开云体育

I would recommend the 7603 with a 7B53 Time Base and a couple of 7A18
Vertical Amps. You can get that combo for $125 or less. With the plethora
of other plug-ins available you would have a versatile system that is
easily repairable and replacements are economical (read "cheap").

73, Dick, W1KSZ

I have (most of) a tektronix 212 scope that has been damaged badly,
and I'm not going to try to fix it. What I will be doing is salvaging
the CRT and building a new scope around it.

I am looking for any information that anyone has on this CRT,
tektronix number 154-0642-00. Anyone with a similar scope, i.e. a 211,
212, 221, etc. if you could open it up and measure any or all of the
following, it'd be very, very helpful.

I need to know:

Heater Voltage) measured between pins 1-2 on the back of the CRT

Cathode Voltage) measured at pin 2

Anode Voltage) Hmmm...probably best measured at C261.

Vertical Deflection) measured across pins 9-10

Horizontal Deflection) measured across pins 7-6


If I could find this information, it'd make things much much easier,
but I could get by with just the heater, cathode, and anode voltages.

Thanks in advance,

Jake

for just doing audio work you dont need a 350 mhz scope
look around for something like a t932 or 2215a.
"group please respond"

i received an enail from deane last night.
are you sure the tripler is actually defective?
the tripler in the 2235 and similar scopes is quite small so an nte528 tv tripler cant be easily fit in
as in the case of a 465/475
and other scopes.
sometimes sphere in canada has them, there is a firm in greece who has them from time to time too

Hi All,

Two questions:

Anyone heard from Deane Kidd recently? Is he still answering e-mails
(vacation?).

I am looking for an HV multiplier for a really good 2235. If I cannot
locate one at a reasonable price I would like to build one using
discrete diodes and capacitors (12 kV for HV and -2kv for focus).
Anyone know what is inside the original multiplier circuits? - or has
a scrap 22xx complete with multiplier for sale?

I have checked the archives but can find very little on the 2235
multipliers just lots about 547s. Trying to remove the potting from
the failed unit seems to be just about impossible. The existing HV
multiplier still works but loads down the power supply and prevents
the -8.6 v from getting past -8.3 before the current limiter kicks in.
Presumably the existing multiplier is leaky when the high voltage is
generated.

Thanks for any information.

Kevin C
Ottawa ON

i dont believe that vhs tapes will die off that quickly

am radio is still very much alive.
maybe NTSC will take a similar course???

I'm part of the minority that gets my signal off the air. The signal has gotten much worse over the part few years, I think the providers don't want to maintain the equipment anymore and are just waiting to go full digital. I hate paying for stuff I can get for free. I wouldn't mind cable, but the fees keep increasing and I watch too much as it is! My daughter keeps hoping...

-Dave

Well, what fun would it be otherwise? Heh...

Would be nice if someone could X-ray one of those puppies to determine where
the cell actually is. But the equivalent part numbers are even more useful;
thanks for posting those.

-- john, KE5FX

On Mon, Feb 05, 2007 at 06:41:41PM -0000, mmoss111 wrote:

This appears to be true with respect to all NTSC test equipment.
I have a ton of signal generators and various NTSC monitors and I
wonder what they will be worth soon with digital TV coming?
Kinda like my 8-track test tapes and now even my VCR test equipment is
getting a lot less use (almost none). My whole shop will be worthless
soon!! Boo-hoo.....

Remember that cable will no doubt continue to supply NTSC VSB-AM
TV for some time into the future in many markets. Too many retro folks
don't have ATSC or QAM capability and many of those folks will happily
expect their NTSC TVs to work on channel 3/4 AM VSB RF from somewhere
for many years yet - maybe until it dies of old age in 15-20 years.

These days only a rather small minority of households get their
TV off the air - cable/satellite penetration is well over 85% in most
places. So the shutdown of OTA NTSC in 2009 won't impact much.

Of course compared to well tuned ATSC HDTV, the image quality on
this old technology is PRETTY bad, but for many people they either don't
notice or think that digital LCD/plasma is STILL way too expensive for
mere TV...

