• 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

MCS 3233 with several issues to fix

ryuuoh said:
I believe that unit does not have a protection relay, instead it uses fuses for speaker protection.
This thread offers some info on correcting the DC offset (the cause of your turn-on thump).
http://audiokarma.org/forums/index.php?threads/mcs-3233-receiver-weak-left-channel.626608/
Click to expand...
I agree. That has to be it. I had the case open today but never thought to look for a speaker relay -- or lack of one. But anyway, you are correct -- it has two fuses labelled "speaker protection." Thanks for the info and link. (This is a surprisingly nice-sounding receiver BTW. I'm sort of shocked -- in a good way.)
 
You can adjust the DC offset by changing the resistance of the R507/R508 resistors. Only do this after you are sure that all transistors are well matched and resistors have not drifted with age or damaged from blown outputs.
The original resistors are 1.2K. A change of 100 ohms its approx. 15-20mV. If your DC offset is 30mV positive, a 1.3K resistor will get it to around 10-15mV.
If your DC offset is + or - 20mV or better, then its fine. Best to check DC after the bias has been set and on for 30 minutes
 
Hey, MCS/AKers. I have an MCS 3223 (no typo) Stereo Receiver that seems to work fairly well and if I read the threads correctly would offer 23 watts per channel. That's surprising as I would guess more like 50 as it's quite loud at only 2-3 on the volume knob listening to FM stereo (weak signal as well). If anyone knows how to go about determining the faceplate bulbs values and what to replace them with I would appreciate it. One is still working while the other two aren't illuminated. Looks like I'll have to solder them as well. Thanks for any response on this in advance.
 
Walle said:
Hey, MCS/AKers. I have an MCS 3223 (no typo) Stereo Receiver that seems to work fairly well and if I read the threads correctly would offer 23 watts per channel. That's surprising as I would guess more like 50 as it's quite loud at only 2-3 on the volume knob listening to FM stereo (weak signal as well). If anyone knows how to go about determining the faceplate bulbs values and what to replace them with I would appreciate it. One is still working while the other two aren't illuminated. Looks like I'll have to solder them as well. Thanks for any response on this in advance.
Click to expand...

Hey there, Walle. I recently relamped a 3233 (not 3223) with help from generous Akers in these two threads below. Should help. Am guessing that relamping either of those models would involve the same process, sockets, lamps, etc. Good luck.

https://audiokarma.org/forums/index.php?threads/mcs-3223-ac-dial-lamps.832205/

https://audiokarma.org/forums/index.php?threads/mcs-3233-lamps.284003/
 
Since we are talking about MCS, I wonder if someone could help me out. I am repairing a MCS 3233 Receiver and the glue around C-516 on the PA board has corroded the leads of the Zener diode next to it. The Zener is damaged and needs to be replaced. There is no component designation next to the Zener, so the only point of reference I can use is C-516. I searched and could not find a maintenance manual for the receiver. Does anyone know the specifications for the Zener? Thank you.
 
Narodow said:
Since we are talking about MCS, I wonder if someone could help me out. I am repairing a MCS 3233 Receiver and the glue around C-516 on the PA board has corroded the leads of the Zener diode next to it. The Zener is damaged and needs to be replaced. There is no component designation next to the Zener, so the only point of reference I can use is C-516. I searched and could not find a maintenance manual for the receiver. Does anyone know the specifications for the Zener? Thank you.
Click to expand...
That is a WZ-120. 12V .5W zener diode. A 1N5242B would be a modern replacement or a 1N4742 would work if you have one laying around. Scanned Document8.jpg
 
Yet another person with a MCS looking for help. i have a 3223 and just finished recapping the power supply and the bulbs. however, now i noticed that the right channel has more volume than the left channel, sounds a bit louder. how can I go about to fix this? I am also a newbie and recapping tje thing was a pain, but it was somewhat succesfull, but now, how can I get the volumes even? I also noticed that when I'm using the turntable, after a bit the left channel dies completely, but i think that's my cable because it gets fixed when I wiggle the cables, but is it really my cable?
 
sabalennon said:
Yet another person with a MCS looking for help. i have a 3223 and just finished recapping the power supply and the bulbs. however, now i noticed that the right channel has more volume than the left channel, sounds a bit louder. how can I go about to fix this? I am also a newbie and recapping tje thing was a pain, but it was somewhat succesfull, but now, how can I get the volumes even? I also noticed that when I'm using the turntable, after a bit the left channel dies completely, but i think that's my cable because it gets fixed when I wiggle the cables, but is it really my cable?
Click to expand...
This thread may help you. https://audiokarma.org/forums/index...-one-channel-is-weaker-than-the-other.941484/
The 3223, 3233, 3235 all use the same power amp section, just run from different voltage levels.
 
sabalennon said:
Yet another person with a MCS looking for help. i have a 3223 and just finished recapping the power supply and the bulbs. however, now i noticed that the right channel has more volume than the left channel, sounds a bit louder. how can I go about to fix this? I am also a newbie and recapping tje thing was a pain, but it was somewhat succesfull, but now, how can I get the volumes even? I also noticed that when I'm using the turntable, after a bit the left channel dies completely, but i think that's my cable because it gets fixed when I wiggle the cables, but is it really my cable?
Click to expand...

It could be the cable.
I lived with a LOUD hum if my red turntable cable got moved. Was ok if it never moved.
Finally just replaced the RCA ends. Since yours acts up when moved it could be the cable OR if it's where the cable plugs into a receiver or amp it could be that jack is loose and needs attention. Good luck.
 
Okay, can we talk about the MCS 3233 meters LOL? My signal strength meter is not working. A video on YouTube gave tips on how to work the needle free. The video showed that the person was able to free his -- and make it operational by removing his wonky signal strength meter from the back of the front panel, opening it up by slicing two piecess of clear tape, using a spray + jewelers screwdrivers to free up the needle, etc. It worked.

But, someone has already been inside my meter. Bad sign = the yellow wires going to my meter are held on by two big blobs of solder. Inside, I saw that a winding (maybe two) of the very thin copper wiring were no longer wound around anything. Inside I also saw a metal terminal where something was once soldered to it -- but no longer is. Should I pull the meter completely (by unsoldering the two yellow wires) really get inside the meter, and see if I can rewind it? Maybe that thin copper wire that's floating around inside needs to be soldered to that one silver terminal?

If I am unsuccessful at fixing this, should I unsolder/remove the two yellow wires going to the meter, thereby taking it out of the circuit? Or is it okay where it is? I don't want anything shorting out -- if that is possible. Or degrading the sound. Many thanks in advance.

BTW, I've seen several 3233 "tuning" meters available for sale, but not a single "signal strength" meter. Even if I bought one, would it be a working one?

signal strength meter better.jpg
 
ryuuoh said:
Most likely your meter movement is toast. Maybe try to find a close size cheap China meter and transfer the dial face to it.
https://www.google.com/search?q=Panel+Meters&tbm=isch&chips=q:panel+meters,g_1:analog:ogQ2bfuT61s=&client=firefox-b-1-d&hl=en&sa=X&ved=2ahUKEwjCqbHEoK72AhX3AjQIHcIRD9cQ4lYoAXoECAEQHg&biw=1288&bih=719
Click to expand...
Thanks for the reply and suggestion. Sounds like s good option. If all else fails, I can keep the non-working meter in there for looks and move on to other things. but I really like the look and sound of this receiver and want to get it back to "normal." Cheers.
 
You must log in or register to reply here.
Back
Top Bottom