2385 Volume pot problem

[ehud99]

Hi guys,
Having problems with the volume knob. it sound dirty scratchy. any ideas on how to get there for a cleaning?
How can I make a deep thorough clean?
If it does not work, does it have any (non original) high quality replacements pots that I can purchase online?
I prefer "planting" a new pot, this one makes me a lot of trouble..
Thanks!

 

[Velox]

Hi guys,
Having problems with the volume knob. it sound dirty scratchy. any ideas on how to get there for a cleaning?
How can I make a deep thorough clean?
If it does not work, does it have any (non original) high quality replacements pots that I can purchase online?

The 2385 volume control is a special potentiometer, rare and I know of no reproductions. Replacements would be very occasionally seen on eBay or similar. Usually a good cleaning with contact cleaner then treatment with FaderLube or similar will do the trick. Unfortunately to get at this control directly the best plan is to remove that board. There is a daughter board on the tone board that just unplugs. But to remove this board assembly to obtain access to the tone/volume pots you really need to disassemble the front, remove the faceplate etc. It is not that difficult but requires going slowly and making sure you create diagrams or mark connectors for exactly where they go, and take lots of photos so you get it back together correctly. With the front of the 2385 off the chassis you could probably get some access to the controls without actually removing the board, but I removed mine as I was going through rebuilding the boards anyway. Good luck with your project

 

[wlhd1610]

As Don says,it requires a fair amount of disassembly to properly access it.
No known replacements available other than a donor pot ,which although rare are available,so be gentle with yours.

Bob

 

[ehud99]

Thank you guys!

 

[ehud99]

The problem gor worst. sometims I am losing the right channel so I Finally managed to find time for it. I am stuck with the disassembly..
On the right side, something is preventing me from pulling the front panel out. what can it be? what am I doing wrong?

IMG-20190730-WA0007

• ehud99
• Jul 30, 2019

IMG-20190730-WA0008

• ehud99
• Jul 30, 2019

 

[Velox]

If you are wanting access to the volume pot then you have much more disassembly to do! Look at my photo in this thread, all of the front panel attachments must be released to open up the tone/preamp board where the volume pot is mounted. That means removing the dial plate, pointer, complete tuning string and pulleys, gyrotouch wheel etc. The lamp assembly must be released from the front along with the meters. ALL of the front plate attachments are then released meaning all jack nuts (stereophones, dubbing etc), button switch screws, power switch screws etc. ALL of the control nuts must be released. Every screw on the front is removed even the balance control screws. The bottom panel has to be removed completely. On the right side of the front you still have the screws in place that hold the right side string pulley plate, those come out. You need to photo and diagram for yourself all of these areas so you can reassemble properly. It is a lot of work but if you go slowly and carefully it will be ok. In the service manual it shows the dial string, pulley and wheel setup which will help with reassembly. The service manual is free online (https://www.hifiengine.com/manual_library/marantz/2385.shtml) free membership. Search on eBay for Marantz 2385 there are tone/preamp boards some with volume pots some without. Good luck with your project!

 

[SoCal Sam]

Previous post has disassembly covered. Time consuming but not difficult. Also, be sure to clean the interconnects on the back panel. Remove hoops, spray, and work contacts with the hoops.

 

[mikey99]

The layout of the 2385 looks very similar to the 2500. On my 2500 I was able to remove the preamp board containing the
volume control from below. Flip the receiver up on end , remove the various screws and retaining nuts from the pots, and
carefully maneuver the board out.

 

[ehud99]

The layout of the 2385 looks very similar to the 2500. On my 2500 I was able to remove the preamp board containing the
volume control from below. Flip the receiver up on end , remove the various screws and retaining nuts from the pots, and
carefully maneuver the board out.

Mikey, where have you been till now?

 

[ehud99]

Anyway, thanks for the push! I managed to access the board and to clean the pot. It is still not perfect but much much better but now, I also clean the push buttons and the other pots but bow, for some reason, Tape 2 input does not work any thoughts on that?

Previous post has disassembly covered. Time consuming but not difficult. Also, be sure to clean the interconnects on the back panel. Remove hoops, spray, and work contacts with the hoops.

Thank you, what do you mean "hoops"? Sorry, I am not familiar with the jargon

 

[SoCal Sam]

...Thank you, what do you mean "hoops"? Sorry, I am not familiar with the jargon

My bad, I forgot Marantz does not have hoops in the interconnect. The interconnect has internal levers that are contact points and can become dirty and lose contact. You have to work the levers to get the cleaner to remove the oxidation. Use a regular RCA cable for that.

 

[wlhd1610]

Did you get the pins properly lined up on the pushbutton board to preamp board connections?
They are hard to see and can be a royal pain.

Also the 2385/2500 pushbutton switches are unlike other Marantz units and require extra attention when cleaning.

Bob

 

[catrafter]

Bob is correct, royal PITA.
Also, is the board with the front panel dubbing in/out jacks plugged in properly? I don't know if that would kill only tape 2.

Tom

 

[ehud99]

D

Did you get the pins properly lined up on the pushbutton board to preamp board connections?
They are hard to see and can be a royal pain.

Also the 2385/2500 pushbutton switches are unlike other Marantz units and require extra attention when cleaning.

Bob

Do you mean the "filters /loudness" push button board? I am not sure.. is it possible that some pins were connected to the rear sockets row and some to the front ones? are there two sets of rows in each socket?

 

[wlhd1610]

The PT top board has three multi pin plugs that connect to the lower preamp board.
The left side PU board has a similar arrangement with connecting to the lower P400 selector switch board.If you messed with the left side boards there are even more(at least a dozen) connectors that can easily be incorrectly hooked back up.

I thought I read that you pulled out the preamp board to access the 4 gang volume control.
Major pain to make sure they all line up...






Bob

 

[ehud99]

Hi Everyone
So Tom was right.. it was the 3 pin connector above the dubbing connectors that was unplugged.
And thanks to Mikey, I was managed to easily access the board again from the bottom and to do another cleaning on the volume pot. This time I managed to spray the faderlube from the bottom side and now it is clean and quite.
Thank you all!
Another question - Do you keep you unit on all the time?
I do but it gets real hot, is it normal? I can put my hand on the cover but it feels very warm.