• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Marantz 4140 questions

Richs_Trains

Richs_Trains

Well-Known Member
hey all, I picked up a 4140 that was fairly dirty with lights out and a bent volume knob (the seller broke the plastic out of the inside of the knob so it would 'look' straight). I am pretty fair at mechanical things, but no so much at diagnosing electronic problems. After replacing all the lamps, using my hot air gun to heat the shaft and get the volume control 90% straight and a general clean up, I re-capped the power supply and the filter caps and cleaned the controls and switches. When I started, I had no rear channels and only the front left in four channel mode. After cleaning the remote/local and the 4ch/2ch power switch, I had all channels working. The only problem I seem to be having is the sound does not come in immediately after the relay clicks, but comes in like it's 'warming up' if I just leave it and not always. If the relay clicks and I don't have sound a quick juice of the volume control brings everything in. I have had this symptom before and it was always something still dirty. I have gone back and cleaned the remote/local, 2ch/4ch and volume control and it didn't cure the problem. Once the sound is functioning, it works without fail. I am wondering if it could be the relay, I did not clean or change it out and I am unsure of a direct replacement from Mouser. Anyone have any insight or suggestions? It actually works fine once you turn it past 1/4 and get the channels to kick in, but I hate not having things right. Thanks Rich

4140_1.jpg 4140_2.jpg

and cleaned up..
4140_3.jpg
 
Register to hide this ad
I would do another cleaning of all the switches, as well as the pre-out main in jumpers and contacts. The dirty dusty units will sometimes require a couple cleanings.

You've confirmed that all four channels work and that cleaning has improved the situation. Try it again making sure you get them All cleaned.
 
bryans12v said:
I would do another cleaning of all the switches, as well as the pre-out main in jumpers and contacts.
Click to expand...


Okay, thanks for the input, I cleaned everything again, polished the inputs with a dremel and blew it out with air (had to haul out the compressor), no change. So, I decided to go after the relay. I had one that was supposed to be for a 4400, so I installed it and powered up on a dbt, no click, no sound. I figured I'd clean the old one and used ultra fine cloth backed paper, re-installed the relay and it has worked every time so far (fingers crossed) and sound comes as soo as the relay clicks. Thanks all!! Rich
 
The relay seems to have been major problem, still had some issues with channels not being there without turning up the volume, but cleaning the switches on the back again seems to have corrected that. I did recap the power amps and found that C605 a 100uf 25v cap had one leg off, don't know what function it served, but the unit worked with it not functioning. Anybody know what C605 does? Thanks Rich
 
Haven't looked at a schematic if this lately but I belive this cap is off the emitters of the diff pair and only 25v rated.

Post a snip of the schematic if you have it handy, I only have the paper version at home.
 
I had the same kind of problem. The pots on the 4-channel Marantz are horrendously tough to get at and clean. Especially the rear channels. All I can suggest is make sure you thoroughly clean everything with DeoxIT. That made the difference for mine. Good luck.
 
You must log in or register to reply here.
Back
Top Bottom