HP 9133xv (for HP-150) floppy drive problem

[Callmejack]

hello !
I have an issue with my HP-150 and I hope some of you could help me. The floppy drive in the 9133xv unit doesn’t fully work, it gives me reading errors when reading floppies. I tried to format a floppy and it seems to be doing something (see video) but then there is also an error at the end. The main PSU has been recapped so I suppose the issue is not from there. Any idea what could be the cause of the problem ?

 

[SomeGuy]

Take the floppy it formatted and try reading it on a PC with ImageDisk or better yet, a flux reader and see if it actually wrote anything. A flux reader can show the "quality" of what was written.

I assume it is not actually ripping up the disk? Are you using a genuine low density disk or high density disks? Have you cleaned the head with a cleaning disk?

How far does it seem to get when reading a disk? Does it reliably show directories and then throw errors as it goes along, or it it hit and miss with any read?

This is a single sided drive, so my first thought would be that whatever kind of pad it uses on the top might be damaged and not be putting proper pressure against the disk.

I've actually acquired some HP 150 parts too that I am trying to get working and have a drive unit with two similar drives. If I needed to diagnose those in detail, I would probably build an adapter so I could use them with a Kryoflux (these use an earlier, smaller header with different pin outs).

BTW, since you seem lucky enough to have a 150 keyboard (I assume you don't have an HIL expansion), those use a 6 conductor RJ12 cable, but can you tell me, is it staight through or does it reverse the wires?

 

[Martin Hepperle]

If you have not yet inspected the drive in detail yet - have a sharp look at the read/write head and its attachment to the sliding carrier.

These SONY drives usually have suffered from hardening grease, leading to stuck eject mechanisms, leading to stuck diskettes, leading to ripped off heads.
Such a broken head might still be in place, just dangling on its wires or a remaining part of its suspension spring. If this is not the case it should be a matter of carefully cleaning the head and possible applying some oil to the mechanism.
Another thing to check is dirt/dust/fluff in the track zero sensor - this may lead to a problem when formatting is finished and the head moves back seeking for track 0.
On the other hand, the drive is probably the single sided variant, which does not have much capacity for applications under MS-DOS.

 

[Callmejack]

ake the floppy it formatted and try reading it on a PC with ImageDisk or better yet, a flux reader

Good point, I checked with Applesauve FDC and there is nothing at all on the disk after formatting.
As soon as I make a DIR it shows the Abort, retry, cancel error message. After the format it show this error


I used DD disks and I have cleaned the head with a cleaning disk,
I will have to open the drive and investigate a little more to see if th head i properly aligned.

Concerning the keyboard wiring, here are picture of both sides of the cable

 

[Callmejack]

If you have not yet inspected the drive in detail yet - have a sharp look at the read/write head and its attachment to the sliding carrier.

These SONY drives usually have suffered from hardening grease, leading to stuck eject mechanisms, leading to stuck diskettes, leading to ripped off heads.
Such a broken head might still be in place, just dangling on its wires or a remaining part of its suspension spring. If this is not the case it should be a matter of carefully cleaning the head and possible applying some oil to the mechanism.
Another thing to check is dirt/dust/fluff in the track zero sensor - this may lead to a problem when formatting is finished and the head moves back seeking for track 0.
On the other hand, the drive is probably the single sided variant, which does not have much capacity for applications under MS-DOS.

Thanks for the tip, I will inspect the drive and see how the head is positioned.

 

[Callmejack]

This is a single sided drive, so my first thought would be that whatever kind of pad it uses on the top might be damaged and not be putting proper pressure against the disk.

i did apply some light pressure directly on the pad and it works (format and file copy).
In order to fix that permanently I pushed the spring down 2 levels and it’s applying just a little more pressure. It seems to be enough to make it work.
Thanks for your help

 

[Callmejack]

Thanks for your help

 

[SomeGuy]

Glad to hear it. I'd just keep an eye on the disks to make sure they are not slowly getting ripped up.

Thanks for the photos of the keyboard wire - yep, they reverse the wires, you can see from the colors. That means if one were to use a straight through cable, that will reverse the ground and +12v. That would be... bad.