Need help with 16500A floppys

[Tony Duell]

> 
> I have an HP 16500A analyzer with original 720k disks.
> 
> Problem is that only the rear drive seems to read the disks.

Does thls machine use the full-height Sony double-head drive that HP used 
all over the place? If so, have you re-greased the eject mechanism? If 
not, do so before you ruin the heads -- that's quite possibly what's 
happened to one of your drives already :-(. I have done a head 
replacement on said Sony drives, it's possible, but not totally trivial 
(and nor is getting the replacement head carriage). 

> 
> I am suspicious that the front drive is bad.  I am using
> stock 720k (single hole for write protect only) and trying
> to format them in both front and rear.
> 
> I also am not able to read the stock originals with any
> program under either linux or dos.  I realize that these
> seem to be formatted in a proprietary HP format.

Are these similar to HP LIF disks, as used on the HP9114, etc)? Have you 
tried the LIF Utilities for Linux on the HPCC site, or the LIF Utilities 
for MS-DOS avaiable somewhere else?


> 
> I luckily downloaded all the kits from the Agilent site before
> they were thoughtfully erased by Agilent.  However these
> programs have not produced anything but floppy images
> which I cannot get onto a disk either.
> 
> I should also explain that I am trying to use the 1.44 disks

Do you mean disks or drives here? Don't try to use 1.44M media, it won't 
work (the density-select hole is in just the right place so that the 
disk-inserted sensor is not activated. It may work better if you cover 
this hole, but I still don't recomend it). You should have no problem 
with a PC 1.44M drive, though.

I've never figured out the details of the HP format, in particular the 
bad-track stuff in the last cylinder. My method has always been to format 
good-quality disks in an HP drive (thus ensuring there is no bad block 
replacement) and to then just bother with the first 77 cylinders.

> I pretty much am convinced the front floppy on the thing is
> bad, so I need one of those.  I don't know if it is common, or
> a weird one specialized to HP yet or not.  I also have not been

If it is the SOny I would guess it is, then it's a 600 rpm drive. The 
interface pinout is non-standard too, but the double speed (and thus 
double data rate) is the main problem with using other drives.

These drives can often be repaired (I've got home-made schematics for 
several versions, I've done mechanical repairs too). If you pull the 
drive, post the numbers off the nameplate and the number on the main PCB 
(it'll be something like FC-9), and I cna see what I can do.

> able to clean it, as I need to buy a fresh supply of alcohol (isopropyl)
> 
> to clean with.


-tony