And downressing 720p or 1080i to NTSC can be done in a couple of
chips these days... (though the 16:9 issue is a PAIN).

--
Dave Emery N1PRE, die@... DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."

Hi everyone,

This is my first post to this group. I build DIY audio for myself and
the more I read/talk to individuals it seems like an Oscope should
definitely be on my list of things to purchase. Honestly, I can't tell
you why I would need a 4-channel vs. a 2-channel scope other than 4 is
greater than 2. But I would be interested in your comments. I am
interested in the 2465B but it seems like prices range from $150 -
$1200. If someone can point me in the right direction, I would really
appreciate it. BTW, I'm guessing that all of you would recommend that
buying an Oscope from eBay (as my first Oscope) would not be
recommended. :) Please let me know if you disagree. Also, my budget
is between $200-$300.

TIA

Stephen

From: mmoss111
To: TekScopes@...
Sent: Monday, February 05, 2007 1:41 PM
Subject: [TekScopes] Re: Tek 528 Waveform monitor, what is it?


This appears to be true with respect to all NTSC test equipment.
I have a ton of signal generators and various NTSC monitors and I
wonder what they will be worth soon with digital TV coming?
Kinda like my 8-track test tapes and now even my VCR test equipment is
getting a lot less use (almost none). My whole shop will be worthless
soon!! Boo-hoo.....

.
Our station just moved into it's new all digital facility and there is still a good bit of the analog stuff that we brought over from our old facility. I hoping they let us go through the old place soon and salvage lots of goodies. NTSC analog probably won't dissappear completely because there is so much of it around and a few of us engineers still left that want the stuff (and use it). There's a guy in Nevada that has "Quadraplex Park" which is a whole bunch of 2" video tape machines which he restored and has working in excellent condition.

Right now I'm looking for an extender card for a 1410 NTSC generator (and 1410 generators and parts for that matter). I just got another one of these from Oregon and should be getting another one soon (old building, I hope). WE used to have one, but someone apparently borrowed it and didn't put it back in it's pouch in the service manual. Learned a lot from this machine and still learning a lot more.

Rex

Be very careful here. There's a reason the Postal Service will not
even ship Lithium cells and it is illegal to ship them via air cargo.

If you happen to dremel into the cell, not only are you getting the
caustic material flung all over, the cell will most likely short-
circuit when it is cut into. Lithium cells can start fires if they
are shorted.

ST has equivalents to the DS devices used in both the 2465B and the
243X/40. The ST devices are slightly lower priced.

ST Micro 8Kx8 DS1225AB equiv. M48Z58Y-70PC1
ST Micro 32Kx8 DS1230 (DS1235) equiv. M48Z35Y-70PC1

--Victor


--- In TekScopes@..., "John Miles" <jmiles@...> wrote:

Is it practical to
Dremel the Dallas part open and replace its integral lithium cell

with an

outboard cell?

-- john, KE5FX

Yes there is compensation circuitry, but this is mainly before the
gate and not adjustable.
I measured the bridge signals at the + and - nodes with 600mV SW
input and no triggering (and shunt resistor accross Miller cap to
keep the bridge at neutral position). At the suspect Ch. A over 10mV
spikes appeared, at the Ch. B maybe 2mV. I interchanged the input
side diode pairs between channels and the result was the signals
also changed from channel. Also the "slope" problem of Ch. A was
nearly cured now (total effect about 2mV of 600mV step), the same is
in my other 3S76.
So it seems that one diode pair has rather high capacitance while
reverse biased (it's not DC leakage). Though the pairs have the same
and correct GaAs colour dots, their shapes are a bit different.
Could be one pair is not original.
In the meantime one of the nuvistor sides diodes of Ch. B died (has
too high forward voltage now)...

