Andres' H5 B1 Build

[AndresPlazaR]

Thanks everyone!

Everything was good and beautiful, until I tried to pull a fast one, installed the 16 MHz crystal (for the HD FDD) very poorly and forgot to desolder the SJ3 pad (at 1am), and blew the fuse of the power supply... Or at least I think that was the reason. Getting new fuse today, and check if I screwed up other components.

[exxos]

Fuse only blows on PSU if overvoltage happens somewhere.. most likely bad connection on a power lead somewhere.

https://www.exxosforum.co.uk/forum/viewt ... 245#p26117

[AndresPlazaR]

Well, I removed the 16 MHz crystal, changed the fuse and things are back to normal... So I will leave it at that.

Just waiting for the power connectors, the crystal for the RTC and the RTC itself, and then will test all the ports with the Atari ST loopback card.

And I'm doing a nice treatment to the case.

[exxos]

[AndresPlazaR]

So, the good news is that the parallel, serial, DMA and MIDI ports and Blitter all passed the test using the Atari ST test kit, so it seems everything is connected fine.

The bad news is that I keep blowing fuses, so there is something wrong somewhere... So maybe not everything is connected fine.

And sometimes the fuse blows with the exact same configuration that, a few moments later or before, does not blow the fuse.

I will read the @exxos post about blowing fuses and will report back.

[AndresPlazaR]

Mmmhh... Not sure, because the "recycled PSU connector" scenario is about the connector in the PSU side, not in the board (that's the one I recycled). But, just to be thorough, I will replace that one.

Any other ideas for an intermittent fuse blow?

[exxos]

Other than what I wrote on the PSU page there isn't anything else.. Fuse blows on over voltage . either PSU is not under load, or your mains voltage is incredibly high.

[AndresPlazaR]

OK, I think we are making progress: I found a solder flake in the board, so I think that was the possible reason for the short. I tried a few times, and I'm consistently not blowing fuses.

Now, I request for some ideas: I connected a Gotek floppy drive, and it only reads until track 3. If I use an ST image with Gembench, it does not boot at all. If I use an empty ST image, eventually it boots, but the Drive A does not work. I tried changing the data cable, different Gotek drive, different WD1772 chip, but same thing. I traced all the connections of the WD1772 socket, and they all seem fine.

I do have linked SJ3 (and no OSC1), I do have the GAL, but JP18 and JP19 are set to 720K. JP22 is set to 2&3 (8 MHz 1772). JP17 is set to drive A internal, B external.

Any clues?

Thanks!

[exxos]

You can set the jumper to the right of the GAL to just feed 8mhz into the 1772.. It will bypass the GAL then. Though sounds like you may need to resolder the 1772 and DMA.. Again if you used cheap sockets, they can even break on first insertion.

[PaulJ]

I am assuming your using one of Exxos's supplies. I have one in my mega that works great. However when I first installed it the 5v was fine but the 12V's was 8 volts. Computer ran but real floppy didn't. Come to find out I had the primary windings in series (EU power). Rewiring for parallel primary it worked great. So if your in Europe (220-240) wall power do you have it wired with the primaries in parallel? Not sure if it would just smoke or give you the symptoms you are experiencing. Just a thought.