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Re: Peak Detector to Validate Tek Const. Ampl. Signal Gen. (067-0532-00)
Jared,
Yes, it had occurred to me that adding a couple hundred mV to the battery voltage would require changes to the surrounding resistors to get back to a target voltage that correctly offsets the Vf of the rectifier diodes. I had not done the calculation, however, to know what the new resistor values should be. Interestingly there is a later version of this same fixture that replaces the mercury cells with alkaline manganese oxide batteries (probably because the mercury cells were no longer available). I was going to consult the service manual for that later fixture to get an idea of what they did to account for the higher voltage of the alkaline cells. I see that I can buy manganese oxide cells from Murata and they look like similar form factor to the cells I see in my unit, only thinner. I¡¯m thinking about how to make a parallel multi-cell pack that will fit in the current space. The mercury cells seem to be less prone to leakage than some modern alkaline cells. I¡¯m also interested in what I can do to prevent leakage from the replacement cells inside the enclosure. ¡ª Jeff Dutky |
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Re: Peak Detector to Validate Tek Const. Ampl. Signal Gen. (067-0532-00)
If you swap to Alkaline cells, swap R10 and R11 to 200K resistors to bring the adjustment of the trimpots back into a useable range due to the higher cell voltage over the original ones.
Also, to those who emailed me, I'll reply this weekend, the last few weeks have been insane at work etc... |
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Re: Peak Detector to Validate Tek Const. Ampl. Signal Gen. (067-0532-00)
I lucked into a 067-0652-00 Peak to Peak Detector on eBay for much less than the going rate. When it arrived I immediately opened it up and checked the batteries. They read only about 1.25 V, while the service manual indicates that they are supposed to be 1.35 V mercury cells. I expect that the drop in voltage indicates that the batteries are spent.
It looks like silver-oxide batteries are close in voltage, as are a couple of extant lithium chemistries (e.g. Li-CuO, Li-CuS, and Li-FeS), but it's not clear I can get them in a button cell size that will match the existing mercury cells. What is the suggested replacement for these batteries? -- Jeff Dutky |
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2432, 2232, and 2230 backup batteries
This is what I got for these scopes:
4X EEMB ER17335 Nonrechargeable 3.6V Lithium Battery with Tabs Li-SOCL? 2/3A Size 2100mAh High Capacity UL Certified Single-Use 3.6V Lithium Thionyl Chloride Free shipping from Amazon when ordered with a bunch of other items. - Bert |
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Re: 524D RCA customized scope on the big sales platform
Yep, I'm sure those "customer is also supplier" kinds of situations happen a lot.
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I read about a company making pulse generators. They used IIRC Motorola transistors in the pulsers, which Moto in turn used to test their transistors. Supply chains got stressed at one point, and Moto received a new pulser, but it didn't work at all. No output, so they opened it up. Inside was a board with no transistors and a note saying something like "We shipped. You SOBs didn't!" And I'd heard of a similar situation at Orthodyne Electronics where I worked for a couple of years back in the early 2000s. They made wirebonders that used Apex power op amps (to drive the ultrasonic transducers to cause the wire and substrate pads to cold fuse) which were chip-and-wire hybrids. But Apex used the Orthodyne bonders to produce the op amp hybrids! They got into a chicken-and-egg situation, but instead of writing nasty notes, VPs from both companies got together and worked something out. Come to think of it, my first job out of college in the late 1980's and early 1990's also had that kind of situation. I worked for Lockheed at the Skunk Works on the U2 project. Lockheed had E-Systems (ironically now part of Raytheon Technologies where I currently work) building some systems that went into the wing pods of the U2. But E-Systems had subcontracted the Lockheed lab where I worked to build fiber optic links to connect their systems in the two pods. So E-Systems was both vendor and customer. Jim Ford ------ Original Message ------
From: "Tom Lee" <tomlee@...> To: [email protected] Sent: 4/22/2022 7:23:21 PM Subject: Re: [TekScopes] 524D RCA customized scope on the big sales platform That¡¯s hilarious, Bob. Thanks for that part of the story. I hadn¡¯t heard before about returning the gifts! |
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Re: 524D RCA customized scope on the big sales platform
That¡¯s hilarious, Bob. Thanks for that part of the story. I hadn¡¯t heard before about returning the gifts!
