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Marantz 1070 left channel issue

N

N8Nagel

Addicted Member
The kitchen system for a long while has been a Marantz 1070, some flavor of SACD-capable DVD player, and more recently I've been using it to test my recently acquired cassette decks. The 1070 has been rock solid as it should be as it was sold to me as recapped and adjusted (it was originally supposed to be a "congrats on the new job" gift paired with a Sony XDR-F1HD, but intended recipient took a H/K 330B instead as she apparently isn't a big radio listener at work so the Sony would have been wasted on her and it ended up in the kitchen instead...)

I have noticed on power up only very recently that the left channel is missing. Originally this made me recheck cables, other (new to me) components etc. However what I've found is it's related to the volume control on the Marantz. If I turn the volume up, eventually it will kick in, and stay in as I turn the volume back down. Is there *anything* other than the physical volume control itself that could be causing this?

If the seller is reading this please don't take this as a sign that I'm in any way unhappy... it's been in regular use ever since I got it, it still works/sounds great other than the above, it's probably about the same age I am, and I thought you gave me a really good deal on it... I just want it to be perfect :)
 
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Agree with above. The relay contacts are dirty. Either clean the contacts, or get another relay. The way to test is to take the cover off so you can see the relay. playing at a low volume, best with headphones, tap the top plastic cover of the relay with the back of a palin pencil or other non conductive stick. If relay is dirty, tapping will make it go on and off
 
OK... so any way to get into the relay short of destroying the cover? I don't see how to without desoldering it which would require major disassembly...
 
Only good way is desoldering..
-Desolder
-Remove cover
-Take a piece of printer paper and spray it with deoxit
-Run it between the contacts, effectively "polishing" them. Should be good as new
 
I was afraid you'd say that. Familiar with the paper trick but there seems to be absolutely no way to release the cover in situ and I don't have the time to completely disassemble this thing at any time in the forseeable future :(
 
Don't clean the relay, replace it. This is mandatory for all vintage amps, even when the relay is seemingly all rift. An old (and therefore worn) relay the biggest source of distortion in an amp.
 
Before you get into the relay, get a pair of interconnects and test the pre out/main in connection. If the external connection solves your problem, clean the rca's interally with pure alcohol, applied with a q-tip (ear bud). The rca's on a 1070, are meant to switch internally when there is no external interconnect between pre and power amp sections. They fail to do so when they aren't clean. Off course, you may choose to leave the external interconnects permanently in place. I had the same problem as you've described - cleaned rca's, no problem since.
 
Thanks KC it's really just a time issue right now. I'm getting crushed at work and what's her face's lease is up at the end of next month. Much as I'd like to be playing with stuff I just swapped in my old Sansui and killed the spare bedroom system; priority now is getting stuff "safe to move" not working :(
 
OK so I finally broke down and bought a new set of picks - Pratt Read this time, not Harbor Freight, and I was able to pop the top on the relay without major disassembly.

NO SOUND... WHAAAAAAAA

got the toner out and started probing... no signal out of volume control... what the heck, deoxit it... It's alive again! Deoxit to the rescue!

*whew*

OK, now I can have a spare bedroom system again :)

KC, I found during the process of troubleshooting that the pre out/main in jumpers are not required for a 1070, did you need those for something else? I haven't touched them since I got the unit but when nothing is connected to the RCAs they apparently short so no jumpers required.
 
Long overdue update. After moving it died again; this morning I finally had time to address it, I burnished the relay contacts with 2000 wet/dry wet with D5 and aggressively bend the fingers for more pressure; working again.

this time I was smart enough to take pictures so that I can search for a replacement relay to have on hand when it fails again. (I wasn't so smart when I did this procedure on my HK 725; the relay cover was missing and it was actually bypassed which made an alarming noise if the preamp was powered down while the power amp was still powered up, so I had to fix it)

So now I have a spare unit; I can now address the same issue on my Luxman R-1120... (left channel doesn't come right in when it comes out of protection, has to be that old crusty relay)

Pretty soon I'm going to have a whole stack of units waiting for new protection/muting relays... guess all my stuff is about that certain age.
 
Glad your 1070 is fixed. I had similar problems with mine,one channel was in and out. After troubleshooting found amps
and preamps were fine. My problem was the balance control. Resoldered connections and that lasted about 6 months.
Finally had to bypass one side of the balance control. The resistive element is connected by a brad and the connection was not making.
Now ok . The 1070 is a fine sounding amp. With the loudness control in , bass is best of any of my other amps.
 
Well that lasted a year and a half.

Does anyone know of a modern equivalent to the original relay? Omron Type LC2-C. Omron's tech support didn't have anything for me when I asked back in late 2016. Left channel went flaky again this AM when I kicked it on to listen to the radio. There's really no room in there to finagle something "wrong" in unless my memory is incorrect.
 
Well this time it wasn't the relay although I did the paper and D5 thing again... it was the left channel pre out/main in jacks. one of the little fingers apparently got oxidized. Ah the joys of 40 year old gear. Still sounds good when it's working right anyway. kc did a nice job on this one apparently.
 
singhVC said:
Before you get into the relay, get a pair of interconnects and test the pre out/main in connection. If the external connection solves your problem, clean the rca's interally with pure alcohol, applied with a q-tip (ear bud). The rca's on a 1070, are meant to switch internally when there is no external interconnect between pre and power amp sections. They fail to do so when they aren't clean. Off course, you may choose to leave the external interconnects permanently in place. I had the same problem as you've described - cleaned rca's, no problem since.
Click to expand...
Thank you for this post 8 years ago. I bought a 1070 as junk, advertised as left channel not working. Started troubleshooting and google found this thread. Plugged in an RCA cable between the main in/pre out jacks, since there were no interconnects, and she sings perfectly now. Now, on to cleaning.
 
I have read this thread countless times to try and see if i could find the answer to my problem but to no avail so here we go;

I got a Marantz 1070 from my neighbor 1 year ago and it sounded perfect.

In the last month, there had been of loud buzz coming out of the left speaker all of a sudden after prolonged listening.

I decided to order a kit for a full recap wich i installed.

Now, the right channel works fine but the left channel is super weak and distorted..

I have tried the main in pre out bridge trick but it does not change anything.

The problem seems to come from the preamp because if i plug a rca cable in the left main in and touch it, it will buzz as loud as the right channel does if i do the same.

Any suggestions?
Thanks!
Benoit
 
DogHouse11 said:
I have tried the main in pre out bridge trick but it does not change anything.
Click to expand...
Not sure what you mean.
Using the 1070 pre-out to another amplifier, is the distortion still present?
Connecting an iphone/ipod/... at minimum volume to the 1070 Main-In then slowly increase ipod volume, is the distortion still present

DogHouse11 said:
the right channel works fine but the left channel is super weak and distorted..
Click to expand...
Dirty switches are common in vintage gear. Try first rocking each switch in turn before fully switching 10-20 times, looking for any change in audio would point to suspect switch.
 
mbz said:
Not sure what you mean.
Using the 1070 pre-out to another amplifier, is the distortion still present?
Connecting an iphone/ipod/... at minimum volume to the 1070 Main-In then slowly increase ipod volume, is the distortion still present


Dirty switches are common in vintage gear. Try first rocking each switch in turn before fully switching 10-20 times, looking for any change in audio would point to suspect switch.
Click to expand...
Connecting my phone in the main in
 
There was no distortion and good volume on both channels when connecting my phone directly to the main in.

I went thrue all the switches with deoxit and generous amounts of rocking. This did not impact the problem. I tried deoxit thrue the front panel for the slider switches, should that be enough?

Thanks for taking the time!
 
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