DM 501A Mode Select Switches Issue
Greetings all¡
I¡¯m having an issue with the bank of mode select switches on my DM 501A. Only the resistance mode switch will latch, unless I keep some light pressure on the resistance mode switch will pressing any of the other mode switches. If I do that I can get any and all to latch, but if I don¡¯t keep that pressure on the resistance mode switch while pressing other switches they won¡¯t latch.
I captured a short video to YouTube to demonstrate this but apparently I cannot include a link here?
Cory Oace
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
On Thu, Jul 22, 2021 at 05:00 PM, Ronan wrote:
I am relatively new in these forums just
trying to get my 2712 fixed.
Hi Ronan: Yes... and there are a good number of very knowledgeable contributors, to TekScopes... who are quite generous with their knowledge and time. Mostly it's all about Tektronix scopes... but, anything Tektronix really. Your're in the right group. -- Roy Thistle
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Re: AA 501A Parts, DM 501A Probes
So, a *sort* of related question, can anybody recommend a ¡°can¡¯t go wrong¡± set of female BNC to female BBC patch cables as well as banana to banana patch cables?
Cory Oace
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Re: Advice on fixing 2465B slow horiz sweep
On Thu, Jul 22, 2021 at 6:02 PM Grayson Evans <wa4gvm@...> wrote: My 2465B has been sitting on the shelf for a few months. I notice when I
fired it up today that the horizontal sweep is slow, by that I mean that
the
calibrator square wave does not line up with the screen scale lines. It
sweep starts out on the left correct but by the time it reaches the right
side, it is off about 1/2 cm.
I checked the calibrator output on another scope and it is correct. The
Delta T measurement shows that the calibrator timing is correct, but it
just doesn't line up with the screen scale. Same for B sweep.
If you're seeing this only for the sweep speed, but consistently for *all sweep speeds* *and for the cursors*, then possibly your horizontal gain has drifted. What's more likely happening is that your scope is suffering from the 2465B capacitor plaque, where the electrolytics on the A5 board leak and wreck the DACs reference (among other things). This would affect the sweep speed, but also a whole lot of other functionality on the scope. If you haven't already changed the electrolytics on the A5 board, it'd be my bet that that's your problem.
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Re: Advice on fixing 2465B slow horiz sweep
Sure, first think I checked.
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
You're right, the dissipation factor means the power loss in the
capacitor. The more power loss, the worse.
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On Fri, Jul 23, 2021 at 10:45 AM Martin <musaeum@...> wrote:
Hi all,
I have an HP 4261A LCR-meter... apart from capacity, it displays dissipation factor. This can be converted to ESR by taking into account capacity and frequency.
I just built a conversion table... but when looking at it I wonder if the D-factor wouldn't be the better choice to judge a capacitor. For one, the D-factor is independent of the capacity, i.e. a D-factor of 0,1 has the same "quality meaning" for a 1uF as for a 10000uF capacitor. Second, the ESR, even when computed to the n-th decimal, does not seem to be a well defined value. What I mean is that you do not have a defined value as for the capacity, there is no information about what the ESR has to be.
Is this because folks better understand the concept of series resistance, or because its easier to measure, that you see so many ESR-meters by now?
Or am I wrong?
cheers
Martin
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
Hi all,
I have an HP 4261A LCR-meter... apart from capacity, it displays dissipation factor. This can be converted to ESR by taking into account capacity and frequency.
I just built a conversion table... but when looking at it I wonder if the D-factor wouldn't be the better choice to judge a capacitor. For one, the D-factor is independent of the capacity, i.e. a D-factor of 0,1 has the same "quality meaning" for a 1uF as for a 10000uF capacitor. Second, the ESR, even when computed to the n-th decimal, does not seem to be a well defined value. What I mean is that you do not have a defined value as for the capacity, there is no information about what the ESR has to be.
Is this because folks better understand the concept of series resistance, or because its easier to measure, that you see so many ESR-meters by now?
Or am I wrong?
cheers
Martin
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
Hey Carsten, does the Mastech MS8911 measure ESR? I can't find that
function mentioned on their website.
