Re: Details on 015-0670-00 Feed-Through Adapter for AM503B?
Hi Jared,
I was one of the designers of the AM503A, AM503B, AM5030 and newer TCPA300/400 products. Let me dig through my parts bins to see if I have one (I think I bought some from RAMs way back?) or at least check the service manual to see if there was a schematic. I remember there was a coding resistor from a pin to gnd and then a short between the output of the power amp into the input of the attenuator for one of the adapters. There was a coding resistor and a coax that went straight into the attenuator input for the other adapter.
Stay tuned,
Mike
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Re: Intermittent power on problems with 2465B
Jon,
Thanks for confirming that the switch is an unlikely source of issues.
Of course the problem now I that I need to wait for another intermittent failure before I can figure out what is wrong. D**n thing worked *again* first time this morning. -)
Regards,
Mark
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Re: A note on PC boards, double and single sided.
On Wed, Jan 6, 2021 at 04:26 AM, Brad Thompson wrote:
Oh, and when overheated
it smelled like warm horse s*it.
Being a city dweller, now I know what that smells like... Raymond
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Re: Intermittent power on problems with 2465B
On Wed, Jan 6, 2021 at 01:17 PM, Jean-Paul wrote:
a/ Certain types tantalum caps had poor seals especially in early SMD parts
days, eg the notorious A5 board corroding leaky bypass caps.
The infamous caps on the A5 board are Al, not Ta. Bonne chance! Raymond
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hi Guys
Am spending the first few days of the newly instigated UK national lockdown calibrating several 500 series scopes ¨C a 545B and a 547.
In each case there is an intriguing point where the manual, as part of the A and B timebase trigger level centering calibration asks you to:
for A Time Base Cal- ground the junction of R19 & R20 ¨C both 545B (Change instructions) and 549 (manual)
for B Time Base Cal ¨C ground the junction of R69 & R70 - both 545B (manual) and 549 (manual)
Now here is the issue. Finding and connecting to the required junctions can be/is hazardous particularly for those of us who have something of the shaky hand syndrome and a well developed sense of self preservation when working with high voltages in cramped spaces.
But wait: there appears to be a simple solution in every case. With the timebase trigger switch in the *Auto* position there is a direct path between those resistor junctions and chassis ¨C the schematic says so and a simple continuity test with the scope off confirms it. Interestingly my version of the 545B manual uses this method in the manual, before changes brought in by the change information.
So am I missing something here? Does the suggested 'jumper lead' provide magic continuity properties? Is there some hidden feature not shown on the circuit diagram?
Any ideas why the obviously easy way is not followed, indeed is specifically disavowed it the case of the 545B change information.
Thanks in advance
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Re: Intermittent power on problems with 2465B
Mark I have never seen an intermittent power switch on any,Tektronix scope, but have seen the power connector plastic shaft mechanically come off.
I suspect a marginal part in the PSU start-up circuit.
If you look at the service manual the power supply troubleshooting flow chart is very good for diagnosis.
Jon
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Re: Intermittent power on problems with 2465B
John: "when manufacturers changed from wet electrolytics to dry the problems with
caps largely ceased"
The cap issues are mixed up a bit:
a/ Certain types tantalum caps had poor seals especially in early SMD parts days, eg the notorious A5 board corroding leaky bypass caps.
b/ All "electrolytic" or ELCO caps use a water based electrolyte. The issue is drying out by loss of water over the years, causing low C and high ESR.
This is a function of:
1/ End seal design, greatly improved in recent decades.
2/ Application eg soldering technique
3/ Operating temperature and time
4/ Internal temperature rise due to ESR and ripple current
5/ Cap tem rating eg 85 C or 105 C or even 135C. Note that the temp rating means that at that external temp and with rated ripple current, 50% of the pars will exceed ESR or C after 1000 or 2000 hours!
In other words limited life!
6/ Quality of mfg eg cheapo junk Chinese no name vs major brands eg Rubycon, Nichicon, United Chem Con, etc.
So the cap life and need for replacement is not a simple question!
In decades of SMPS design and manufacture we specified 105 C and 135C lytics and bought from the US firms like Sprague, then the Asian firms mentioned above.
For TEK scopes, they used good quality parts, so very seldom are the lytics defective in PSU
BIG exception is the 2465/B A5 control board SMD corroded caps, bad SMD seal design!
I just replaced a 9 uF 150V lytic in 7603 backplane 50 V filter, corroded at one end.
RE "exploding" lytics: Yes I had a few in 100-1000W SMPS, it was always a backwards +/- error
Bon Chance,
Jon
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Re: A note on PC boards, double and single sided.
Thanks, I always seem to do better when I know not only *what* I'm doing, but also why.? Considering that we're often repairing rather old PC boards (and yes, I dealt with those things when they were hatched....), I thought this might be useful.
Harvey
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On 1/6/2021 12:00 AM, Jim Ford wrote: Nice PCB summary, Harvey!? I've seen what is probably FR-3 in consumer electronics but I've never worked with it.? FR-4 or RF/microwave laminates, yes.? FR-4 is as common as dirt.? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Harvey White <madyn@...> Date: 1/5/21 5:55 PM (GMT-08:00) To: [email protected] Subject: [TekScopes] A note on PC boards, double and single sided. Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4).? There are others, but these are most common.Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together.? You see it in a lot of commercial (expensive or not...) equipment.? It is mostly brown...Glass Epoxy (FR-4) has a higher temperature tolerance, is pretty stable, is more difficult to burn, and is constructed of a glass mat of fibers held together with epoxy.FR-3 is easy to drill, and the epoxy does not kill drill fast. FR-4 has glass fibers instead of paper, and eats drills.? Tungsten Carbide drills are the ones needed for this material if you want to drill many holes.? (yes, a normal carbon steel drill will end up looking like a pointed needle after enough holes.Tektronix used FR-4 or more exotic materials.? I haven't seen any FR-3 except perhaps in later, Chinese made products dating somewhat after 2000 or later.Early PC boards were single sided, that is , a layer of epoxy gluing copper foil to a board.? Early boards had a problem, the epoxy was not a good grade (less "good" than now) , and with an older, non temperature controlled iron (UNGAR, or 30 watt anybody), the foil could get overheated, the epoxy could fail, and the trace could lift off the board.More modern boards tend not to be as fragile, with better epoxy.The bottom line is that even with things that are single sided (more later), the foil is harder to "lift".? However, part of this ruggedness has to do with temperature controlled soldering equipment, which minimizes board overheating.? You can still do it, of course, since the average soldering iron tip is hotter than the epoxy can stand over a prolonged period.? However, soldering quickly doesn't harm the board.DESOLDERING, however, generally involves heating the board more, using perhaps a higher temperature, and runs more risk of separating the trace from the board.? The amount of heat depends on the iron tip, the temperature, the solder, and the amount of time it takes to remove solder.? More expensive desoldering equipment can harm the board less.... However, technique is also important.Enter two sided boards.? These have copper foil on both sides. If any part is an SMT (surface mount technology) or SMD (same thing, but surface mount device), which *many* modern devices are, and some are? limited to... Then you have the same as a normal single sided board and you need to be carefulIf, on the other hand, you have a through hole part, the the board is plated through as if there were a copper eyelet connecting the top and bottom traces.? While this has increased mechanical strength over a single surface pad, well... Not necessarily the answer of answers.Let's assume that you have a through hole part, and you heat the lead and remove the solder, but not all of it.? Now you decide to pull the part lead out with pliers.? If you've gotten enough solder out to free (partially) the bottom trace, and even a bit of the top, but NOT enough to completely clear the inside of the hole.....You can pull out the plating on the plated through hole much as if you pulled out the center part of an eyelet crimped on both sides.? If you are dealing with dual layer boars, the being able to rattle the part lead inside the hole indicated that it isn't still soldered in, and I can recommend NOT pulling the lead out regardless.If you have one lead, and desire to remove a part, then heating the one lead that won't come loose is taking a chance, but not as likely to pull out the center plating on the hole.If you have a multi-layer board, then life gets more difficult. Multi layer boards have traces that go to the edge of the hole, and have 4 or more layers.? It is the plating between top and bottom layers (typically) that connects the outer layers to the inner layers.? Should you remove that "jumper" by pulling out a parts lead on a 4 layer (or more) board, then you've isolated that track in the middle of the board stack.The only way to fix that is to find where the middle layers were connected to, and then run a jumper.Some Tektronix boards are indeed multiple layers.? Some of those boards may have a weak epoxy holding the traces.? Some boards may connect to an inner flat layer (power or ground) which means that the hole has a big heat sink attached to it, and will need a lot more heat to get the joint hot, because your're trying to heat up a lot more metal, even if it's a big layer in the middle of a board.A further problem happens when the soldering iron is too cool, and can't heat up the joint.? You'll overheat the joint over time, because some things will get hot, and not quite enough.Too hot with the tools, and you let the epoxy (and board.....) deteriorate.All of this takes experience, good tools, some understanding, and a bit of care.Hope this explains removing parts from boards.Comments welcome.Harvey
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Re: A note on PC boards, double and single sided.
Nice PCB summary, Harvey!? I've seen what is probably FR-3 in consumer electronics but I've never worked with it.? FR-4 or RF/microwave laminates, yes.? FR-4 is as common as dirt.? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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Show quoted text
-------- Original message --------From: Harvey White <madyn@...> Date: 1/5/21 5:55 PM (GMT-08:00) To: [email protected] Subject: [TekScopes] A note on PC boards, double and single sided. Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4).? There are others, but these are most common.Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together.? You see it in a lot of commercial (expensive or not...) equipment.? It is mostly brown...Glass Epoxy (FR-4) has a higher temperature tolerance, is pretty stable, is more difficult to burn, and is constructed of a glass mat of fibers held together with epoxy.FR-3 is easy to drill, and the epoxy does not kill drill fast. FR-4 has glass fibers instead of paper, and eats drills.? Tungsten Carbide drills are the ones needed for this material if you want to drill many holes.? (yes, a normal carbon steel drill will end up looking like a pointed needle after enough holes.Tektronix used FR-4 or more exotic materials.? I haven't seen any FR-3 except perhaps in later, Chinese made products dating somewhat after 2000 or later.Early PC boards were single sided, that is , a layer of epoxy gluing copper foil to a board.? Early boards had a problem, the epoxy was not a good grade (less "good" than now) , and with an older, non temperature controlled iron (UNGAR, or 30 watt anybody), the foil could get overheated, the epoxy could fail, and the trace could lift off the board.More modern boards tend not to be as fragile, with better epoxy.The bottom line is that even with things that are single sided (more later), the foil is harder to "lift".? However, part of this ruggedness has to do with temperature controlled soldering equipment, which minimizes board overheating.? You can still do it, of course, since the average soldering iron tip is hotter than the epoxy can stand over a prolonged period.? However, soldering quickly doesn't harm the board.DESOLDERING, however, generally involves heating the board more, using perhaps a higher temperature, and runs more risk of separating the trace from the board.? The amount of heat depends on the iron tip, the temperature, the solder, and the amount of time it takes to remove solder.? More expensive desoldering equipment can harm the board less.... However, technique is also important.Enter two sided boards.? These have copper foil on both sides. If any part is an SMT (surface mount technology) or SMD (same thing, but surface mount device), which *many* modern devices are, and some are? limited to... Then you have the same as a normal single sided board and you need to be carefulIf, on the other hand, you have a through hole part, the the board is plated through as if there were a copper eyelet connecting the top and bottom traces.? While this has increased mechanical strength over a single surface pad, well... Not necessarily the answer of answers.Let's assume that you have a through hole part, and you heat the lead and remove the solder, but not all of it.? Now you decide to pull the part lead out with pliers.? If you've gotten enough solder out to free (partially) the bottom trace, and even a bit of the top, but NOT enough to completely clear the inside of the hole.....You can pull out the plating on the plated through hole much as if you pulled out the center part of an eyelet crimped on both sides.? If you are dealing with dual layer boars, the being able to rattle the part lead inside the hole indicated that it isn't still soldered in, and I can recommend NOT pulling the lead out regardless.If you have one lead, and desire to remove a part, then heating the one lead that won't come loose is taking a chance, but not as likely to pull out the center plating on the hole.If you have a multi-layer board, then life gets more difficult. Multi layer boards have traces that go to the edge of the hole, and have 4 or more layers.? It is the plating between top and bottom layers (typically) that connects the outer layers to the inner layers.? Should you remove that "jumper" by pulling out a parts lead on a 4 layer (or more) board, then you've isolated that track in the middle of the board stack.The only way to fix that is to find where the middle layers were connected to, and then run a jumper.Some Tektronix boards are indeed multiple layers.? Some of those boards may have a weak epoxy holding the traces.? Some boards may connect to an inner flat layer (power or ground) which means that the hole has a big heat sink attached to it, and will need a lot more heat to get the joint hot, because your're trying to heat up a lot more metal, even if it's a big layer in the middle of a board.A further problem happens when the soldering iron is too cool, and can't heat up the joint.? You'll overheat the joint over time, because some things will get hot, and not quite enough.Too hot with the tools, and you let the epoxy (and board.....) deteriorate.All of this takes experience, good tools, some understanding, and a bit of care.Hope this explains removing parts from boards.Comments welcome.Harvey
