Marantz 2230 Left volume issue - Newby

[MrBillinMinn]

Hello, this is one of my first times posting here as I recently got back into vinyl and now have gone down the 70's equipment rabbit hole!

I just picked up a Marantz 2230 at an estate auction. It was unbelievably dirty, (see pics) but somehow still worked (for the most part). I did a little clean up (cleaned the pots) but the left channel is not as loud as the right channel. I've tested using the tuner and a turntable, and different pairs of speakers.

One clue that I found interesting is that none of the "effect" knobs (bass, mid, treble, loudness, high/low filters) seem to affect the sound coming from the left speaker, but they all DO change the sound on the right channel.

As a 60+ year old who loved vinyl and 70's equipment growing up, I am thinking of having a hobby of trying to learn the electrical side of these things. As of now I really know know much about testing, and need to learn more about voltage, resistors, capacitors, and all the rest of the stuff inside these things, but I am wondering if the info above is enough for some of the experts here to offer an opinion. I'm also looking for some good resources to read/watch for some introductions to these topics. I already have a soldering station!

Check out how dirty this was!

Bill

 

[jd3rdcoast]

There are plenty of 2230 threads to read and learn on this forum. Get a vacuum and a 2" paint brush to begin getting the dust/dirt out. Can also use a shopvac as a blower with brushing outside with both covers removed. Did you try getting Deoxit D5 or other contact cleaner into the switches effect switches? Tiny hole in the back of them then work multiple times.

Sounds like a problem on the Tone board P400. There are 4 2SC1000 Transistors that are on the Top Ten Worst Transistors list found in DIY forum. Replace with KSC1815Y. As well as a handful of capacitors.

You can test the amp section by using a patch cord from another device with a preamp-out or a phone direct into the 2230 Main-In RCA Jacks on the back. Turn phone down first, start music, then slowly raise phone volume. If both sound equal and good, the amp is not your issue and points to prior circuits like the Tone and Pre-Amp section. Conversely, you can jump your Pre-Out signal into another known working amp and see if same problem occurs which would isolate your Pre-Amp section as well.

 

[MrBillinMinn]

There are plenty of 2230 threads to read and learn on this forum. Get a vacuum and a 2" paint brush to begin getting the dust/dirt out. Can also use a shopvac as a blower with brushing outside with both covers removed. Did you try getting Deoxit D5 or other contact cleaner into the switches effect switches? Tiny hole in the back of them then work multiple times.

Sounds like a problem on the Tone board P400. There are 4 2SC1000 Transistors that are on the Top Ten Worst Transistors list found in DIY forum. Replace with KSC1815Y. As well as a handful of capacitors.

You can test the amp section by using a patch cord from another device with a preamp-out or a phone direct into the 2230 Main-In RCA Jacks on the back. Turn phone down first, start music, then slowly raise phone volume. If both sound equal and good, the amp is not your issue and points to prior circuits like the Tone and Pre-Amp section. Conversely, you can jump your Pre-Out signal into another known working amp and see if same problem occurs which would isolate your Pre-Amp section as well.

Thanks for the great reply! I have seen some of the 2230 threads, and have read the ones with channel issues too. Lot's of great stuff on here. I did the first part of what you wrote - I cleaned it up a bit in a similar fashion to what you described, and I DID use Deoxit D5 on the pots and switches, but I might do another round.

On the other threads I read, I hadn't seen anyone mention one channel not being affected by the tone controls.

I'm going to try a few of your ideas, Thanks!

 

[MrBillinMinn]

Thanks for the great reply! I have seen some of the 2230 threads, and have read the ones with channel issues too. Lot's of great stuff on here. I did the first part of what you wrote - I cleaned it up a bit in a similar fashion to what you described, and I DID use Deoxit D5 on the pots and switches, but I might do another round.

On the other threads I read, I hadn't seen anyone mention one channel not being affected by the tone controls.

