H5C1- firST STeps

[PhilC]

@JezC its certainly a good idea to buzz ut the connections to / from the floppy and of course the floppy cable you're using. Try it without the GAL in as a normal 720K drive first though.

[exxos]

I also suggest doing the fixes for the board just in case you are hitting some side effect of a already known issue.

viewtopic.php?f=89&t=5600
viewtopic.php?f=89&t=5256
viewtopic.php?f=89&t=6042

[JezC]

@JezC its certainly a good idea to buzz ut the connections to / from the floppy and of course the floppy cable you're using. Try it without the GAL in as a normal 720K drive first though.

Thanks @PhilC - no GAL fitted yet! I'll re-check that the floppy cable & drive still works on my H4 board just to be sure & then try to bell out the signals to the 1772 & sound chip just in case.

[JezC]

I also suggest doing the fixes for the board just in case you are hitting some side effect of a already known issue.

viewtopic.php?f=89&t=5600
viewtopic.php?f=89&t=5256
viewtopic.php?f=89&t=6042

Ok, thanks @exxos - I will check those as well (pretty sure I've not done them all as some were found since I last put this board aside to work on "other things") :roll:

[JezC]

Ok, just adding some details here from a few minutes testing earlier today...with no clear outcome just yet.

I tried the problematic H5 board without any floppy again & it reported 0 floppy drives (it's the modified TOS 1.04 with IDE support included), then booted to the desktop with no floppy icons visible.

Then I tried it with the floppy drive connected (both the ribbon cable & the power lead)but no floppy in the drive & it showed the 1 floppy drive...but never got to the desktop...so that seems to be different behaviour than I recorded previously.
I'm pretty sure it booted to the desktop with no floppy in the drive but then bombed when the floppy was inserted & accessed (or it crashed during boot with a floppy inserted prior to powering on).

So, that seems to give me a slightly easier test case than I had before...but tomorrow I'll test with the same ribbon cable & floppy on my H4 board just in case the change in behaviour relates to the floppy drive itself...

[PhilC]

@JezC ibe got the same problem on a Mega ST. Sometimes it even boots from floppy. I believe it’s a case of a broken track in the Megas case.

If I was you I’d check the logic chip and then meter out the tracks between the DMA and WD and the WD and the floppy(including where it goes through the logic chip, can’t remember what 74LS chip it is).

I did an H5c1 for another forum member and there was a dodgy track on it, so light just be that.

[JezC]

@JezC ibe got the same problem on a Mega ST. Sometimes it even boots from floppy. I believe it’s a case of a broken track in the Megas case.

If I was you I’d check the logic chip and then meter out the tracks between the DMA and WD and the WD and the floppy(including where it goes through the logic chip, can’t remember what 74LS chip it is).

I did an H5c1 for another forum member and there was a dodgy track on it, so light just be that.

Ok, thanks for the suggestions Phil. I took the precaution of printing out some of the schematics earlier in the week, so I can go through them & check things off as I go.
I just wish I'd printed them on A3 rather than A4 :lol: :roll:

[PhilC]

Best get your microscope out with A4 @JezC

[JezC]

Best get your microscope out with A4 @JezC

I've cut & pasted a few relevant parts of the PNG file into a word document & printed that out, so not as bad as it could be @PhilC !
But it would be even easier to read if every page were printed on A3 ;)

[JezC]

Best get your microscope out with A4 @JezC

I've cut & pasted a few relevant parts of the PNG file into a word document & printed that out, so not as bad as it could be @PhilC !
But it would be even easier to read if every page were printed on A3 ;)

Well, when trying to follow the printed schematics, it's apparent that @PhilC was bang on the money - the printed text is not clear enough to be able to follow easily :(

It's fine when magnified on the png, so I guess it need to be A3 printing with smaller areas of the schematic on every page.

It also looks like the A4 printer needs some new toner which just makes matters even worse... :cussing: