Low Hours Tektronix 2445a, 4 Channel 150 Mhz Scope, Guaranteed, Calibrated

US $438.00

Douglassville, Pennsylvania, United States
Jan 29th

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The Tektronix 2445A is a dual time base 4 channel 150 MHz oscilloscope. It features the best of an analog signal path with digital control eliminating the dirty switch contacts that typically plague analog scopes. With the digital control, cursor assisted measurements are enabled, setups may be stored and recalled and has an automated “get me a visible trace” feature. I could go on for pages but there is plenty of model information on the web including the full operation manual. However, any and all questions are welcome. This Tektronix 2445A is a fine, very low-hours example with option 10, GPIB that has been initially tested and evaluated, disassembled, stickers removed and cosmetically cleaned, functionally cleaned, repaired as necessary, fully calibrated, reassembled and finally performance tested to within published specifications. I also replaced the battery with a date coded higher capacity lithium battery as the original has been in service for more than 25 years; OEM replacement batteries lack the manufacturer date code. This battery holds the calibration constants and is often not replaced by other sellers because a complete calibration is then needed. The power supply was removed, disassembled, inspected, all electrolytic caps measured for ESR (equivalent series resistance, the common problem with inverter power supplies as this has), defective or marginal caps replaced, reassembled, reinstalled and tested. As a final quality assurance, it has been used on my bench for over a week to be sure no new or previously undetected issues arise. It is ready for immediate use and should provide years of trouble free operation. PHOTOS of actual item for sale, many photos show multiple images due to the Ebay photo limit: In the first photo an overall view of the top, left side and front are visible. It is displaying its pleasure at being refurbished, recalibrated and ready to work. The inset in the lower left shows the scope passes all confidence tests from start up as a working, calibrated scope should. Photo 2 on the right shows the right side and bottom. On the left are close ups of the worst flaws on the unit; top photo shows a nick in the front plastic bezel surround located on side near channel 4 input; middle photo shows some case rash on the bottom near right corner; lower photo shows some case imperfections on the top near the left, these appear to be original but not sure. Overall, the exterior looks exceptional. Only close ups disclose the minimal case issues. The upper portion of photo 3 shows the rear of the instrument; note the 2445A decorative handle insert is present. Also the lower photo portion shows the new replacement battery on the A5 board. Photo 4 shows all channels in operation with each displaying a different frequency and waveform signal. This shows the operation of composite trigger where all traces are stable regardless of their individual characteristics. In photo 5, channel 1 is displaying a 1 millisecond time mark signal from a time mark generator slaved to a GPSDO (GPS disciplined oscillator, traceable to NIST). As can be seen with the sweep of 1 millisecond per division, the time marks match the division marks. Also, the cursor assisted period measurement function is shown agreeing with the time marks. Photo 6 shows the use of the dual time bases on the same 1 millisecond time mark signal. The upper trace shows the A sweep with an intensified portion, the intensified portion is shown in the lower trace at the B sweep speed of 200 microseconds per division. Both sweep speeds are shown in the lower right corner of the CRT. Note there are 5 divisions between the marks on the lower trace as expected. Photo 7 shows just the B sweep time base running at 200 microsecond per division and displaying a 200 microsecond time mark. Again the time marks align with the division marks and the cursor assisted period measurement agrees. Photo 8 shows the display for a 100 millivolt standard signal from a PG506 calibration generator (traceable to NIST) applied to channel 1. The voltage measurement using cursors is shown in the upper right. The volts per division setting is 20 millivolts as shown in the lower left, note the square wave tops and bottoms are 5 divisions apart as they should be. Here again in photo 9, a 20 millivolt standard signal from a PG506 is applied to channel 2. The voltage measurement using cursors is shown in the upper right. Again the readings are correct as are the number of divisions. Although this scope is conservatively rated to 150 MHz, photo 10 shows it has no problem triggering and displaying a 400+ MHz sine wave. Because of the bandwidth, at this frequency, the amplitude is more than -3db so the voltage per division, cursor assisted readings are degraded. Also true waveform representation can’t be relied on at frequencies way beyond the scope’s capability. Photo 11 is a photo showing 1783 operation hours and 695 on/off cycles shown recorded on the scopes internal registers at the time the photos were