I'm going to try a few of your ideas, Thanks!

And thanks for the schematic!

 

[ivandezande]

I can't believe it works at all looking like that....

Put it in the laundry sink with top and bottom covers removed, spray your favorite cleaner all over, and hose it down with hot water. Repeat. Let it dry, if your oven has a warm setting that'll work.

DeOxit all controls. Then we can troubleshoot.


Keep in mind every 2230/45/70 I've worked on (a lot) has needed more or less all transistors replaced to be quiet. Even the outputs.

 

[MrBillinMinn]

I can't believe it works at all looking like that....

Put it in the laundry sink with top and bottom covers removed, spray your favorite cleaner all over, and hose it down with hot water. Repeat. Let it dry, if your oven has a warm setting that'll work.

DeOxit all controls. Then we can troubleshoot.


Keep in mind every 2230/45/70 I've worked on (a lot) has needed more or less all transistors replaced to be quiet. Even the outputs.

I should have written my post better. I posted the "before" pictures in my post, but by the time I posted those pics I actually HAD cleaned it up and used deoxit on all of the pots. I cleaned it up similarly to what jd3rdcoast suggested. I didn't plug it in until it I had the dirt & dust pretty well cleaned up. I'll post a "current condition" pic soon.

I'm trying to learn about this stuff on a kenwood kr-3010 receiver (non working so far) and I am just starting to get familiar with circuit boards. This Marantz one might be a job for someone more qualified than I am. I recently paid about $700 to have a non working Pioneer SX-1010 completely rebuilt, so I'm hoping not to go that route with this Marantz 2230.

Thanks for reply!

 

[jd3rdcoast]

I forgot to mention an easier way to check if problem is in PreAmp or Amp. Use a set of patch cords from Pre-Out and cross the Left Pre-Out to Right Amp-IN and vis-versa. If the problem that was in Left channel moves to the Right speaker we can assume the issue is coming from the Left Pre-Amp section. If problem remains in Left Speaker then issue should be in the Left Amplifier board circuit (P750).

It's also a good idea to try and resolve the current issue prior to shot gun cap and transistor replacements. That way will know if you introduce any problems due to mistakes in your following work. Perform same upgrades to each channel once have isolated and repaired the problem in left side.

 

[ivandezande]

I should have written my post better. I posted the "before" pictures in my post, but by the time I posted those pics I actually HAD cleaned it up and used deoxit on all of the pots. I cleaned it up similarly to what jd3rdcoast suggested. I didn't plug it in until it I had the dirt & dust pretty well cleaned up. I'll post a "current condition" pic soon.

I'm trying to learn about this stuff on a kenwood kr-3010 receiver (non working so far) and I am just starting to get familiar with circuit boards. This Marantz one might be a job for someone more qualified than I am. I recently paid about $700 to have a non working Pioneer SX-1010 completely rebuilt, so I'm hoping not to go that route with this Marantz 2230.

Thanks for reply!

Ah gotcha. That's good.
$700 is steep......they better have replaced near everything.

 

[MrBillinMinn]

I forgot to mention an easier way to check if problem is in PreAmp or Amp. Use a set of patch cords from Pre-Out and cross the Left Pre-Out to Right Amp-IN and vis-versa. If the problem that was in Left channel moves to the Right speaker we can assume the issue is coming from the Left Pre-Amp section. If problem remains in Left Speaker then issue should be in the Left Amplifier board circuit (P750).

It's also a good idea to try and resolve the current issue prior to shot gun cap and transistor replacements. That way will know if you introduce any problems due to mistakes in your following work. Perform same upgrades to each channel once have isolated and repaired the problem in left side.

Thanks again! I am trying to get back to working on the 2230, and I finally got around to using your easy preamp vs amp plan. I did that and it sent the left problem to the right, so it makes sense that it's on to the preamp side. I'm wondering if I should buy one of those "rebuild kits" and start with the preamp part.

Thanks again. Bill