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Zenith Z171 plus WDXT-GEN debug

Twospruces said:
Sure I would be happy to. I'll send along the card info as well.
Click to expand...
here it is; pretty small rom. more than 1/2 empty. Quite different from the one you have posted.
The rom label - 62-000100-003

Came from WDXT-GEN with "F320" BIOS
product number 61-000222-02 F329
"REX X3"

I think your rom is an example of "Option 2B" aka the Dynamic Formatter whereas mine is "Option 2A" WX2 Formatter. (as explained in the WDXT-GEN user guide document).

Mine is the F320 option; yours must be F300.

I wonder if the roms are interchangeable? hmm.
 

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Twospruces said:
here it is;
Click to expand...
Thanks. I have added it to my web page.

Twospruces said:
pretty small rom. more than 1/2 empty.
Click to expand...
The ROM size byte of 10h, and the altered last byte, are good signs.

Twospruces said:
I think your rom is an example of "Option 2B" aka the Dynamic Formatter whereas mine is "Option 2A" WX2 Formatter. (as explained in the WDXT-GEN user guide document).

Mine is the F320 option; yours must be F300.
Click to expand...
It must be. I can see the text of "Are you dynamically configuring the drive - answer Y/N" in my ROM.
 
Learned a bit more-

* the drive with the "stuck stepper" isn't stuck at all, it just only seems to go in one direction. The coils buzz out ok
* turns out I can rotate the steppers easily when de-powered. Both drives move easily.
* If I rotate all the spindles counter clockwise, both drives rotate the spindles clockwise till they bottom out.
* then the "bad" one just rattles around at the bottom while the "good" one swings the arms quickly rail to rail back and forth.

I have also swapped the controller boards between the 2 drives. no difference. so the issue with the stepper tracks the mechanical.
Strange, unless one coil is shorted to chassis.

I have also tried grounding the DRIVE READY signal to see if that changes anything. it does not.

Anyhow I am close to stumped as to things I can fiddle with to try and get one of these MFM drives to be READY.
I am sort-of convinced that the MFM controller is OK, and working.

Since the drives spin up and spin down on power up, and neither signal "READY" it seems reasonable to assume they are simply not ready and not functional.

As to why, who knows.


If I focus on the drive that seems to have a working bi-directional stepper function, I have no idea why that is not working.
There must be some kind of internal test happening that fails the drive.

none of the videos online of either a KC-20B or KC-30B show an unconnected drive that remains spinning up. What I see are drives that spin up and spin down again. Any working KC-20B drive seems to stay spinning during power up, but it is the boot drive so that makes sense.
 
thanks for all your help. I've concluded this activity; no point in trying to go further. I have a different project I will go after.
I did open up the drives. I think they've been opened before. Neither had any obvious mechanical problems, but one of the drives had a visible defect on the disk platten. I have to assume these drives are failing some kind of self test.

I think the replacement project is going to be to build a new XT-CF/ISA card with the following features

1) combine main memory upgrade with addition of a CF card socket AND an IDE interface for a Connor CP-2124 that I have
2) the memory upgrade will extend the conventional ram by adding an additional 256k of SRAM above 640k
3) in addition the memory upgrade will be a 2MB EMS card
4) it will plug into the Z-171 upgrade bus connector
5) fully internal
6) since the HDD will take up to an amp on +5V, I will include a 5V buck converter and drive the HDD solely from external power source, leaving the internal 5V regulated supply alone.
 
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