There are many who say the Sequerra Model 1 is the best FM tuner ever designed, and after hearing it, I think they may be right. This is the rackmount broadcast monitor version, in silver, apparently rarer than other variants of this already-quite-rare tuner. It receives well, the audio quality is fantastic, the CRT panoramic/tuning/vector display works wonderfully, and it is remarkably sensitive: the video showing reception of various stations was taken inside a steel building with the doors closed, and no antenna attached, just a balun. (I have tested numerous radios and FM tuners and have never found one that clearly received these stations in our building with the doors shut, even with an antenna.) We received this tuner in good condition, but it wasnt initially working correctly. It turned on, but the display indicated 189.3 MHz and would not change when tuned. Our technician, a retired EE, inspected, repaired, and improved it; his full notes are below. In summary, he: Repaired the -15v supply by replacing its shorted output filter capacitor, which fixed the tuning problemUsed Deoxit to fix intermittency on the left-side buttonsReplaced the LM301A op-amps with sockets, and plugged in a pair of TL071As (see photo) Replaced the leftmost display digit (an HP smart LED display module) with a spareFixed an unsoldered wire that seemed to be a factory defectReplaced all four #1815 incandescent panel lampsand fabricated a new smoked polycarbonate display panel with milled edges, to replace the original glass, which shattered during disassembly. (Having seen it both before and after the replacement, I can certify that it looks damn good.) The only significant flaws I can notice on the unit are as follows (see photos as well):Minor scuffs on the top rear and sides of the chassis, from ordinary use/installation/deinstallationA scratch on the top of the faceplateScratches to the finish of the right-hand rack handle Minor delamination of the very bottom of the faceplate backlight diffuser, which is only visible if you look down into the Power and Dolby sections from above and in front.Included are: the original op-amps if you wish to swap them out, and a custom-built wooden shipping protector. Listing notes:Comes with 30-day returns.We can only ship items and respond to messages Monday through Friday, on business days.Please contact us immediately if you have any questions or if there are any issues.Technicians notes, verbatim: 6/23/23 Sequerra Model 1 FM tuner s/n 1117. Component date codes 1974. Belongs to Renew Computers. Display comes on, but is stuck on 189.3 and does not change with the tuning knob. I found the manual and made a jumper for the rear panel accessory jack which connects the tuning potentiometer output to the tuner control voltage input. That did not fix the stuck frequency, but the voltage range at the jumper was 7.2v to 32 volts, which matches what the manual indicates. The accessory jack also has the +15V and -15v supply voltages and the -15V pin read near zero. I removed the bottom cover and was able to find and fix the problem with the -15V supply; the output filter capacitor was shorted. It was an axial cap rated 350 uF 16 V. I replaced it with Nichicon PW, 330 uF 16V. That fixed the tuning problem, and the tuner worked with good clean audio output on both channels. Some of the control buttons on the left side are intermittent, particularly ones controlling the CRT display modes. I removed the button assembly and treated all of the contacts with Deoxit. Working on the buttons gave easy access to the left side circuit board so I removed the original LM301A output op amps and replaced them with high quality sockets, allowing a new owner to easily plug in whatever op amps they like. These op amps place limits on how good the noise and distortion of this tuner can be and much has been written about newer op amps with better characteristics and preferences among them. For now, I put in TL071A’s (see picture). The original LM301A’s are included and if for some reason those, or one of the other types requiring compensation caps are put back in, wire leads into the circuit board are provided so that can be done without having to remove the board. The left most LED display digit was intermittently malfunctioning, displaying either a 1 when it should be blank or vice versa, and occasionally other garbage characters. These are H-P display modules wit built in latch/decoder/driver chip. They are HP 5082-7302. I probed the input pins and proved that the problem was a faulty display module, not the counter circuitry upstream. I replaced it with one I had in stock. I noticed an unsoldered connection of a wire to a feedthrough terminal at one of the sealed units toward the rear of the tuner. This appeared to be a factory defect. I don’t know whether it caused any problems, but I soldered it. One of the #1815 incandescent panel lamps was burnt out, so I replaced all 4 of them with new ones. During the repair process, when the front glass panel was removed, it shattered. New ones are not available, so I made one from smoked polycarbonate plastic. It is the correct dimensions, has been milled on the edges, and is clean and pristine. This is now a clean and fully functional example of this rare and famous FM tuner!