Micro peripherals Drive controler?

[tofro]

What you should see when the drive starts up:

Index pulses (once per revolution of the disk) - BTW - that seems to be wrong in the list of pins above - it's actually "IN", not "OUT", as it's generated by the drive)
Steps to move the head to track 0
Track0 that signals "Im there"

Obviously, you won't see real pulses on the lines with your multimeter, but you should see a slight variation in current on the lines.

Tobias

[cybervet]

Ok I checked all the lines and the ones that stay constantly high when giving the dir flp1_ are:
18 DIR (dir step direction)
20 STEP (step pulse)
30 RDATA (read data)
32 SIDE1
The rest of the lines behave as expected
I guess there is a problem in head seeking, am I in the correct direction? That can only be a logic problem (TI2793)?
Tassos

[tofro]

Tassos,
yes, looks like that - unless the board has any drivers between the FC chip and the drive - which I doubt.

Outdated floppy controller chips are hard-to-find items, wish you luck finding one.

Regards,
Tobias

[Dave]

I believe from my reference book that the TMS2793NL is an equivalent IC. There are two on ebay for under $10.00.

[cybervet]

Already ordered a tms2793 and a wd2793, (I hope thats where the problem is) I will keep everyone informed when they arrive .
Thanks again Tassos

[cybervet]

Hi I am trying to find schematics or a service manual for the MicroPeripherals/Sinclair I/F , I am trying to figure out what is the purpose of the variable resistor and the variable capacitor on the PCB.
Thanks
Tassos

[tofro]

From the data sheet (attached) I learned that you can 'tune in' some of the timings and currents, could be write precompensation delay, VCO centre frequency or phase comparator (not that I knew was all this means...). I'd leave them alone.

Regards,
Tobias

Sorry. Could not upload the data sheet - was too large.

[cybervet]

haha I think I will need a chinese dictionary.......... it's all Greek to me
Tassos

[cybervet]

TMS 2793 arrived today and was replaced , now everything works fine now.
Thanks to everyone for your help
Tassos

[Dave]

And there you have it!