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Re: 212, 213, was Re: [TekScopes] New kid on the block...
On Thursday 10 February 2022 12:48:39 pm Michael A. Terrell wrote:
Try this link to the military version of the 212 manual on my Google Drive.Got it, thanks. I don't know why I had such a hard time with that other instance of the google drive file... Sometimes it works for me, and sometimes it doesn't. Either of you guys have any thoughts about where I might score some batteries for these scopes? -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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Re: Super Clean 570 Curve Tracer on Craigslist
Thanks, Roy. And TekWiki¡¯s picture of a T52 (aka T0520) shows a spiral. So it has PDA even at the low acceleration of 4kV.
Dave Wise From: [email protected] <[email protected]> On Behalf Of Roy Thistle via groups.io Sent: Friday, February 11, 2022 11:06 AM To: [email protected] Subject: Re: [TekScopes] Super Clean 570 Curve Tracer on Craigslist On Fri, Feb 11, 2022 at 08:12 AM, Dave Wise wrote: The T51 CRT, used in the 535 (circa 1954) was the first Tek CRT with the post acceleration helix. 570 uses T52 CRT, which AFAIK has the post acceleration helix. -- Roy Thistle |
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Re: 212, 213, was Re: [TekScopes] New kid on the block...
On Thursday 10 February 2022 12:41:40 pm Jared Cabot via groups.io wrote:
That guy linked on tekwiki is me. :):-) I've uploaded the battery replacement document to tekwiki, so take a look.Got it, thanks. I have some spare bare PCB's as in my video if you want to build the rectifier upgrade in that document too. (I can probably scratch up all the parts needed too, if you want to buy it as a kit).I might be interested. How necessary is that mod? And what sort of cost are we talking about? Also, the 212 user manual on that Tekwiki page was one I recreated and re-typeset as close to the original as I could. It's much better than a scanned version, as I went to the trouble of redrawing the diagrams as vectors so it will print out as a booklet in high quality as per the original. (Print it duplex, 2-up (so 2 pdf pages per side of paper, I think that will work for a booklet)I snagged that already... Dunno if I'm going to want to print it out or not, we'll see. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin |
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Re: Super Clean 570 Curve Tracer on Craigslist
On Fri, Feb 11, 2022 at 08:12 AM, Dave Wise wrote:
The T51 CRT, used in the 535 (circa 1954) was the first Tek CRT with the post acceleration helix. 570 uses T52 CRT, which AFAIK has the post acceleration helix. -- Roy Thistle |
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Re: Super Clean 570 Curve Tracer on Craigslist
On Fri, Feb 11, 2022 at 07:19 AM, bobkrassa wrote:
It's one of the first ones (low serial number) that has the darker (brownish-blue?) Tek blue. -- Roy Thistle |
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Re: Dennis Tillman
Not good. I pray he is okay. Have accrued so much information and help from him over my time on Tekscopes.
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On 2/11/22 13:30, Vince Vielhaber wrote:
I emailed him recently but never got a response. |
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Re: Dennis Tillman
I emailed him recently but never got a response.
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Vince - K8ZW. On 02/11/2022 11:58 AM, Dave Daniel wrote:
Has anyone heard from Dennis Tillman recently or have any recent news --
Michigan VHF Corporation -- nobucks dot net K8ZW - |
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Re: 7B50 - Schematic Question
I've done a bit more checking (sorry if this is a bit long).
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For starters, I checked the waveforms at TP101 and TP111. The manual shows TP101's waveform going from the centerline to the second positive division and TP111's waveform going from the centerline to the second negative division. Both images show 5mV/DIV and, according to the VOLTAGE AND WAVEFORM TEST CONDITIONS page, the "vertical deflection factor shown on the waveforms does not include attenuation factor of the 10X probe." Given that, I presume that two vertical divisions represents 100mV on those images. Using a separate scope (465B), with the 40mV output from the calibrator connected through a 50-ohm terminator to a 7A26 with its attenuation set to 5mV, TP101's waveform is 100mV P-P but is offset +50mV from what's shown. TP111's waveform is also 100mV P-P but is offset +30mV from what's shown. I presume this means that either the 7A26 isn't adjusted for vertical output properly or the 7704A is handing the 7B50 the wrong triggering signals. BTW, I made sure to adjust the Brightline of the 7A26's output with it switched to GND before checking those waveforms. I also found that -15V SWITCHED is not connected directly to the -15V supply point but is run through R819 making it the "-15V DCPL #3" rail so that accounts for that value being a bit low. BTW, R819 is shown on the schematic as being 100 ohms but is listed in the parts list properly as 10 ohms which agrees with what's on my board. +15v is also going through a 4.7-ohm (R393) making that actually "+15 DCPL #1" (not to be confused with the other "+15V DCPL #1" on schematic <6>) but that's dropping about 500mV or more which seems excessive and I'm suspecting C393 may be leaking. I haven't remeasured those Vbe and diode delta values but will do that and report back but, in the meantime, do you think the waveforms for TP101 and TP111 are significant enough to track down first? Thanks, Barry - N4BUQ ----- Original Message -----
From: "Ozan" <ozan_g@...> On Wed, Feb 9, 2022 at 06:26 PM, n4buq wrote:The LVPS voltages are well within specification. There are 4.7-ohm resistorsI saw your other message too. They didn't label decoupled -15V differently so it |
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Re: Dennis Tillman
I am also worried about Dennis, He asked me to E-mail him to discuss a few
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things and I have sent some messages but never received a reply. So Dennis if you are out there I would still like to get in touch. Eric -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of ChuckA Sent: Friday, February 11, 2022 12:17 PM To: [email protected] Subject: Re: [TekScopes] Dennis Tillman My last email to him was in Sept last year asking if he received the 7CT1N service manual I sent him, never got a reply. Chuck On 2/11/2022 11:58 AM, Dave Daniel wrote: Has anyone heard from Dennis Tillman recently or have any recent news-- See Early TV at: www.myvintagetv.com |
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Re: Dennis Tillman
My last email to him was in Sept last year asking if he received the 7CT1N service manual I sent him, never got a reply.
