9114 disc drive issues

[John Garza (3665)]

I don't see much around here for the 9114. But I have one (not an A or B, just 9114) and I've tried it with a 41 and 71 and both report medium errors during the initialize/formatting process. At first I thought bad diskettes as these were salvaged from my old stock from in the 90's. But.. they all pass FORMAT and CHKDSK on a PS/2. 720Ks as HD diskettes don't seem to work at all in the 9114.

What I've done so far - from the ground up....
* replaced the battery and charged it
* fixed a mechanical issue with the diskette seating/ejecting
* cleaned the heads with alcohol
* lubed the rail and worm gear
* run the initialize with the top off - I can see the heads move across the surface of the disk.

Any ideas? Or is there a repair guide for these things?

Thanks!

-John

[35/45/55/80/70/65/67/67T/97/97S/91/92/21/22/27/25C/29C/19C/10/
31E/32E/33C/34C/37E/38C/41CX/71B/28S/19B/12C/15C/33S/35S/32S/
48GX/50G/Prime/DM42]

[BobVA]

- Do you have a good battery installed? (just the AC adapter won't work and a weak battery will cause all kinds of issues).

- As you note, you need to use 720k (non HD) media.

- If the eject wasn't working properly there may be damage to the head (as I recall the head could get hung up on the disk shutter?)

- There is a small repair guide

Bob

[John Garza (3665)]

New battery, charged overnight with a spare Topcat charger. Not running with the unit plugged in. Battery power only.

Most of the things in the repair guide I've already done. They just seemed obvious. A little penetrating oil cleared up the gummy old lubricant.

The heads look good. They don't look bent or loose. The top one is on a springy 'floating' platform, but I think that's normal. Watching the mechanism as I insert a diskette, the head seems to land gently on the surface of the disk.

The error message I get is towards the end of the process - the head goes back and forth a few times then back to the outer rim and starts stepping in a track at a time. It does that until the head is at or very nearly at the end - then the error message. If the head was dead I'd think it would error before that. But I could be wrong.

-John

[Martin Hepperle]

You might also want to check the track 0 sensor.
Sometimes dust and fluff collects in the gap, blocking the light beam.
Cleaning with some tissue soaked in alcohol should do it.

Martin

[John Garza (3665)]

The track 0 sensor looked clean.
But nevertheless, I cleaned it with a flattened Q-tip wetted with alcohol, then compressed air.

It seems to have made it worse. It errors after only the first 2 tracks or so.
It likely was not the culprit originally since this sensor detects if the head is on the outer edge of the diskette and I never had any problems there. But it may be evidence there was some dust in there and I just pushed it in a little deeper!
Time for some magnification work...

-J

[cruff]

You might try a bench power supply in place of the battery. I had a two year old battery that would no longer turn the disk spindle.

[John Garza (3665)]

Brand new battery ordered from Amazon. Disk spins fine and head moves back and forth.

I'm thinking I may have made it worse by cleaning the sensor.
Before, the head stepped across all tracks before it gave an error.
Now, it errors on the first one.

Not sure if the sensor is completely sealed or not.
Maybe a drop of alcohol seeped in.
I'll leave it with the top off for few days to allow it to evaporate.

-J

[Dave Frederickson]

(03-31-2023 01:26 AM)John Garza (3665) Wrote:  Any ideas? Or is there a repair guide for these things?

There's the CE Handbook. http://www.hpmuseum.net/document.php?hwfile=2716

Refer to Section V for running the built-in diagnostic self tests.

(03-31-2023 02:18 AM)BobVA Wrote:  - There is a small repair guide

Also, PeterP's repair manual. https://www.hpmuseum.org/guest/peterp/9114repm.pdf