Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- TekScopes
- Messages
Search
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
On Sun, 17 Jun 2018 17:04:07 -0400, you wrote:
On 2018-06-17 2:21 PM, machineguy59 via Groups.Io wrote:To avoid blanket statements: I've found that some Mouser prices are...About Digikey (Canada). They are FAST: Once I had parts in hand about 12 cheaper than Digikey prices. I've also found that Mouser does not carry some parts that I need (they went Altera rather than Xilinx, and apparently carry NO Xilinx parts. Didn't check Digikey for Altera). I'm in the southeast, so Mouser is closer for me and a bit faster. As in any buy, consider how many you need and what the economies of a bulk buy happen to be. SMT resistor may be 15 cents in unit quantities, in lots of 100, you may be paying 0.5 cents. Once you start ordering that kind of stuff, as long as you don't order too many, the shipping is the killer. You tend to want to spend enough that the shipping is not more than the parts total. Harvey
|
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
On 2018-06-17 2:21 PM, machineguy59 via Groups.Io wrote:
...About Digikey (Canada). They are FAST: Once I had parts in hand about 12 hours after ordering on the web. Next day is usual. For me they also have much cheaper shipping than Mouser. --Toby |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Menahem, You may address me as Ron, or Mac (for machineguy).? I usually use Mac on the net and Ron in the "real world".? As a brief introduction, I am 78 years old, retired electronics engineer, now hobbyist, living in Iowa, USA.? Its hot here too (94 degrees F on many days), but air conditioning keeps it at a nice 73 degrees.? I got into repairing Tek scopes because they were everywhere during my working years but unaffordable.? I read the report on your 2465B scope restoration and decided I could do that too.? I now have six 24x5 scopes sitting in my lab, three work, one is being "built" and two are donors.? My wife wants me to "thin the herd" but we have an agreement: She wont throw out my scopes and I wont throw out her dishwasher.? My technical abilities are competent but not expert, too many years in management.? My repair objectives are equal or better than OEM (which in the case of Tek equipment is world class performance).? My three fully working scopes seem to achieve that goal.
toggle quoted message
Show quoted text
Honestly, I was surprised and a bit offended when you first deprecated my updated list.? I had posted it to help someone who was creating a new list "from scratch".? He had asked for help and received little response.? So I offered the list I use.? I was embarrassed that it had two errors but I do think it helped him.? You might do better for him and I encourage you to post a list.? But this one is the best I have.? I use it and it works. I agree with you, Nichicon is a better choice than Panasonic.? This is evident in their specifications.? Panasonic lists an ESR that is 30% or more worse in ESR than Nichicon.? This may account for the difference you measured in ripple reduction between the two.? (BTW, you may want to check your photos in the file section.? There are only two photos, not four and I believe the key photos are missing.)? But I used Panasonic in six locations.? Based on my agreement with your advice, I have changed my list to use the Nichicon equivalent in these locations.? For what its worth, I have preferred Nichicon to Panasonic for some time, just had not updated my list. Like you, I give little weight to forecast life expectancy over 5000 hours.? But if all important parameters are equal, I use life expectancy as a factor. Also like you, I used to avoid "over voltage" specifications in electrolytic capacitors.? But my research showed that higher voltage rated caps often had lower ESR and manufacturers often suggested de-rating their caps in hard stress applications by as much as 50%.? I reasoned then that if it was good for high stress applications, it was acceptable for moderate stress applications.? This discussion and my recent research has given me confidence in that decision. Finally, I use Digikey for parts.? I have no disdain for Mouser but Digikey is more convenient to me.? They are less than 200 miles from my home, shipping is fast (typically two days from order to arrival here), and cheap (as low as 3.95 US for a complete set of caps).? So my list does not include Mouser part numbers. ? Again, thank you for your explanations.? I hope mine are useful to you. Ron On ?Sunday?, ?June? ?17?, ?2018? ?02?:?46?:?49? ?AM? ?CDT, M Yachad <yachadm@...> wrote:
MachineGuy (I¡¯d really like to address you by your real name!) Thanks for that info from the tin-man. I can certainly relate to the manufacturer¡¯s published data. I will take this into consideration the next time I have to select caps. To address certain points: 1.??? I am not at all biased against Panasonic caps. They are superb, and I use the EB in Linear audio applications all the time. They are my go-to for that specific application. 2.??? I also use the Panasonic TSHA and ED/EE Snap-ins as my go-to PSU filter capacitors, with Nichicon GU as my second choice. 3.??? So, the question arises, WHY do I NOT recommend the EB in THIS Tek PSU application? 4.??? It is important to understand the function of a cap in each particular place in the circuit. In any PSU application, the AC ripple BETWEEN the Bridge rectifier and the Regulators is enormous. AFTER the regulators, the AC ripple is negligible. 5.??? A few years ago, to quieten my curiosity, I did a test on an older amplifier using 4 new apparently identical 4700uF 25V and 50V capacitors mounted BETWEEN the Bridge and the bank of Regulators (some 78xx, 79xx, 317, 319). The Nichicon HE caps reduced the residual AC ripple to approx 1V p-p (with no discernible difference between the 25V and 50V cap). The other caps reduced the residual ripple to 2V p-p. See attached pictures. This is a test which any of you can easily do, any time. /g/TekScopes/album?id=59343 6.??? That proved to me that the HE has a significant advantage in reducing AC ripple, over another respected brand-name cap. On the datasheets, all the numbers pretty much matched up, but in the real world of flowing voltage and current, my scope waveform showed a substantially significant advantage to the HE. 7.??? However, AFTER the regulators, where ripple is negligible, an EB is an excellent choice. The superior capability of the HE regarding ripple damping is of no advantage here. On this Tek PSU, has anyone actually done any research to specify each cap¡¯s function? From the postings here, I don¡¯t think so. I haven¡¯t. So, unless someone is willing to go and locate each cap on the circuit, and determine whether it is in a low-ripple part of the circuit (where an EB would be acceptable), or it is in a high-ripple part,? I think that we need to globally specify HE or PW (functionally equivalent), in order to be on the safe side for ALL applications. That¡¯s what I did, with full confidence that my choice would give me the lowest ACTUAL ripple on all circuits. If a user installs EB in a high-ripple area BEFORE the regulators, will the machine work? Of course it will. But will it work as well, if an HE or PW is installed? My test states not. After all, a SMPS with loads of AC ripple in all parts of the circuit, is NOT like a linear PSU, at all. It¡¯s the difference in being able to tune a high-performance engine, to get the last ounce of available HP out of it. The posters who are asking these questions are people who do NOT have any substantial electronics background, theory or practice. I think it is incumbent on us (the techs with long experience) to point them in a direction which will give them an optimal and safe solution, so that they don¡¯t have to tear their hair out, buying parts which don¡¯t fit, or worrying whether what they choose will last or not. Regarding the Lifetime numbers of the data provided by MachineGuy: A 5000Hr lifetime is provided for a (boiling) CONSTANT temperature of 105¡ãC. If the caps in my Tek scope are reaching that temperature, then my scope is on the way to the garbage dump, very quickly, and the 5000hr lifetime is functionally irrelevant. I have measured the temperature of my HE caps in my A2A1/A3 PSU block, and the hottest individual cap temperature which I measured was 38¡ãC. The average temp of the caps was room temperature. And it IS hot here in Israel ¨C I¡¯m not just talking about the fires from the Gazan terrorists. ¡°For every 10 degree Centigrade decrease in operating temperature, the capacitor life is extended by a factor of two.¡± So, if my HE caps are running at a constant 40¡ãC, then their expected lifetime is 5000 x 2 to the power of 6 (=64, check my math) = 320,000 hrs = more than 36 years; scope on all the time, never being switched off. Given that the data supplied above stated that cap¡¯s casing would breakdown after about 15 years, then there is no apparent benefit HERE of choosing a 10000 hr cap over a 5000 hr, except for the status. So, IMO what we should be concerned about, is WHAT does the waveform look like at all the HIGH-RIPPLE positions in this Tek SMPS PSU circuit, and then select the cap which dampens that ripple most effectively. To my experience, the Nichicon HE fits the bill most effectively. Menahem |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Chuck Harris
Then you should have seen it in my last post, but here
toggle quoted message
Show quoted text
it is again: ------------------------------------------------------ Ok, we are all engineers here, so, we know that ripple voltage is pretty directly related to frequency, current, and capacitance by the equation: i(t) = -CdV/dt [We can drop the "-" sign if we remember to get our dV in the right direction so that we don't get a negative capacitance.] Looking at the oscilloscope traces, we see that in: case 1) C = ?, dV = 2V, and dt = 5ms, and in case 2) C = 4700uF, dV = 1.2V, and dt = 5ms. Solving for i, we get 1.13A Rearranging the equation and substituting the mystery cap's ripple voltage: C = idt/dV = 1.13A x 5ms/2V = 2820uF Hold the phone there Menahem! If that really is a 4700uf Brand X cap, it is either short 2000uf, or has about an ohm of ESR... [EIA guidlines show a 4700uf, 25V, has to be less than 0.099 ohm ESR, and a 4700uf, 50V, has to be less than 0.071 ohm ESR.] So, which is it: A 2800uf capacitor marked as 4700uf? A less than 0.1 ohm ESR cap with 1 ohm ESR? A fib about the capacitance value? -------------------------------------------------------- Do you have an answer? -Chuck Harris M Yachad wrote: Talk, I'm listening. |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Chuck Harris
Well, consider me chastised.