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I own a 561A and two 564Bs. They were mainstream in the mid 1960s. 10MHz bandwidth and a far sharper trace than you will ever see on a DSO. They all take the same series of two plugins, Vertical and Horizontal; (interchangeable if you like vertical traces or you could use two Vertical units for Lissajous figures and LF phase comparisons). The A version in both cases had a vacuum tube-based LV power supply, the B was all solid-state. Not such a big differentiation since the plug-ins were all hybrid tube/transistor units. There were lots of plug-ins, including sampling to about 500 MHz IIRC, SAs, single and dual differential amps, a wireable dual op amp unit, and up to 4 input channels. I have around 20 different plug-in types. The biggest deal about this family was the 564. It's a split-screen STORAGE scope storing waveforms electrostatically on the phosphor screen using secondary emission, with the upper and lower halves of the screen separately eraseable and settable to storage or non-storage mode. I believe this was the first widely adopted storage scope from any manufacturer. More than any other Tek units, this was the family that popularized plug-in scopes, so much so that HP started by disparaging them and ended by imitating them. One of my 564Bs is a Mod 121, which adds variable time delay auto-erase. The remark that the storage function is "finicky" is mostly only true if you try to calibrate it without following the manual. Once properly adjusted, mine have remained stable. Storage display contrast is a bit low, but very useable within the 10MHz bandwidth. They are also cheap to buy today. They're mostly reliable, with two well known problems: the CRT filament is supplied by a dedicated winding on the main power transformer but is elevated to -3300V by the HVPS. This has led to failures of the paper insulation on that winding. I fixed my 561A by adding a separate transformer with the secondary rewound (on a side-by-side nylon bobbin) with suitable insulation and leads long enough to reach directly into the HVPS box without splices or terminals. The leads were individually insulated with small tubing (there's only 6.3VAC between them, and double insulated with shrink tubing over that to withstand the 3300V. The other problem is the potting failure on the HVPS transformer. I think it may only affect the B series, but I have never had the problem. The 561/564 family could be thought of as the precursor to the 7000 series, and my main scope today is a 7854.
Cliff
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Re: A note on PC boards, double and single sided.
Harvey White wrote on 1/5/2021 8:55 PM: Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4).? There are others, but these are most common.
Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together.? You see it in a lot of commercial (expensive or not...) equipment.? It is mostly brown... Hello-- Older imported electronics used a phenolic-based laminate-- typically medium to dark brown and liable to losing its traces when the repairer applied too much heat. Oh, and when overheated it smelled like warm horse s*it. 73-- Brad? AA1IP
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Re: Intermittent power on problems with 2465B
I have never had to replace caps in any of the 2400 series that I have had come through here, including the 2465A that I now use. I have also rarely had to replace a cap in any of the hundreds of 500 series that have been on my bench. I believe that when manufacturers changed from wet electrolytics to dry the problems with caps largely ceased. Luckily I have never had a dry cap ¡°shoot up to the ceiling.¡± I have had a number of capacitor failures in 321 series, probably due to heat and the lack of fan cooling. I do have an old family radio though that I am afraid to turn on due to the possibility of rocketry. (grin)
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A note on PC boards, double and single sided.
Printed circuit boards are generally made with one of two materials (there are others), either a paper epoxy (FR-3) or a fiberglass epoxy (FR-4).? There are others, but these are most common.
Paper epoxy (FR-3) has a lower temperature tolerance, is not as mechanically stable, can be burnt easily, and is constructed of paper and epoxy holding it together.? You see it in a lot of commercial (expensive or not...) equipment.? It is mostly brown...
