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Re: All TekScopes email sent to Spam
Chuck Harris
Hi Dennis,
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I am well aware of that, and my email, according to spamhaus, was in the list. And, I know who put it there, because he smugly told me he did it. To get out of the list, spamhaus requires you give them your name, real verifiable address, phone number, and a bunch of other stuff that I would have to be insane to trust they would not abuse. The sad point is that a single person, can get spamhaus to put an email into the blackhole forever with no evidence of any wrongdoing. Spamhaus is a group of Social Justice Warriors, and like SJW's everywhere, they don't allow little things like facts to get in the way of their mission. It has nothing to do with the user's ISP, purely the email address. I know this because my email provider gave me the same username with rcn.com, starpower.com, and erols.com. Only the latter was blocked. I got out of the list when I threatened both Verizon and yahoo with a lawsuit for unlawfully blocking me from my customers, and more importantly my aged mother. -Chuck Harris Dennis Tillman W7PF wrote: Hi Chuck, |
Re: Looking for Power Cord for 400-series Scope
I've considered cutting an IEC cord (hopefully finding a thinner version since, as you point out, the more common styles are thicker) and just using a common velcro wrap as a "keeper". The clip would be nice but having that ground connection is more important to me.
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Thanks, Barry - N4BUQ ----- Original Message -----
From: "Michael A. Terrell" <mike.terrell@...> |
Re: Looking for Power Cord for 400-series Scope
They were quite common at one time. They used a thinner outer jacket to make them more flexible. Some computer power cords are similar, and you could cut off the IEC C13 connector.
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At one time, I worked for an asset recovery company, and we sold those used Belden cords in batches of 100 from scrapped computer terminals and other minicomputer hardware. Does anyone have a '70s or '80s Belden catalog to look up the specs? Michael A. Terrell -----Original Message-----
From: n4buq <n4buq@...> |
Re: When Posting Photos Please include the following...
I prefer to keep the text of discussions and the relevant pictures together, so I create an album on Tekscopes first, then put the pictures in, copy the URL to the album from my browser, and use that URL in my messages.
With respect to the future, I prefer to user the Tekscopes album feature, this way the pictures will be available for all users of Tekscopes since they are already logged in inGroups.io, and if I some day do something stupid with my Goofle account, at least the pictures are safe.. :-) Leo |
Re: When Posting Photos Please include the following...
stefan_trethan
I'm lazy and most times can't be bothered to log into groups.io, let
alone search for some photo. Unless you provide a freely available direct link I probably won't look at it. I realize that is no great loss to anyone, but just wanted to point out if you want your photos seen a direct link (ideally with no login) is in your own interest. There are many free services that host photos and let you share them via a URL, such as google photos. Tinypic also worked great but now they have annoying ads. For archival purposes the group photo space might be ideal, but for accessibility it's almost as bad as Yahoo was. ST On Thu, Jul 26, 2018 at 4:08 PM, Dennis Tillman W7PF <dennis@...> wrote: Just a reminder: |
Re: 2215A LVPS repair
Hi all,
Bruce, thanks for your addition, for now I only can test "dry", so without the PS actually working, because the FET's and diode's are not here yet. But I did some measurements on the driver signal driving the gate of the FET (without a FET installed) The switcher in my scope does free run at 66,5kHz / 15usec, and delivers zero-going OFF-pulses with a 2usec width. Rise and fall times are about 100nsec each. I measured the same signals, but now with a 1nF capacitor installed at the G-S pins. Basically, what I see is that there is no difference in the rise-and-fall times, only the high level (in between the low 2usec pulses) becomes a bit dirty. But since the FET is switching ON around 3,5V - 4V, the part of the signal that becomes dirty is way beyond the point where the FET switches "ON", so that should not be a problem. So, my (probably) premature conclusion is: the FET I ordered should work fine. It's capacity does not have any effect on the rise-and-fall times, it's own turn-on time is way smaller than the applied pulse, and the ON-resistance is lower, so dissipation should be lower. But, we all know Mr. Murphy (only few people know he actually was an optimist) so -as always- the proof of the pudding will be in the eating.... I took some pictures of the signals and I put them in the album again: /g/TekScopes/album?id=64919&p=pcreated,,,20,1,0,0 To be continued, Un saludo, Leo |
When Posting Photos Please include the following...
