C31V Won't Power Up

[Drayman]

Hi, newbie here- Thanks in advance for your help.

I have an early C31V with the volume buttons (Serial ER1041). It's been poorly stored in a box in a shed, but otherwise undisturbed for years.
PROBLEM: Plug it in, press red Power button, it wont turn on. Totally dead. No clicking, no lights, nothing. I don't have the remote so can't say if that would work.

At first I assumed it was the power relay. They are still made and can be easily acquired. (Potter & Brumfeld T90 Series - Now TE T9A series.) But it has no markings- is it 12V, 5V, or 5-12V?

Then I read these threads about button panel issues:

Problems with my C31V preamp

My C31V is having problems with the channel selectors. Some of the buttons on the front panel work (Speaker 1, Speaker 2, Mono, Phono, VCR Copy 1->2, VCR Copy 2->1) while the rest do not. Very similar issues described in these threads...

audiokarma.org

https://audiokarma.org/forums/index.php?threads/new-to-me-c31v-issues.626867/
https://audiokarma.org/forums/index.php?threads/mcintosh-c31v-issue.241770/

Is it possible the unit doesn't fire up because the Power button isn't working?
Would cleaning the panel be in any way bad?
Alcohol, acetone, DeOxit 5?
I don't see any burned traces, and the last time plugged in it worked, although it was looooong ago,

Any and all help appreciated!

 

[clinic-audio]

Hello Drayman

Very difficult to see what is wrong when the unit is not in front of me

Have you checked continuity of the switch ?
C31V got troubles after some years .
The factory used strong adhesive who dammage tracks on pcb dehind the front panel .

The glue fixing the iron part is corrosive and destroy the tracks on the printed circuit board

check if every switches are working or not

 

[Drayman]

Thanks, clinic-audio!
That makes more sense than the power relay.
It looks like the whole bottom row is dark, top row still shiny.
How do I check the switches? Multimeter I assume, but which connections?
Also, if it is the glue, how to fix it without breaking it?
I presume the boards are not available. Does that mean replacing every trace on the PCB with solder?
This is getting deep!
Thanks again for your fast reply.

(Image: circled switch is red power button.)

 

[clinic-audio]

That makes more sense than the power relay.Yes !
It looks like the whole bottom row is dark, top row still shiny.yes, not good in my point of view !
How do I check the switches? Multimeter I assume, but which connections ? that's the question ! no , no, seriously just the part with two pin just search contact with your ohmmeter when you puch on the knob
Also, if it is the glue, how to fix it without breaking it ?acetone only where the glue is
I presume the boards are not available. Yes, there are not but I can make one if you need it but it is very very expensive
Does that mean replacing every trace on the PCB with solder ? no not necessary only the dammaged are
This is getting deep ! yes but I already did some more complicate
Thanks again for your fast reply. you are welcome

Patrice
working on MCINTOSH units since over 45 year long

 

[Drayman]

Thanks, Patrice!
Here we go, will update...

Dré

 

[act1292]

If I remember correctly, the adhesive covered only 2 or 3 traces. I don't recall the power button being one of them but I wouldn't rule it out. It's been a while since I did troubleshooting on this.

 

[Drayman]

All switches are functional. Continuity across pins only when switch is pressed.
Fuses are all good, too.

 

[Drayman]

There is nothing wrong with the PCB. The traces are all good and there is continuity to the cable connectors. Now I'll never get the thing back together...
Back to power solenoid?

 

[clinic-audio]

your fuse holder look very oxyded
did you teck fuses contacts with your ohmmeter to seeif fuse is fine