I also found over 10mV DC accross the plugin ground connection (from
connector pin 9 and soldering tag to chassis) due to bad contact
between tag+srew and chassis. (There is a relatively large net
current flowing there because of DC filament heating.) Moreover the
3 securing screws in the back plate were loose. This seems all
unrelated to the "slope" problem but explained some of the
instabilities I noticed before.
Albert


--- In TekScopes@..., "jvanderwall1941"
<jvanderwall1941@...> wrote:

Sorry I can't help with your first problem, as I am unfamiliar with
that generation of Tek samplers.

However, the prescience of your samplers is a consequence of what

the

scope designers call "blow-by", their name for those components of

a

signal that can pass through a sampling gate between strobes. This

is

of course limited to quite low frequencies, so a step will show up
more or less intgrated over time, i.e. sloped. Usually there is
compensation built into the circuits surrounding the gate. It

should

be covered in the manual, as there may be one or more adjustments

to

cancel it.

Regards,

Jonathan

--- In TekScopes@..., "aobp11" <ao_te_z@> wrote:

----> > Another unrelated problem: one channel of one 3S76 has
prognostic

talents! With one or more square wave steps on the screen, the

trace

clearly slopes down or up a bit even *before* the step.

Consistently

during about 0.3-0.4 us. I did not yet try to find the cause,

but I

have my opinions about this and I'm curious to read comments on

this

feature.
Albert

Hi Michael,



If the relay is opening again after closing, it is not getting coil voltage
from its own contacts. If you burnish (clean) the relay contacts, it will
probably hold in until the power switch is turned off.



It is not usually necessary to check the +8650 volts on the CRT anode. If
the -1350 is present, then the +8650 will be OK. All of the other power
supplies must be working properly before you bother to measure the -1350.
The other supplies are: -150, +100, +225, +350, and +500.



Stan



_____

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of Michael Petereit
Sent: Monday, February 05, 2007 8:19 AM
To: m38a1_1962
Cc: TekScopes@...
Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years



I tried again. Since the CRT is completely covered I cannot see any
filament working.
Shortly before the tube's diameter gets wider some connectors for
deflection I guess. Even there some color avoid having a look onto any
filament.
Is it really colour or might it be dirt ?
The tube is such long you can't have a look from the back unless you
remove the backcover. But I would like to avoid as much disassembling as
possible unless it worked once. Then any other cleaning will happen and
I try to "renovate" the item.

I'll try to get a high voltage adapter for my Gossen multimeter. Then
I'll check the -1350V and the 8960V.

br,
Michael

m38a1_1962 said the following on 05.02.2007 03:35:

Before you go too far with the chassis cleaning and wholesale tube
testing, check and repair the low voltage power supplies first (be
especially wary of the bypass capacitors across the precision voltage
divider resistors). If the voltages are all in tolerance, look at the
high voltage rectifier tubes under the top HV cover to see if their
filaments are glowing. This will tell you if the HV oscillator is
working. If they are glowing, the CRT filament should also be glowing.
You won't be able to fix anything else until the power supplies are
working. BAMA has a 535_545 manual listed for free download if you are
in for some troubleshooting. Good luck.

--- In TekScopes@yahoogrou <mailto:TekScopes%40yahoogroups.com> ps.com

<mailto:TekScopes%40yahoogroups.com>,

Artek Media <manuals@...> wrote:

Be careful, the CRT heater gets its supply directly from the big
mains power transformer, *not* from the HV transformer. When the
isolation is bad then the HV won't start. See many earlier posts
about CRT filament or heater problems.
Albert

--- In TekScopes@..., Michael Petereit
<michael.petereit@...> wrote:

I tried again. Since the CRT is completely covered I cannot see any
filament working.
Shortly before the tube's diameter gets wider some connectors for
deflection I guess. Even there some color avoid having a look onto

any

filament.
Is it really colour or might it be dirt ?
The tube is such long you can't have a look from the back unless

you

remove the backcover. But I would like to avoid as much

disassembling as

possible unless it worked once. Then any other cleaning will

happen and

I try to "renovate" the item.

I'll try to get a high voltage adapter for my Gossen multimeter.

