Still, you should be aware of it. I put one on the indicator, and the other I mounted behind the indicator panel, inside the chassis. If it is the stereo indicator you need, be sure to tell the Marantz representative that! Factors that affect these parts include age, frequency of use, heat, and signal characteristics. If a rectifier blows, you can cook off a lot of the rest of the unit. If you're not technically sophisticated, just skip this tip - you don't want to electrocute yourself, or ruin your prized Marantz.
So each two bulbs are in series, like an old Christmas lamp string. The trick is to make sure that the resulting current requirement is less than that of the factory-specified bulb. Repeat if needed, then clean any dust and grit out with a strip of paper towel, or or other lint free material. When the corrosion was present the signal would intermittently cease for very short periods. Sometimes it takes a few tries, and sometimes you simply have to maintain them at a higher rate than anything else in the unit. I have seen melted plastic bezels from using full sets of 250 ma bulbs.
Don't use oil or tuner cleaner on relays. Cleaning or replacing the relay fixed the problem in most instances. Please warn your readers about cleaning their controls. Something you can do to replace the smaller bulbs is series a couple of bulbs that aren't the right amperage, but the right physical configuration. It kicks up the amplitude of the low bass and higher treble signal components when the level of the music is low. Things that change include the actual capacitance, the internal resistance, the apparent inductance of the part, the breakdown voltage and the leakage. And, with the preamp gain setting lower, the loudness contour is further engaged, hence stronger bass and treble enhancement.
So these are prime candidates for a replacement program. Use polarized parts where polarized parts were used probably everywhere. Eventually, they will either fade away in capacitance, open, or short out, this last behavior often causing circuit damage. When you replace an electrolytic, use the same value in microfarads. The idea is to increase the levels just enough to match the amount that your ears lose sensitivity to those tones as the overall level of the music drops. Note that the extra current requirements can add up, as can the extra heat, which amounts to a twenty five percent increase; think twice before replacing an entire set with higher current bulbs.
They corrode like everything else, but because they handle so much power - high voltage and some significant current in some cases as well - they're a bit tricky to clean up. So a 6-lamp panel that is completely dark most likely has 3 good bulbs still in there. The fine print on the can says test on plastics before using - Duh - how would you know? Or else replace them all a better idea, anyway. That's my friend Mike on the tower below the antenna. In signal circuitry, the electrolytics perform more than signal transmission functions, they also are part of the inter-circuit impedances, and those can affect frequency response and phase shift, both of which can produce immediate and annoying! For instance, if you have trouble getting the right bulb for the dial pointer because of current ma requirements, you can often take two higher current bulbs that are physically correct, and series them, mounting one in the designed location, and the other somewhere handy inside the chassis where it won't show.
I don't know how much extra current is available for the lights on a per-unit basis, though I know of no case where this has caused a problem with the power supply. The finer grit is better, don't use anything courser than the 600 grit. I think we can be confident that Marantz got this right very consistently based on the observed performance of the units. In short, basically everything changes, and rarely for the better. Even when that is true, because the resistance of a hot filament is nonlinear and varies with the design of the filament, you must measure the current drawn by the series string and actually verify that it is under the rating for the Marantz unit.
It is a dancing flute, a haughty bassoon and the plaintive call of a lone French horn. That doesn't have to be a critical problem; A good design will put a value in there that based on the rated tolerance of the resistor itself lands dead-center in the middle of the needed value, and so there is some room for change. For audio circuits, high precision metal film resistors are great. This tip describes an way around the problem for bulbs that match physically but not electrically. The second thing is that they actually get noisy. Back to replacement specs; specify the same, or higher, voltage rating on the electrolytic.
After applying, run pots through their full range at least ten times, perhaps more. The loss of signal was so short that it was infuriating. I'm now looking for a junk receiver to repair my previously near-mint 2270. The oil is a good deal in this case, because since the connectors don't have to move, unlike a switch, the oil will just sit there. Of course, you can push this even further with the bass equalization controls on the preamp. The receivers had a protection relay between the amp outputs and the speaker terminals. The Sound of Marantz is the sound of beauty, and Marantz equipment is designed to bring you the subtle joy of its delight.