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Cheers Tom Sent from my iThing; please forgive the typos and brevity On Apr 22, 2022, at 11:45, Bob Haas <robeughaas@...> wrote: |
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Re: DM501A Input Leakage Source
Roman,
I¡¯m seeing somewhat less compared to what you see on the 200 mV DC range. And it varies between plug-ins with one being ~6 mV highest and the lowest being ~2 mV. Of course shorting the input zeros out the reading. What is interesting is that when placing the EXT/INT switch on INT the offset minimizes. A quick look at the schematic shows several functions being switched in different parts of the circuit aside from merely transferring from the front panel jack to the rear card edge connector finger. I don¡¯t have time right now to investigate why. I also have a couple of DM502As and threw them in a TM frame. They read 0.1 and 0.2 mV with the input open (not shorted). Pushing the EXT/INT switch didn¡¯t change the reading either nor did shorting the input. So I suspect that they need to go through the zero calibration process spelled out in the manual. The manual provides some helpful block diagrams showing switching and signal routing that may assist you with your investigation. And one other thought - have you checked for any ripple in the DC supply lines from the TM frame power supply just to make sure that it isn¡¯t helping this issue? And how clean are the card edge finger contacts? A slightly elevated ground condition through dirty fingers can cause many strange artifacts as well. Greg |
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Re: Tektronix P6021Current Probe Termination
That's too expensive for me.? It's nothing more than the ring and BNC from a standard tektronix probe with the ID pin shorted to ground.? I need to get around to making one.
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Harvey On 4/22/2022 4:16 PM, Greg Muir via groups.io wrote:
If you are going to use the P6021 with a 7A14 the part number of the adapter is 131-0750-00. There is a guy peddling the adapter in new condition on ePay. |
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Re: Tektronix P6021Current Probe Termination
If you are going to use the P6021 with a 7A14 the part number of the adapter is 131-0750-00. There is a guy peddling the adapter in new condition on ePay.
The 7A14 can also use the P6019, P6020 and P6022 current probes. But use with the P6019 and P6020 probes results in reduced performance. Greg |
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Re: 524D RCA customized scope on the big sales platform
Steve,
You are correct. While working in Denver television at the ripe old age of 18 I worked with RCA TR-3, TR-4 and TR-70 machines and all had built-in video monitors and scopes. The scopes were specifically designed for video monitoring using pushbuttons to select what you wanted to view. Not to date myself but I also worked on two RCA TRT-1¡¯s (RCA's first video tape machine product) which had (4) 7-foot racks of fire-breathing vacuum tubes. After getting the TRs we then donated the TRTs to Denver Fire Department who had just set up a microwave video training system to their fire stations and was in need of VTRs. I ended up training the fire guys on maintenance and such but they quickly realized that these monsters were going to be a big liability both time and cost-wise. Greg |
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Re: 524D RCA customized scope on the big sales platform
In almost every case, studio VTRs used Tektronix waveform and vector scopes. B&W picture monitors in VTRs tended to be Conrac, but most color picture monitors in Ampex VTRs were Tektronix 650 series.
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?? Bruce Gentry, KA2IVY On 4/22/22 15:40, stevenhorii wrote:
If I am not mistaken, the big RCA 2¡± quad video recorders used by most |
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Re: 524D RCA customized scope on the big sales platform
If I am not mistaken, the big RCA 2¡± quad video recorders used by most
studios had both a Tektronix waveform monitor and vector scope built into them. On Fri, Apr 22, 2022 at 21:25 Greg Muir via groups.io <big_sky_explorer= [email protected]> wrote: The 524 series scope was designed specifically for measuring video |
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Re: 524D RCA customized scope on the big sales platform
The 524 series scope was designed specifically for measuring video signals. A later model ¨C the 524AD ¨C was included as part of the RCA station ¡°package¡± (RCA demanded stations buy only RCA equipment to get better deals) but still held the Tektronix name on it. The 524AD was a modified version to meet RCA requirements for more detailed video analysis.
