Now that you used 'soft eraser' to 'fix' your contacts, try to find a
solvent that would clean the glue left behind eraser when that glue becomes
hard and prevents contact. The Pink Pearl is something that temporarily
fixes contacts and leaves a residue that makes life very difficult when
problem comes back.

The erasers were cures invented by 'board swappers' in computer industry. It
did solve their problem for that day, but caused lot of problems for anyone
coming to this machine afterwards; the softness of eraser was ratcheted up
and at times eraser for ink had to be used (some of them had fine ground
sand to increase hardness).

Regards

Miroslav Pokorni

--- In TekScopes@y..., "stever1k" <stever1k@h...> wrote:

My 465 seems to work just fine except that the Ch1 input rotary
switch is flaky and it will distort the display a lot. Wiggling it
around will cure the problem but seems temporary. Ch2 switch is ok
and no problems.

Using the calibrator as an input I can get a nice looking waveform
although with some overshoot on Ch1 no problems and nice display
with no overshoot on Ch2 input.

When it goes wacky the display using the calibrator input has
diminshed amplitude and looks like all you see is the leading edge
and then a decay. Looks more pulse like. If I wiggle the switch a
lot it will come back and look normal.

Makes you think the switch is very dirty and clearly intermintent,
Is there any easy way to clean these things or am I just going to
have to find a replacement?

Hope you good scope guys can give me some advice.

steve

Well I have fixed the problem, on the circuit board where the input
stage is for the channel there is a cover and under that cover is
where my problem was. Seems there are two little pots (I think) on a
plug in module and when the module was wiggled it made a good
connection. I took the module out and cleaned the pins with a very
soft eraser to remove the oxidation and it fixed the problem.

The last remaining problem is the light that illuminate the various
ettings on the rotary switch is dead burned out. I hate to think
what it takes to replace them or even where to find them. How big a
job is to replace that lamp?? Where would I get one from..Not Radio
Shack I bet.

Steve

My 465 seems to work just fine except that the Ch1 input rotary
switch is flaky and it will distort the display a lot. Wiggling it
around will cure the problem but seems temporary. Ch2 switch is ok
and no problems.

Using the calibrator as an input I can get a nice looking waveform
although with some overshoot on Ch1 no problems and nice display
with no overshoot on Ch2 input.

When it goes wacky the display using the calibrator input has
diminshed amplitude and looks like all you see is the leading edge
and then a decay. Looks more pulse like. If I wiggle the switch a
lot it will come back and look normal.

Makes you think the switch is very dirty and clearly intermintent,
Is there any easy way to clean these things or am I just going to
have to find a replacement?

Hope you good scope guys can give me some advice.

steve

I have 2 Lots (2 Probes each) of hardly used:

P6137 10X Passive probes, up to 400Mhz (with right
2400 Scope) Readout & ID for 2400 Series
Oscilloscopes.

Asking $250CND for both lots or $150CND each lot,
as always negotiable.

If you are interested, please contact me directly at:

lt57ven@yahoo.ca



__________________________________________________
Do You Yahoo!?
Yahoo! Health - Feel better, live better
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From: amacbradley [mailto:macbradley@earthlink.net]

Hi Everyone, with particular thanks to those who sent or posted
answers. Thought I'd give an update and ask one more question.
The scope works great. The Type D had a wire broken on the vertical
position pot, I soldered it back on and it works/worked. I'm still
not sure it works right.

Get a manual for the same or later serial number. You'll never
figure out how to calibrate it on your own, due to the several
interacting balance adjustments inside.

The Type K works great! Nice sharp traces
some 40 years old.

That's a good simple amp, but I'm prejudiced in favor of
the L (which I have), which is a K plus a x10 AC booster
for those low-level signals.

Anyway, when I run a voltage from the CAL OUT to the input, the
screen shows a reduced voltage. Say for example 3 volts amplitude
(after probe x volts/cm etc) when the CAL OUT is delivering 5.2 volts
according to a digital voltmeter. And sometimes the waveform
has "slumped shoulders" on the leading edge of the waveform.
Any ideas?
Mac

Your procedure is open to interpretation. If you put a DMM
on the CAL OUT jack, you will not get the meter reading you
perhaps expected. The calibrator output is a square wave
where the negative peaks are 0 and the positive peaks are
the voltage on the knob, in other words, peak-to-peak,
which is perfect for calibrating a scope but not much
good for a meter. A meter will give various wrong readings,
depending on whether it is DC, VAC (averaging) or VAC (true-rms).
No meter that I know of reads peak-to-peak.

