exxos's Atari, Amiga & retro forum

I have double-checked my soldering on the fix PCB and everything looks fine but the fix PCB stops both floppy and SatanDisk working when installed in my H4.

Some testing with my multimeter.

With PAD1 disconnected from the GAL pin 7, I see 5v on IC6 pin 19 (HDCS), 0v on PAD1 on the fix PCB and 5v on pin 7 (FDCS) on the GAL socket.

With PAD1 connected to GAL pin 7, I see 0.3v on IC6 pin 19 and 5v on PAD1. There are no active disk icons in this state.

Are you sure the pad on the pcb isn't shorted to gnd ?

PAD1 is not shorted to GND. Have checked both in the H4 and out.

Can I confirm which way the inverter is expected to work. Looking at the SN74LVC1G04 pinouts, the feed from PAD1(FDCS) is the input and the inverted output is sent to IC6 pin 19.

So the 5v from GAL pin 7 to PAD1 shows 5v and thus IC6 pin 19 is 0v. It looks like the inverter is working correctly?

Are you sure your connection into the GAL socket is solid? I've found it difficult to get reliable connections into sockets with anything other than ICs or good pin headers. They'll generally pass the multimeter continuity test just fine, but won't pass data reliably at high frequencies.

FWIW, on my fix, which is basically a duplicate of Icky's, I soldered onto pin 19 on IC5, which is another source for FDCS. Works like a charm.

I have soldered PAD1 to IC5 pin 19 and same results. No floppy and no SatanDisk. As I said the inverter chip is working as far as I can see and sending 0v to IC6 pin 19.
I will try this on my other H4 tomorrow and see if I get the same result or not. Time for bed now.

Just confirming that Gazak’s H4 is now up and running so this is now 3 live in Queensland. Not sure when Paul will commence building the other 2.

We will be testing Gazak’s H4 today with his UltraSatan hard disk.

Nice job for the guys down under. :thumbup: :thumbup: :thumbup:

Okay, worked on this today. Helps if you put the LS245 in the right position on the fix PCB! Once the IC was in the right place, this DMA buffer fix PCB worked fine.

Also, tested the UltraSatan and this worked fine with the floppy disk. Didn't need to replace the resistors as indicated by Exxos.

We also turned on the floppy 1.44mb GAL chip and this worked fine as well. Could access 1.44mb and 720k floppy disks.

So today was very successful for testing the H4. All testing was done on board #3. So now need to do the DMA fix and floppy 1.44mb updates on board #1 and #2.

Great stuff well done! :cheers: