¿ªÔÆÌåÓý

If you emailed in the last two weeks and did not receive? a reply , please email me direct today.

DO NOT PLACE REQUESTS THROUGH TEKSCOPES !!!!! :-)

I will be chained to the computer all day today and tomorrow trying to get caught up

Dave
ARTEKMEDIA


On 1/25/2012 6:45 AM, Heinz-Peter Deutsch wrote:

?

Dave,
did you received my mails, too ??
Or are they gone to nirwana .....

Peter
===========================================

Dave et all

We at Artekmedia alive and well...but buried in a host of issues.

I would suggest if you made a request in the last two weeks and have
received no reply that you resend ..Dave Casey in particualr I do not
see anything recent from you ..please resend

Sorry all for the inconvenience

Dave

--
Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir
belohnen Sie mit bis zu 50,- Euro!

-- 
Dave & Lynn Henderson
Manuals@...

PO Box 175
Welch,MN 55089

¿ªÔÆÌåÓý

Heinz

...please resend

Dave

On 1/25/2012 6:45 AM, Heinz-Peter Deutsch wrote:

?

Dave,
did you received my mails, too ??
Or are they gone to nirwana .....

Peter
===========================================

Dave et all

We at Artekmedia alive and well...but buried in a host of issues.

I would suggest if you made a request in the last two weeks and have
received no reply that you resend ..Dave Casey in particualr I do not
see anything recent from you ..please resend

Sorry all for the inconvenience

Dave

--
Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir
belohnen Sie mit bis zu 50,- Euro!

-- 
Dave & Lynn Henderson
Manuals@...

PO Box 175
Welch,MN 55089

Dave,
did you received my mails, too ??
Or are they gone to nirwana .....

Peter
===========================================


Dave et all

We at Artekmedia alive and well...but buried in a host of issues.


I would suggest if you made a request in the last two weeks and have
received no reply that you resend ..Dave Casey in particualr I do not
see anything recent from you ..please resend

Sorry all for the inconvenience

Dave

--
Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir
belohnen Sie mit bis zu 50,- Euro!

¿ªÔÆÌåÓý

Dave et all

We at Artekmedia alive and well...but buried in a host of issues.

?Been flying back and forth to Florida twice a week trying to get my mother in-law placed in an assisted living facility ( Alzheimer's). I have a couple of consulting clients as well that I spend two days a week with here in MN ergo the need to fly back and forth .? I think I will likely be back in the office here in MN now for at least two weeks. To add insult to injury I appear to be having ISP problems as I am sporadically missing whole "blocks" of email. I got back yesterday and will start digging out today ..there seems to be about 700 emails to sort through so the volume is beyond anything I can reasonably sort through with a smart phone on road. :-P

I would suggest if you made a request in the last two weeks? and have received no reply that you resend ..Dave Casey in particualr I do not see anything recent from you ..please resend

Sorry all for the inconvenience

Dave




On 1/24/2012 11:55 PM, Dave Casey wrote:

?

Speaking of Artek, has anyone heard from Dave lately? His last post was on the 7th. I'm trying to spend my money with him and as yet I've not heard back.

?

Dave Casey

-- 
Dave & Lynn Henderson
Manuals@...

PO Box 175
Welch,MN 55089

Quote: Back to the +50V supply: It's a little risky, but I'd suggest to remove Q876, monitor the +50V output with your DVM, and power-up the scope. ...

I agree.?

For the next step, I would simply pull connectors P900/P901, then bridge the sense feedback with the respective supply, and measure the supply rails again. This requires only five connections and P900/P901 are in close proximity, so the connections are easy.? This is a linear power supply, not a switched mode supply, so operation with no load does not harm anything.

I would also pull P971/P962.

Doing so disconnects the power supply from its loads and allows isolation of the trouble to a specific circuit / board by re-connecting one board after one.?

Just keep going, David - one step at a time. We will bring this beauty back to life.

Cheers,

Magnus

--- In TekScopes@..., "Stan & Patricia Griffiths" <w7ni@...> wrote:

I have pretty good results when I solder-suck the notches dry and use new
silver-bearing solder in them.



If you have some bad strips, I have quite a lot of new ones and ones I have
salvaged with a solder sucker. You can find them in my Parts Shop.







