开云体育

On 03/16/2018 09:01 AM, Fabio Trevisan wrote:

Well, not only it has a fan, but it was, like your very sticky.
Upon initial application of WD40, it didn't come loose immediately

This matches the way old Husqvarna sewing machines get.
Cleaning with solvent such as kerosene, then applying Triflow lube is best for
a good repair that lasts. Just adding Triflow can be enough in some cases.

Hello Lop,
Apparently we will walk hand in hand with our two recently acquired 76xx scopes (mine is a 7623A).
When I opened up mine, the very slow fan was the first thing I realized. Before I opened it, I was just so happy that I thought the 7623A didn't even have a fan (oh man, that 464 fan sound is annoying!).
Well, not only it has a fan, but it was, like your very sticky.
Upon initial application of WD40, it didn't come loose immediately, as it's common when we use WD40, so powerful WD40 is at loosening these things.
But it seems that the oil / grease residue of this particular fan gets really, really sticky... almost like tar.
I`m sorry that I didn't take pictures of the process, but here's what I did:
1. Firstly, remove the fan from the motor's shaft. It comes off easily, but don't risk pulling it out by the blades. Insert a flat screwdriver between the motor frame and the fan and use it as lever, so to push the fan out.
2. On the two sides of the motor, there are two small aluminum baskets that are help in place by two bent tabs. they hold inside them two generous tabs of felt, that are there to store the lubricant that keeps the sintered (porous) brass wet.
Unbend the tabs so to make the aluminum baskets loose. They wont come out because they're on the inner side, between the fan's frame and the rotor, but making them loose will allow you to apply WD40 generously inside them. This will soften the old oil, as well as wet the lint tabs.
3. Then, apply WD40 the closest as possible to the joint between the shaft and the bearing, so to create some pressure for the WD40 to enter the gap.
I used my fingers to hold around the WD40 needle, the shaft, and the bearing plate, so to allow only space for the WD40 to go in but little space for it to come out, in an attempt to increase the pressure into the gap. I don't know if it really helps, but it gives you an idea of how desperate I was, because even WD40 was having troubles to loose this thing.
4. At last, to help accelerate the process, I attached the shaft to my drill machine, and applied some continuous rotation while I kept pouring in WD40.

After a couple of minutes, the shaft was turning completely loose.

As a last measure, knowing that WD40 oil is quite volatile and don't last too long (to remain as a more permanent lubricant), I applied fine machine oil (sewing machine oil) to the felt tabs, sparingly, so to soak them completely.
I let the excess drip on paper towel, then I put the aluminum baskets back in place, holding them firmly from the back and re-bending the tabs.
It's important to hold them tight in place WHILE you are bending the tabs, so that they hold firmly into place, otherwise they will rattle and make noise.

Wish you luck.

Rgrds,

Fabio

Hi Lee,
You are in luck. There is no reason to waste your time making a battery pack. This company makes a perfect duplicate of the original battery pack and they do not charge much for it. Anyone with one of these scopes should write their contact information down. I have used them for years. They are excellent. You wouldn't know their replacement from the original except their replacement batteries hold a greater charge than the original Tek batteries.

This info is in the archives somewhere. But here is the information on the battery replacement company again:

Dennis Tillman W7PF

The 7633 I just got running had a stiff fan that needed poking to get started. It was replaced with a fan from my other now parts scope. The the scope and fan are so clean it almost looks like the unit was hardly used. My theory is the fan just stiffened up from years of sitting. Is there anyway to repair this thing? I would like to have a backup. I wanted to wait and ask before I started tearing into it. /g/TekScopes/photo/37195/3?p=Name,,,20,1,0,0

All done!
Total cost - 12,50 USD. :)
I think the knob is good and all work fine.

Can you say again what mainframe and what plugins you are using?

My 7603 manual does not have a part C1016, also 'Code 5 fail' sounds like an error code from a mainframe or plugin that has a built in microprocessor.

Regards,

Roger

No specific experience with a 317, but did you replace electrolytics as
well? Its old enough to give it consideration.

