Color Classic hard drive recognition Problem (almost Solved)

[Staysweet]

I have a Hard Drive boot Issue with Colour Classc I
Every time I tried to boot my CC , starting sound OK, screen OK but the hard drive spin up and then short happy mac on screen in a moment and then spin down and down again!

It's Obviously Neither hard drive problem nor Logic board, Connecter, power 
I 'm sure It's analogue board problem Because  I have three Colour classic  I can test and replace each part

Replace analogue with normal one is the definite solution!  It boots normally!

Which part of the analogue board causes this problem?

 

[dochilli]

Check the voltages (5 and 12V). May be leaking caps in the AB.

 

[Dan68040]

Staysweet, did you find out what was the cause of your problem on the Analog board?

 

[Dan68040]

I am having the same problem with one of my color classics. I found a shortage of voltage from the analog board. I am getting 4.5v & 10.5v instead of the normal 5v & 12v.

a drop of 1.5v is enough to disturb the hard drive fonctions.

I did a full recap of the analog board, and I still have the voltage drop. I am thinking of increasing the PP1 pot on the analog board a little till I get a regular 5 & 12v and see if it would fix my HD problem.

 

[fidelware]

Sorry for repeating this topic, but I have this same problem, I have changed all the capacitors, has anyone solved it?