Loud, Low Hum When Marantz Turned On

[Steven Tate]

At the bottom of the service manual are several pages of parts lists, organized by board. Look for the P800 section (power supply) and look for prefix C, like C801, then look for the ones that are electrolytic (the type is listed on the chart). These will correspond to the numbers on your board. It will give you values in capacitance and voltage rating. Next step is to compare what is on the board to the list. Occasionally they differ. When they do, go with what is on the board if it looks original (no sign of resoldering on the bottom). Do you have soldering/desoldering experience? If not, work on some throw away boards before diving into your Marantz. If you do decide to recap your power supply, a good cap type would be Nichicon PW series like rBuckner described. Get them from Mouser or Digikey. One last piece of advice: take good photos of the board before you change anything. Make a record of the negative side of every cap (usually has a stripe on that side of the cap), and when you remove a cap, compare the polarity to the silkscreen marking on the board. On rare occasions, the board is marked wrong. You want to replace polarity the way it was originally if it differs from the board markings, otherwise, things may go pop and sizzle. If you are new to this type of work, start by reading Echowars excellent primer here:

http://audiokarma.org/forums/index....udio-gear-eh-heres-the-tools-you-need.333423/

 

[rBuckner]

^^^ Very good advice and nicely fleshed out post Steve!

 

[KutzlerTrans]

As a Dentist, Steve is trained to get to the Root of the problem.

 

[Steven Tate]

As a Dentist, Steve is trained to get to the Root of the problem.

Lol. So true. As a barely-past-newb stage hobbyist, I still remember the basic questions I had when I started. Sometimes the most basic info is hard to find in the threads because it is second nature to nearly everyone and never gets discussed.

 

[Kevbo]

Be aware that the values on the schematic may not be what is in your unit. I did a quick rundown on the electrolytic caps in the 2240B manual. The values on the left are in uF/vDC. The part numbers are from Mouser.

220/63: 647-UPM1K221MHD6
100/50: 647-UPW1J101MPD
22/35: 647-UHE1H220MDD
330/50: 647-UPM1K331MHD6
470/16: 647-UHE1E471MPD
10/50: 647-UPW1J100MDD
47/16: 647-UHE1E470MDD
220/10: 647-UHE1E221MPD

Wow! Thank you so much. My father had recommended Mouser as well. I will be checking these out later today after work! Again, I can't thank you enough. I'll be in touch!

 

[Kevbo]

At the bottom of the service manual are several pages of parts lists, organized by board. Look for the P800 section (power supply) and look for prefix C, like C801, then look for the ones that are electrolytic (the type is listed on the chart). These will correspond to the numbers on your board. It will give you values in capacitance and voltage rating. Next step is to compare what is on the board to the list. Occasionally they differ. When they do, go with what is on the board if it looks original (no sign of resoldering on the bottom). Do you have soldering/desoldering experience? If not, work on some throw away boards before diving into your Marantz. If you do decide to recap your power supply, a good cap type would be Nichicon PW series like rBuckner described. Get them from Mouser or Digikey. One last piece of advice: take good photos of the board before you change anything. Make a record of the negative side of every cap (usually has a stripe on that side of the cap), and when you remove a cap, compare the polarity to the silkscreen marking on the board. On rare occasions, the board is marked wrong. You want to replace polarity the way it was originally if it differs from the board markings, otherwise, things may go pop and sizzle. If you are new to this type of work, start by reading Echowars excellent primer here:

http://audiokarma.org/forums/index....udio-gear-eh-heres-the-tools-you-need.333423/

Great information!! Thank you very much! My father is really good with soldering, so he will be accompanying me (whether he knows it or not), haha. I do want to learn to solder though, so I will work on that. And yes, we have found that Marantz seems to be labeled incorrectly once in a while, and last time we dove into the Marantz, I took MANY pictures. I think our hardest feat so far was restringing that damned thing. Did take ENOUGH pictures before removing it. Eight hours later (yes, eight), we finally got it.

 

[Kevbo]

Here are pictures of the capacitors on the PSU....I think it's the PSU. haha I did orient them for a good view on my computer. I fear uploading them may have rotated them again. Let's hope not.

 

[Steven Tate]

One of the challenges with the power supply is that Marantz used a really tough to clean brown glue on the large caps. I think it was to stabilize them for shipping. But once you remove the solder, you have the challenge of getting the cap to break loose from the glue, and once you get the cap off, you have the challenge of cleaning the brown glue off of the board without damaging the board. It's doable, but don't be in a hurry. Take your time and don't put too much stress on the board.

 

[KutzlerTrans]

Take a 6" pocket ruler and sharpen end and add a slight bend to use as a handy scraper to remove glue.

I have the sharp short one with the side ground in a semi circle for cleaning between tight solder joints like transistor legs.

 

[Kevbo]

Take a 6" pocket ruler and sharpen end and add a slight bend to use as a handy scraper to remove glue.

I have the sharp short one with the side ground in a semi circle for cleaning between tight solder joints like transistor legs.

Awesome! Great advice. Thank you!. Should prove interesting to attempt. hahaha

 

[mikey99]

Hopefully the PS capacitors will solve this. But have you tried moving the receiver out to another room/location
just to make sure that hum isn't being picked up from some other device or the power line ? Should be easy to
test with just the receiver/headphones.

 

[Kevbo]

Hopefully the PS capacitors will solve this. But have you tried moving the receiver out to another room/location
just to make sure that hum isn't being picked up from some other device or the power line ? Should be easy to
test with just the receiver/headphones.

Yes, I have. Same issue. Good point, though. Thank you.

 

[Kevbo]

Just wanted to let everyone know that my dad and I replaced the 8 capacitors on the power supply and the humming is gone. Seems to have been the issue! Thank you so much everyone for the help. I really appreciate it. This is the second issue I've had and this forum came to the rescue right away. Really enjoying Audiokarma and all who are willing to help non-electronic savvy people, such as myself.

 

[Kevbo]

Both left and right? May be time for a power supply recap.

Be aware that the values on the schematic may not be what is in your unit. I did a quick rundown on the electrolytic caps in the 2240B manual. The values on the left are in uF/vDC. The part numbers are from Mouser.

220/63: 647-UPM1K221MHD6
100/50: 647-UPW1J101MPD
22/35: 647-UHE1H220MDD
330/50: 647-UPM1K331MHD6
470/16: 647-UHE1E471MPD
10/50: 647-UPW1J100MDD
47/16: 647-UHE1E470MDD
220/10: 647-UHE1E221MPD

These were perfect! They fit the buck on each and ever one!

 

[bryans12v]

 

[rompstar]

Here are pictures of the capacitors on the PSU....I think it's the PSU. haha I did orient them for a good view on my computer. I fear uploading them may have rotated them again. Let's hope not.

checking in / did you ever fix this hum ?

I have a Marantz SR220 which has a hum too, even at 0 volume, all inputs selected don't matter, I replaced the two power filtering capacitors and the hum still there. Wondering if it is actually the transformer ?

 

[dankik]

checking in / did you ever fix this hum ?

See post #33. Yes, he did.