Re: Question on the "formatter" Z chip

Reporting progress...or rather lack of it.

The 4K" Z8613 Z chip was purchased, duly arrived and I burnt a 4k 2732 with the necessary LLF program. Then ran BLU to try it out. Unfortunately it was not successful. The stepper exibits (to my thinking anyway) weird behaviour . Let me elaborate...

BLU 0.90 recognises the drive ok and goes through the motions of formatting but the stepper barely deviates from the park position? It tries to move a little bit with each step but each time returns back to being hard up against the stop. I'm assuming what is SUPPOSE to happen is that it flicks around to track zero, then gradually counts back eventually getting to the rest position? This does not happen. When the second part of formatting occurs (after BLU tells you to remove the jumper) the stepper again moves just a little from the park position and the program stops with an error.

Some other observations..

1. Just prior to LLF, (at the point where the BLU tells you to insert the jumper) I can manually move the stepper to head 0. It's quite loose at that point in the sequence and there is no resistance. Then when I continue the formatting process it nicely steps back to the the park position as if it is formatting the disk. Once the second part of formatting commences the stepper tries to "step" from park then BLU gives up.
2. When the drive is switched on with the formatter Z chip, after the initial pause of inactivity the stepper motor steps from the rest position to track 0 (with red light flashing). Then it quickly flicks back to park. There doesn't seem to be any self check
3. When the normal Z chip in present the stepper goes about mid way, stops for a little while then returns to park. Again, there is no self check.

Regarding the two Z chips, I'm assuming this is normal behaviour if the disk is not formatted (in incompletely formatted) as the stepper can't find any tables, tracks or anything, so doesn't even try a self check?. However, It's interesting that they both cause different behaviour on startup.

So, I'm a little stuck now. I suspect the stepper logic. It's as if it doesn't receive all the commands it should (like when to go to track 0 during formatting). I've replaced logic chips at U15 and U41 which I believe are involved in telling the stepper what to do. No change.

It could be the formatting Z chip itself I suppose. You never know if these things are working or not, but it does seem to cause deliberate behaviour on startup.

Anyway, that's where it is. Any suggestions welcome.

Terry (Tez)

On Tue, Apr 12, 2016 at 9:19 AM, Terry Stewart <terry_at_email.domain.hidden> wrote:

> >Hi, Terry.
>
> >You will need a 4k byte EPROM (2732). That's why the Z8 part is
> different for the 10M ProFile - it brings out more address lines.
>
> >All the firmware images are available from Bitsavers.
>
> Great. If shipping can be arranged I'll make the purchase and keep the
> group abreast of developments once it arrives.
>
> Terry (Tez)
>
> On Tue, Apr 12, 2016 at 9:14 AM, snhirsch <snhirsch_at_email.domain.hidden> wrote:
>
>> Hi, Terry.
>>
>> You will need a 4k byte EPROM (2732). That's why the Z8 part is
>> different for the 10M ProFile - it brings out more address lines.
>>
>> All the firmware images are available from Bitsavers.
>>
>>
>> On Monday, April 11, 2016 at 4:46:21 PM UTC-4, tezza wrote:
>>>
>>> >Remarkable! I guess I should always look on e-bay for hen's teeth.
>>>
>>> >I'll find out how much shipping is to New Zealand.
>>> >There is no guarantee buying this will get the Profile up and
>>> running...it could need more than a low-level format...but I should at
>>> least give it a shot.
>>>
>>> >Thanks Al.
>>>
>>> >Terry (Tez)
>>>
>>>
>>> A follow up question though. Is the required EPROM image for the Z8613
>>> piggyback chip available anywhere? I'm assuming the piggyback is for a 2716
>>> like the other variants?
>>>
>>> Tez
>>>
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