toggle quoted message
Show quoted text
I'm guessing that you and I have a different idea of what constitutes an attack. The math is simple, tried and true, and leads to the inescapable conclusion that if everything is as you said, the capacitor you are comparing to the HE can't be 4700uf. Let's talk about that. -Chuck Harris M Yachad wrote: Chuck |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Chuck Harris
So, let see if I got this straight:
toggle quoted message
Show quoted text
You did a comparison between brand X and Nichicon HE caps, and you found that the Nichicon HE outperformed the brand X capacitor 2 to 1. Even gave us some pretty pictures. Ok, wait, there is some fine print: The brand X cap is old, and apparently to avoid embarrassing the manufacturer, you won't tell their name. [Wait! 3:40AM, and the text just changed! Now the other cap is 4700uf 25V and 50V, not just an old cap... I hate it when that happens...] Ok, we are all engineers here, so, we know that ripple voltage is pretty directly related to frequency, current, and capacitance by the equation: i(t) = -CdV/dt [We can drop the "-" sign if we remember to get our dV in the right direction so that we don't get a negative capacitance.] Looking at the oscilloscope traces, we see that in: case 1) C = ?, dV = 2V, and dt = 5ms, and in case 2) C = 4700uF, dV = 1.2V, and dt = 5ms. Solving for i, we get 1.13A Rearranging the equation and substituting the mystery cap's ripple voltage: C = idt/dV = 1.13 x 5ms/2V = 2820uF Hold the phone there Menahem! If that really is a 4700uf Brand X cap, it is either short 2000uf, or has about an ohm of ESR... [EIA guidlines show a 4700uf 25V has to be less than 0.099 ohm ESR, and a 4700uf 50V has to be less than 0.071 ohm ESR.] So, which is it: A 2800uf capacitor marked as 4700uf? A less than 0.1 ohm ESR cap with 1 ohm ESR? A fib about the capacitance value? You state that any of us can do the same test at anytime... How is that so? You didn't tell us anything about the brand X capacitor we are testing against... So, I guess absent any information we have to take your word. Absent more information, I probably won't. -Chuck Harris M Yachad wrote: MachineGuy |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
MachineGuy
(I¡¯d really like to address you by your real name!) Thanks for that info from the tin-man. I can certainly relate to the manufacturer¡¯s published data. I will take this into consideration the next time I have to select caps. To address certain points: 1. I am not at all biased against Panasonic caps. They are superb, and I use the EB in Linear audio applications all the time. They are my go-to for that specific application. 2. I also use the Panasonic TSHA and ED/EE Snap-ins as my go-to PSU filter capacitors, with Nichicon GU as my second choice. 3. So, the question arises, WHY do I NOT recommend the EB in THIS Tek PSU application? 4. It is important to understand the function of a cap in each particular place in the circuit. In any PSU application, the AC ripple BETWEEN the Bridge rectifier and the Regulators is enormous. AFTER the regulators, the AC ripple is negligible. 5. A few years ago, to quieten my curiosity, I did a test on an older amplifier using 4 new apparently identical 4700uF 25V and 50V capacitors mounted BETWEEN the Bridge and the bank of Regulators (some 78xx, 79xx, 317, 319). The Nichicon HE caps reduced the residual AC ripple to approx 1V p-p (with no discernible difference between the 25V and 50V cap). The other caps reduced the residual ripple to 2V p-p. See attached pictures. This is a test which any of you can easily do, any time. /g/TekScopes/album?id=59343 6. That proved to me that the HE has a significant advantage in reducing AC ripple, over another respected brand-name cap. On the datasheets, all the numbers pretty much