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the birdies were coming from broadcast stations
buy some 10 db n type attenuators from ebay and put them between the gen and 492
deane kidd might have some too

For some unknown reason, suddenly the trace(s)on my 2445A is(are) half
an inch wide. The focus knob doesn't do much. All the other controls
(shift, intensity etc) work normally. Any ideas where to look
appreciated.
cheers
Mike

Hello,

Since I had to pull the main board out I replaced all the Caps at one
time the two 18000 UF and the 1000UF with newer style electrolytics I
have a Sencor at work and will test the old ones monday.

Good news no somke appeared but no -5V either. According to the
manual
I downloaded from BAMA p4-28, I have found the problem lives in these
three or four parts the rest seem to be resistor. I am also seeing
10vac on the +5 lug with my DVM no AC on the 32V.

U762 Opamp, Q762 and Q766 and Q768 I do have a good output DC 5 and
32 volt supplies. I am seeing +3/4V at the neg test point and shows
1V on ththe A/C scale.

It would be really helpful if I had a schematic of the PSU or some
more advice. I am thinking on taking those two new caps in to test on
Monday.

Any advice 100 % welcome,

Charles

EHT regulation?..........................................Don C.

I would like to adapt a 5441 Oscilloscope to a custom application.
The fabrication is straight forward.

However, the CRT is just WAY TO BIG. With all of the mechanical
concerns satisfied, would it be feasable to adapt, say, the SC503 CRT
for such an application?

The biggest question is, "Will the SC503 CRT be FAST enough for the
writing speeds, both storage and non-storage, for the 5441?"; you see
the SC503 as a mainframe is rated to 10 MHz, I believe, and the 5441, 60.

I do know that the CRT in my 7704A and the spare CRT I keep are the
same as that used in the 7904A. In addition, the SC502 and SC504
share the same CRT.

I'd just like to know that I'd work before I start looking around for
a SC503 or worse, start butchering one!



I do have the 5441 and really like it as storage scopes go. It's
really small compared to my 7704A!



Looking ahead, what would some of the modifications that I'd have to
make? On which specifications should I be focusing?



THANKS GROUP: THE TM5515 is a go!

Cross Post (with permission) from another list.

++++++++++

I have a Tektronics type 547 scope that my wife is making me get rid of
because it is taking up too much of her precious space. As much as I want to
keep it I was wondering if I was to dismantle it would the be anything in it
that would be of any use in a radio project?


Feel free to post it, though I can't believe anyone would want to buy it as
shipping would probably be more than it's worth. The last time I powered it
up it was working fine and it has the 1A1 dual trace module.


Tom kf4yyd
Fredericksburg, Va
<kf4yyd@...>

I would really like to repair an old 221 scope if possible but I'm
beginning to have some doubts. There is some corrosion on the circuit
boards but I hate to give up just yet. I First need to repair the crt
socket. The 11 pin socket is broken and the wires have been removed.
I need to replace the socket and I need to know the socket pinout. Can
someone tell me which colored wires go with the crt socket pins?
Thanks ...................Paul

He folks,

any idea why my 516 scope has developed the bad habit of changing
trace width and height when the brightness control is turned? The
trace(s) are otherwise fine.

Thanks,
Joe

Not sure I've ever seen those options mentioned, but the minimum discernible
signal should be in the specs. The noise floor of a 49x in 100 Hz RBW is
around -125 dBm in band 1. The 8640B goes down to -139 dBm, so it may be
time to tighten up a few connectors in the 8640B if you can still see it!
(Either that, or perhaps those option codes refer to some kind of internal
preamp. Would be interesting to know for sure... Deane and Stan, have you
ever heard of those?)

I recently posted the TekScopes issue announcing the 492 for another fellow;
it's still on my web space, and will be for a few days (until I need the
space back), if you or anyone else would like to grab a copy:


It's about 12 MB, not a great scan for browsing but looks OK when printed.

-- john, KE5FX

I'm still learning my way around the groups. I may have sent replies
to individuals rather than the group. Sorry about that.


I went inside and checked all the cabling and found a few connections
that were a bit loose. Most of them were push-on SMB connections.
After tightening them all up, all the birdies flew away. :)




My 492 has mod UB and kit KE/FE installed. Would you happen to know
what those are?


What's the lowest power signal that this should be able to resolve at
minimum span, max resolution, and with the minimum noise filter
engaged and with video filtering set to narrow?

I'm asking because whatever it is, my HP 8640B won't go that low,
even at its -130dBM range with the vernier turned down all the way.
I'm impressed!