taken. Although these numbers can be changed at calibration time, I did not alter them. I believe these hours to be accurate and attest they were not altered by me. Photo 12 shows the inside of the scope that further supports the low hour usage. When I took it apart for cleaning, the fan was nearly clean and they are typically pretty dirty. The fan and inside could have been cleaned to give this appearance. One thing that can’t be easily or completely cleaned is the CRT anode lead. The upper left portion of the photo shows the bright red insulation on that anode lead. These are high voltage leads and as a result attract dust and dirt and become a dirty gray-brown with age and use. The idea of replacing the anode lead just to deceive someone is pretty far fetched and the seller to me made no implication of how much it was used. Also note how all the inside is shiny. Outside the case, the power supply halves have been split. The ESR meter is shown attached to one of the numerous caps and reading very low resistance of .63 ohms as wanted. Note the other half of the supply is behind the one under test. Although this scope will work good as new and looks great for a 25+ year old instrument, it is used and has some cosmetic flaws, blemishes and very minimal wear as shown. Any broken parts have been repaired or replaced and all portions function as the manufacturer intended. Items such as cables, etc. are not included but shown for demonstration purposes only; only the scope is offered for sale. PRICING AND OPTIONS: Reasonable best offers receive scope as shown, power cord, 30 day warranty and 14 day right of return as detailed below. Buy it now receives scope as shown, correct angled power cord, 120 day warranty and 14 day right of return as detailed below. Free options include new clear CRT filter instead of used blue filter installed as shown; good used portable storage pouch and mounting plate attached on top; installed in used rack mount (delete handle, rear feet, pouch and mounting plate); CD with operation and service manual plus any purchased probes instructions. State option(s) wanted at checkout by leaving a note in either Ebay or PayPal or none will be provided. The following subject to prior sale: Correct used, tested P6133 150 MHz voltage probes available for $50.00 each that include the "witch hat" hook grabber and ground lead with clip. Correct used, tested P6009 1.5 KV peak, 150 MHz, 100X high voltage probe for $100.00 each. Encoded, automatically changes scope scale, with "witch hat" hook grabber and ground lead with clip. Also new P6009 in original sealed bag available for $160.00 each. Correct used, tested P5100 2.5 KV peak, 250 MHz, 100X high voltage probes for $150.00 each. Encoded, automatically changes scope scale, with "witch hat" hook grabber and ground lead with clip. Correct used, tested P6015 40 KV peak, 75 MHz, 1000X high voltage probe kit with ground lead and clip in fitted plastic storage box for $400.00 each. No readout pin so operator must multiply reading by 1000. Note that deratings apply, refer to probe instructions or inquire with your needs. Correct used, tested P6022 6 amp current probe, up to 935 Hz to 120 MHz response, with termination, ground lead with clip and instructions for $400.00 each. Correct used, tested P6021 15 amp current probe, up to 60 Hz to 60 MHz response, with termination, ground lead with clip and instructions for $360.00 each. Feel free to contact me about your probe needs. Used with perhaps marking that I could not remove but unscratched fully functional polarized viewing hood for $30.00; or like new perfect polarized viewing hood for $45.00; nice for high ambient lighting conditions. Original printed operation manual in good condition for $50.00; free download on the web or from me but maybe you like to hold a real book! Also original printed option 10 GPIB interface manual for $10.00 To purchase any options, use best offer with the buy it now cost or your offer plus amount for each option wanted. All options carry the same warranty and right of return as the scope itself. Options ship for free with your scope. After it is packed, options are not available with free shipping. I suggest a note detailing the options you desire to avoid any confusion. WARRANTY, RIGHT OF RETURN: I provide a full like new equipment warranty for 30 or 120 days as explained above from your receipt of this instrument. If during the warranty period it fails to operate or perform to the manufacturer's original published specifications, ship it back packed well and it will be repaired, adjusted as needed and performance tested for calibration free of charge or in the rare case where repair is not possible, your purchase price will be refunded; buyer is responsible for shipping costs. Additionally, I provide a 14 day satisfaction guarantee. If you are not happy with your purchase for any reason within 14 days of receipt, ship it back for a full refund of purchase price and the original shipping charge. Buyer will be responsible for return shipping but that can be negotiated in the case of negligence on my part. Please see my feedback and you will see this just doesn't happen, I disclose all instrument