Sherwood (DRACO) Micro/CPU 100 Tuner
"the world's first computer controlled tuner"
Pristine Condition; Inside & Out
Everything works. Needs a new battery for the memory. Batteries are readily available.Free Shipping via Fedex in 48 contiguous USA. Outside the 48 ask for a quote.
The demo in the link below will give you more information
Here is the complete review from the "Tuner Information Center":Sherwood Micro/CPU 100 (1977, $2,000)
The FM-only Micro/CPU 100 was designed by Larry Schotz of noise-reduction circuit fame and manufactured for Sherwood by Draco Laboratories, which also sold it for awhile under their own name after a dispute with Sherwood. Under either name, "the world's first computer controlled tuner" is a unique, powerful 30-pound beast with excellent sensitivity and very good quieting on weak stereo signals. The Micro/CPU 100 has the varactor equivalent of 6 gangs with an analog-style tuning knob and digital LED frequency readout, similar to the McIntosh MR 80, and 4 station presets. Hidden behind a front-panel door are switches for de-emphasis and the two IF bandwidth settings, among other things, and variable muting and output level knobs. The Micro/CPU 100 is programmable to automatically display station call letters in an alphanumeric readout for each frequency. The circuit board has slots for 5 ceramic filters, but in our panelist Eric's unit one of the slots was empty (and soldered closed) and appeared to have never contained a filter. Because this unit was previously "repaired" in a questionable manner, however, we can't be sure whether its performance is typical of all Micro/CPUs. Alternate channel selectivity is good, and the overall sound of the tuner is well above average, but adjacent channel selectivity is poor (perhaps that omitted filter would have come in handy).
Our contributor Bill says, "I completely rebuilt the power supply on a Micro/CPU 100. I modded the battery backup by eliminating the outdated and defective charging circuitry and simply installed a 3-cell battery box on the rear panel. I replaced all the electrolytics and several tantalum capacitors. After all that, it played and then the digital readout went intermittent. After 24 hours of labor, I gave up. That said, the rest of the unit works great and it remains one of the best, clearest, most sensitive tuners I've ever heard. The varactor-based tuning works like gangbusters, but circuitry-wise they are fragile." Bill also notes that the outdated digital tuning circuitry and "prototype-like board layout" make the tuner difficult to work on.
Stereo Review's breathless review of the tuner may have been the source of Sherwood's claim that this behemoth was "routinely viewed as the world's finest FM tuner." Brent Hilpert's website has an incredibly detailed page on the Micro/CPU 100, with a ton of good-quality photos, and plenty more interesting stuff on early digital electronics. The Micro/CPU 100 is very rare and only shows up on eBay a couple of times a year. It can sell for $450-625 in good condition, or as low as $250-300 in lesser condition or with an operating problem.
Our contributor Jay offers this background info: "Sherwood and Draco never published manuals, but there are some board diagrams in circulation which were the originals from Sherwood or Draco. You can try Rick at Allegro Sounds and there is another guy in Chicago - can't think of his name right now, but he's a Sherwood authorized repair center. Both claim to have them. At one point I thought I had convinced the Chicago guy to allow a preferred audio repair guy to get copies of boards as needed, but then he balked. The following was reported to me by a former Draco tech, John Friese (sp?), who maintained a repair shop in the Santa Barbara, California area, and was an authorized Sherwood/Draco repair facility. John has since retired and could never locate his copies of the board diagrams after he sold the business. John always claimed that the better versions of this unit were the best-sounding units he ever heard, even preferring them to his Marantz 10B and 20B. Sherwood and Draco had business issues and, as part of the settlement, Draco got the tuners and technology. John and a partner (Dick Glydewell (sp?)) bought out the leftover stock of parts, supplies and units, after Draco sold off what they wanted (having dropped the price from $2,000 to $1,000) and these guys were the licensed repair facility for Draco.
"There were three iterations of the design. The first iteration of the units had the name 'Sherwood' on it. The two later iterations were Draco and you can almost see where the 'Sherwood' name was simply brushed out. Per John, the Sherwood version was problematic, particularly with some of the boards. He certainly knew from memory where everything was on the inside of these units. At one time I had three of these and he could tell me pretty much the location and color of most of the bigger 'cans' and boards, etc. Later versions were superior (though I have seen and heard threads where others differ on this) and less problematic. I have found that to be true. The two later versions, per John, were similar in quality and sound, and certainly more problem-free except for battery leakage issues."
Will be packed in a 22x18x12" box weighing 34 pounds 10 ounces