IIRC, you calibrate the calibrator by setting it to OFF and
reading DC V on an internal test point. You adjust an internal
tweak for exactly 100VDC. See the manual for the full info.

As for the slumped shoulders, you most likely haven't adjusted
your probe's compensation. The crudest form of probe is
a simple resistive voltage divider. As soon as you use it
at frequencies above a few kHz, you will find that the
scope's input capacitance drags down the response. In the
time domain, this translates to a rounded leading edge on
sharp waveforms. To compensate, all "real" probes contain
a small capacitor, so the resistive divider has a capacitive
voltage divider in parallel with it. If the capacitive divider
and the resistive divider have the same ratio, the probe will
convey all frequencies equally. Since different scope inputs
have different capacitances, the probe's capacitor is adjustable.
When you move the probe from scope to scope, you should always
check the compensation and adjust as needed.

Regards,
Dave Wise

I would check each of the tunnel diodes on a curve tracer and make sure none
of them are installed backwards. they are installed in clips and if someone
was trouble shooting this 3T77 before you got to it, they could have removed
the TD's to test them and put them in backwards . . .

Stan
w7ni@easystreet.com

Been a while since I mentioned these but I finally got things sorted
out. Just got a 3T2 and it turns out that the 3S1 and 3T2 are
completely operational. Was able to view a 1200 mhz sine wave on one
of my RM561As. The 3T77 is definitely faulty. Anything special I
should know about this plug in? I'm well aware of the input limitation
of the 3S1 and the dangers of careless handling of the sampling diodes.

George

Hi Everyone, with particular thanks to those who sent or posted
answers. Thought I'd give an update and ask one more question.
The scope works great. The Type D had a wire broken on the vertical
position pot, I soldered it back on and it works/worked. I'm still
not sure it works right. The Type K works great! Nice sharp traces
some 40 years old.
Anyway, when I run a voltage from the CAL OUT to the input, the
screen shows a reduced voltage. Say for example 3 volts amplitude
(after probe x volts/cm etc) when the CAL OUT is delivering 5.2 volts
according to a digital voltmeter. And sometimes the waveform
has "slumped shoulders" on the leading edge of the waveform.
Any ideas?
Mac

--- In TekScopes@y..., "Mac Bradley" <macbradley@e...> wrote:

Hi,
So I just got a Tektronix 535A. And I've got a few questions.
1. I guess this device is about 40 yrs old or so, and has some

dust in it. Any recommendations about cleaning? Good idea/Bad
idea? Best way to do it? How about watching out for the high
voltage supply?

2. there's a trace-I get about a 5mm wide vertical band from

horizontal centerline up, and it sweeps left to right. Not what I was
hoping for, but still encouraging. Running a cable from the CAL OUT
to either of the inputs in the Type D differential amplifer doesn't
seem to affect it. To me that seems like a preamplifer problem? Am
I right or wrong? Any opinions on how to fix it?

3. I bought a 535/545 manual only to realize it's not the right

one for the 535A. Anybody interested?

I hope that's not too many questions for one post.
Thanks in advance for reading this and contributing to my Tek-

education.

Mac

Hi Bob,

There is something odd about the nomenclature you used for your scope. I
don't think "D44" is the correct or entire number. Here is a little
background that may help:

The first scopes in this series were the 5100 Series. These were all 2 MHz
scopes with the same 3-plugin power section and various display sections
that could be put on top of (or beside) the power/plugin section. There
were 5 different display sections available for the 5100 series. The power
supply/plugin section was called the "5103N" and each of the display
sections had their own number, too, as follows:

D10 = Single beam, non-storage
D11 = Single beam, storage
D12 = Dual beam, non-storage
D13 = Dual beam, storage
D15 = Single beam, storage, fast writing rate.

To complicate things, Tektronix gave the various combinations of power
supply/plugin sections and display sections still another nomenclature.
For example, the 5103N/D10 combination was also called the "5110", the
5103N/D11 combination was called the "5111", etc. This early series of 2
MHz scopes had no readout capability which is what the "N" in 5103N means.
The first plugin that went with those scopes also had no readout capability
as indicated by the "N" in their numbers. Your 5A18N's for example cannot
supply readout information to your mainframe and there is no modification to
make it happen.

Later, Tek brought out the 5400 Series of mainframes that were similar to
the 5100 Series but with a lot more features. For example, the mainframes
had readout capability as standard, but you could DELETE readout by
selecting Option 01 and save $325. The 5400 Series also had 60 MHz
bandwidth. The early plugins would work in the 5400 mainframes but only at
2 MHz and without readout.