shortcomings and/or flaws. Better to be forthright than vague and shady, quality is the expectation. Obviously, any tampering voids the warranty and satisfaction guarantee. Do not remove tamper proof stickers or open the instrument up until the warranty expires or you are prepared to assume responsibility. You break it (the seal), you own it! Also any obvious physical abuse or other misuse voids the warranty, so don't beat it with a hammer or hook it up to a 20KV. It must be returned in the same condition it was shipped for any credit. SHIPPING, PAYMENT: Shipping will be per Ebay calculator for USPS mail within the U.S.A. International sales through Ebay’s global shipping program. Unconfirmed addresses may delay shipment. Free pickup by buyer is always welcome. Other shipping options available, just ask. I prefer PayPal but will accept any suitable funds. Obviously, other funds will delay shipment until they clear. WHY BUY FROM ME: You see this model on Ebay for far less and they say it’s good, so why should you buy from me? Quality. You get a scope that has been used so it might have some dings and things but I show you all flaws before you buy. It has been cleaned so no old stickers or sticky spots where stickers were. It has been cleaned inside too so it dissipates heat as intended. All broken items repaired or replaced. It has a new battery so your investment works for years to come. It has been calibrated using traceable standards and checked to meet or exceed the manufacturer’s original specifications. Unless your bench is equipped with thousands of dollars of relatively new equipment, this scope will be your pride on the bench and provide years of trouble free service. Let’s debunk some of these other myths. What does “Fully tested,” “Works great,” and “Fully functional” mean? The only way to fully test and therefore determine it works great or is fully functional is to do the performance test as dictated by the service manual. If the seller has the capability to accurately do the performance test, he has the equipment to do the adjustment portion of a full calibration, so why doesn’t he do it? Because he doesn’t have that calibrated equipment; he can maybe see a signal from a generator or from the built in calibrator. By the way, that calibrator is to adjust compensation on probes. So you get something that works, sort of, maybe. Certainly no verification of calibration and unknown if everything works. And terms like “displays trace” and “powers on” means even less function has been verified. Even showing a horizontal trace or a few only means it sweeps. It doesn’t mean the sweep speed is correct or if it can trigger or if it has vertical. It is probably safe to assume the CRT works and it has some HV but not more than that. Let’s say you get real lucky and get a scope that was calibrated a few years ago and actually works well enough for your work. First off, play the lottery! I can guarantee it will fail in the near future if the battery has not been replaced. I buy these scopes too as feeder stock and I’ve seen recent calibrations but never, ever a replaced battery, not one. The original batteries are date coded and they all were from the 1980s, so not replaced. Those batteries are over 25 years old and are failing now and yours will too. When it does, the calibration constants will be messed up so if it was close before, it won’t be. Also you will get errors on start up and a row of dots or question marks on the bottom readout row. Then you can send it to me or another vendor for a new battery and calibration or just buy one that’s ready for another 20 years that is complete, clean, calibrated and guaranteed. I think you have to question some sellers that say they calibrate the scopes they sell too. Some say they replaced caps in the power supply or did this and that, but no photos of the work or replacement and few, if any photos showing actual performance against standards. Why wouldn’t they replace the battery to preserve your investment? The cost to do so is minimal compared to the cost of the scope and this is a known problem; it will fail! This is not an opinion, it is a fact based on science; even common sense tells us a battery doesn’t last forever. Maybe it is because they really are not doing a full calibration because after a battery replacement, a full calibration must be done. Maybe they check a few things with whatever equipment they have, maybe not everything needed or calibrated or traceable. A full calibration is needed after battery replacement including all the steps of adjustment, not just a check; though a complete check is then necessary to ensure a proper result too. I have many other scopes available for refurbishment with an assortment of options in the 2465A, 2465B, 2467 and 2467B models. Please inquire with your needs.

Condition	Seller refurbished : An item that has been restored to working order by the eBay seller or a third party not approved by the manufacturer. This means the item has been inspected, cleaned, and repaired to full working order and is in excellent condition. This item may or may not be in original packaging. See the seller’s listing for full details.
Seller Notes	“See listing.”