P.S. All the numbers above are for a 7904. I assume they are the same in a 7854.

From: dutchbosstard
Subject: [TekScopes] Re: Just got a tek 555 for free, and in need of some advice!
To: TekScopes@...
Date: Monday, July 9, 2012, 4:03 AM

?

ill look into 3-in-one oil, i think ive seen some before around the machine shop at my university.

I see that you painted the carts of your 555 scopes? this might come off as another dumb question, but are the two provisions for plug-ins on the 555 cart just there as a holding rack for 2 extra plug-ins, or is it actually possible to somehow connect those plugins on the cart to the actual scope?

I appreciate your offer, and as it turns out, i might actually need a part. the day i turned it on, at my friends house, I dropped one of the white little things that the outside panel screws get screwed into, i just tried to find it in the parts list, but I dont know what their exact name is.

-Robby

--- In , Keith Knox wrote:
>
> Hi Robby,
> ??
> At the present time I am working on 4 Tek 555 scopes. I have 3 of them working, 555 #4 is not working yet but will be soon.
> ??
> As for the fans I use a drop of 3-in-ONE oil and find that it works very well. Fans must spin freely or they will not run or they will run slowly.
> ??
> Test points for LV power supplys are on the bottom of power supply unit.
> ??
> Because the Tek 555 is a dual beam scope, there are two -1350 HV adjustments. One for each cathode.?? The HV Anode lead that plugs into the CRT will provide about +8650 volts.
> This totals out to 10KV accelerating voltage.
> ??
> When you get your Tek 555 working,?? remember that the upper beam will only write to the upper 4 cm of the crt and the lower beam will only write to the lower 4 cm of the crt.
> ??
> I have some spare parts for 555 scopes.?? Let me know if there is anything you need.
> ??
> Have attached??photos of my three working 555 scopes.
> ??
> Keith
>
>
> --- On Fri, 7/6/12, dutchbosstard >
>
> From: dutchbosstard
> Subject: [TekScopes] Re: Just got a tek 555 for free, and in need of some advice!
> To:
> Date: Friday, July 6, 2012, 10:01 PM
>
>
>
> ??
>
>
>
> awesome. so when i get it back to my house ill carefully hit it with 40 psi. im guessing that shouldnt damage any tubes as long as im careful. My air compressor is sanborn reciprocating compressor - ive never noticed any oil in the lines, only a small bit of moisture from when i drain the tank all the way. it also has a air filter on the input.
>
> so i guess ill just utilize a dry cloth until i get the scope back to my house.
>
> a few questions about the test points - when the time comes that i power up the scope, where are the test points for the low voltages from the power supply? are they in the PSU box? or are they somewhere inside the scope? also, when i opened up the case yesterday i found the -1350V test point for the CRT, but I was under the impression that the total accelerating voltage for the crt is 10kV. where is that test point located, and should i worry about it?
>
> also what fuses should i see for the main fuse, and the filament fuse in the PSU box?
>
> thanks,
>
> Robby
>
> --- In , tubesnthings@ wrote:
> >
> >
> > Valid concerns! Set air pressure no higher than necessary, say below 40
> > psi.
> > Use caution and common sense - 40 year old dust doesn't belong in your
> > lungs - do it outside and wear a mask.
> >
> >
> >
> > In a message dated 7/6/2012 1:43:15 P.M. Pacific Daylight Time,
> > childwhereugo@ writes:
> >
> > since i have an air compressor at home, should i try blowing out all the
> > dust? Ive heard that you can do this to electronic equipment, but i am kinda
> > terrified to do this since i dont want to have anything become
> > unconnected, or cause anything to short out, or worse yet - damage a tube.
> >
> > are these valid concerns, or am i overacting? my air compressor is usually
> > set to 100 PSI.
> >
>

From: KeepIt SimpleStupid
Subject: Re: [TekScopes] 224 Battery Pack
To: TekScopes@...
Date: Monday, July 9, 2012, 8:03 PM

?

It should be the same as the 211, 212 scope I think.? There was some discussion on Tekscopes that there are actually two different cup holders that have slightly different dimensions. I bought the paks, less connectors, from www.bulbtronics.com.? Their part #, 5149.? You need two pack at a total cost for two of about $30.? Their order # is BAMED4149.? Note the 5 changed to a 4. The part is hard to find on their website.? Look under medical batteries Siemens. --- On Mon, 7/9/12, photo692002 wrote: From: photo692002 Subject: [TekScopes] 224 Battery Pack To: TekScopes@... Date: Monday, July 9, 2012, 7:19 PM ? Is anyone aware of a supplier for the battery pack or the cells within? I want to sell this scope and would like to suggest to the buyer where a pack might be obtained. Larry

Do you have a dual time base, a 7B87, or a 7B80/7B85 (or equivalent)
which you could use to check if the A intensified by B display is
correct?