Glass Epoxy (FR-4) has a higher temperature tolerance, is pretty stable, is more difficult to burn, and is constructed of a glass mat of fibers held together with epoxy.
FR-3 is easy to drill, and the epoxy does not kill drill fast. FR-4 has glass fibers instead of paper, and eats drills.? Tungsten Carbide drills are the ones needed for this material if you want to drill many holes.? (yes, a normal carbon steel drill will end up looking like a pointed needle after enough holes.
Tektronix used FR-4 or more exotic materials.? I haven't seen any FR-3 except perhaps in later, Chinese made products dating somewhat after 2000 or later.
Early PC boards were single sided, that is , a layer of epoxy gluing copper foil to a board.? Early boards had a problem, the epoxy was not a good grade (less "good" than now) , and with an older, non temperature controlled iron (UNGAR, or 30 watt anybody), the foil could get overheated, the epoxy could fail, and the trace could lift off the board.
More modern boards tend not to be as fragile, with better epoxy.
The bottom line is that even with things that are single sided (more later), the foil is harder to "lift".? However, part of this ruggedness has to do with temperature controlled soldering equipment, which minimizes board overheating.? You can still do it, of course, since the average soldering iron tip is hotter than the epoxy can stand over a prolonged period.? However, soldering quickly doesn't harm the board.
DESOLDERING, however, generally involves heating the board more, using perhaps a higher temperature, and runs more risk of separating the trace from the board.? The amount of heat depends on the iron tip, the temperature, the solder, and the amount of time it takes to remove solder.? More expensive desoldering equipment can harm the board less.... However, technique is also important.
Enter two sided boards.? These have copper foil on both sides. If any part is an SMT (surface mount technology) or SMD (same thing, but surface mount device), which *many* modern devices are, and some are? limited to... Then you have the same as a normal single sided board and you need to be careful
If, on the other hand, you have a through hole part, the the board is plated through as if there were a copper eyelet connecting the top and bottom traces.? While this has increased mechanical strength over a single surface pad, well... Not necessarily the answer of answers.
Let's assume that you have a through hole part, and you heat the lead and remove the solder, but not all of it.? Now you decide to pull the part lead out with pliers.? If you've gotten enough solder out to free (partially) the bottom trace, and even a bit of the top, but NOT enough to completely clear the inside of the hole.....
You can pull out the plating on the plated through hole much as if you pulled out the center part of an eyelet crimped on both sides.? If you are dealing with dual layer boars, the being able to rattle the part lead inside the hole indicated that it isn't still soldered in, and I can recommend NOT pulling the lead out regardless.
If you have one lead, and desire to remove a part, then heating the one lead that won't come loose is taking a chance, but not as likely to pull out the center plating on the hole.
If you have a multi-layer board, then life gets more difficult. Multi layer boards have traces that go to the edge of the hole, and have 4 or more layers.? It is the plating between top and bottom layers (typically) that connects the outer layers to the inner layers.? Should you remove that "jumper" by pulling out a parts lead on a 4 layer (or more) board, then you've isolated that track in the middle of the board stack.
The only way to fix that is to find where the middle layers were connected to, and then run a jumper.
Some Tektronix boards are indeed multiple layers.? Some of those boards may have a weak epoxy holding the traces.? Some boards may connect to an inner flat layer (power or ground) which means that the hole has a big heat sink attached to it, and will need a lot more heat to get the joint hot, because your're trying to heat up a lot more metal, even if it's a big layer in the middle of a board.
A further problem happens when the soldering iron is too cool, and can't heat up the joint.? You'll overheat the joint over time, because some things will get hot, and not quite enough.
Too hot with the tools, and you let the epoxy (and board.....) deteriorate.
All of this takes experience, good tools, some understanding, and a bit of care.
Hope this explains removing parts from boards.
Comments welcome.
Harvey
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The book, "The Cathode-Ray Tube," Dennis shipped via Media Mail on 1/2/2021 arrived here in Southern California today, 1/5/2021.
Three days in transit is not bad...
And, it arrived safely, in good condition and autographed by Peter Keller.
Thank you, Dennis.
--
Best wishes,
Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)
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Re: Tek 4041 GPIB Controller
I posted details of the process I used to recover the files from these 40 year old 4041 tapes on this thread in vcfed.org
I also found a 4041 UTL2 ROM file on an MP2501 tape - the first software loadable ROM Pack I've found for the 4041. More details in the link above.