One neat thing about all of the 5100 and 5400 series of mainframes is that
they could be reconfigured from benchtop to rack mount if you had the
mechanical parts to do it. You could get them in a kit . . .

So . . . to take advantage of the bandwidth and readout of the 5400 Series,
Tek brought out some new plugins and these are what you need to use the 5400
series readout feature. A 5A38 or 5A48 will give you dual trace (two of
them will give you 4 trace) with readout and a 5B40 or 5B42 (one timebase)
or 5B44 (delayed sweep, two timebases in one plugin) will give you readout
for the sweep speeds.

From the "D44" nomenclature, I suspect you have a rackmount configured 5444
(R5444) which is a 60 MHz, dual beam, non-storage mainframe, but you
apparently have no plugins that will drive the readout. There is a pretty
good explanation of this in the 1976 Tek Catalog.

Hope this helps,

Stan
w7ni@easystreet.com

I have a Tek 7704a oscilloscope that I purchased from e-Bay about a
year ago. It being 25 or so years old, it has its foibles, but with
the 7A26, 7A24, 7B85 and 7B80 plug-ins, it is a really nice, useable
and durable machine.

Early this month (July, 2002), I developed some problems in the Z-
Axis system. I toyed with getting a new mainframe, but then emailed
Walter Shawlee of Sphere Research. They are in B.C, and I am in
Ontario, but after a couple of emails, I decided to send the
mainframe to Sphere.

I got it back today. The mainframe had been serviced and re-
calibrated at a very reasonable number of hours and very reasonable
price. In part, Walter said "it's nice looking 7704A, definitely
worth fixing".

I had to do the front panel calibrations on all four plug-ins after
the mainframe calibration, and of course, this is to be expected.

I am very pleased with the results, with Sphere's work, and the fact
that this venerable old machine remains in top form and reliable
working condition.

Thanks, Walter.

I have a mint 7704A with a dead power supply (the switching circuit
will not worK). Anyone have a spare supply floating around ?
Failing that, anyone need a mainframe for parts ?

Thanks, Dick, W1KSZ

Does anyone know the number of the mini probe that can be used on the
475?I'm troubleshooting smd and my probe tip is really to big.Thanks for any
help you may give me.


Bill

First off i would like to thank the ppl who answered my question on my 475
low voltage ps.Now i have another problem with the schematic that i
ordered.I'm trying to read the timing and horizontal display switching.But
the schematic is to light for me to see it,especially in the middle of it.If
anyone can help me i would surly appreciate it.Thanks again for those who
helped me before.

Bill

Hi folks,

Don't know if this is the appropriate forum for this or not.

I've got a Tektronix Type 76TU Line Voltage Control Unit on sale at
eBay, and I'm trying to get the word to the appropriate type of
people so I can get it sold! :-)

I've got a starting bid of $25 on it, with a Buy It Now of $200. The
reserve is less than half of the Buy It Now price.

The item is in excellent working condition and is 100% original.

Thanks!


Ryan Ball
xyar@dsl-only.net

Hi, all,

I don't know if posting to the "Files" area automatically generates a
post to the message area, so I thought I'd mention it here and provide
a bit of text for searches. My 2445 would not fire up at all - -
totally dead. And this was after a period of disuse - - no other
cause was obvious. Turned out to be a zener diode had deteriorated
over the years and changed the shape of its "knee" so that it no
longer worked as intended in the circuit. See the story in the
"Files" area.

Chuck W6PKP, EE retired.

Does anyone have the low voltage ps schematic for the 475?I have it from a
cd i bought,but i can't read it most of it was printed to light to make it
out.Thanks for any help u may give me.

Bill

Hi again,

Also I have serched hi and lo and can not find a bit of info on this
unit. Any info would be greatly appreciated.
Thanks

bob

Howdy!

I have just aquired a Tektronix D44 Scope. It is a 5000 RM series
scope, that I know. It has readout option installed i do believe, Not
really sure. Currently 2 5A18Ns and 1 5B10N installed. The readout
controls allow for 4 traces with this configuration. My QUESTION is
what do i need to display readout data?

Thanks

bob

I bought a cd for maintance for my 475.The problem is it's in pdf format.I'm
trying to enlarge the schematics so i can print them out,butthey just keep
printing so small i can't even make them out.Does anyone have an idea how i
could do this?Thanks for any help u may give me.

Bill

There is a general test-equipment group at test-equipment@qth.net. See
http://mailman.qth.net for info on how to subscribe.

-- jm