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Hi All,
I've gotten my 5L4N tuned well enough to make use of it. Learned a heck of a lot in the process! It's still a bit sketchy. Getting frequency linearity was _just_ barely achievable, but I think it's within spec and will do fine for my skill level so far.
Now I _really_ want a logarithmic overlay/shield for the screen. I'm thinking it would help tuning the log sweep amplifier as well. The "Tektronix Cookbook of Standard Audio Tests" has some nice charts that "Tektronix, Inc. Encourages" us to copy or print for our own use. This includes 20k and 100k log scale charts. I was thinking of using them as a template or printing them on some projection foil sheets. But they would take some careful scaling to be the right size for a 5111A screen.
Does anyone have a line on these overlays? I'm not finding them as an accessory in the 5L4N manual, including the interim manual. So I don't know what part number to search for. Are there other overlays that might be useful as well?
Thanks,
Dave
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I knew I'd seen one before, but somewhere a bit off:
It's on the scope in the main picture for the 5440, , but without a 5L4N.
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Dave,
Are the overlays replacement plastic windows for the CRT bezel, or are they something that goes on top of the plastic window?
How precise do the overlays need to be? I assume that the X-Y translation of the overlay is not important, since you can easily shift the trace on the CRT horizontally and vertically, but how precise does the spacing between the vertical marks need to be?
I thought that I saw something like these on Sphere's stuff page last year, but those may have been for a 500-series scope, or maybe something completely different, and I certainly have not seen them listed recently.
-- Jeff Dutky
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Sphere has their "Hoods, Filters, & Bezels" page, , but doesn't include the 5000 series audio log scale screens. Given what I've seen they are actual implosion screens, not overlay transparencies.
Walter, despite not having any available (didn't expect you would), do you know the part number?
I've seen one on a scope on eBay before, and was quite tempted to attempt to buy it just for the screen. I think it might have been the last 5L4N equipped scope that was up for auction and was snipped by an auto-bidder. So wouldn't have gotten it anyway. And I think it'll be vastly more economical to make my own than deal with purchase of such a rarity.
My grand plan is to print a properly sized overlay on clear transparency that I can layer on a clear implosion shield. This place is full of old guys like myself? We all remember the days when we printed presentation materials on clear 8 1/2" x 11" transparencies, right? Foils, we used to call them. Heck, we were still using those when I started at Intel in '91. I think I've seen boxes of them stuffed in drawers in the printer rooms at work. I think all the printer rooms were cleaned out during COVID shut-down. But next time I'm in the office I'm going to rifle the drawers for them.
My hope is someone out there has a PDF with an overlay ready to go, or knows where Tek might have such a thing already. The only thing I've found is the example at the end of the audio cookbook. I did a test print of that last night. It would take a fair bit of fussing to get scaled properly. I might be better off building my own in PowerPoint or Word.
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Dave,
That (making an overlay) was exactly the bush that I was beating around (or building up to?). It looks like you can buy clear vinyl sheet that can be printed on with a laser or ink jet printer, so you could have an overlay that would adhere to the implosion shield like a Colorforms sticker (search for Vinyl Sticker Paper on Amazon).
I'd try drawing up your own. I'm not sure that Word or PowerPoint are suitable; maybe Visio would be a better tool? Better still would be an actual drafting program. I don't know what there is for Windows, but on the Mac there is an old and reliable program called MacDraft by a company called Microspot. They have a free 14-day trial version that should be more than adequate.
I would expect that even without a good image you can calculate where the vertical lines are supposed to go based on measurement of the existing CRT graticule. The vertical lines clearly don't line up with the graticule lines, but each line is clearly labeled, and the left and right edges might be aligned to the left and right edges of the graticule.
-- Jeff Dutky
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Ah, the old plastic transparencies!? The late, great Bob Pease of National Semiconductor used to refer to them as "analog PowerPoint".Jim Ford?Sent from my T-Mobile 4G LTE Device
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-------- Original message --------From: "Dave Peterson via groups.io" <davidpinsf@...> Date: 3/3/22 7:58 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Wanted: Log (and other?) overlays for 5L4N use. Sphere has their "Hoods, Filters, & Bezels" page, , but doesn't include the 5000 series audio log scale screens. Given what I've seen they are actual implosion screens, not overlay transparencies.Walter, despite not having any available (didn't expect you would), do you know the part number?I've seen one on a scope on eBay before, and was quite tempted to attempt to buy it just for the screen. I think it might have been the last 5L4N equipped scope that was up for auction and was snipped by an auto-bidder. So wouldn't have gotten it anyway. And I think it'll be vastly more economical to make my own than deal with purchase of such a rarity.My grand plan is to print a properly sized overlay on clear transparency that I can layer on a clear implosion shield. This place is full of old guys like myself? We all remember the days when we printed presentation materials on clear 8 1/2" x 11" transparencies, right? Foils, we used to call them. Heck, we were still using those when I started at Intel in '91. I think I've seen boxes of them stuffed in drawers in the printer rooms at work. I think all the printer rooms were cleaned out during COVID shut-down. But next time I'm in the office I'm going to rifle the drawers for them.My hope is someone out there has a PDF with an overlay ready to go, or knows where Tek might have such a thing already. The only thing I've found is the example at the end of the audio cookbook. I did a test print of that last night. It would take a fair bit of fussing to get scaled properly. I might be better off building my own in PowerPoint or Word.
