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Re: Ground leads on 6108 Passive Probes
--- In TekScopes@..., "Philip" wrote:
The P6108 is a member of the 5 mm probe family. The 5 mm refers to the diameter of the ground sleeve. The ground wire for this probe is the same one used on the P6105, P6106. and the older P6053 family. The end that attaches to the probe has an exposed small metal clip which resembles the shape of a horse shoe or the upper case Greek letter Omega (the symbol for the unit of Ohms). The metal is beryllium copper, which is a good conductor and also has spring like properties. If the ground lead you have has a small socket covered in a molded plastic shroud, then this is a lead for a newer probe, one of the P613x family. They are not interchangeable. Tek offered the ground leads for the 5mm probes in 3 lengths ¨C 3, 5, and 12 inches. The older P600x series use a similar designed ground clip, but it is slightly larger as the probe bodies were larger. - Steve |
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Re: Need part 2232 CRT and source for a tube
¿ªÔÆÌåÓýHi Tom,
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That's what I read somewhere, that the -00 tube was for the early units.
The one in my scope is the -10 and it does not have the mesh. At least it is not
brought out on pin 12 like in the 2215A.? The HV multiplier has a short
flexible?lead and connector..
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I scored a "for parts" 2215A today for mostly shipping cost so we will see.
If necessary, I can add in the -100 volt supply.
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Anyway, off to the archives.
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Thanks,
Tom
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Re: Variac's
--- In TekScopes@..., David wrote:
Use of a Variac with old tube equipment is to protect the power transformer as mush as possible. Vintage equipment, especially antique radios and test equipment, many times have unique power transformers that can't be found as replacement parts (i.e., unobtanium). The power transformer is often the single most expensive component in the equipment. Don't risk it any more than absolutely necessary. (Experience talking here.) If there is a shorted of very leaky filter capacitor on the seccondary side, the transformer is in serious danger unless care has been taken to lessen the risk. A Variac can help reduce that risk. There are caviats to that... the rectifier on the secondary side might be a tube as well, and might not start passing current until the primary voltage is pretty high, posing significant risk. If the unit under test has been on the shelf (unused) for a number of years, I have wired in a separate filanment transformer to get the filments hot so that the power supply can start to work normally. If the equipment has been on the shelf for several years, the filter caps might need to be reformed. Starting off with a low voltage helps to reform them properly rather than hitting them with full voltage, and possibly causing an immediate short. With solid-state equipment, the same risks exist, but you can start everything at low voltage and monitor voltages and currents without damage to the power transformer. One last comment... a fuse sonetimes doesn't work in time to avoid damage to the power transformer, so don't be lutred into complacency by the presence of a fuse. If you value your equipment, take the precaution! It might take a bit more time, but it could save you $$$ or scrapping a nice piece of equipment. Cheers, Dave M |
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Re: Need part 2232 CRT and source for a tube [1 Attachment]
Tom Jobe
¿ªÔÆÌåÓýHi Tom,
I think the CRT for your 2232 is identical to the one in a
2215A (154-0861-00), unless you have one of those late 2232's that has the
shorter HV lead?on the CRT (154-0861-10). The HV multiplier changed on the
last 2232's. It did not have a flexible lead coming out of the multiplier, the
CRT HV lead plugged directly into it on the front side. The Tekscopes archive
has some discussion?about the later "dash 10" version of the 2232
CRT.
I?do believe that all of those 154-0861-xx CRT's use the
"expansion mesh" (or whatever it was called).
tom jobe...
