lttnorth
New Member
Just out of curiosity, why is the owner’s manual a big deal? It’s really boring and standard; how is it any better/different from the service manual?
MCS 3125 acquired - rare catalog included?
Just out of curiosity, why is the owner’s manual a big deal? It’s really boring and standard; how is it any better/different from the service manual?
NAD80
Super Member
The service manual on a lot of units leaves out the operation of the unit, sometimes the specs as well. You have a "new" unit and at times it's hard to know all the features and hook ups of the unit. Like soft clipping, bridging, phono loading, speaker loads, fuses. Ittnorth Welcome to AK.
goodolpg
Just an old fart trying to help.
Might be boring, but the 3125 owners manual is extremely rare.
Granted for its size, the 3125 controls are rather pedestrian and it does not have as many "bells and whistles" (though it has WAY MORE lights) than many other monster receivers.
One thing I am curious about a statement on the MCS 3125 page at classic receivers https://classicreceivers.com/mcs-3125
that states "MCS was the house brand for JC Penney back in the 70's and the 3125 was their top of the line receiver at the time. It pumps out 125 watts per channel but the user manual warns that it is capable of 200 watts per channel."
Would like to see if that is true.
Service manual does have some specs but no operating procedures.
Jan 1981 Stereo Review article says the Impedance switch "does not seem to affect the amplifier operation but merely changes the sensitivity of the clipping light to suit either 8 or 4 ohm loads". But "the instruction manual makes no mention of its function".
goodolpg
Just an old fart trying to help.
You anywhere near Ceres, CA?
One of mine came from there (of course it could have been originally sold somewhere else), the other from Kennewick, WA.
Hifirob2
NEC and Klipsch rock!
Thanks for that. Now, if they had called me back when they were designing this thing, I would have substituted the mic mixing and impedance switches with a subsonic filter, and an FM IF bandwidth selector.
I think mine came from Georgia. Wherever it was from, I'd like to thank the person that (most likely) maxed out their JC Penney credit card to get it new.
I think mine came from Georgia. Wherever it was from, I'd like to thank the person that (most likely) maxed out their JC Penney credit card to get it new.
lttnorth
New Member
It does indeed!
Here are pics as promised; it is real. I’m unable to scan until tomorrow though. Speaker impedance explained in the second photo.
Attachments
Hifirob2
NEC and Klipsch rock!
Thanks so much for the scan. I really appreciate it! I hope to never see my clipping lights come on. My building has pretty thin walls, so I can't get away with crazy high volumes.
I also wish there was a way to over ride the servo lock when tuning FM stations. After you remove your fingers from the tuning knob, the servo kicks in, and tunes the station for best signal/lowest noise. Weaker stations from far away that are right next to strong local ones get pulled over to the stronger one as soon as I release the tuning knob (usually). A minor complaint, but I would like to disable that feature. I listen to a lot of stations from San Diego, - about 117 miles SE of me.
I also wish there was a way to over ride the servo lock when tuning FM stations. After you remove your fingers from the tuning knob, the servo kicks in, and tunes the station for best signal/lowest noise. Weaker stations from far away that are right next to strong local ones get pulled over to the stronger one as soon as I release the tuning knob (usually). A minor complaint, but I would like to disable that feature. I listen to a lot of stations from San Diego, - about 117 miles SE of me.
lttnorth
New Member
Not counting the cover, table of contents and the foldout function block diagram... 25 pages.
Lavane
Lunatic Member
The other end of the valley. Close to Yuba City.
The 3125 is big and garish but if I had the chance to pick one up in good condition at a good price, I would jump on it. I love anything that is different or not the usual big brand item from the 70s......although I love the big brands as well. I decided I was going to pick up a STA 2000 a few weeks ago and started the hunt for the right deal when I came upon the SA 2001 I just got. If something is in good shape (or at least decent) and is a reasonable price, I am interested in it........since I just traded my PL 518 I will look for an MCS turntable.
woofercooker
Well-Known Member
Could someone point out where the clipping indicator is on this(3125) receiver? I can't seem to locate mine. Thanks.
Hifirob2
NEC and Klipsch rock!
In the stack of function LEDs to the left of the tuning knob, I think the clipping indicator is near the bottom - by the protection LED.
woofercooker
Well-Known Member
Thanks, I see it now... Should have looked closer last night.
goodolpg
Just an old fart trying to help.
More likely your crackling noise is a cracked PCB solder joint that expands ever so slightly when it warms up or a faulty signal transistor.
First step is to see if it occurs on both channels. If it has a pre-main jumper that would also help in isolating the problem.
First step is to see if it occurs on both channels. If it has a pre-main jumper that would also help in isolating the problem.
lttnorth
New Member
so, an update. I uploaded the fully scanned manual to HiFi Engine since it was too big to be uploaded here, but I guess it's being reviewed now? Anyway, there isn't a page set up yet for the 3125. How does one go about doing that? Not totally familiar with using that site...
I did however upload the cover image of the receiver from the manual with some specs here
https://www.hifiengine.com/gallery/images/modular-component-systems-model-3125.shtml
I did however upload the cover image of the receiver from the manual with some specs here
https://www.hifiengine.com/gallery/images/modular-component-systems-model-3125.shtml