Unable to boot disks.

[grone]

Hello there,

I have a Macintosh Plus I found in the rubbish. It came with a WD 20MB hard drive which won't boot -- so I bought a System 6 boot disk off eBay, which also won't boot.

The computer itself takes a long time to turn on (30 minutes or so, and then requires turning the power on and off a few times until it will display anything on the screen).

Just wondering if there are any fixes to attempt first. I have opened it up, and nothing appeared to be obviously borked.

 

[bibilit]

First of all, congratulations about finding and saving a Plus.
The Plus should boot right away to the flashing mark, if not probably a Ram issue of floppy one.
Try removing the drive for another test.
the drive should probably be cleaned and lubricated anyway.
Find yourself some ram sticks for a further troubleshooting.

 

[grone]

First of all, congratulations about finding and saving a Plus.
The Plus should boot right away to the flashing mark, if not probably a Ram issue of floppy one.
Try removing the drive for another test.
the drive should probably be cleaned and lubricated anyway.
Find yourself some ram sticks for a further troubleshooting.

I'll give that a go. I was thinking of upgrading to 4MB anyway - if it helps with troubleshooting then I at least have a reason.

 

[Phipli]

If the screen isn't showing for 30 minutes I'd guess its more than the floppy drive. You should probably start with recapping the analogue board and checking for dry solder joints. Still a good idea to regrease and clean the floppy drive and heads.

 

[grone]

Drive is cleaned! I had no idea that much dirt could accumalate through such a small opening...

Also cleaned and re-seated the RAM.

Still not booting - got the long warm up of somewhere between 10 and 30 minutes until the screen turns on. It rejects the disk without even sounding like it attempts to read it.

Is there a recommended location to purchase the re-cap kit from? I have the international board with three RIFA capacitors.

 

[grone]

I've removed the old capacitors from the analogue board and will get about to ordering new ones tonight. Also ordered 4MB of RAM from the US of A.

Hopefully it works when it's all back together.

 

[joshc]

Sounds like a weak power supply. Beyond just a recap, remember to also re-solder any weak joints. The typical ones are the joints for the yoke connector and logicboard connector.

After re-cap, you can test voltages at the floppy port on the back of the Plus.

 

[bibilit]

Was the drive head cleaned as well ? Where do you get the floppy disk from (is system Ok)

keep in mind that upgrading to 4 Mb, a resistor should be cut from the Logic Board.
A long warm up is not the normal behavior, the Plus should chime then the gray solid screen should be present, and depending of how much memory is present will go to the blinking mark in a couple of minutes.

 

[grone]

Was the drive head cleaned as well ? Where do you get the floppy disk from (is system Ok)

keep in mind that upgrading to 4 Mb, a resistor should be cut from the Logic Board.
A long warm up is not the normal behavior, the Plus should chime then the gray solid screen should be present, and depending of how much memory is present will go to the blinking mark in a couple of minutes.

I cleaned the heads. I bought the disk off eBay - it's a pirated version.

The system chimes as soon as the switch is flicked. It's the screen that takes a long time to power up.

 

[Phipli]

I really don't think the screen taking an age to warm up is likely to be a drive fault, sorry for contradicting. A screen works with no drive plugged in, so why would a stiff mechanism and dirty head stop the screen working?

 

[grone]

I really don't think the screen taking an age to warm up is likely to be a drive fault, sorry for contradicting. The screen works with no drive plugged in, so why would a stiff mechanism and dirty head stop the screen working?

I'm seeing it as two faults.

1) System won't boot.
2) The screen takes a long time to display an image.

In an attempt to narrow down the potential causes, I'm following the suggestions of whoever posts in here. I certainly have no knowledge myself!

I have bought RAM for the boot issue.
I am re-capping the analogue board for the screen issue.

It has been a fun exercise so far. I am currently unemployed so it's good to be cleaning up what is otherwise junk. On that note, if anyone has a paying job for me...