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Re: Variac's
Rob
¿ªÔÆÌåÓýI read the various replies and think you got some good advice. If I can be so bold I would take the conversation in a couple of directions it didn¡¯t go. I would have perhaps hopped if you are indeed not versed in tube based equipment and just starting, etc. Trust me I am not expert but there are a few things this forum has helped me understand and I would like to pass on. ? I actually find a variable transformer most useful for solid state power supplies and amplifiers where the solid state devices; especially power transistors can short. This way one can bring up the rails slowly which can help immensely in troubleshooting such equipment. ?Especially if the variable transformer has a rudimentary amp meter with it. However one must be careful not to apply this same technique to switching power supplies as bringing them up slowly is not good to do. ?In tube based equipment the same applies for shorted filter capacitors, etc. I suppose but tubes by their nature need to have a relatively higher current, etc. So for me personally a variable transformer isn¡¯t quite as useful. ????? ? Another method applied a lot for TV repairs and tube equipment is a light bulb in series with the load. It is a technique I recommend you research if you haven¡¯t already. You can find a lot of information on that. ? Finally it is important to keep in mind that most variable transformers are not isolation transformers. I went ahead and wired mine to one. ? Anyway just trying to be helpful. I am sure that others with more experience may expand on this somewhat. It¡¯s important to keep in mind my electronics experience is somewhat dated so please listen to me with a grain of salt as there are true experts in the forum ranks. ???Rob ? ? From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Steve Purcell
Sent: Tuesday, January 22, 2013 3:04 PM To: TekScopes@... Subject: [TekScopes] Variac's ? ? Hi All, ? I'm getting set up to work on tube equipment and I'm under the impression that with old and unknown tube instruments it's best to bring up the voltage slowly using a variac while monitoring the current for anything unexpected. ? Does that sound reasonable? As an integrated circuit guy I wouldn't have thought that very useful but perhaps it is for tube circuits. ? Another question I have is about what variac to purchase. There are some cheap Chinese ones on e-bay but the real thing appears to be 10 times the price. Since I'm just a hobbyist would the cheap Chinese one work well enough or should I?search for a used one of higher quality since I can't afford a $900 Variac. ? Thanks in advance Steve |
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Re: Missing pages in Tek 7854 waveform calculator manual
¿ªÔÆÌåÓýHi David,Albert was right, my manual is missing the same pages ! Herbert Am 23.01.2013 00:06, schrieb David Holland: ? |
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Re: Need part 2232 CRT and source for a tube
¿ªÔÆÌåÓýIt looks like the tube has a factory defect where they failed to weld the
pin 5 lead to the strap going to the astig element. I wonder if there is any way
to externally weld it? Induction welding, laser, other? I can't use high voltage
as there is no access to the element. I attached a picture showing the fault. If
I tap the tube, the screen comes into focus. I verified all the connections
externally.
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Next question,
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Somewhere I read that a tube from a 2215A would work. However, that tube
uses a mesh electrode whereas the 2232 tube does not. The only difference that I
can see is they connect the mesh (pin 12) to a -100 volt supply.
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I need to find a junker 2232 with a good tube.
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Regards,
Tom
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Re: Variac's
Alex
Keep an eye on your local Craigslist. I found a cheap authentic Variac
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from a ham radio operator. But something to consider about used Variacs is that the brush can be worn out, and it's a tough part to find. --- In TekScopes@..., Steve Purcell wrote:
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Re: Possible P6042 part...
Alex
The probe transformer is easy to damage. It's sensitive to physical shock. When you can't balance out the DC on low ranges, it's very likely that the Hall sensor has been damaged somehow. Can't be fixed AFAIK.
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--- In TekScopes@..., "klauszietlow" wrote:
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Re: Missing pages in Tek 7854 waveform calculator manual
I scanned those pages, and processed it up into a PDF.
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I'll stick it on KO4BB. If someone wants a direct email I can do that as well. I put pages 22, and 23 back also in this collection. (Thanks to Tom for emailing me back PDF's of 22 and 23.) David On Mon, Jan 21, 2013 at 11:16 AM, Albert <aodiversen@...> wrote:
Hi David, |
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Re: Variacs - Voltac / Yokoyama / Matsunaga
Dick,?