Id also check power supplies (voltage and ripple) while its “bad”

Bad caps would be my first thought for something of that age

But beyond that I cant make much more in the way of useful suggestions

David

On Thu, Mar 15, 2018 at 12:02 PM CZ4A via Groups.Io <artofruin1285=
[email protected]> wrote:

Hello everyone,

A couple of months ago, I purchase a Tektronix 317 scope, serial 3507, and
an assortment of 10x probes from a NH Craigslist ad. This is my first
scope. I intend to use it for helping diagnose my vintage tube audio
equipment. This old war horse has seen its share of battles- the front
bezel is all nicked up, the carrying handle was replaced with heavy-duty
rope, and there isn't a single straight panel left! However, the inside is
in excellent shape and was all original except for some replacement tubes.
The scope has the manual too. It was last calibrated by Tek in Boston on
10/27/1977 according to a sticker on the front.

Before I fired it up for the first time, I replaced the half-dead 6080
tube and replaced the following paper caps with film caps of the same
capacitance and same or greater voltage: C806 and C815 in the HV circuit,
C171 in the preamp section, and C603, C614, C638, C668 in the LV power
supply. All the other tubes checked out OK on my tester. While warming up,
the trace comes in nice and bright. The horizontal and vertical positioning
are just about dead-on.

However, as the 317 warms up to full temp, the trace drifts off the
screen. After fiddling with some knobs, I was able get it back by cranking
the horizontal knob fully clockwise and turning the intensity up a bit.
Vertical is more or less the same. The trace shows up only as a dash at .1
and greater V/div, but appears as a loop at .05V and lower. No amount of
adjustment of the time base knobs brings back the nice, straight line. I
can get the trace to fire off a sweep sometimes by turning the red Trigger
Selector, V/Div, and Time/Div knobs a certain way, and the speed of the
"sweep" roughly matches the Time/Div setting, but it only shoots once. The
traces wiggle when I touch the probe, so it is picking up, it's just not
displaying correctly. In the horizontal amp circuit there were three
6BQ7A/6BZ7s, which are notorious for cathode-to-plate shorts. They all
tested good with no shorts on the tester, but to be sure it wasn't those I
replaced them with three good 6DJ8s I had on hand- no dice, same behavior.

If this is something that can be fixed with simple calibration, let me
know, but I see nothing that relates to this odd behavior in the manual. I
see no arcing or sparking with the covers off. Any other tips I could
follow to get the trace back to normal?



--

Sent from Mobile Annoyance thingy, please pardon any typos

I'm almost the same: I didn't need one, but I snapped one up at that price!

Hi Benjamin, So you want to relearn electronics but don't want to fix the 475 to learn ? That is confusing.

1) If you go through the 475 S/M from page-1 to last page , you will find the problem and fix the unit. Since this old scope is new to you, this will give you a record of readings you take and get you familiar with it and teach you too. A DMM will find MOST problems in a scope. If you have one scope you will eventually need a second to fix the other.

2) Get a copy of the 1989 Tek manual; TROUBLESHOOTING YOUR OSCILLOSCOPE ; GETTING DOWN TO BASICS , # 068-0315-00. Still ;the best out there. I got mine from K04bb.com , though a few websites have it. It says do NOT remove the scope cover until you have isolated the fault to a section. Also, the front panel is the best tool you have for troubleshooting... The 88 page manual is a STUDY-manual, not something to flip-through. When you use it correctly , it will find the problem in your scope ! But , this haphazard , go here , go there , try this , try that , BS is the Wrong Method.

3) Spend an hour or so , trying every knob / switch / dial and documenting that it is working......and working correctly. Make a list or photocopy the User Guide for your notes. Let's say, ......95% of problems a scope has will be demonstrated by the front panel settings and you can open the schematic and isolate to the part or ckt , and you have not even taken the cover off yet ! ! ! Drives me crazy to read , ' I have no Hor Trace" only to find out later ' oh yeh, the trigger level was off and I never bothered to select Auto-Mode " !

Only took me 4 hours to figure out what they wanted. Funny stuff. I was bored anyway.

Hey Lop Pol,
I don't have the manual of the 485 (besides the page you posted), but it seems you guessed it, apparently it's calling for measuring the voltage between the 2 points...
This is what's called a differential voltage measurement (as opposed to absolute measurement, which is taken in relation to ground... or in other words, while you hold the ground lead at the ground level = 0V).
Rgrds,
Fabio
P.S. In time, careful about taking differential voltage measurements if you're using a BENCH voltmeter (a voltmeter that is powered by mains, and not by battery).
A bench voltmeter usually have its ground lead internally connected to the ground (all the way through its power cord to the building's ground, or earth). Those voltmeters are not suitable to perform differential voltage measurements in other equipment that are - just as well - grounded. You would end up shorting to ground the point of the circuit where you connect the ground (black) lead.