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Re: Intermittent power on problems with 2465B
I have always been opposed to 'recap' actions.? The cost, labor, and possibility of error are all too great.? As is often (but not always wisely) said, if it ain't broke don't fix it.
Electrolytic capacitors, particularly in power supply circuits, are a different story, but not that much.? I often will leave those alone if they are working well, and I have had very few problems.? And of course, just because a part is brand new doesn't mean it's also good.
If you enjoy soldering, go for it.
Bob
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On Tuesday, January 5, 2021, 05:10:43 PM PST, Roy Thistle <roy.thistle@...> wrote: On Tue, Jan? 5, 2021 at 01:57 PM, David Campbell wrote:
Ignore those advising anything but a total recap.
I don't fully understand why one is making such a general anecdotals claims... unless... 1) it is an "err on the side of caution" type admonition. 2) it is on the "recommendation" of some YouTube presenters. 3) it is meant as sarcasm. For 1) I'd think...? but won't claim.... that many of the individuals available to make sufficient use of 1) might cause more damage to PCBs than cure, when "replace all" replacing capacitors. For 2) Some YouTube presentors are making a similar claim ("to replace all capacitors.") Some of those YouTubers, however, are also selling "intruments" to "detect" capacitor failures... which raises my suspicions of a confict of interest. For 3) If so... then point taken... though, sarcasm taints the message... as there are many individuals ...highly trained, and highly experienced in Tektronix equipment... opining on this forum... who may have seen "similar" things... but would not posit such general claims.
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Re: Tek 4041 GPIB Controller
Gary,
I sent you a private message.
Monty
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I discovered before Christmas that I had 4041 EZ-TEST that I had gotten in 2000. I spent last week working to recover them and several other tapes. All the recovered files are posted on my 4041 github repository: .
Details of the recovery process are in this thread I just posted on vcfed.org:
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Re: Peter Keller's Book Mailing Status (Minor Correction)
For those doing this stuff in the future, thir IRISPEN
When? had windows, I used the IRISPen 6 for taking numbers off of tax statements.
With Fedex and UPS, I get notifications and can move delivery for a fee.? I've moved UPS to the UPS store and FEDex to a FEDex location.? I have done this primarily for high dollar signature required items.
The book,? Dennis is doing it on his own time.? The Forum members are getting a value Added education should any member decide to do a group buy.? Dennis.? Next time charge extra for tracking unless it's way past the estimated due date.
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On Tuesday, January 5, 2021, 8:03:35 PM EST, Greg Muir via groups.io <big_sky_explorer@...> wrote:
In this present world of ¡°instant gratification¡± utilizing electronic means to send messages and documents I do realize that it is somewhat difficult for some people to understand the sloggingly slow process of the US Postal Service.? I wanted to make a few comments regarding this.
1.? Media mail is expected to be slower than normal mail approaches.
2.? The US Postal Service has been crippled by the pandemic, funding, volume and politics.
3.? I have recently experienced packages sent via Priority Mail to take over a week to be delivered.
4.? Delivery times will vary depending upon the delivery areas and route conditions.
5.? I am a patient person.
6.? I have plenty of things to read until my book arrives.
7.? If I die before it does, I have others who may be interested in receiving it to read.
¡°Nuff said.
Greg
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Re: Intermittent power on problems with 2465B
On Tue, Jan 5, 2021 at 01:57 PM, David Campbell wrote:
Ignore those advising anything but a total recap.
I don't fully understand why one is making such a general anecdotals claims... unless... 1) it is an "err on the side of caution" type admonition. 2) it is on the "recommendation" of some YouTube presenters. 3) it is meant as sarcasm. For 1) I'd think... but won't claim.... that many of the individuals available to make sufficient use of 1) might cause more damage to PCBs than cure, when "replace all" replacing capacitors. For 2) Some YouTube presentors are making a similar claim ("to replace all capacitors.") Some of those YouTubers, however, are also selling "intruments" to "detect" capacitor failures... which raises my suspicions of a confict of interest. For 3) If so... then point taken... though, sarcasm taints the message... as there are many individuals ...highly trained, and highly experienced in Tektronix equipment... opining on this forum... who may have seen "similar" things... but would not posit such general claims.
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Raymond Domp Frank
Jean-Paul
John Williams