Then

I'll check the -1350V and the 8960V.

br,
Michael

m38a1_1962 said the following on 05.02.2007 03:35:

----
If the voltages are all in tolerance, look at the

high voltage rectifier tubes under the top HV cover to see if

their

filaments are glowing. This will tell you if the HV oscillator is
working. If they are glowing, the CRT filament should also be

glowing.
-----
No, according to 535-545 manual the CRT filament gets 6.3V from the
mains transformer.
Albert

Hi Chris,



I used to demo the 492 as a "receiver that looks like a scope". This made
it much easier for the average person who was not familiar with spectrum
analyzers to quickly grasp how it worked. I used the video output to drive
a Radio Shack telephone amplifier by plugging the video out directly into
the suction cup microphone input on the amp and I think the levels are just
fine. The Radio Shack telephone amp is powered by a 9 volt battery so it is
portable and cheap. Use zero span and slope detection for FM signals and
peak detection for AM signals. At shows where I was exhibiting more than
one spectrum analyzer, the 492 provided the audio for a TV signal and the
2710 provided the video. For those of you who may not know, you can
actually get a TV picture to display on the screen of a 2710 spectrum
analyzer. The biggest complaint about this was that it was not in "color".
My response was that "green is a color".



Stan



_____

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of Chris Johnson
Sent: Sunday, February 04, 2007 12:06 PM
To: TekScopes@...
Subject: [TekScopes] Tek 492 SA experts, can you answer these questions?



I'm learning my way around the 492 and don't yet have manuals for it.
(I'd rather get print manuals than a CD copy...got a set for sale?)

I'd like to be able to use the 492 as a receiver for AM and FM
transmissions, to be able to hear them.

My 492 has options 1,2, and 3, so the only IF option I have to work
with is the 10 MHz IF output.

I need to know what are the output specs for the IF output, so I can
determine how much gain I'm going to need. I plan to preamplify the
IF output, feed it through a detector/demodulator, and then need to
add more gain to bring it up to a level suitable for further processing,
including audio band filtering and level adjustment.

I would PRESUME that the correct mode to run in will be zero span,
is this right?

Not having actually used an analyzer in this application before,
I'd appreciate it if anyone could give me a how-to guide on the setup
and configuration of the analyzer and outboard equipment. If I'm
wrong about how to do it, I'd rather know before I get started.

CJ

I picked up a cheap 541 last week which worked, but not very well. The fan had broken free from it's mounts and was sitting on the chassis- I had to beg the guy I bought it from to please turn it off, I didn't really need further demo. It turned out that all the DC supplies were at least 20% low. I was surprised that it worked as well as it did! I adjusted the -150 back to where it is supposed to be (and the triggering vastly improved), but none of the other supplies changed at all. Is that normal? Even if the other supplies have their own problems, shouldn't they be traking the -150 to some degree? After about 5 power cycles the relay has stopped working, but the tube looks ok. I've had to manually engage the other relay (after warmup time). Everything in the back of the scope is really grungy with possible long term hi temp. It looks like had a long life, but the CRT is in great shape (light blue trace/phosphor). It was used for testing heads at Ampex.

-Dave

This appears to be true with respect to all NTSC test equipment.
I have a ton of signal generators and various NTSC monitors and I
wonder what they will be worth soon with digital TV coming?
Kinda like my 8-track test tapes and now even my VCR test equipment is
getting a lot less use (almost none). My whole shop will be worthless
soon!! Boo-hoo.....

Greg,

Thanks for your good suggestion. The signal at the input of the trigger generator looked great and I assumed the balance circuits was okay. I checked the adjustment for trigger balance and found that the junction of r200/c200 was at -3V rather than +65mv. I adjusted for the +65mv and it syncs very good now. I should have checked the external sync too.

Thanks for your good help.

Jerry

Greg_A <greg.a@...> wrote:
Jerry hi,

I looked for you schematics and I think you could concentrate on signal flow from Q184, Q190 up until U200 pin #15 - that should be trigger in for that chip.

Greg