Macintosh Plus Internal Hard Drive *Mod*

[Trash80toHP_Mini]

Cool. Is there a difference between the chassis ground and logical ground for practical purposes?

The MoBo is always grounded to the chassis, the peripheral device chassis (other than the those mounted to the incredibly S-T-U-P-I-D plastic sleds that take up egregious amounts of cubic inside the cavernous bays in a Mac case) are "always" connected to chassis ground.

Is logical ground a buffered/clean reference signal on a circuit separate from ground fill on the MoBo?

I know clean ground is sometimes important, but back then? :?:

 

[uniserver]

tried it . still doesn't boot the HD,

pin 11 is ground... and that has a wire soldered to it.

its gotta be something else.

he has a note in here i am not sure what he means...

i counted 40 over and disconnected the one, still didnt work.

 

[techknight]

Well that throws my idea out the window. Does the hard drive provide termination power, and is terminated?

 

[Cosmo]

i have an plus with built in hdd. It looks it's been done professionally at shop back in time, just the way pictures show in this thread. I'll if i can take few pictures, some are atleast at retromaccast already.

 

[uniserver]

those are great questions!

i tried a ibm 40 mb, there were some jumpers on it... looked like a group of 3(probably id jumpers), the jumper was in the middle, tried all 3, there was another group of jumpers i tried them one by one...

after each thing i tried followed by powering down the drive and plus.

for giggles i grabbed this quantum 160mb, this one had the removable resister packs, tried it with and with out.

i even tried the cable on backwards just for giggles.

( glad i didn't burn out the scsi chip or a drive )

i think i need to just start over fresh.

 

[uniserver]

wow great please post those pictures in this thread kind sir.

 

[techknight]

I would hook the internal drive back up, start it up off an external drive with SCSIprobe, and run SCSI probe and see if its complaining about termination, or if it sees the drive at all.

 

[uniserver]

good idea, ok ill pull it back apart hook it up and check scsi probe

last i checked it would not boot the external with the internal hooked up.

that is what leads me to believe i have the wires soldered to the wrong places.

 

[Cosmo]

i'll try to have some pictures up here tomorrow night.

 

[techknight]

if it wont boot with the internal hooked up, you either miswired the cable/misnumbered the cable, or more likely, introducing termination issues.

 

[Trash80toHP_Mini]

. . . or an ID conflict, I recall reading about chnging jumpers on the internal, but nothing about testing for ID conflicts by changing the external's ID.

But I haven't really been paying close enough attention . . . neither of my pluses are functional ATM. :-/

 

[techknight]

that could be as well...

 

[uniserver]

i'v tried different id's

 

[James1095]

If your analog board is not making enough power to run the internal HDD, then it will soon die completely. Spend the 20 minutes to replace the electrolytic capacitors on it and you will likely get years of reliable service. It's easier and cheaper than hacking in a second power supply for the drive.

 

[uniserver]

on the plus the analog board is flawless, its just i know it was never designed to handle the load of a hard drive.

with the classic, yeah i should have serviced the analog board, but, it was easy enough to slide in this power brick and just solder one wire to the hot on the power switch and the other to the white 120vac power port.

also with the classic even thought the analogue board is weaker, the tube still comes in clear and bright.

 

[Cosmo]

The picturers are .. not been taken. I was tired and stuped last evening, tried to open the Plus with openining only 4 screws.. you know what happens. The battery holder dept. fell off from the another end. Need to fix that first. :disapprove:

 

[uniserver]

oh no, sorry about that

 

[Cosmo]

Njaah, it's matter of few seconds work. Just need to take it to work and get it done. I'll get back to this soon.

 

[uniserver]

And then you will snap some pictures of the soldered scsi cable ? thanks.

 

[Cosmo]

And then you will snap some pictures of the soldered scsi cable ? thanks.

For sure, while i am at it. It will be done