matched up, but in the real world of flowing voltage and current, my scope waveform showed a substantially significant advantage to the HE. 7. However, AFTER the regulators, where ripple is negligible, an EB is an excellent choice. The superior capability of the HE regarding ripple damping is of no advantage here. On this Tek PSU, has anyone actually done any research to specify each cap¡¯s function? From the postings here, I don¡¯t think so. I haven¡¯t. So, unless someone is willing to go and locate each cap on the circuit, and determine whether it is in a low-ripple part of the circuit (where an EB would be acceptable), or it is in a high-ripple part, I think that we need to globally specify HE or PW (functionally equivalent), in order to be on the safe side for ALL applications. That¡¯s what I did, with full confidence that my choice would give me the lowest ACTUAL ripple on all circuits. If a user installs EB in a high-ripple area BEFORE the regulators, will the machine work? Of course it will. But will it work as well, if an HE or PW is installed? My test states not. After all, a SMPS with loads of AC ripple in all parts of the circuit, is NOT like a linear PSU, at all. It¡¯s the difference in being able to tune a high-performance engine, to get the last ounce of available HP out of it. The posters who are asking these questions are people who do NOT have any substantial electronics background, theory or practice. I think it is incumbent on us (the techs with long experience) to point them in a direction which will give them an optimal and safe solution, so that they don¡¯t have to tear their hair out, buying parts which don¡¯t fit, or worrying whether what they choose will last or not. Regarding the Lifetime numbers of the data provided by MachineGuy: A 5000Hr lifetime is provided for a (boiling) CONSTANT temperature of 105¡ãC. If the caps in my Tek scope are reaching that temperature, then my scope is on the way to the garbage dump, very quickly, and the 5000hr lifetime is functionally irrelevant. I have measured the temperature of my HE caps in my A2A1/A3 PSU block, and the hottest individual cap temperature which I measured was 38¡ãC. The average temp of the caps was room temperature. And it IS hot here in Israel ¨C I¡¯m not just talking about the fires from the Gazan terrorists. ¡°For every 10 degree Centigrade decrease in operating temperature, the capacitor life is extended by a factor of two.¡± So, if my HE caps are running at a constant 40¡ãC, then their expected lifetime is 5000 x 2 to the power of 6 (=64, check my math) = 320,000 hrs = more than 36 years; scope on all the time, never being switched off. Given that the data supplied above stated that cap¡¯s casing would breakdown after about 15 years, then there is no apparent benefit HERE of choosing a 10000 hr cap over a 5000 hr, except for the status. So, IMO what we should be concerned about, is WHAT does the waveform look like at all the HIGH-RIPPLE positions in this Tek SMPS PSU circuit, and then select the cap which dampens that ripple most effectively. To my experience, the Nichicon HE fits the bill most effectively. Menahem |
|
Re: Tek 2337 (looks mint) on Goodwill.
Same form factor as the 2335 and 2336; each one has a different feature in
toggle quoted message
Show quoted text
integrated lid. The 2336 has an LCD readout of the intensified sweep time. My first scope was a 2336; still have it as my go-to portable. Dave Casey On Sat, Jun 16, 2018, 11:10 AM Artekmedia <manuals@...> wrote:
Looks like it is very clean, If I still lived in Ft worth I'd run over |
|
Re: My 422
Ohio. here I thought you were east coast somewhere...no problem on the meters ...once in awhile things fall into place...like the item etc is down the street (from me), literally, I walked down and shipped it out for a fella!