CJ

Gregor,

With the exception of the stop sweep circuitry, a TR 501 is identical to a
TR 502. The TR 501 was actually intended to be used with the 7L12. The
stop sweep feature only works with the more stable 7L13 or 7L14. A typical
configuration is a 7L13 Spectrum Analyzer, TR 502 Tracking Generator, DC
508A/07 1.3 GHz Frequency Counter and a TM 503/07 Power Supply. The
combination stops the spectrum analyzer sweep to allow the frequency counter
to count the tracking generator frequency at the center frequency that the
spectrum analyzer is tuned to. When the counter has finished counting the
center frequency, the sweep continues to the right of the center frequency.

You can do something somewhat similiar using a 7L12, TR 501, DC 50x (or any
high frequency frequency counter), and a TM 503. You use the analyzer's
manual sweep mode and tune the spectrum analyzer sweep to the frequency of
interest. With counter connected to the auxiliary output of the TR 501 it
will count the tracking generator frequency at whatever point the spectrum
analyzer sweep is manually tuned to assuming the 7L12, and TR 502 are
properly synchronized. You can also use the zero span mode which stops the
sweep at the center frequency as well.

It is very helpful to have a frequency counter connected to the tracking
generator's auxiliary output. Rather than being limited by the 7Lxx
spectrum analyzers' readout accuracy of 1 MHz or less, you can determine the
exact frequency that the analyzer is tuned to easily.

Brian, WB6QED

Hi!

I'm looking for a TR502 tracking generator for my 7L12 for a long time now,
but now I found an ebay offer for a TR501 that seems to have the same
functionality. Is that correct, or what are the differences between TR502
and TR501? On an internet page I found the hint "Tektronix TR501 tracking
generator 100kHz-1.8GHz for 7L12 (no sweep stop)" But what is this sweep
stop functionality?

Regards Gregor, OE1GLC

I have a question on the power supply replacement of the caps on the 5V
side the Negative polarity is reversed on the - 5 side? The old caps
are not marked and I figured it out from the shield being insulated on
the -5V side.

If anyone has a schematic of the PSU it would be great!

Charles

I have a Tektronix 7603 mainframe, with a 7D02 logic analyzer plugin.
Unfortunately, I don't have any probes, personality modules or
manuals. I'm not really what constitutes normal behaviour when you
just turn it on or not, so I'm wondering if it's seriously unhealthy.
When I turn the scope on, the screen fills with nines and underscores,
like this:

9_9_9_9_9_
9_9_9_9_9_
9_9_9_9_9_

The longer the scope is on, some of the 9's will start changing into
other characters like semicolons and equal signs. It almost seems
like I'm looking at a memory dump? Does anyone have any thoughts on
the meaning of this output?

--
Paul Anderson
VE3HOP
wackyvorlon@...

"May the electromotive force be with you."

In another forum it was referred to as using your scope in "hillbilly differential amplifier" mode.

Just had to share

Hugh

"John Miles" <jmiles@...> wrote:

Sounds like the whole RAM is battery-backed, not just the address space used
to hold calibration constants and instrument state. Is it practical to
Dremel the Dallas part open and replace its integral lithium cell with an
outboard cell?

It wouldn't be the first time something like that has been done:



Not Dallas, but it's the same idea.
-ls-

Sounds like the whole RAM is battery-backed, not just the address space used
to hold calibration constants and instrument state. Is it practical to
Dremel the Dallas part open and replace its integral lithium cell with an
outboard cell?

-- john, KE5FX

I have found that the FRAM devices are not a viable option in the
243X/40. Sadly I must report that what looked like a very promising
alternative to the DALLAS RAM/Lithium cell combo has turned out to be
a dead end.

I have been testing for over one month now on a 2430A, 2440 and 2465B
and everything seemed fine. My last test was to actually determine
the read/write frequency to the device.

It turn out a 2430A writes to the battery-backed devices as often as
once every microsecond. Since the FRAM device as a maximum of 10^10
read/write cycles (before it loses its NV capability) a quick
calculation reveals that the 2430A scope will render the FRAM device
a volatile device in one to three months.

For now I can only recommend the DALLAS (or other vendors)
RAM/Lithium cell combo pack device for use in Tek scopes.

Sorry for getting everyone's hopes up for a more inexpensive
replacement for NVRAM.

--Victor Silva

The 1S2 manual has found a new home.
Dennis

Any one have a manual for measurements corp. 159 ? Thanks, Mike