Stan



_____

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of phosphorphile
Sent: Monday, December 19, 2011 2:32 PM
To: TekScopes@...
Subject: [TekScopes] Re: Back to soldering ceramic terminal strips





Hi David,

As I'm still learning good technique for reworking ceramic terminal strips
I'm hyper-concerned about wrecking the scopes I work on. The one I'm
restoring now has been worked over quite a bit by a trouble-shooter who
lifted wires and components here, there, and everywhere chasing down
problems. My inclination is to, like with convetional terminals, wick out
the nasty old solder and make a new, shiny soldering job, the idea being to
restore the orignal beautiful work done by Tek. I'm finding that approach to
be ephemeral at best. So now I wick off only excess solder and then reflow
with a bit of the silver bearing stuff. I get mixed results, still too much
leaching of the silver plating in the strip notches. Someone said it's nigh
impossible to avoid that so I guess the terminals, bright an idea it was by
Tek, is really a one shot proposition.

Stan has Tek solder spools for sale on his website so now my solder hunt is
done.

Arden

--- In TekScopes@... <mailto:TekScopes%40yahoogroups.com> ,
David <davidwhess@> wrote:

I have a spool of the Radio Shack 62/36/2 that I bought years ago and
while it is thin, there is certainly enough to do a reasonable number
of connections if you do not overdo it. The thin size is because it
is intended for surface mount parts that use silver metalization.

The only real electronics store here in the St. Louis area
() has an old bin full of the Kester
62/36/2 solder tubes but their inventory management is not good enough
for them to be listed online. For the price, I think it was about the
same value as the Radio Shack silver solder. They are certainly less
expensive online even with shipping.

This seems reasonable although it is no clean flux instead of
activated rosin:

oll-/380118400075?pt=LH_DefaultDomain_0
<
Roll-/380118400075?pt=LH_DefaultDomain_0&hash=item5880d27c4b>
&hash=item5880d27c4b

That 4% low temperature silver solder (not the lead free stuff) from
Parts Express would no doubt be better but sure is expensive. Better
to use the 2%, extra flux if necessary, and use a good lower
temperature soldering iron.

On Sun, 18 Dec 2011 01:14:32 -0000, "phosphorphile"
<gumbear@> wrote:

Well, gentlemen, you made me do it. I rose to the challenge and dropped
by the local RS. No 62/36/2 on its hook. The computer said they had
two in stock. Shoplifted, no doubt. But while looking over the
shoulder of the store clerk (yes, that's what they used to be called) I
asked what the specs were. 0.015 dia., came the reply. Worthless! Too
small for soldering ceramic terminal strip notches. You'd put half a
spool into one notch if you cleaned it out and refilled it. $3.00 a tie
point is a bit too much. Not much better, the stuff I got from MCM,
Kester made 0.020 dia. for about half what RS sells theirs for but no
bargain because I had to pay shippijng. So the hunt goes on for 0.031
or thereabouts, ....TekScopers shall not be forgot!

Confirmed. While Xmas shopping yesterday at the Sherman Oaks Mall in

LA I stopped in at the Radio shack and found two Radio Shack part #
65-035 for $6 each. I bought them both....

Hello.
Watch this:

¿ªÔÆÌåÓý

I've had that happen too but it appears if you hit Reply.

Arden

¿ªÔÆÌåÓý

¿ªÔÆÌåÓý

¿ªÔÆÌåÓý

Some of the new uv LEDs exhibit very little visible light and would be less likely to cause unwanted visible response (due to excitation wavelengths) on a camera. Of course, certain plastics used over a CRT face could also block this same uv.
I'm working with some 365 nm LEDs right now that could give one a "sun" tan! Of course, these newer-model ones are surface mount. I wonder if ceramic bars could be improvised for use as a heat-sinking mount?

That's what I was thinking; that they may have run the heaters off DC to prevent hum and it would be easier to supply 150mA heaters than 300mA in the tube era. Now it would be simple to use a three terminal regulator IC to provide 6.3 volts.

Don Black.