Just a reminder:
If you announce to TekScopes members that you posted photo(s) to a TekScopes photo album please include a link to their exact location, the title of the photo album, and if it was created some time prior to your post date, the creation date of the album. If you take a moment to these three things in your announcement it will save everyone interested in looking at your photos the time it takes to hunt through the photo albums. Yes, I know you can order the albums by date created or by title. Don't assume your photo album will be looked at immediately in which case it can be quickly found by creation date. Consider the case where someone reads your post years later and wants to see the photos. Dennis Tillman W7PF -- Dennis Tillman W7PF TekScopes Moderator |
Re: Replacing Electrolytics in a 465/465B
Hi Victor,
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I'm asking $8 each (shipping included) for one board for U.S. destinations. Since shipping would be calculated separately for overseas, the boards would be $5 each. Do you have a shipping carrier preference? Looking at USPS, the prices are rather high to France but I ma be looking at the wrong options. Thanks, Barry - N4BUQ ----- Original Message -----
From: "Victor via Groups.Io" <vmcfer@...> |
Re: All TekScopes email sent to Spam
Hi Chuck,
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A common misconception is that an email Sender whose IP address is listed on a DNSBL (Domain Name System-based Blackhole List) is 'blocked' from sending out email. In fact Senders are in no way prevented by DNSBLs from sending email. The Spamhaus DNSBLs are used only by RECEIVING mail systems on private networks and are used voluntarily. Spamhaus does not tell a 3rd-party mail system what to do with an item of email, the 3rd-party mail system asks Spamhaus for an opinion and Spamhaus responds to that request with its opinion. In effect the receiving mail server asks the Spamhaus DNSBL "Does this Sender's IP Address exist on the Spamhaus database?", the Spamhaus DNSBL simply responds with a "Yes" if present or, if not present does not respond at all (no response means "we have no opinion on that IP Address"). Dennis Tillman W7PF -----Original Message-----<snip>
-- Dennis Tillman W7PF TekScopes Moderator |
Re: All TekScopes email sent to Spam
Chuck Harris
A long while ago, I engaged in an email conversation with
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a group member that did not like what I had to say, and rather than talk to me about it, he reported my email address to the misguided SJW folks at spamhaus. From that point on, my email was rejected by every ISP that used their lists of "known" spammers to "protect" their customers. Verizon FIOS accounts were, at that time, using yahoo as their email system, and they were one of the ISPs that were using the spamhaus lists. Verizon has subsequently dropped yahoo to avoid an antitrust violation punishment. To get off of the list would have required me to send spamhaus all of my private information, which I thought was an excessive requirement under the circumstances, so I let it be. I had other email accounts. When you use yahoo's email services, you are given the option during setup of deciding whether you want your spam protection to be none, moderate, or full. It defaults to full. You can change that setting at any time by logging into your yahoo account and adjusting your preferences. Given that groups.io has siphoned off great quantities of yahoo's groups, it would not surprise me at all to find out that yahoo has retaliated by banning groups.io to the spam lists. -Chuck Harris machineguy59 via Groups.Io wrote: I thought our group was using "groups.io" not Yahoo. Yahoo should not be involved unless they are your email client. I use Yahoo email client and web based email. That Yahoo client dumped all of my messages to SPAM one day last week. But I marked them as "Not Spam" and everything has be good since then. |
Re: Looking for Power Cord for 400-series Scope
The manual I have shows a Belden number. I looked for that as well but no luck.
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Thanks, Barry - N4BUQ ----- Original Message -----
From: "Michael A. Terrell" <mike.terrell@...> |
Re: 2215A LVPS repair
Dont forget the gate drain capacitance, whilst it may be smaller than the gate source capacitance the voltage swing across it can be large. The miller effect due to Cgd can usually be easily seen in the switching characteristics.
