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thanks morris. I am going to try and buy the silver solder from stan's parts shop. I might also try and buy the cover clamps from there also since there is a minimum $10 order.

will I need to use flux with this tektronix silver solder, or is it already flux-cored? All the soldering I have done has always been with 60/40 flux cored solder, so I have never used flux and solder separately. If I do need to use flux, which kind should I use with this kind of solder?

As far as the fan goes, couldnt I just cut the wires and after I take it apart, soak it if necessary, and re-lube it, reconnect it back using these insulated male/female disconnect connectors from home depot? I know it would probably look tacky, but couldn't this possibly be better than having to solder/unsolder, especially if i ever need to pull the fan out again? Or do I just need to suck it up and stop being a pansy about soldering? haha.

this is what I had in mind if i were to just cut the wires:



let me know what you think, I am still going to try and buy about 15-20 feet of silver solder, in case I ever need it.

also since im not gonna be able to power on the scope until I get that fan taken care of, I did find V799, did some reading and looked up the datasheet, checked it with my multimeter and it measured zero ohms between pins 3&4 and 2&7. pin 5 is the plate, and i'm not sure if i could check it's resistance.

let me know what you think,

-Robby

--- In TekScopes@..., "Morris" <vilgotch@> wrote:

Hi again Robbie,

In answer to your questions, firstly no, you don't have to soak the bearings if you can get them turning. I have found that a lot of gunk collects there in some scopes if they were used in a dusty environment so I just like to give them a good clean. If 3-in-one works then go with it.

Tek solder would be ideal if you can get it. If it appears cheaply on ebay then so much the better.

The easiest way to check the sensing diode is to see if it lights up. Checking the filament pins with an ohmmeter will work but it should be obvious by inspection. Note that those tubes have an internal spring contact that shorts across the diode (anode to one side of filament) if and when the filament burns out. That's a fail safe mechanism to make sure the regulated heater voltage fails low.

It's good that you have the A type newer timebases. They can be a bit finicky to get going but hopefully the tunnel diodes in them are OK. We'll see once you've got through the preparatory stuff.

Let us know how you get on,

Morris


--- In TekScopes@..., "dutchbosstard" <childwhereugo@> wrote:

first I would like to say thank you for the very clear advice.

I have been slowly going through the manual since the day i got the scope, but i definitely need to read it thoroughly instead of just kind of skimming it. Yes, i did read the part in the manual about running it with all plug-ins installed. If anyone would like to know, I believe my scope may be a 1967 model, since there is a little information diagram on the bottom of the power supply that has written that it was inspected in '67. It also has the newer 21A and 22A time bases, and the vertical plugins that came with it are the type 53/54K and the type M 4 trace plugin. I do not know the name of the style of screw-in connector, not a BNC. they look like these:




can someone give me the name for those things? i guess i should be happy that the 2 probes that came with the scope have the same strange looking connector. the timebases have BNC connectors.

as far as the fans go, would it really be necessary to soak them in diesel fuel, if i happen to get em turning after disassembly? I know that electric motors and generators often use oil-lite bearings, i've never heard of the bearings losing their oil, but then again I dont know much about oil-lite other than it feels strange, looks strange, and has an interesting smell to it. However, if i cannot get the 555 fan to get turn nicely after taking it apart, i will surely follow your advice word for word.

as far as solder goes, I did indeed read where it says in the power supply to use the silver bearing solder. what I am confused on is: is this solder flux cored, or do i need to solder it with external flux (ive only ever soldered with 60/40 flux cored solder) or does this specific solder need flux? my last solder question is, should I buy this tektronix solder off of ebay?



as far as V799, the thermonic diode, I just did a little reading about it online, could i look up the datasheet to find the pins, remove it and measure the resistance of the filament to make sure its not blown that way?

thanks,

Robby


--- In TekScopes@..., "Morris" <vilgotch@> wrote:

Hi,

Let me add some comments from an experienced Tek scope (including a 555 scoposaurus) restorer to the excellent advice you have had so far:

I gather you are not experienced with vacuum tube equipment although you have worked with high voltage before. I assume you know how to be careful around gutsy power supplies, there's more than enough juice in the 555 to kill you.

At this stage you have had the scope running after a fashion so you can probably assume that the CRT is OK, you know the time delay relay works, no electrolytics have blown up, no smoke got released and the power supplies are at least producing enough to a give you a green flash. That's all very encouraging.

What I would do now is to stop and read the manual thoroughly so you become familiar with what's there, where the test points are and how the thing works. Then I would give it as thorough a clean as possible as has been discussed. The next thing to do before anything else is to get the fan working. The best way to do that is to remove it altogether which involves unsoldering the leads from the tagstrip, taking careful note of where to reconnect them. If there is no little roll of silver solder with the scope you need to go and get some - the commercially available silver bearing solder stuff is not exactly the same as the Tek solder but is preferable to ordinary 60/40 which should not be used.

Taking the fan motor apart is pretty straightforward, just make sure you record where everything goes so you can reassemble it. The bearings can be soaked in thin oil (such as 3-in-1), diesel fuel or kerosene to clean all the gunk off and then lubed with something thicker. Car engine oil is probably OK. Once it spins freely, you can put it back. Eventually you might do the same for the fan in the power supply but for now just put some oil into the oil holes on the bearings.

Once both fans are running you can run the scope again and check the LV power supply voltages at the test points. Start with the -150 which is the master reference for everything else. You don't need to measure the HV just yet but make sure the heater voltages are right. The heater supply is regulated using V799 in the power supply, a special thermal sensing diode type 2AS15A. If it's failed with an open filament then the heater voltage will be low to pretty well all the tubes in the scope. If V799's not lighting up you will need to suspend all operations until you can find a replacement (plenty available on eBay).

Incidentally I missed whether you mentioned which timebase & vertical plugins are installed. Please let us know. Don't try to run the scope without plugins.

Once you've done all that, get back to the brains trust here and I'm sure you will get excellent advice on how to proceed further.

Good Luck!!

Morris

--- In TekScopes@..., "dutchbosstard" <childwhereugo@> wrote:

so yesterday i got real brave and decided to power the scope up. the power supply had the proper 5 amp fuse, but the heater supply had an 8 amp fuse instead of the 7 amp one. i checked the fan in the power supply and i tried turning it by hand and it seemed to spin pretty well, but the larger fan in the 555 was harder to turn, and i also had to remove its dust screen since the dust screen was pressed in, preventing the fan's movement. i powered it on with all the covers off and the PSU fan came on right away, but i noticed that the 555's fan wasnt powering on. all the tubes started to glow and i heard a relay click and then i started fiddling trying to find a beam. i rotated both of the horizontal display knobs and i couldnt get a trace, but every time i turned the know, a trace would appear for a slit second. both beams did this. after the scope had teen turned on for a whole minute, i decided to shut the thing off since the fan in the 555 didnt come off. the fan in the PSU box also had originally started rotating rather slow, but kept gaining speed until after about 30 seconds it started rotating extremely fast.

now this might be a dumb question, but could I have damaged anything by powering it on with a 8amp heater supply fuse instead of the listed 7amp? and also, is there any difference between a "slo-blow" fuse and a "time-delay" fuse?

also, what should i do about the fan in the 555? should i disconnect it and try to power it up with 115v on its own?