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On Thu, Jul 22, 2021 at 3:51 PM Carsten Bormann <cabocabo@...> wrote:
On 2021-07-22, at 14:28, Richard Peterson <saaber1@...> wrote:
I use an IET DE-5000 LCR meter.
Recommend.
Another good, but even cheaper addition: Mastech MS8911.
(Don¡¯t fall for the MS8910, which is not very useful.)
The MS8911 has a 0.1 V mode which can be used to avoid switching on semiconductor junctions.
It also uses up very little space in the instrument drawer :-)
Gr¨¹?e, Carsten
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Re: Tektronix RAMS (Surplus) Store - Odd hours?
At the risk of making it any busier in there, it may be one of my favorite places in the whole world. Despite being a complete greenhorn when it comes to most of the equipment, sneaking out of my engineering job once or twice a month to browse and try to figure out "what the heck is this for" was one of the things that helped me survive my often stressful day job. I even brought my first son pretty shortly after he was born, and once he was old enough to want to push a button, it was like carrying him into a candy store. (We behaved ourselves, though!)
I like to tell people that the selection is quite random and variable - it's almost a time capsule from a 90's-2000's office. Old computer software and hardware, office furniture and equipment, as well as all of the expected test equipment, etc...a box of unprocessed 4" silicon wafers, novelty corporate giveaways, microscopes, luggage, you name it, it might be there one day, but maybe not the next. Prices, though, are basically unbeatable...if it's there, it is almost always the cheapest way to get it, from what I've seen. The old fol--ahem--regulars line up hours (I assume) ahead of time so they can make a bee line to the highest value differential amplifiers or whatever those are and shovel them into a basket to flip on ebay.
Not me, I'm in it to learn, and to slowly (slowly!) fill my own house up with stuff I might possibly need one day. :) I've struck gold a few times - a full size ESD workbench for $35, a roll-up steel cabinet for about the same, this fake-wood-veneer Panasonic automatic pencil sharpener on my desk (they don't make 'em like they used to, brother!) are the things that come to mind first, but yeah, I probably don't want to see the full inventory.
Anyway, I love this store, but nobody else need beat me to the line ;)
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Re: Advice on fixing 2465B slow horiz sweep
On Thu, Jul 22, 2021 at 03:02 PM, Grayson Evans wrote:
My 2465B has been sitting on the shelf for a few months. I notice when I
fired it up today that the horizontal sweep is slow, by that I mean that the
calibrator square wave does not line up with the screen scale lines. It sweep
starts out on the left correct but by the time it reaches the right side, it
is off about 1/2 cm.
....
--- To rule out the simplest case, is "VAR" knob of sec/div switch in the calibrated position? Ozan
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
Roy,
Just checked and it works perfectly. And so this will be my first and last ESR post on TekScopes.
Thanks for the help!
George KD6NEW
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On Jul 22, 2021, at 4:48 PM, Roy Thistle <roy.thistle@...> wrote:
Hi Glydek:
Apologies ... must have missed the notification. (Your in now.)
PM if problems.
Great! Look'n forward to your PCB!
--
Roy Thistle
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Re: Replace/Repair TM 500 Module Side Panel Latch
On Thu, Jul 22, 2021 at 08:10 PM, n4buq wrote:
I wondered if the finish might be superior to what some of the local shops
might be providing. For the price difference, it's probably in my best
interest to go with Shapeways.