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On Thu, Mar 3, 2022 at 12:41 PM, Jim Ford wrote:
Ah, the old plastic transparencies!? The late, great Bob Pease of National
Semiconductor used to refer to them as "analog PowerPoint".
He used that phrase on the Bob Pease show (of which far too few episodes exist, at least on YouTube), but I thought he was referring to acetate sheets, not vinyl sheets. -- Jeff Dutky
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Well, I'm no polymer expert; what is the difference?? ?ISTR that acetate fabric was considered inferior to polyester; 3 decades ago we had to spend extra for polyester for my wife's wedding dress after seeing acetate turning brownish, even in the fabric stores.JimSent from my T-Mobile 4G LTE Device
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-------- Original message --------From: Jeff Dutky <jeff.dutky@...> Date: 3/3/22 11:24 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Wanted: Log (and other?) overlays for 5L4N use. On Thu, Mar? 3, 2022 at 12:41 PM, Jim Ford wrote:>> Ah, the old plastic transparencies!? The late, great Bob Pease of National> Semiconductor used to refer to them as "analog PowerPoint".He used that phrase on the Bob Pease show (of which far too few episodes exist, at least on YouTube), but I thought he was referring to acetate sheets, not vinyl sheets.-- Jeff Dutky
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I thought vinyl too, but then realized getting a good flat application could be challenging. CRT shields are hardly ever without blemish nor exhibit ideal finish, and just an old fashion transparency was what my brain had in mind. How my mind often works: I have some sense of a solution in my subconscious, and it takes some zen to allow it to come forward. It came to me that what I wanted to do was print an image to one of those old transparency sheets. Something I've done a lot of. I wouldn't be surprised if I have some old design review foils filed away somewhere.
Somewhere in the back of my mind I seem to sense I read in a Tek document that a template of the log overlay was available for printing. But that could just be wishful thinking transposing itself to a memory circuit. The only thing I've found is the cookbook, and those aren't at all scaled to fit a 5000 screen. I've scrolled the 5L4N interim and Artek manual I bought (thanks Dave) for a template to no avail.
I'll probably build my own. The image from the 5440 page provides a good example, and web research on how to create a log plot basically boils down to putting log10(n) in a calculator and measuring. We're not splitting atoms here. It will hardly be the first time I do my own graphics. Thanks for the Mac pointer, by the way. I'll have to look that up.
Like the DIY 5000 plug-in extenders I built out of JAMMA harnesses, good enough to do the job, but ultimately I'd prefer the real deal from Tek. Ain't nothing like the real thing ...
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Jim,
The vinyl sheets will be much "softer" and more flexible than acetate sheets, and the vinyl sheets may self-adhere to the surface of the implosion shield. I mentioned Colorforms because that's how those toys work, except that the the Colorforms "stickers" adhere to another vinyl sheet, rather than a sheet of some other plastic (I expect that the implosion shields are made of polycarbonate, but I don't actually know that for sure).
I'm not sure what plastic is used for cellphone screen protectors, or if it's actually even plastic (the better screen protectors are a thin sheet of tempered glass) but I think that there's a separate adhesive layer involved.
Dave,
You could probably craft a complete replacement implosion shield from an appropriately thick sheet of polycarbonate, and draw or print the log lines on that. I haven't paid close attention to the implosion shields on the 5k or 7k scopes: are they similar to the shields on the 400-series portable scopes? That is, do they have special cut outs to fit into the bezel, or are they just a blank square of plastic sheet?
In any case it would probably be better to have the overlay on the back side of the implosion shield, so that it's closer to the plane of the CRT image.
-- Jeff Dutky
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Thanks, Jeff!? You learn something new every day, if you're lucky.? :)JimSent from my T-Mobile 4G LTE Device
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-------- Original message --------From: Jeff Dutky <jeff.dutky@...> Date: 3/3/22 4:13 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Wanted: Log (and other?) overlays for 5L4N use. Jim,The vinyl sheets will be much "softer" and more flexible than acetate sheets, and the vinyl sheets may self-adhere to the surface of the implosion shield. I mentioned Colorforms because that's how those toys work, except that the the Colorforms "stickers" adhere to another vinyl sheet, rather than a sheet of some other plastic (I expect that the implosion shields are made of polycarbonate, but I don't actually know that for sure).I'm not sure what plastic is used for cellphone screen protectors, or if it's actually even plastic (the better screen protectors are a thin sheet of tempered glass) but I think that there's a separate adhesive layer involved.Dave,You could probably craft a complete replacement implosion shield from an appropriately thick sheet of polycarbonate, and draw or print the log lines on that. I haven't paid close attention to the implosion shields on the 5k or 7k scopes: are they similar to the shields on the 400-series portable scopes? That is, do they have special cut outs to fit into the bezel, or are they just a blank square of plastic sheet?In any case it would probably be better to have the overlay on the back side of the implosion shield, so that it's closer to the plane of the CRT image.-- Jeff Dutky
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Turns out MacBook's default "Pages" document tool was sufficiently capable to construct a good facsimile of the overlay as pictured on the TekWiki 5440 page. Nice that the layout measurements translated accurately to printed dimensions.
Just need to decide on printable transparency sheets. I like the colored light filter sheets. Could have some fun there.
I'll post some pics for fun.
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Dave,
yeah, I saw the color transparencies, but it didn't occur to me to use them as a scope filter. I might need something like that when I replace the 485's CRT with the blue phosphor one I bought.
I look forward to your pics.
-- Jeff Dutky
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Dave Peterson