MCS-3253 vintage receiver mystery

[Tomcow]

Any thoughts on a vintage receiver MCS-3253 in this case that relays on perfectly but has absolutely no output at all.No hiss,no sound,nothing.It’s as if something isn’t connected somewhere.Full volume knob all the way up,nothing.

 

[goodolpg]

First thing I would check is tape monitor and dubbing (if it has those) switches.
Next I'd have to wonder if the controls might be dirty and need cleaning.
For starters, WITH THE POWER OFF maybe turn any knobs from end to end over and over and over...source selector, speaker selector, balance, monitor, etc. Do all of them, maybe you'll get lucky and knock some crud off a switch that hasn't been used in decades.

Can you post pictures of the front and back so we can see how things are wired and position of the switches?

 

[Tomcow]

All controls were cleaned and deoxided.Everything was working well until I slightly adjusted what I thought were the meter adjustments trim pots.I went to hook it up and noticed both output meters were pegged!!! Now nothing.No sound,no meter movement,nothing.But when I turn the receiver on the speaker relay clicks and the receiver all lights up,just silence.

 

[Tala Mink]

If the meters were pegged there was probably a sizeable amount of dc on the outputs of the amp, if there are fuses from the power supply to the amp section that would cause them to blow.

if a fuse that supply's power to the amp is blown that would allow the relay to click but there would be no sound, if the fuse is replaced it will probably blow again or the relay wont click which is pretty likely if there was enough dc to max out the meters.

I cant find a schematic for the 3253 so this information may be completely useless if it only has one fuse.

 

[petehall347]

it is apparently the same as a NEC AUA-7000E
https://audiokarma.org/forums/index.php?threads/mcs-3253-receiver-service-manual.753960/

 

[Tomcow]

Follow up.I rechecked the circuit boards closely under a good light and found two transistors with a loose solder joint.Resoldered both along with checking all others and receiver plays fine now.Checking old solder joints is important when troubleshooting!!

 

[Catmanboo]

Follow up.I rechecked the circuit boards closely under a good light and found two transistors with a loose solder joint.Resoldered both along with checking all others and receiver plays fine now.Checking old solder joints is important when troubleshooting!!

That is lesson no.3 of basic troubleshooting. Lesson 1, fuses check. Lesson 2, switch & pot cleaning. Usually my sequence, anyway. Good job sniffin' that little detail out, now to