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Has to be at least a tripler with 6kV diodes and 10nF caps/10kV each. For a
tripler - 3 diodes and 3 capacitors...

Greg

At 12:17 AM 2/6/07 +0000, Kevin John Chadwick wrote:

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

Emacs!

Jerry,
you welcome. I see you probably used R186 trig bal to adjust voltage. that -3V
was probably coming from out of Q190.

good job,

Greg

At 08:24 AM 2/5/07 -0800, Jerry Massengale wrote:

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 <<mailto:greg.a%40dslextreme.com>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

At 07:13 AM 2/4/07 -0800, you wrote:

Greetings,

I have an SC501 that has poor sync. The unit works better at Usec settings
than Millisec settings. I can swap U200 with a unit that works good and see
no improvement. I can set 2 units side by side on extenders and compare
voltages and waveforms and not see anything suspicously different between

the

two. One is stable and locked, the other is very, very, close but not

stable.

When the sync on the bad unit is at it's most stable point, the blanking
output slows dramatically and the screen flickers.

The power supply voltages are good with no apparent ripple. The Msec timing
cap, C230 measures the same on both units(0.987uf and 1.02uf).

I am attaching the schematic for the U200 circuit. Suggestions are

welcome. I

would love to see a datasheet for U200. It is a Tektronix made IC, pn
0155-0055-00.

Jerry

Emacs!

Would anyone have a copy of Stan Griffiths' Book "Oscilloscopes: Selecting
and Restoring a Classic" they would be willing to sell at a reasonable
price? Please reply to me off-list.

Thanks in Advance

Walt
wb2vsj@...

These scopes have similar CRTs:

SC501 (PN 154-0699-00)
MR501 (PN 154-0703-00)
212 (PN 154-0699-00)
211 (PN 154-0642-00)

In my 212 manual the CRT circuit shows .6V AC (that's POINT SIX VOLTS) coming from T250 across T270 (2 coils - one is in series with the filament and the other winding is parallel with the filament (note: the filament is @ 1,000 volts negative with respect to ground)

C261 is not the anode voltage - that's the lower end of the HV supply (the cap is only rated at 25Volts)
This is a mono accelerator CRT - that means is does not have any accelerating voltages acting on it after deflection.

In my SC501 manual they show a -980Volt test point which is where the filament sits below ground.
Pin 3 is a little low than this (not sure how much lower (connected to 10 Meg to -980 volts)
Pin 4 is focus (adjustable - still lower than G1)
Pin 5 I believe is the anode (in the SC501 is also connected to pin 8 and 11) A 65 volt supply feeds a 47.5K and a 82.5K to ground - the tape is to Pin 5 on the CRT.
On the Sweep amplifier of the SC501 they show voltages of +33.8Volts (Pin 6) and +33.1Volts (Pin 7) horizontal deflection pins.
On the Vertical Amplifier (SC501) they show +32.3 Volts on Pin 9 and +32.9 Volts on PIn 10 of the vertical deflection pins.
Hope this helps - I haven't taken my 211 apart or measured my SC501's but the information is out of the manuals.
I have swapped CRT's in an SC501 and an MR501 with no problems. Haven't tried any 200 series swaps yet.

Rex


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






.

---- "Richard W. Solomon" <w1ksz@...> wrote:

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

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]On
Behalf Of arthurok
Sent: Monday, February 05, 2007 7:43 PM
To: TekScopes@...; toobr02b
Subject: Re: [TekScopes] First post - Hello and a question


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

For a real bargain look at a 465M, much better that either of
those two, I've owned both, and much more portable than
the 76 series.
The 465M is a real sleeper... a great scope except when you want
to sell one.
I like my 7623a very much except when I need to carry it
somewhere.

----- Original Message -----
From: toobr02b
To: TekScopes@...
Sent: Monday, February 05, 2007 5:50 PM
Subject: [TekScopes] First post - Hello and a question


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










Yahoo! Groups Links

Hi from Deane:
Yes, I am still alive and well and still rather sarcastic as follows. You want the HV multiplier from the 2235 scope but you don't include the Tek part number. Yes, I can go find the manual and then the schematic and thefile number and then the part number, but you have the part in your hand. All of us that have parts for Tek items use the same part numbers and it sure makes it easier to help. I have about one hundred multipliers and I know that I don't have the 465M multiplier but I don't know the number for the 2235.
Deane

I was originally going to suggest one of the T9xx scopes for portability and really low cost, but there are no expansion options at all. The 5000 series scopes are cheap and have a large CRT, (and I think there is an audio range spectrum analyzer for a reasonable price). But the bottom line is that the 7603 has the same size CRT and it's much better quality. Every 7603 I have (5) has a linear power supply, so they are not that hard to repair. As stated below, those Tantalum caps are the only typical problem (and some people would even disagree with that).

-Dave

Hi, Paul,

* REPLY SEPARATOR *

On 05-Feb-07 at 21:08 Paul Anderson wrote:

I just recently bought one of these for my 7603 mainframe scope, are
they suitable as a general purpose timebase? I'm not rally familiar
with the capabilities of this particular plugin, though I am planning
on replacing my 7D02 logic analyzer plugin with it and a 7A26 dual
trace plugin.

The 7B85 is easily usable as a standard timebase. It was, as I recall (someone check me on this?) designed as a 'companion' unit to the 7B92A to create the capability of delta measurements.

Happy tweaking.


-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies --
kyrrin (at) bluefeathertech do/t c=o=m
"If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"

I just recently bought one of these for my 7603 mainframe scope, are
they suitable as a general purpose timebase? I'm not rally familiar
with the capabilities of this particular plugin, though I am planning
on replacing my 7D02 logic analyzer plugin with it and a 7A26 dual
trace plugin.

--
Paul Anderson
VE3HOP
wackyvorlon@...

"May the electromotive force be with you."

Stephan,

By taking your time and watching for sellers with good feedback ratings. Buying through Ebay can be a very good way to go. Tektronix 465's and HP 1740's are great oscilloscopes with 2 channels and often have builtin multimeters. These are well within your budget and both are well supported and manuals are readily available. Groups like 'Tekscope' and 'hp_agilent_equipment' are superb resources.

I personally suggest using PayPal for an added layer of buyer safety.

Jerry

toobr02b <toobr02b@...> wrote:
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

While it's true that you don't NEED a 'scope with a bandwidth of
several hundred MHz for audio range use, I'd have to agree that a
7000 series 'scope is an excellent choice. They're versatile, very
inexpensive indeed these days, and easy to come by.

Their technical performance is also excellent, really about as good
as you're likely to find anywhere.

The 7000 series was the premium line of its day. They were built for
pure performance, not to fit a modest budget.

The only thing against them today is the fact that they're getting a
bit old, and failures in the scope mainframe power supplies are pretty
common now. Those failures are cured by replacing the tantalum caps
in the switch mode power supply more often than not. It's a pretty
simple repair that costs just a few bucks plus your labor.


CJ

From: "Richard W. Solomon" <w1ksz@...>

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



Good choice. Sometimes the Mil versions go begging. Also consider a 465.

-John

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