 

[cheesestraws]

The main thing here is that until you're pretty confident that you've got stable voltages coming out of the PSU, anything else in the system may be acting weirdly or glitchily. So while you're likely right that there are two faults here, you may find it difficult to debug the first until you've got the power issues sorted (I'm fairly sure that the second issue is straightforwardly related to power). So I'd strongly recommend dealing with point 2 before trying to make too much progress with point 1.

Sorry to hear you're unemployed, that's a miserable time :-(

 

[Phipli]

I'm seeing it as two faults.

1) System won't boot.
2) The screen takes a long time to display an image.

In an attempt to narrow down the potential causes, I'm following the suggestions of whoever posts in here. I certainly have no knowledge myself!

I have bought RAM for the boot issue.
I am re-capping the analogue board for the screen issue.

It has been a fun exercise so far. I am currently unemployed so it's good to be cleaning up what is otherwise junk. On that note, if anyone has a paying job for me...

Sorry to hear you're out of work. I will be shortly too. Hopefully not for long for either of us.

If the voltages are off due to the analogue board (see Joshc's post above) then many things might not function correctly. Does the floppy disk have one hole or two?

I wouldn't worry about the booting issue until I'd sorted the screen as the one might be causing the other.

 

[joshc]

In these cases as well, testing without the floppy drive first can help - since it is powered on/initialised when the computer is switched on, so it uses up some juice doing that. If your PSU is marginal/weak, that won't help matters. So testing without it is a way of seeing if that makes anything better or not. But either way, yep, focus on the analog board with new caps first and go from there.

 

[grone]

The new capacitors arrived, and are now installed.

The screen is powering on immediately; but we're still unable to boot a floppy disk.

Voltages measure 4.98V and 12.09V without making any adjustments.

The connectors on the analogue board all needed new solder - some joints were cracked and seemed hollow inside.

Will wait for the RAM to arrive and see if that helps.

 

[bibilit]

Are you getting to the question mark ? if the answer is yes, your drive can be faulty.

If the disk is ok, no reason the Plus won't boot from it.

You can carefully try to turn the Plus with the drive connected but hanging loosely outside the casing (back casing removed) then having a look at what is happening.

the upper carrier should drop and heads get in contact with the disk.

 

[Phipli]

Is your boot disk 800k or 1.2MB?

 

[Phipli]

Note I have several drives that won't read disks from other machines, likely due to head alignment issues. They work fine with disks formatted in their own drive. I've had issues like this back into the 90s, and suspect abusive former owners. We never had the same problems with machines we owned from new. Because of this, I've always really disliked floppy drives/disks. I'd really strongly suggest using a FloppyEMU (well worth the investment for a Plus!) or an external SCSI device (SCSI2SD ideally, others will be better positioned to give advice, I've actually not used anything like that on the Plus I've been loaned, just an external floppy and 20SC).

 

[grone]

Are you getting to the question mark ? if the answer is yes, your drive can be faulty.

If the disk is ok, no reason the Plus won't boot from it.

You can carefully try to turn the Plus with the drive connected but hanging loosely outside the casing (back casing removed) then having a look at what is happening.

the upper carrier should drop and heads get in contact with the disk.

I removed the drive and loaded a disk with no power, and the disk is opening up and the heads are making contact just fine. I can see that the head carrier has barely moved from where I put it after cleaning the drive - the grease has not run along the thread (the shaft has rotated maybe 90 degrees maximum).

EDIT: The heads *are* moving just fine. I put them forward as far as they go, re-assembled, inserted a disk, powered down, removed the drive, and the heads are back at the home position. I must have re-assembled originally with the heads in almost exactly the home position. They continually spit out the disk, though.

I am getting the question mark. If I power on the external HDD and turn on the Mac, then the screen is black for a short while and a second light comes on the HDD, until it finally ends up at the same ? disk screen.

 

[grone]

Photo of the recapped analogue board, and the squeaky clean logic board.