toggle quoted message
Show quoted text
I am in the north bay/ napa area but travel all over the place for my jobs ( music performance) and I never know if and when till hired....geez that reminds me I have reeds to make too......summer is my busy time although it seems to run in spurts. i will post both collector and base. I do want to match the xstrs better. so I do need to go back in. my pwr supply is pretty much limited to 25V at 4A absolute max before it sags. and I will post what I did to open the loop and test. next is my just acquired 475 that needs attention ( I am borrowing one). this one has options 4 (RFI) and 7 (AC/DC). also has a mod 93 what ever that happens to be. I will have to ask the group.....someone will know. Problem is using the Cal signal ( only test i ran when I purchased. ) collapses as it is moved vertically up or down to go off the screen...like it hits a wall and collapses into it at the top and bottom of the screen. at least it has a trace and controls work.....I am hoping just a pwr supply issue. may be vertical amps, or dirty sockets....do not know...I have not opened the case. currently I am in the SF bay area, back to moms in the hills ( Railroad Flat...East of Stockton)..I dislike having to be in two places!? that is also why info is not so fast while working on something and sometimes stuff get left in one place or the other and things wait for a week or more.....I am care taker for mom...84 going on 300..... nuff on this Your assistance has been greatly appreciated. ¸é±ð²Ô¨¦±ð On 2018-06-16 04:52 PM, Jeff Urban wrote:
Ohio here. Not exactly a stone's throw. If I could get there it would be with my friend the truck driver who goes that way alot, but I either couldn't stay more than a few minutes or need another way home. Driving it is out of the question for me. |
|
Re: Repairing plated through holes.
I got a reel of component lead from the Orlando Sprague factory when it was shut down. I was working for an asset recovery company and they considered any damaged spools as worthless. There are several thousand feet of that tin plated steel on the reel. We had a whole pallet load of reels that were sold to another company.
toggle quoted message
Show quoted text
Michael A. Terrell -----Original Message-----
From: Jeff Urban <JURB6006@...> |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
On Sat, 16 Jun 2018 16:54:09 -0700, you wrote:
Excellent suggestion!!!er... no At that time (roughly 1900), I think that all they had they had leyden jars. Sadly, he was only made of tin, one piece of him (Nick Chopper) replaced at a time (I think it was a curse), since he had chopped off a piece each time and had it replaced by tin... Don't as the obvious questions, they were never answered in the books). On the other hand, he was likely tin plated steel, since he rusted in the rain. I don't remember tin rusting... Had he been more modern technology, he'd have a voltage rating, and ESR, and a temperature rating (which I think was mostly ambient at the time). Harvey |
|
Re: Repairing plated through holes.
tom jobe
Hello Stefan,
toggle quoted message
Show quoted text
Your plan will work fine for a few Rivnuts, and to extend the life of your tool, use a fairly hard bolt (hex head 'Allen' bolts are often fairly hard and tough) and then use (or make) a nut that is longer than a regular nut. Then use some kind of an extreme pressure lubricant everywhere, like molybdenum grease or what you ever else you might have on hand. Ordinary grease or oil is much better than trying to do this 'dry' with no lubricant. Use several greased washers under the nut to act more like a ball bearing thrust washer, because the Rivnut will want to spin from you tightening the nut. You just hold the 'bolt' in place with one wrench at the top and tighten the nut to squeeze the Rivnut into place. How long your homemade tool will last depends on what material your Rivnuts are made of, and how good your installation tool is. Even the official 'store bought' Rivnut tools will have the hardened steel 'bolt' fail every so often, depending on which quality of Rivnuts you are using just because it is a very hard 'pull' to squeeze the Rivnut into place. It is very easy to over tighten the Rivnut and your tool, so it is good to do a test on a scrap piece first so you know what it feels like, and how many turns of the nut it takes to install your Rivnut? with your installation tool when the Rivnut is installed properly. It is easy to pull the threads out of the softer Rivnuts (such as aluminum) by over tightening the tool YouTube has many videos about all of this too, so check them out for other variations of homemade simple Rivnut installation tools. tom jobe... On 6/16/2018 8:46 AM, stefan_trethan wrote:
You can still buy the pop rivet nuts, but much more $$ than that. |
|
Re: Repairing plated through holes.
On Sat, Jun 16, 2018 at 04:37 pm, Jeff Urban wrote:
I "pinned" my dolby board on my sansui 8080db using 24 gauge copper wire that I tinned and put through all the holes. It worked really well. I need to get over things not looking perfect. This 465 that I just finished up has a jumper wire from the - BR to (I think) C1562. It works fine but it looks terrible. I literally lost sleep thinking about that stupid bodge wire. I have a tendency to think things are worse than they actually are also. I replaced some diodes in the ceramic strips on my 485 thought I did a terrible job. Lost sleep for days. Opened it up a month or so later to "fix" it. Looked at it and it was done well nothing to fix. Mental illness i suppose. Sorry if this drifted too far OT |
|
Re: Repairing plated through holes.