David,

More below:

Because I was unsure of where to take readings on the caps as they
appear to have four pins, I took scope ripple readings from P890
connector on the A10 rectifier board. I hope this was OK. With probe set
on X1 and AC setting, I measured a max ripple of about 0.5 Volts P/P on
P890-1/5/2/ P890-4 was quite flat, I couldn't hardly measure any ripple.

Your ripple measurements sound OK, so your filter caps are most-likely good. Just remember many of the supplies are not up to normal output voltages, so their output currents are lower than normal, and therefore, ripple on the filter caps will be lower than during normal operating conditions (good or bad caps). The outer pins are the - pins and the center-most pin is the + pin.

On pins 6 and 7 of the 130 volt section, I wasn't able to measure the
ripple on the 250uF cap because I couldn't get my scope's two channels
to be in sync.

I should have also said to use Chop mode. I think you must have been using Alt (alternate) mode. Also, I should have said that once the +50V supply is working, you can measure ripple on C806 via single-ended (referenced to ground) using one probe only, like the other caps. You'd want to be using a 10X probe, espescially if your using DC coupling.

I did manage to take some voltage readings from the 130
volt section though. Voltages on Q850, VR851, and Q852 were all minus
about 30volts instead of plus 50 volts.

That's probably OK, since the +50V supply is dead, and you're basically measuring the negative side of the bridge rectifier and cap (C806).

The proper fuse in this line has
been replaced at some time in the past with a different style in-line
type fuse holder and hooked up to the original fuse "prong type
holders", so it looks like there might have been a problem with this
section in the past. Do you think that these minus readings indicate
that the AC hasn't been rectified properly and that there might be a
problem with the diodes?

David.

Back to the +50V supply: It's a little risky, but I'd suggest to remove Q876, monitor the +50V output with your DVM, and power-up the scope. If you're lucky, the +50V supply will come up to normal. Q876 is the current sense differential amp. Its job is to cut back the output voltage if the current through R875 (1 ohm), and thus the +50V supply's output, gets too high. This could happen because of for example a shorted cap somewhere else in the scope. I'm thinking the "B" trasistor has a C-B short, but that's just a guess.

Maybe you want to get someone else's opinion before you do what's suggested above.

You could also remove and check both transistors in Q876 with a diode-check function on a DMM. The scope could remain off.

Also, it might would help if you could mark-up a hard copy of the schematic with all of your voltage readings so far, scan it in, and post it somewhere for us to see. I'd suggest to use a red pen (red for bad). Mainly just the +50V supply section is needed.

Jimmy

¿ªÔÆÌåÓý

?

Tek W Plugin 100-3269, mod kit 040-0447-00: ...improves overdrive recovery characteristics...

?

Just?"found"?this?NIB mod kit dating from 1971, complete with pre-stuffed gold pcb, matched transistors?and other components, even silver solder and hookup wire -?sealed in compartments of a plastic bag.

?

Later?W's incorporated this mod, so I think I'll preserve this kit?as is.

Let me know if anyone would like to see pictures.

Bernd Schroder

?

?

In a message dated 1/24/2012 6:10:23 A.M. Pacific Standard Time, ataylor@... writes:

Low phosphor response or fast decay shouldn't be as much trouble if you can mount some UV LEDs inside the hood so they can be left on continuously during the shot, or right up to it if there's visible interference. If you use a color camera it should be blind to any true UV reflections - but not necessarily the "visible" part of deep blue or near-UV emission. These cameras usually have bandpass filters so the white balance won't be upset by UV or IR illumination. Some experimenting should be able to assess the camera response. If there's a problem it may be possible to cascade another white balance filter (since true color response isn't needed) to sharpen the passband edges, or a filter that will pass mostly the phosphor emission wavelengths but block the rest.

Ed

On 25/01/2012 00:20, Jochens Feldhaar wrote:

to read your messages, I always have to leave my Thunderbird standard
display and call the source text, there your message is OK and readable,
but for some reason it will not appear in the normal message text window.

They get flagged as spam by my server which runs Spam Assassin.

Try sending in plain text rather than html.

Gordon

¿ªÔÆÌåÓý

Hello Heinz-Peter,

to read your messages, I always have to leave my Thunderbird standard display and call the source text, there your message is OK and readable, but for some reason it will not appear in the normal message text window.
Just my 0.02€ cents.....

