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There could be many reasons for channel loosing. I would definitely clean pushbutton switches. Unfortunately, they can not be opened to properly clean and lubricate inside contacts and sliding plate as they are sealed. Push lever can be pulled out and you can clean sliding plates, but this is...

This is original wiring. You can flip board or desolder wires. However, if you plan to recap then this will be huge disassembly. You should also clean all pots and switches. Spraying them will only be short term solution. There are many threads about this preamp and work to be carried out on...

In most cases these small value capacitors (capacitance value is up to few hundred nF) are not used in signal path, so almost any will do. However, you can choose polypropylene (PP) film capacitor for general use. Measure raster (distance between legs) to be the same as originals, voltage is not...

They are capacitors, black is 15 nF, 100 V. If it is cracked, you should replace it, but replace them on both channels.

If both switchable outputs are dropping at the same time then right channel which comes to switch board might be dropping. Right channel is going to switch board on point 27 and goes to two outputs through switches on points 28 and 30. If input is dropping, then both outputs are dropping too...

Hello, if your static noise is constant, I would trace signal with scope from preamp outputs toward inputs to see which board 'generates' noise. Then you can narrow your problem. It might be that some power supply rail have problem if static is in both channels.

Difference in brightness could be as two bulbs are differently manufactured. Best would be to change both same lamps at the same time. But brightness is not very different at your picture. I am glad that it works.

Looking at the schematics I see that missing parts are used for power supply for meter board for MC2205. As you have MC2200 you don't have meter board and those parts was not installed at factory, as your amp does not need them. So all should be good. MC2205 and MC2200 have same power supply...

Today's caps are usually smaller than old ones since capacitor manufacturing technology advanced during years. You should be fine with these, just observe polarity of caps. You can see on mine pictures that new caps are smaller than old ones. I have noticed that you are missing few parts from...

Yes, replace all 5 caps and bulbs. Bulb is #7382, size T-1 3/4, 14V, 0.08A.

You can easily check lamps just as John described. While power supply board is out it is recommended to change electrolytic capacitors, it is very easy job to do. As I can see on your picture, yours are still original and very old. Two 2200 uF caps can be the cause that bulbs are not working...

There could be a number of things including switchboard and many more things. Is weakness of channel affected when you play with pushbuttons? If yes, dirty switch could be the problem. If no, there could be a lot of other things.

I agree with Bob, probably connectors or wire that carry right signal from switch board to right output board. Or bad solder joint on rca connectors or ground point. You can touch connectors while playing music to see on which end of cable you have a problem. Do this with reduced gain on output...

I would suggest to use TO-3P isolator. I have marked in red circles parts of transistor metal surface without isolator between heatsink - so you have just very thin amount of air between collector and heatsink. I would also avoid to connect collector like you did, in green circle. When TO-3...

The 'other' side of Q221 should newer be on 0 V so 25 V is more than enough. However, if Q221 was damaged, I suspect that 'other' side of this transistor went towards ground. Check all transistors and diodes on driver board on right side of schematic. When I got MC2200 (which uses same driver...

Do you hear pops with and without music playing? You can turn on only amp while preamp and all sources (CD, tuner, computer.....) are completely off and wait to hear pops. If you hear pops when only amp is turned on, then there is definitely problem in amp.

I agree with others, if you have schematics and scope or signal tracer and average skills it is very easy to trace signal and find where is lost. Print or follow block diagram and you can easilly find where and on which board signal is lost. Fix that and then restore it. Sure, capacitors should...

If mode selector switch is problem, then you would get same behaviour when using Aux inputs. Since you have both channels when aux is used, I would eliminate mode selector switch as problem. Check again, to be sure, all modes while using aux input. If all works well, mode selector switch is not...

I bought these from Mouser: 598-DCM413U050DC2B They have identical measures as originals (diameter, post spacing, post diameter, post height.....) as original ones, with slightly highier capaticance. You can allways check dimensions against original in supplied datasheet at Mousers site.

Hi all, I just got Marantz receiver SR320. It has been sitting unused for more than 25 years. It is rather simple unit with STK 4833 for power amp and analog tuner. Power amp is working, but tuner is very missaligned. Does anyone have service manual for this model, or for model SR220 which...

Congratulations, that's excelent news! This Krell should also be a piece of audio art and I am sure that listening to it and Mac's amps will be pleasure. I am waiting for news to follow...

These resistors should be flameproof. If they are fine, I would not change them.

If you are not sure of amp condition, use 'bulb tester' for first turn on. You should change electrolytic caps, if they are still original. Bad, cold solder joints around connectors are known problem. Sometimes two switchs at back should be cleaned. This is very simple amplifier but it would...

I know that these are more expensive, but both time when I needed them, 'yours caps' was not available so I did not have a choice:) On 2016 price of 'mine caps' was for one piece 36 eur and today is 41 eur. With this trend price is just going to be highier in the future. If I got the chance, I...

Yes, if diode is open, it won't have any effect, but inductive voltage from coil when relay is disengaged might break driver transistor. But I have never seen that this diode was bad in any device that uses relays. Indeed, my MC2200 does not have this diode, but MC2205 has diode. Perhaps diode...