Thanks,
Barry - N4BUQ
Easy enough to ask them if they are using an FDM ( fused deposition modeling) printer, an SLA (Stereolithography) Printer or an SLS (Selective Laser Sintering) printer. If they are using SLA or SLS, then your results should be just as good as SHAPEWAYS. SLA makes nice, accurate, high quality prints, but the selection of materials is limited and may not be as strong as the other methods. FDA printers can print in NYLON or ABS, both of which should be strong enough and durable enough for the task. Good luck. I'm following your progress and looking forward to seeing the results. -- Michael Lynch Dardanelle, AR
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Re: Replace/Repair TM 500 Module Side Panel Latch
I wondered if the finish might be superior to what some of the local shops might be providing. For the price difference, it's probably in my best interest to go with Shapeways.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Michael W. Lynch via groups.io" <mlynch003@...>
To: [email protected]
Sent: Thursday, July 22, 2021 6:29:43 PM
Subject: Re: [TekScopes] Replace/Repair TM 500 Module Side Panel Latch
On Thu, Jul 22, 2021 at 03:08 PM, Siggi wrote:
Note that Shapeways uses an SLS process which produces parts with great
strength and very good dimensional accuracy. This may or may not matter for
your part(s) but the quality and strength and flexibility of the parts I've
had them print is much better than what consumer FDM printers produce.
The SLS system produces better prints by far, SLS delivers near molded
quality parts.
--
Michael Lynch
Dardanelle, AR
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Found a new 010-0262-00 Tek 211 probe, can be yours if you need it.-
This is that odd L-shaped scope probe that is hard-wired into the little low frequency 211 mini-scopes. Hakan confirmed it fits the 211 for sure below B080000, and it may also work in the 212 and 214, although the suffix there is -01 or -02. Anyway, no use to me, it's new and with a peltola jumper cable (no idea why). Contact me off list and I can send it to you. Postage is maybe US$8 in north america. Hopefully it will bring some unit back to life.
Fires burning like crazy up here, so far we are still OK in Kelowna, hoping we don't lose power.
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
still lots of great stuff on this page.
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
Sorry Roy, my topic is not spam. I am relatively new in these forums just
trying to get my 2712 fixed.
Have a good one
Ronan
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Re: in-circuit capacitor testing (ESR tester) -- ideas appreciated.
Hi Glydek:
Apologies ... must have missed the notification. (Your in now.)
PM if problems.
Great! Look'n forward to your PCB!
--
Roy Thistle
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Re: Replace/Repair TM 500 Module Side Panel Latch
On Thu, Jul 22, 2021 at 03:08 PM, Siggi wrote:
Note that Shapeways uses an SLS process which produces parts with great
strength and very good dimensional accuracy. This may or may not matter for
your part(s) but the quality and strength and flexibility of the parts I've
had them print is much better than what consumer FDM printers produce.
The SLS system produces better prints by far, SLS delivers near molded quality parts. -- Michael Lynch Dardanelle, AR
|
Re: Looking for data on 9-pin Vacuum time delay relays used in old Tek-scopes
Those Surplus Sales prices are not practical for hobbyists, especially down here in Australia. I will post the schematic of my hack later today. It has the advantage of not requiring any alteration to the scope and if you have a reasonably stocked junk box, should cost nothing.
Morris
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Advice on fixing 2465B slow horiz sweep
My 2465B has been sitting on the shelf for a few months. I notice when I fired it up today that the horizontal sweep is slow, by that I mean that the
calibrator square wave does not line up with the screen scale lines. It sweep starts out on the left correct but by the time it reaches the right side, it is off about 1/2 cm.
I checked the calibrator output on another scope and it is correct. The Delta T measurement shows that the calibrator timing is correct, but it just doesn't line up with the screen scale. Same for B sweep.
Could this be a screwdriver/pot adjustment (too good to be true Im sure), or some software calibration? I have maint manual which seems to reference R860 for horizontal gain, but discusses a CAL 01 procedure in detail, more detail than I can follow.
Any one else have this problem?
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Re: Replace/Repair TM 500 Module Side Panel Latch
On Thu, Jul 22, 2021 at 2:53 PM n4buq <n4buq@...> wrote: Cost for plastic, including shipping and fees, was $0.70 more than what I
was quoted by the local printing shop that I'd checked.
Note that Shapeways uses an SLS process which produces parts with great strength and very good dimensional accuracy. This may or may not matter for your part(s) but the quality and strength and flexibility of the parts I've had them print is much better than what consumer FDM printers produce.
|
Martin
Glydeck
Michael W. Lynch