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Re: Curve tracer advice: RF instability.
On 11/28/2014 5:42 AM, 骋鰎补苍 Krusell goran.krusell@...
[TekScopes] wrote: A small ferrite bead also seems to work well, just slip it over the base lead before inserting the part. In a few cases you will need a bead on all leads. |
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Re: Curve tracer advice: RF instability.
Mark Wendt
On 11/28/2014 05:53 AM, magnustoelle@... [TekScopes] wrote:
Hello John,Magnus, That's a heck of a nice adapter you put together there! Nice write-up too, and some very good pics to go with. I know what my next bench project is going to be. ;-) Mark |
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Re: Relay for modern scope needed
I'm looking for help locating a replacement relay for my TDS5054.. It's the AC/DC select relay on the attenuator hybrid. It doesn't click, and there's leakage between the contacts.Hi Andy, There's a few dealers showing stock here. Don't know if they have minimums, though. It looks like Rutronik will let you adjust from 1000 to QTY1. Didn't check some of the others, but Verical won't sell 1. Jay |
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Re: Curve tracer advice: RF instability.
Hello John,
nice to hear about your successful repair. I can confirm that the well-known use of ferrite beads is an effective method to prevent oscillations. This is why I have used plenty of them in my own adapter, see I might have gone over the top with it, but the little "puppy" I have built can test 2N5160 transistors (with an Ft of 500 MHz or higher) without any oscillations. Cheers, Magnus |
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Curve tracer advice: RF instability.
I recenlty bought and restored a 7CT1N and have just made a simple adaptor for transistor testing.
Whilst everything works fine with AF devices, the set-up seeems unstable when testing higher-frequency devices (Ft around 300 to 400MHz). 1. Is this a common issue, and 2. do Tek place suppression networks in their adaptors? John |
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Re: 545 on Jackson Mi Craigslist
I think that the scope in that Craigslist ad is a 545A or 545B, not a 545.
If I recall correctly, the 545 has a plain black HORIZONTAL DISPLAY knob, while the 545A and 545B have the 5x horizontal magnifier switch coaxial with the HORIZONTAL DISPLAY knob. -Kurt On Thu, Nov 27, 2014 at 7:58 PM, Paul Amaranth paul@... [TekScopes] <TekScopes@...> wrote:
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Re: Weird cursor problem on 2465 scope
Hi Siggi. Thank you for your suggestions about this problem.
Yes is mine 2445 oscilloscope back then, and was the only problem found on it. In my case also, the problem was .47uF ceramic cap MKP type. As you know I am crazy with caps! Therefore entire A1 board removed (not so easy), and all caps replaced. If I remember correctly many .22 uf caps also exist on the same board. But as I said before, all replaced. |
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Re: 5103N filtercaps
Good Day,
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I agree that replacing the el. caps is a lot of work, but it is certainly do-able. Allow me to include a link to my own pictures, which show the replacement work I have made on a 5441 (similar to the 5103 family). A friendly hint: Some supply connections are made "via" the electrolytics caps' packages. The solder slugs of the outer "aluminum can" provide these connections. These connections need to be restored, if one uses modern electrolytic caps as replacements (as shown). Cheers, Magnus
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Re: TEk 475 removing replacing big electrolythics
In repairing and Re-capping a lot of 400 series scopes, I found that the
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easiest and "cleanest way possible to remove the big filter caps was to cut the leads to the board with dykes where possible and in some cases actually destroy the cap to get at the leads to be cut. Once the caps are physically are out of the way , THEN you can easily get at the leads still soldered in the board with a solder sucker and braid and end up with nice clean mounting holes without butchering the lands on the board. Today's caps are far smaller and more efficient than the original "beer can" sized monsters that were originally used, Make sure you pay attention to the positions and orientations of the polarized leads on the original caps as well as the ground traces so that the new caps can be installed in the same way -----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] Sent: Thursday, November 27, 2014 8:07 AM To: TekScopes@... Subject: Re: [TekScopes] Re: TEk 475 removing replacing big electrolythics Hello all, I do it differently. I'm not saying that this way is wrong or anything. I just use a different approach. When I had my powered solder remover I would remove all of the solder from the tabs and the pins. Then I would straighten the bent tabs so that I could wiggle the cap back and forth until it would come off of the board. Now I use solder removing braid to perform the exact same operation. This is just the way that I do it. Thanks, rich! On 11/27/2014 6:43 AM, John Bosak johnbosak@... [TekScopes] wrote:
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Re: TEk 475 removing replacing big electrolythics
Hello all,
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I do it differently. I'm not saying that this way is wrong or anything. I just use a different approach. When I had my powered solder remover I would remove all of the solder from the tabs and the pins. Then I would straighten the bent tabs so that I could wiggle the cap back and forth until it would come off of the board. Now I use solder removing braid to perform the exact same operation. This is just the way that I do it. Thanks, rich! On 11/27/2014 6:43 AM, John Bosak johnbosak@... [TekScopes] wrote:
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Re: Relay for modern scope needed
What about here? ;initiative_id=SB_20141127044242&SearchText=FTR-B3GB4.5Z ;initiative_id=SB_20141127044242&SearchText=FTR-B3GB4.5Z
I know, could be somewhat slow to receive, but compared to backorder times you've found, could be an option! I've oredered a lot of item on that site; to italy they take 6-8 weeks with free shipment, way less with courier :) |
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Re: TEk 475 removing replacing big electrolythics
I would recommend against removing the main PCB. It is a major undertaking and one is liable to damage other things in the process. I removed all the caps using an oscillating tool to cut the tabs. Find one on eBay here().
It is much easier using a power tool. I completed the process in 15 minutes. I have some pictures of the rear of the PCB where the power caps are mounted and would be happy to share them with you if you will send me your email address. I also have a connection check list so you can confirm all tabs are connecting to their proper components. John Bosak Sent from my iPhone |
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Re: TDS-420 SMPS
Sorry to resume an old thread, hoping to help.. I had the same startup problem on my TDS420 PSU; after a bit the psu would turn on correctly and continue to work until next day.
Next day the psu wasn't starting again; protection was kicking in every 1-2 seconds. The main problem was caused from the overcurrent protection; even without load, the protection would kick in. I've disabled the protection (risky, i know) and now it works correctly. Let me know if you need more details. |
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Re: Slightly OT: Book about oscilloscopes in USSR
Stefan Trethan
In case the link does not work for you:
<> Interesting to learn the premier USSR scope lab is behind some of the faster Picoscope products. Only recently I was on their website and surprised to see that they have some serious gear (most USB scopes are just a joke). ST On Thu, Nov 27, 2014 at 6:36 AM, curbinap@... [TekScopes] <TekScopes@...> wrote: Found this link on the internet where you can download an interesting book about oscilloscope development in USSR. The book is titled <People.Years. Oscilloscopes>. It is written in russian (although Introduction is also in english), but has plenty of very interesting photos. |
John Sykes
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