The scope graticule is calibrated in IRE units [(unit)] which applies to the various setup levels of the video, blanking, and sync of the NTSC signal. The 524D did not possess a very good way of allowing the user to inspect the video on a line-by-line basis. The 524AD incorporated a 10-turn sweep delay potentiometer to do so plus several other refinements and had a video output jack (SO-239) to which could be connected to a conventional analog video monitor to see each sampled line accented to know where you were looking. Quite unique for its time. The RCA version 524AD was the first Tektronix scope I was exposed to and learned on when I was 15. It can also be used as a general purpose scope as well. Simply change out the graticule for a normal scope one. Greg |
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Re: 524D RCA customized scope on the big sales platform
Until Tek starting building their own CRT's in 1953, they were purchasing CRT's from RCA and Dumont, who were competitors. Tek wasn't getting the best quality tubes, so they made a point of putting the sub-standard RCA CRT's in scopes they sold to RCA. As one vintageTEK Museum volunteer puts it: "we made it a point that those tubes would return home".
-- Bob Haas |
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Re: 524D RCA customized scope on the big sales platform
On Fri, 22 Apr 2022, Jeff Dutky wrote:
I'm not interested in this specific scope, but I grabbed the pictures for both the RCA affiliation, and the visible graticule, which I don't see mentioned on the TekWiki. I am almost completely ignorant of NTSC waveform monitoring; does anybody else know what that graticule represents, how it's used, and what it's called?It is the standard graticle used to read a NTSC video waveform: the zero is, well, zero - the transition between video and sync the sync pulses are displayed below the line - ideally down to 40 the video is above the line with white levels reaching a peak of 100 at the top of the graticle and the black level dropping down to the dotted line but not down to zero. The display was usually used at line rate (1750kHz) and not at frame rate (60Hz) but both displays had their uses. You would use this to setup a camera for example so the whites are white, the blacks are black, and the checks are checks etc. Too much white and the video gets into the audio on a transmitted television signal and you would hear it as a buzz on you black and white 21 inch Admiral. Naturally you want the right amount of black and white to give you a decent picture. When colour was added, the chrominances information was added as a varying 3.58MHz subcarrier riding on the luminance waveform. A separate vector scope was used to setup the chrominance so the reds were red and not green etc. but the level of the colourburst at the front of each line and level of the chrominance riding the luminance waveform could be monitored with this display. -- Richard Loken VE6BSV : "...underneath those tuques we wear, Athabasca, Alberta Canada : our heads are naked!" ** rlloken@... ** : - Arthur Black |
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Re: 524D RCA customized scope on the big sales platform
On Fri, Apr 22, 2022 at 09:47 AM, Jeff Dutky wrote:
Video signal is coded as black ~ 10% (dashed line is at 7.5%, probably black level spec) white is 100%, sync pulses are at -40% (bottom half graticule). The reason for 0 to 100% and -40 to 0% ranges, with a dashed line at 7.5%. Ozan |
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Re: 524D RCA customized scope on the big sales platform
On 2022-04-22 12:47 p.m., Jeff Dutky wrote:
I'm not interested in this specific scope, but I grabbed the pictures for both the RCA affiliation, and the visible graticule, which I don't see mentioned on the TekWiki. I am almost completely ignorant of NTSC waveform monitoring; does anybody else know what that graticule represents, how it's used, and what it's called?I couldn't find the listing. Can you make the pics available somewhere? Is it an ordinary vectorscope graticule? e.g. Tek 1720, etc. --Toby |
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Re: Tektronix P6021Current Probe Termination
The probe and its termination (passive, 134, or 7A14) are designed as a system. As you can see in the P6021 manual, the Passive Termination box is a complex RLC network with several calibration adjustments. If the probe worked decently with a plain 50-ohm resistor, Tek would have used it.
Dave Wise From: [email protected] <[email protected]> On Behalf Of jimbert4 via groups.io Sent: Friday, April 22, 2022 8:53 AM To: [email protected] Subject: Re: [TekScopes] Tektronix P6021Current Probe Termination Will it work better with no termination box if I use a 50 ohm oscope input? What termination is it looking for? |
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Re: 524D RCA customized scope on the big sales platform
I'm not interested in this specific scope, but I grabbed the pictures for both the RCA affiliation, and the visible graticule, which I don't see mentioned on the TekWiki. I am almost completely ignorant of NTSC waveform monitoring; does anybody else know what that graticule represents, how it's used, and what it's called?
-- Jeff Dutky |
Jared Cabot
Bob Haas
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