On Sat, 16 Jun 2018 16:37:07 -0700, you wrote:
On Fri, Jun 15, 2018 at 07:28 pm, lop pol wrote:If it's done well, then it should last. plated through holes/doubleIn hifi audio restoration circles they have a process they call "pinning". This is used on Marantz Dolby decoder boards and other things that were two sided but only had plated through, no rivets, gripplets or anything. sided boards were done for mil-spec work in the 1970s. If you're designing a board, the main problem is that there are parts where you simply can't solder both sides of the board. Not talking a via here, that's another matter. You could easily take a soft copper tinned wire of the right gauge, stretch it a bit to harden it, and do the same. No need to have a box of resistor ends, although that will work. Nope, wave soldering a straight wire will likely cause it to fall out. You'd need a C shaped wire or perhaps a Z shaped wire (narrow Z). When soldering the board, it should be vertical, or you should have crimped the wire over before. may be thicker plating on the holes (I thought it was 1 oz copper, plated through to 1 on the holes, 2 on the board, tin lead plated, then etched, leaving 2 oz copper on the boards and 1 in the holes.) I think that the quality of the epoxy bonding the copper to the boards has gotten better, or I've gotten a LOT better at soldering quickly and accurately over the years. Decent question. Harvey |
|
Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Excellent suggestion!!!
I "asked" Nichicon (did a google search: "Nichicon electrolytic capacitors application"). Nichicon said: "The degree that applied voltage effects the life of the capacitor when used below the rated voltage is small, compared to the degree that ambient temperature and ripple current effects life. Therefore, when estimating the life of a capacitor, the voltage coefficient to the applied voltage (Fu) is calculated as 1." They even tested large 50 volt electrolytics at 60%, 80%, and 100% of rated voltage for 5000 hours. The three lines fell on each other as one line. You can read it here: (Note that my list uses Nichicon electrolytics at 0.4, 0.5 and 0.65 deratings.) Similarly, Cornell Dubilier is less convincing (no test data) but still firmly states: "Higher rated voltage capacitors may be substituted for lower rated voltage capacitors as long as case size, DF, and ESR ratings are also compatible." Or Illinois Capacitor who is quite optimistic (overly optimistic?) of the benefits: "The expected life can be increased by the ratio of applied voltage to rated voltage for the capacitor where the applied voltage is 80% or lower of the rated voltage. ¡ By de-rating, the life expectancies beyond 15 years can be achieved. When life expectancies exceed 15 years the expected life of the capacitor should be limited to 15 years mainly due to the sealing materials deteriorating over time." TDK simply allows it (no benefits) by stating: "The permissible voltage range for continuous operation lies between the rated voltage and 0 V." Wikipedia has a great article which states: "Applying a lower voltage may have a positive influence on electrolytic capacitors. For aluminum electrolytic capacitors a lower applied voltage can in some cases extend the lifetime." Electric Engineering Stack Exchange discussion indicate the ESR of a 50 volt rated capacitor to be as much as half the ESR of a 25 volt rated capacitor. See this: Of course this may not always apply but it did for the Nichicon caps I researched and specified in my list. BTW, was Dorothy's tin man really made of aluminum from an empty capacitor can? |
|
Re: My 422
Ohio here. Not exactly a stone's throw. If I could get there it would be with my friend the truck driver who goes that way alot, but I either couldn't stay more than a few minutes or need another way home. Driving it is out of the question for me.
Anyway, I AM going to see about the scope testing itself. There is no technical reason it should not work and ground is absolutely not a problem. Now if you needed some differential readings in the vertical, that would be a problem. I'll put up some pictures if I can find batteries for this batteryaholic camera I got. I was going to build a PS for it but I have to get 3 volts at about 7 amps ! Even though it runs off AA cells, they can put out that, and more. I might do that tonight. Meantime, post yours. I would like to see what those collector (not the test point) waveforms look like at about 26 VDC input. That is about what they would get with 125 VAC at the wall, which is actually the new nominal. Now that I mention it, I am not sure what range mine is set for. If it is set for like 110 volts, changing that might help. |
Michael A. Terrell
Jeff Urban
to navigate to use esc to dismiss