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Chuck On 2/11/2022 11:58 AM, Dave Daniel wrote:
Has anyone heard from Dennis Tillman recently or have any recent news about him? I have not seen a post from him in a very long time. --
See Early TV at: www.myvintagetv.com |
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Dennis Tillman
Has anyone heard from Dennis Tillman recently or have any recent news about him? I have not seen a post from him in a very long time.
DaveD -- This email has been checked for viruses by Avast antivirus software. |
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TDS3PRT Printer
A kind staff member at Tektronix Technical Services finally located and provided heretofore difficult to find instructions for the TDS3PRTprinter. This document is now posted on Tekwiki at .
This convenient small thermal printer plugs into the rear compartment of TDS 3000 and TDS3000B series scopes, but has been discontinued Although the intended paper rolls are NLA, Sony paper designed for medical printers can be used as a substitute. Sony type UPP-110S is a matt-finish paper while UPP-110HG is the high-gloss version. These print fine, but as the rolls are too large in diameter for the TDS3PRT, the paper must first be rewound to 1.2-inch diameter rolls. Also, since the medical paper seems to have a plasticised backing, it must be cut with knife or scissors as the printer's plastic cutting edge stretches, rather than cuts it. Bruce, KG6OJI |
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Re: Super Clean 570 Curve Tracer on Craigslist
Serial number 100!
A minor note but I wonder if that¡¯s the right spare CRT. Surely a curve tracer doesn¡¯t need post-deflection acceleration. Or did all Tek CRT¡¯s have the spiral accelerator track? Dave Wise From: [email protected] <[email protected]> On Behalf Of n4buq via groups.io Sent: Friday, February 11, 2022 5:49 AM To: tekscopes <[email protected]> Subject: Re: [TekScopes] Super Clean 570 Curve Tracer on Craigslist That thing looks like it rolled off Tek's assembly line just yesterday. Very nice! Thanks, Barry - N4BUQ ----- Original Message ----- From: drawding@...<mailto:drawding@...> Hello, |
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Re: 7904 problems
walter shawlee
Odd and seemingly "impossible" trace distortion (especially when power and signals internally are good) usually has one of two causes:
1. Internal CRT damage caused by physical shock (glass supports broken or parts of the gun/deflection system bent due to inertia). Sometimes visual inspection can reveal this, but not always. The actual damage can be quite small to the eye. 2. Something is magnetized, which can be internal to the CRT, or external in the chassis area. If it is possible to lift the CRT from the chassis and still be powered, it can help to localize the source. if the effect goes away or dramatically changes when the tube is lifted, the problem is an external field in the chassis. Some earlier Tek CRTs had gun alignment MAGNETS glued to the glass around the gun area, it is possible the magnet may have fallen off, and is now in the chassis area, a double magnetic problem. If the issue is mechanical damage, only CRT replacement can fix it. If the issue is magnetic interference, many remedies are possible. Long ago I built up a very large de-gaussing coil that could pass over an instrument or tube, it was powered from a beefy 24VAC transformer and could demagnetize most objects. This is a very handy tool (a left over from the color TV era), and can resolve many odd issues that seem to be "impossible". They were automatically powered on the clean the color CRT mask every time the unit was switched on. How do things GET magnetized in a scope? easy, something with a DC magnetic field was too close, a speaker, circulator, battery operated drill, magnetic tool, electromagnet or other item, and stayed there too long. An alternating field randomizes this effect, and helps to eliminate the temporary polarized field in ferromagnetic materials like hardware and tube elements. If the damage is too strong, the coil cannot fully eliminate it, and part removal or a much more powerful field can be the only recourse. The smaller the coil diameter, the more powerful the field flux will be, so one that just passes the CRT diameter can be more effective at clearing a bad tube than one that passes over the whole instrument.. Don't forget that the CRT itself is VERY easily influenced by external magnetic fields of all kinds when it is operating (that's why the SHIELD is there), and the shield can be damaged by physical shock, machining and heat so that is loses its properties. It is a lot more fragile than it looks. all the best, walter (walter2 -at- sphere.bc.ca) sphere research corp. |
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Re: 7904 problems
I have seem some TEK CRTs that used small magnets taped to the CRT used to fine tune the CRT. I bought a 475 that had these magnets on the CRT and they were obviously original to the CRT. The tape that secured them had become brittle over the years so I had to add some new tape to keep the magnets in their original position. Could it be possible that the problem is related to such magnets? Perhaps they are present and have shifted out of place? Or perhaps they might have attracted a piece of foreign mater that is distorting the beam?
-- Michael Lynch Dardanelle, AR |
ebrucehunter
Michael W. Lynch
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