Mac 512K with Hyperdrive 20 having issues

[mpfjr]

Hello. 

TLDR below:

New here as you can see.  This computer has driven me onto the interwebs looking for solutions.

So I get this 512K off of Facebook Marketplace.  I wanted it because it had all the extras that I so seldom see included.  Keyboard, numpad, mouse, tote bag, mouse pad from back when, and it looked in pretty good condition. Not much yellow etc.

So I get it home and start looking at it and see it has a Hyperdrive 20.  Didn't know what that was so I looked online.  Seems it is a add on hard drive that has a connector that snaps down over the processor and has a ribbon cable up to a board that the MFM cables connect to.  Then there is a power supply with both 5 and 12v out that connects to the drive.  I tested the power supply, found the voltage on the 5v was low so I turned the voltage adjustment screw until the 5v rail got to 5v (it was 3.9v) and the drive spun up. The drive sounded nice actually and then I heard the heads do a seek and that sounded good too. No grinding, no clicking just a nice sounding drive. 

So I hooked it all up again, flipped the power button and it landed on a 0F00064 error.  I tried a few more things and nothing got me to a indication it was going to boot up.  So I unplugged the drive and rebooted.  Got to a floppy disk ? indicator and thought I was good to go.

Took it all back apart again and inspected the floppy drive.  Lubed it up and got all the moving parts moving again, the read head looked clean so I put it all back together.  Worked ok for a test or two.  I then plugged my floppy emu into it and booted up loderunner.  Worked fine.  Turned it all back off and put it away for a few days.  Then wanted to try getting the hyperdrive going again.  A few more attempts and still nothing. Then after maybe the 20th power on I got a different error. This time it was 064.  So I went back in and unplugged the drive again and booted it back up. Once again I got the floppy ? icon.   Ok so I inserted a disk.  Got the 064 error right away.  Ejected disk with paper clip, rebooted, tried again.  This time it started to read the disk.  Got to "Welcome to Macintosh" and then the screen starts to flicker and it doesn't go past this point.

Thinking it is a floppy drive issue I turned it off, removed the disk with a paper clip again, booted back up with floppy emu connected.  Tried to load some stuff, if I pick any 800k image by accident, I get the 064 error.  If I pick a 400K image, it does the same thing the physical drive does.  Gets to "welcome to macintosh" the screen flickers and it doesn't go further.

Hoping this is a normal common issue with these old things and someone can tell me what's up.  I figure I need to replace caps or something.

Thanks!

TLDR: Hyperdrive doesn't boot up no matter what I try. Disk spins up, sounds fine. 064 errors so I d/c the cables to ignore hard drive atm.

Floppy clean and lubed.  ejects fine.  Reads disks

Recently any attempt to read anything from the floppy bus results in "welcome to macintosh" message and it freezes with a flickering screen.  This includes floppy emu.

 

[Dog Cow]

Your Sad Mac error 0F0064 means that the Mac's boot loader in ROM found the boot blocks on disk, but wasn't able to load the System file.

Tried to load some stuff, if I pick any 800k image by accident, I get the 064 error.  If I pick a 400K image, it does the same thing the physical drive does.  Gets to "welcome to macintosh" the screen flickers and it doesn't go further.

Stick to 400K disks for now. The single-sided 400K drive can read 800k disks, but only the bottom side, meaning the Mac's ROM will find the boot blocks on your 800K disk, but then will show Sad Mac 0F0064 as it can't load the System file from the top side of the disk.

 

[MOS8_030]

My 512K Hyperdrive requires hitting the reset switch after power up to boot from the HD.

I did some work on my system a while back as documented in this thread:



I replaced the PS for the Hyperdrive and recapped the analog board.

 

[mpfjr]

@MOS8_030 I saw that video on youtube with the same thing. The theory was it doesn't reach the correct power level before it asks for boot loader info.  I did try that reset trick. I even waited extra time.  Also with a new power supply I got from Amazon.   I also tested the voltage on the molex that plugs into the hyperdrive card. *I think*.  I may have to re-check.

@Dog Cow Sounds good but what about the screen flicker issue?  I made a quick video and threw it up on my youtube channel.  (unrelated to mac stuff).    Also the question about why it freezes up on that part.

 

[MOS8_030]

I think the HD doesn't have sufficient time to spin up when the Mac is first powered up, that's why the reset is required.

At least that's how mine behaves.

Well you're on the right track by isolating the components.

If you haven't already I'd start by replacing the caps on the analog board.

 

[Dog Cow]

@Dog Cow Sounds good but what about the screen flicker issue?  I made a quick video and threw it up on my youtube channel.  (unrelated to mac stuff).    Also the question about why it freezes up on that part.

I have been thinking about your situation since last week. If I understand your story correctly, your Mac had been able to boot Loderunner OK, but now when you boot this disk you get the flickering Welcome box?

This is a little tricky to debug without more information, but generally in my experience the flickering box at startup is caused when the software tries to access an invalid memory address.

 

[mpfjr]

I have been thinking about your situation since last week. If I understand your story correctly, your Mac had been able to boot Loderunner OK, but now when you boot this disk you get the flickering Welcome box?

This is a little tricky to debug without more information, but generally in my experience the flickering box at startup is caused when the software tries to access an invalid memory address.

Not just this disk.  Anything on floppy emu or the physical floppy drive.  It just says "welcome to macintosh and then it starts flickering as in the video link.  Never proceeds further.  Well I can't say never, but I walked away for several minutes to change over laundry and when I cam back it was still there.  My theory is that some of the capacitors have gone bad now that I've been using it after who knows how many years. They are not putting out enough energy so the system is starving for power.  I have cap kit for the motherboard and I have a forthcoming cap kit for t he analog board. Going to replace them all and see what happens.

 

[Dog Cow]

 I have cap kit for the motherboard and I have a forthcoming cap kit for t he analog board. Going to replace them all and see what happens.

I think your time and money would be better spent looking elsewhere. But if I'm wrong, and it is a capacitor problem, I think it's more likely to be on the analog board than the logic board.

To get some more information about the present capacitors, do this:

1.) Turn on your Mac 512K without any disks or anything to boot from

2.) Let it sit at the question-floppy screen

3.) Turn down the brightness knob if you're concerned about CRT burn-in

4.) Wait about 8 hours or so.

Now try to boot the Mac 512K. You can power it off then on again if needed.

Report back what happens when you try to boot some disks.

.

 

[mpfjr]

Thank you Dog Cow.  I see what you are driving at.  However the system is currently in pieces on my bench while I await the arrival of the analog cap kit.  Yes, I could put it back together without doing any capacitor replacements and do your test and I might do that this weekend. Thank you.