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Bruce On 26 July 2018 at 20:20 satbeginner <castellcorunas@...> wrote: |
Re: 2215A LVPS repair
Hi all,
with respect to FET's, I'd like to think of them as purely "Voltage" driven. So, imho you're both making the same point: If an one fet has a bigger input capacitance than the other, the drive circuit needs to be able to reach the required ON-voltage by delivering a higher current to charge the higher input capacitance of that FET. If a FET need a higher input charge (nC) to switch on, that may be just the combination of ON-voltage and Input capacitance of that particular FET. Basically: Q = C x V , Charge (Coulombs) = Capacitance (F) x Voltage (V) The FET i ordered (IPA60R280E6) has a GS threshold voltage of 3-3,5V, so the 14V puse should be high enough to drive it, Voltage wise. The original FET IRF710 has a GS threshold voltage of 4V. I like the idea of running the chip by applying a test voltage of 28V down to 14V as used to test the chip as described in H?kan's document, and, while running, put a 1nF capacitor (imitating a worst case FET) in place of the real FET's G-S. This way, using a second scope, I can see if the driver circuit is capable of driver this higher, capacitive load. All this with Q9030 removed of course. If not, I even may change (lower) R909 a bit. A combination of R909 at 39Ohm and 200pF (original FET) would give an approximate risetime of 8ns; A combination of R909 at 39Ohm and 1000pF (replacement FET) would give an approximate risetime of 40ns. For now I ignore the ristime of Q908, the drive transistor in this comparison. I will try the capacitor test later this afternoon. Assume the switching frequency of the PS is 40kHz, thus having a period of 25us, so even with a dutycycle of 10% ON-pulses (ON-time 2,5us) the new risetime should work OK in terms of pulse duration. The thing that might be a thingy could be the power consumption of the FET during the ON-OFF transitions, and for that reason it can be helped to increase the risetime by reducing R909 to force the FET to switch fully ON faster. On the other hand, having a way lower ON-resistance could make up for the power consumption durig transistions So far my thoughts, any ideas? Un saludo, Leo |
Re: Replacing Electrolytics in a 465/465B
Hello Barry,
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Nice job and clean solution congrats. I have 2 x 465B and one 465 that need to be recap soon. I would love to get 3 boards. What is the price for them. Also I live in France did you accept international shipping? Also the related cost. Please let me know. Have a nice day. Victor -----Original Message-----
From: n4buq <n4buq@...> To: TekScopes <[email protected]> Sent: Wed, Jul 25, 2018 1:05 am Subject: [TekScopes] Replacing Electrolytics in a 465/465B Recently, I had a problem with the LV supplies in my 465B. Thinking it was a shorted electrolytic can, I decided to replace all of them (although it turned out to be a shorted tantalum but had already pulled the cans before finding the real problem). I decided to design a small PC board on which to mount modern snap-in caps. THe board mounts with standoffs in the exising larger holes that are left when the cans are removed and allow replacement of the snap-ins if/when they fail and that can be done without further soldering on the original board. Pictures of the board and the process are in the following album: /g/TekScopes/album?id=64929 If anyone is interested, I have extra boards for sale. Thanks, Barry - N4BUQ |
Re: All TekScopes email sent to Spam
If you're using Yahoo mail to read messages, it's happening because you've hit the Spam button instead of Delete.? The button locations move, and it's easy to hit the spam button if you're not careful.? I do it about once every other week with some of my email.? Three times I've received a nastygram stating that I've been terminated from IO because of this, but there is always a link to rejoin the group in question if it was an error.? That's always worked, so far.
-Dave From: Andre de guerin via Groups.Io <testing_h@...> To: [email protected] Sent: Wednesday, July 25, 2018 12:25 PM Subject: Re: [TekScopes] All TekScopes email sent to Spam Same here. Any ideas? www.cwgsy.net/private/mandoline "Error 008472. Horrible bug encountered. $Deity knows what happened." ? ? On Wednesday, 25 July 2018, 19:36:02 GMT+1, Carl Hallberg via Groups.Io <n9ess@...> wrote: Help, Now all my TekScopes email is sent to spam folder.? Is this a Yahoo problem?? Carl Hallberg? (W9CJH) |
Re: tants new vs old
Just wanted to get a little clarity here and also do an update. Went through a number of the scopes I have now and have found three of them where the wet tant has already been replaced with aluminum electrolytics same one that is leaking on the 466 board I am working on. On one of them it was replaced with a 1000uf 10v and on another a 1000uf 35v was used they replaced a 1000uf 10v wet tant they are both larger but fit in place. There is no way to fit a three times capacitance increase in place for that one found a 3300uf 16v that is closest to it at 3 times. There is a very small wet one used on the 464/466 that is 3.6uf 125v that is leaking on the one board I can get a 10uf 160v to replace it think it will fit but would using a solid bulb type of tant same uf but higher voltage be a better choice?
Made a list of wet tants used and what aluminum lytics I could get to replace with and most are close for fitting there are three leakers on this board and one iffy. Jim |
Re: Looking for Power Cord for 400-series Scope
Wasn't Tek using Belden power cords at that time?
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Michael A. Terrell -----Original Message-----
From: Phillip Potter <p.potter@...> |
Re: Looking for Power Cord for 400-series Scope
Phillip Potter
I wish to add my two cents...
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I purchased some power cord to replace the butched one on my 453 (w/ same wire specs) only to find that it was too big (overall size) to fit the cable clamp on the scope! I was forced to whittle the outside sheath down to get it to fit... I was not happy but did end up with a cord that included a plug with a cord holder.? I learned my lesson; never assume... I know, I know! Phil On 7/25/2018 5:05 PM, n4buq wrote:
Okay, Jim. I took a second look and the power entry section is just a small part of the back panel so that would be a fairly easy replacement. |
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