Toshiba PA7224E 12V rail

[silence012]

Hi guys,

I am restoring a Toshiba PA7224E FDD and getting weird values on my 12V rail.

If I measure voltage on 12V on FDD connector without battery it shows ~15.3V. With a battery attached it is ~13.2V or something like that.

For 5V rail everything works fine as it is regulated by TL1451 chip. For 12V rail, I cannot figure out how it supposed to be regulated. So not sure if there is an issue with my FDD board or it is just designed like that.

I would really appreciate any help, or if someone has the same model and willing to measure voltage on 12V rail.

Thanks in advance,
Branko

 

[silence012]

OK, it seems that it requires some "load" in order to stabilize a voltage. Once battery or FDD is connected it will regulate voltage between 12-13V.

There are some interesting think that I found. My board is FFD5C2, and it seems that it has an 10uF/50V electrolytic capacitor that is not used at all It is C21 on that board.

I am doing reverse engineering of the board, and will soon share the schematic.

Cheers