Commodore 116 completely dead

[Flavio]

Hello,
Just received a C116 that completely do not start. Not even the power led turns on.
As usual I am not a technician but this sounds good to me... my hope is that the custom chips are ok and "only a more standard component" is dead.
Any suggestions?
I have tried measuring "some" voltages and I've noticed there are 0V on the 7805... could this be an issue on the 7805 itself or somewhere else?
Thank you

 

[VintageVic]

Have you checked you have 5V on the psu? How about the power switch, is
it going through it?

 

[Ruud]

I've noticed there are 0V on the 7805... could this be an issue on the 7805 itself or somewhere else?

If you only have 0V on the output, It could be the 7805. But the word "are" suggests that there is 0V on the input as well. This means a broken PSU or a broken switch (I assume you switched it).

 

[Flavio]

I have checked the PSU and it gives 14V without load so I would say it's OK... I have just found a problem on the switch of an Amstrad 6128...I check ASAP. And yes, I have no input and output voltages on the 7805 but I am going to check again.

 

[Flavio]

I have checked the voltages on the 6 pins of the switch and I have the picture results (please forgive if it's not so technical but I hope it is clear enough). The enlightened ones are the only voltage I measure, and the measuring does not change if the switch is on or off...
"I suppose" the "near the switch voltages" are the input ones and I shoud have the same on the output when I turn the computer on, right?
If I am right and the switch is dead: do you think it's repairable? if so, there is an online "manual for dummies"? If not, can you help finding one?
Thank you

 

[VintageVic]

Actually, looks like you should use 9V DC (1amp) power supply. And not 14V.
If I understand what you drew, your power switch may be ok. What about the fuse?
Do you have voltage before and/(or not) after the fuse?

You could download Commodore 116 schematics from Ray Carlsens website, here:

Index of /rcarlsen/cbm/c116

Study the schematics, it will help you understand what should be going on and where on the pcboard.