Hello Group,
I was browsing the local auction site from Brazil (not evil bay... but just as evil) and just saw this item:


There are 75 transistors in the lot, all listed in the description.
It's selling for BRL 50,00 which is roughly USD 15,00
Maybe someone is looking for some hard to find transistor?
In case you have interest, I can liaise if you need.
Rgrds,
Fabio

Well I think when they said connect to the TP they meant it. Connect to both at the same time. Thats what I did and I think that its right.

Ok. I'm failing at something here. I set channel 2 to the center graticule. I have 11.800V in my DVM. I turn the position pot for 12V which causes negative deflection. Turning the main gain r629 and as far as I can bring my trace back is back to the center graticule.

This is the spot to get some help.

After reading threads for a few years, my thoughts on how to help people
help you:

Get the service manual(Check, good start)

Get a good picture of the scope, there are a "lot"!!! of knob position
combinations that have to be considered. For example, It does not sound like
it, but a check to be sure your not in horizontal external would be good.

If there are not signs of mechanical damage, cycling the switches on a scope
that has been sitting can help, flipping it in and out of horizontal
external a few times to see if you have some switch dirt that will loosen
up. A dirty Beam find button has a history of fooling people.

Another thing is to give us an idea of what other tools you have to work
with.

Any scope history? Serial number?

Some idea of your general location.

Then it's to the power supply, do some reading first

From an educational perspective "getting a crappy digital toy" depending on
what it is, to look into the scope might have some merit.

Take some time and don't be in a hurry
John

For all those GHz digitizer junkies out there...

60fs is a short pulse for sure! Shortest pulse thing I designed (about 15 years ago) was frequency
quadrupling 250fs pulses with 30% efficiency. It was not straightforward. 250ps is a pulse of light
only 75um long. 60fs is 15um long - far thinner than a human hair!

The trickiest thing is measuring and verifying the pulse length, because there is no
detector/electronics that works remotely that fast.


Craig

If you are a member of the group, you should see a photos button on the left side when you access the group with the web interface. You can create an album and put your pictures there. Then copy the URL of the picture and send it in a message so we can see it. Please note that we need the name you give the picture so it can be found.

Do you have a copy of the service manual for your scope? The 2465B manual should have the same power supply as your 2445B. If not, look around on the tekwiki site.

If you have an original foot, I can make a mold and pour plastic feet. I've already done it for some older Yaesu and Kenwood rigs.

Vince.

--
Michigan VHF Corp.

Hi Bert,


That would be great. Even though the foot has the same part number on the 314, it would be good to confirm correct fit on that unit. Let's wait until I get results from Lee - I actually sent him several variants to try to get the best fit. Once that's determined, I can send you a sample of that size.


PM me your address, please.


Jeff

________________________________
From: [email protected] <[email protected]> on behalf of Bert Haskins <bhaskins@...>
Sent: Thursday, March 15, 2018 9:39 AM
To: [email protected]
Subject: Re: [TekScopes] Back feet for 335 scope



On 3/15/2018 11:07 AM, Jeff Davis wrote:

Hello all,

Here's an update on the project to develop replacement back feet for the Tek 335 scope. Lee Houde has graciously provided me with a sample foot, which I've measured and modeled. I sent a first set of samples to Lee, which he fitted to his scope. They worked and were usable, but not perfect. Lee gave me some great feedback and some photos which I used to revise the models and print a second set. They're on their way to Lee now. With any luck they'll be a great fit and I'll send out another update to the group at that time.

Jeff

If you would like another tester, I would be happy to volunteer.
I have a 314 and a 335.

Thanks,
Bert

On 3/15/2018 11:07 AM, Jeff Davis wrote:

Hello all,

Here's an update on the project to develop replacement back feet for the Tek 335 scope. Lee Houde has graciously provided me with a sample foot, which I've measured and modeled. I sent a first set of samples to Lee, which he fitted to his scope. They worked and were usable, but not perfect. Lee gave me some great feedback and some photos which I used to revise the models and print a second set. They're on their way to Lee now. With any luck they'll be a great fit and I'll send out another update to the group at that time.

Jeff

If you would like another tester, I would be happy to volunteer.
I have a 314 and a 335.

Thanks,
Bert