IIc Plus issues

[Henry Pedro]

So I think I may have damaged my IIC+

With the internal drive connected it will not boot. Beeps but theres garbage on the screen.

With the internal drive removed it starts up, returns the "Unable to find a disk online" message and drops to Applessoft.

With a 3.5" external drive connected but no disk inserted it does the same.
With a disk inserted it doesn't start up (garbage on screen)

With a 5.25" drive connected it starts, and boots normally.

I'm shuddering at the prospect, but would this be an IWM chip failure, or could it be something else?

[cb meeks]

Post by Henry Pedro
So I think I may have damaged my IIC+
With the internal drive connected it will not boot. Beeps but theres garbage on the screen.
With the internal drive removed it starts up, returns the "Unable to find a disk online" message and drops to Applessoft.
With a 3.5" external drive connected but no disk inserted it does the same.
With a disk inserted it doesn't start up (garbage on screen)
With a 5.25" drive connected it starts, and boots normally.
I'm shuddering at the prospect, but would this be an IWM chip failure, or could it be something else?

Does sound like it is the disk controller. Can you confirm you are getting the correct voltages on the IWM chip?

[Henry Pedro]

Post by cb meeks
Does sound like it is the disk controller. Can you confirm you are getting the correct voltages on the IWM chip?

What voltages should I be looking for?

[cb meeks]

Post by Henry Pedro

Post by cb meeks
Does sound like it is the disk controller. Can you confirm you are getting the correct voltages on the IWM chip?

What voltages should I be looking for?

I don't know enough about the IWM to know what voltages it needs but I'm sure it's documented online.

A couple of things you can do to troubleshoot a (possibly) dead chip (or faulty) is check that it's receiving a good steady voltage (whatever it needs). My guess is 5V but I don't really know.

Second thing is check to see if any clock signals or data/address lines are talking. You can use a logic probe for that (if you have one). So, for example, if the data pins of a chip (any chip) are a constant high or low, then that could be a sign it's not working.

Just really depends on the chip.

I don't have a IIc+. I only have normal IIc's. So I can't speak too much about it.

[Henry Pedro]

Post by Henry Pedro
So I think I may have damaged my IIC+
With the internal drive connected it will not boot. Beeps but theres garbage on the screen.
With the internal drive removed it starts up, returns the "Unable to find a disk online" message and drops to Applessoft.
With a 3.5" external drive connected but no disk inserted it does the same.
With a disk inserted it doesn't start up (garbage on screen)
With a 5.25" drive connected it starts, and boots normally.
I'm shuddering at the prospect, but would this be an IWM chip failure, or could it be something else?

Solved...
Somehow managed to corrupt track zero of three floppy disks. Any sort of access whether it be a bootup, or any access of any kind would result in a system crash.
I have never seen this sort of behaviour before. But I suppose the Apple 3.5" drive in a IIc+ is a different animal than a 5.25" drive connected to a //e.

[e***@gmail.com]

Check the floppy drive connection cable for short circuits.

Did you find a way to fix track 0 of damaged floppies?