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全部信用评价 (607)
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1***1 (93) - 买家留下的信用评价。去年购买已获认证I highly recommend this seller, who was very helpful and flexible. Our lovely cup and saucer set arrived promptly and carefully packaged. This was truly the best experience I have had in making an Ebay purchase.
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p***n (632) - 买家留下的信用评价。超过 1 年购买已获认证The C128 arrived quickly, was extremely well packaged, and is exactly as described and pictured. Just to emphasis, this was likely the best package item I have ever received on Ebay and reasonable shipping costs, KUDOS! Excellent transaction and follow-up communications. Thank you for a very successful transaction! Highly recommend the seller.
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9***a (2) - 买家留下的信用评价。过去 6 个月购买已获认证Pocket Pal Planner arrived quickly and in good condition.
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a***b (1108) - 买家留下的信用评价。过去 6 个月购买已获认证Nice little pocket pal planner, fast shipping, thanks
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h***0 (1607) - 买家留下的信用评价。超过 1 年购买已获认证Perfect! exactly as described, quick shipping, well packed, A+++ seller
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r***h (446) - 买家留下的信用评价。去年购买已获认证Great packaging! Thank you!
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(3)
2021 年 03 月 31 日
Very limited functionality, problematic manual, not good for beginners
This kit is advertised as "designed to produce a sine wave audio signal between 5Hz and 50KHz"; while this is theoretically true, the actual kit only includes parts to make an oscillator generating about 440 Hz without adjustability. The sales text says "Potentiometer R9 provides fine tuning of the output frequency by +/-15KHz", but in fact there is essentially no frequency adjustment given the components provided. The product seems aimed at beginners to electronics, yet the sales text refers repeatedly to "Wein" bridge which is a misspelling of "Wien" bridge; not so great for teaching. This might seem minor, but the entire manual that comes with the kit is full of sloppiness, confusions, and flat out incorrect information (although kudos to the kit maker for at least providing manual at all). Sales and manual text says "Output Amplitude: ~2V pk-pk (for 9V power source)", but in reality it is closer to 4Vpp, and not adjustable. The only adjustments on the circuit board allow for slight modification of the sine wave symmetry. Sales text says "Operates on 9VDC battery", but no hardware is included for connecting a 9B battery; a 2 cent 9V battery connector should be part of the kit. The waveform provided is a significantly distorted sine wave. The manual has several lapses in regards to component identification and component orientation that are likely to confuse beginners, resulting in an inoperative kit. The two LEDs supplied with my kit had NONE of the usual characteristics for identifying the polarity (e.g. notches or flats on the plastic case, different lead lengths). The circuit board has seven holes for terminal pins, but only five pins are provided, and in the form of a 5 pin header; the instructions say nothing about cutting the header up into pieces to use for this purpose, and there are two pins short of what should be there. This product could be improved by a refresh of the manual, better selected parts provided with the kit (e.g. LEDs with polarity identification). 440 kHz is an odd frequency for a signal generator; the kit could be improved by including the parts to produce the more common 1kHz frequency.
2016 年 06 月 02 日
Supply and Demand
These are very expensive eraser refills, but that is the law of supply & demand.....they are not being made anymore, so whoever has them can charge whatever they think the market will bear. I needed them for my electric erasers, so I paid the price. Delivery was fast, so no problems there. My only complaint is that the product was pictured with the box, but what I got was just some erasers in a plastic bag....no way to get a warm and fuzzy about whether they were really the same item (same manufacturer and model) as what was pictured. But they seem to work OK, so again, no complaints.
2019 年 07 月 03 日
Good overview of Tektronix 300, 500, and early 400 series oscilloscopes
This is an older book, recently republished by the VintageTek museum. Its text has all the earmarks of and older amateur/self-published book, with a clunky font that looks like it was done on a typewriter, or maybe an old daisy-wheel printer with a rough-by-today's-standards typeface. The photos, while adequate, are a grainy black and white. The book itself is a softcover with glue binding, which is not ideal for such a thick volume. The page size versus binding thickness makes for stiff and springy page turns, and certainly the reader needs to forcefully hold the book open, lest the binding tension and paper springiness turn pages or simply close the book when you get careless. But none of that is important. This is a reference book for certain older series of Tektronix oscilloscopes, and for people interested in that subject, the roughness of the typography and binding are minor concerns. Within the series covered, the book covers and illustrates all of the frames and modules, their photos, their original selling prices, features and specifications. Most photos show only the front of the equipment or modules. And this book does not cover every older model of Tektronix scope. The author was clearly focused on certain series, but that still covers a lot of ground. I have a 'beef' with the book: Its title. It would appear to be a general book about selecting a vintage scope to restore, and then restoring it. In fact, while it does have sections related to restoration, it is primarily a catalog of certain series of Tektronix scopes. It does not cover other brands, and it is not really a 'primer' about restoration of vintage electronic test equipment either. If you have an interest in vintage Tektronix oscilloscopes, especially those in the selected series, you will want this book in spite of its shortcomings. Here is an excerpt from the eBay listing: "This book covers Tektronix 300- and 500-series oscilloscopes and plug-ins, and early 400-series (410, 422, 453/4 and 491 spectrum analyzer) but NOT the later 400-series such as 465 or 475", so let that be your guide. So, as a fan of vintage Tektronix scopes, I recommend this book to like-minded readers. However, I WILL be contacting VintageTek about their inaccurate eBay listing (re: hard vs soft cover).