, 2018, 02:28:54 pm »
400Hz must make interesting sounding transformer buzz and arcs.
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 


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