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Pl let me know when you next move house. 73s, Cslim, 9v1cs, On Wednesday, January 23, 2013, Richard Solomon wrote:
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Re: Variacs - Voltac / Yokoyama / Matsunaga
Richard Solomon
You should have been around when I moved to Tucson from Boston. To
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lighten the load, I gave away about 1/2 my stash. Included were two GR Variacs with Volt and Amp Meters. One 10 Amp and one 20 Amp. I kept the third one for my use. I won't mention the 7 TEK scopes I gave away !! 73, Dick, W1KSZ On Tue, Jan 22, 2013 at 3:43 PM, Robin Whittle <rw@...> wrote:
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Re: Variacs - Voltac / Yokoyama / Matsunaga
I have never seen an original Variac. In the 1980s I bought a new
Voltac - by Yokoyama Electric Works Ltd (not Yokohama). This is a 240V 300VA Type B-1, with output to 260V. (Australian mains power is now 230V.) Recently I was able to find, after months of eBay searching (saved search so I get emails), I obtained a 1500 VA model as well. These are beautifully made, with fully enclosed metal cases and screw terminals. Religious folk often deride materialism, but I derive profound satisfaction and pleasure from owning and using these devices - as I do my Tek scopes and now two Iwatsu SS-3510 50MHz synchroscopes. There's a massive 3kVA one on eBay now, in Austin, Texas: This one looks similar to our 1500VA model: but is a 2kVA model "130V". They step up a little, so this one probably has a 120V input. There's a poorly photographed 1kVA model here: While Googling I found this 1kVA "Matsunaga Mfg. Co. Ltd." "Slide Regulator" which looks like an earlier design: I couldn't find any substantial mention of the Yokoyama Electric Works However, I did find the Matsunaga Manufacturing Company: with "Slide Regulators" as their first of several product lines. The Google translation of one of their pages: indicates the company is based in Yokohama. The company was founded in 1952, has 50 employees and the while the founder is deceased, the Managing Director is Yoshio Furuya Yosuke Matsunaga. Perhaps there was a separate Yokoyama Electric company, also in Yokahama, because a modern Matsunaga product: looks different in detail from the Yokoyama units, there's no indication that the company changed its name, and this: with metal rod handles, is different in every detail from the Yokoyama models I have and which I have seen pictured on the Net. My units have no handles, but those pictured on the Net which do have pressed metal handles. - Robin |
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Re: Need for Termination Feedthrus
RonC
Here's a little reading material.
It'll help you understand why using terminators and matching impedance, plus using attenuators, is a good thing. Basically to keep "ringing" from distorting your signal the transmission (coax) needs to have the same impedance(ohms)on both ends, the input and at the end connected to the DUT. Otherwise you will get part of the signal you sent from your signal generator reflected back to it which will affect the waveforms. Same as having too much SWR on a CB radio. You can build your own pads to match the impedance and attenuators. Here's an attenuator, with pads, that I built, along with some links to the information behind it. |
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Re: Variac's
On Tue, 22 Jan 2013 13:04:27 -0800, Steve Purcell
<steve.purcell.k@...> wrote: Hi All,I have never worked on tube equipment where I thought it was necessary. I usually use my variacs for power supply troubleshooting where I already know something is not working correctly. Another question I have is about what variac to purchase. There are someI pick them up used at garage sales, swap meets, and Craigslist and build an enclosure if necessary. None of mine have meters as I have found the dials to have fine accuracy. In one case I ground a replacement brush from the carbon rod of a carbon-zinc D battery. |
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465B Service manual
Artekmedia
¿ªÔÆÌåÓýIn order to ascertain serial number coverage of most Tektronix manuals (other than what you see on the front cover from time to time) Look at the parts list sections and the change sectionsThe 10000 series numbers are for units manufactured in Guernsey, Unfortunately neither of my 465B manuals list any info on Guernsey units . The break point for the two USA manuals occurred at serial B06000 ( Beaverton Built) which occurred in early 1982. The USA manuals may be? useful for the 10000 series with minor differences in some areas. I would look at the date codes on the caps and transistors to get an approximate extimation of the date of manufacturer and then try a USA manual based on the info above (i.e. before or after early 1982) Dave "Service? Manual Forensic Anthropologist" ArtekManuals.com TIP: Chris I have changed the subject line on this thread to get you more specific help than the generic one you posted On 1/22/2013 2:04 PM, Bob Albert wrote: ? -- Dave Henderson Manuals@... PO Box 175 Welch,MN 55089 651-269-4265 |
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Re: replacing 475 psu electrolytics
Here's the pattern I use:
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I use long bare #12 wires, about 10 inches long with standoffs formed at the PC end. That way I can thread the new cap into position without taking the entire scope apart. Works great as long as you do not damage the board while taking the old caps out. On Tue, Jan 22, 2013 at 09:46:36PM -0000, jonathanrwbrooks wrote:
I want to replace electrolytics in my 475 and not to worried about keeping the old cans. I have seen reference to using a "daughter" board to make the grounding through A9 with a modern radial lead mounted on top of the daughter board. Sounds quite neat and was looking for advice. --
Paul Amaranth, GCIH | Rochester MI, USA Aurora Group, Inc. | Security, Systems & Software paul@... | Unix & Windows |
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David Hess