I wonder if your readout troubles are related. The stored trace
intensify command could be controlled through the readout or from the
same place the readout is controlled from. Verifying it should be as
simple as disabling that function by pulling a transistor but I did a
cursory search of the service manual and did not find out it.

You might try fiddling with the contrast adjustment on the front of
the oscilloscope to see if that affects anything. I know mine has
trouble with the intensified display when using some dual time bases.

On Mon, 9 Jul 2012 12:36:13 -0400, David Holland
<david.w.holland@...> wrote:

Yup. Blanking looks good to me...

I'll double check the pot, and make certain its smooth. It looks
like I have some reading to do in the manual....(this is certainly
going to be umm.. interesting)

David


On Mon, Jul 9, 2012 at 11:32 AM, <larrys@...> wrote:

Are the parts that are supposed to be blanked getting blanked?
-ls-

David Holland <david.w.holland@...> wrote:

Hello all,

I'm kind of getting around to poking at my 7854 scope.

The stored trace brightness is excessive, and the adjustment won't go
down any further. I'm reasonably certain the pot is good, since
it'll smoothy vary over what range it does have. (From "too bright",
to "cr*p, I'd better turn that down before the CRT gets burnt").
Normal display, and readout's are of a more reasonable intensity, and
have goodly range. (Readout isn't working correctly, but that's
not the problem I want to concentrate first on.)

Before I crack the covers, any suggestions of which parts of the
service manual would be most relevant to read...

thanks in advance...

David


------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

?

Is anyone aware of a supplier for the battery pack or the cells within? I want to sell this scope and would like to suggest to the buyer where a pack might be obtained.

Larry

Do you have a dual time base, a 7B87, or a 7B80/7B85 (or equivalent)
which you could use to check if the A intensified by B display is
correct?

I wonder if your readout troubles are related. The stored trace
intensify command could be controlled through the readout or from the
same place the readout is controlled from. Verifying it should be as
simple as disabling that function by pulling a transistor but I did a
cursory search of the service manual and did not find out it.

You might try fiddling with the contrast adjustment on the front of
the oscilloscope to see if that affects anything. I know mine has
trouble with the intensified display when using some dual time bases.

On Mon, 9 Jul 2012 12:36:13 -0400, David Holland
<david.w.holland@...> wrote:

Yup. Blanking looks good to me...

I'll double check the pot, and make certain its smooth. It looks
like I have some reading to do in the manual....(this is certainly
going to be umm.. interesting)

David


On Mon, Jul 9, 2012 at 11:32 AM, <larrys@...> wrote:

Are the parts that are supposed to be blanked getting blanked?
-ls-

David Holland <david.w.holland@...> wrote:

Hello all,

I'm kind of getting around to poking at my 7854 scope.

The stored trace brightness is excessive, and the adjustment won't go
down any further. I'm reasonably certain the pot is good, since
it'll smoothy vary over what range it does have. (From "too bright",
to "cr*p, I'd better turn that down before the CRT gets burnt").
Normal display, and readout's are of a more reasonable intensity, and
have goodly range. (Readout isn't working correctly, but that's
not the problem I want to concentrate first on.)

Before I crack the covers, any suggestions of which parts of the
service manual would be most relevant to read...

thanks in advance...

David


------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

From: photo692002
Subject: [TekScopes] 224 Battery Pack
To: TekScopes@...
Date: Monday, July 9, 2012, 7:19 PM

?

Is anyone aware of a supplier for the battery pack or the cells within? I want to sell this scope and would like to suggest to the buyer where a pack might be obtained.

Larry

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?

I'm attempting to bring a 453 (FET's) back to life. There is no trace, nor sign of an "off-screen" glow. Both sets of deflection plates are at the correct potentials, and the heater is not O/c.

Initially, the EHT section did give the correct regulated outputs (-1.96/+8kV), but this must have been a transient condition, as it refuses (for the most part) to produce any EHT at all. After a prod around and the odd component substitution, I can see the start of an oscillation in the driver Q930, but this gently subsides over a second or two as the scope warms up. This has happened several times.

This suggests a possibility there is one secondary which is being loaded to the extent that the oscillator formed around the transformer does not have a loop gain of >1. I'd like to disconnect the EHT secondaries one-by-one, but I'm nervous at leaving the CRT connected in case the grid end up +ve.....

1. is it OK to remove the CRT base connector with the anode still hooked up?
2. Is it OK to remove both the CRT base and the final anode connection whilst powering the EHT section?

Cheers

John