Regards, Jochen DH6FAZ

Am 25.01.2012 01:06, schrieb Heinz-Peter Deutsch:

¿ªÔÆÌåÓý

On 23/01/2012 03:08, jtjewell83 wrote:

?

David,

More for you below. Hope it helps:

> >
> > Could also be C866 is shorted, but that would be extemely rare.
> > To eliminate that, pull one side up temporalialy, and power up and
> > re-measure R860 volts.
> >
> +69V with ref to ground.

I think you measured the "high" side of R860(the 130V supply line). Maybe I should have said measure the collector of Q860; this is the same as the base of Q869 and the low side of R860; or should be if connections are OK. Again, this would be with one end of C866 lifted.

>
> I must thank you for your persistent help so far Jimmy, very explicit
> instructions that are very easy to follow!

Thanks.

>
> re cap ripple testing, do I put scope probes only on the cap pins of
> each individual cap to test each cap?

First, did you see my earlier posting about measuring ripple with an old analog meter that has an "OUTPUT" terminal? Anyway...

Hello Jimmy.
Yes , sorry that I didn't reply to your question. The answer is that I do not now have an analogue meter at all!

Here's how I would check for excessive ripple using another (test) scope. This will work for all of the big filter caps that have one terminal connected to chassis ground. DO NOT use this method for the filter cap (C806) in the 130V supply because neither one of its terminals is connected to chassis ground:

<<<<<>>>

1. Ground a 10X probe hooked to the test scope to chassis of problem scope. Use a good-quality clip lead to extend the probe's ground lead if the length of the ground lead is not enough for easy measurements, AND INSULATE the 2 alligators' connection with some black electrical tape so this won't short something out if it accidentally touches anything.
2. Set test scope channel to 50V/div. (Use 5V/div if you've got a scope that does not auto-sense probe attenuation). Be sure to use a 10X probe.
3. Set test scope channel to AC coupling and vertically center the sweep. (You can initially use DC coupling if you want to see the DC component also.)
4. Set test scope for Line trigger, and about 10mS/div. Adjust trigger for a steady sweep (flat line when probe tip is not connected to anything).
5. Carefully probe the "hot" side of each big filter cap. For most, the "hot" side is the "+" terminal. However, for some like C808 (1800 uF) for the -50V supply, it would be the "-" terminal.

If the cap is good, you should see a sweep that's still nearly flat. I'm thinking no peak-to-peak waveform on a filter cap should be more than about 3V. If necessary, increase vertical sensitivity to 5V/div, or less, so V peak-to-peak can be more accurately measured. You DON'T won't to overdrive the test scope's channel amp by using too much sensitivity (As a general rule, don't let the waveform go vertically too much off the top/bottom of the screen.) It is good to return the test scope's channel to the 50V/div before going on to the next cap!!!!!

To check filter cap C806 in the 130V supply use two 10X probes, two scope channels of the test scope, set one channel for "Invert" and use the "Add" vertical function. Make sure both channels have equal V/div settings, and they are adjusted for equal gain. This is basically a differential measurement. To verify test scope's settings (equal gains, etc.), probe a common signal point with both probes and make sure there's no (or very little) signal/ripple.

It will be good to post your ripple measurements.

Because I was unsure of where to take readings on the caps as they appear to have? four pins, I took scope ripple readings from P890 connector on the A10 rectifier board. I hope this was OK. With probe set on? X1 and AC setting, I measured a max ripple of about 0.5 Volts P/P on P890-1/5/2/???? P890-4 was quite flat, I couldn't hardly measure any ripple.
On pins 6 and 7 of the 130 volt section, I wasn't able to measure the ripple on the 250uF cap because I couldn't get my scope's two channels to be in sync. I did manage to take some voltage readings from the 130 volt section though. Voltages on? Q850, VR851, and Q852 were all minus about 30volts instead of plus 50 volts. The proper fuse in this line has been replaced at some time in the past with a different style in-line type fuse holder? and hooked up to the original fuse "prong type holders", so it looks like there might have been a problem with this section in the past. Do you think that these minus readings indicate that the AC hasn't been rectified properly and that there might be a problem with the diodes?

David.

Regards,
Jimmy