will it compute? btl's attempt to build the H4

[btl]

Yes, that's probably where my mistake was. I have a couple of SN74LVC1G11DBVR, but only one STM6315RGW13F. That's why I thought I had spare. It was the only 4-Pin SMT IC I have, so I am quite sure ;-)

Never mind, Ingo, i'll get the chips somehow.

I've been tinkering the afternoon, but i can't get ASCI (i have a CosmosEx) working.

- when CE gets plugged, floppy drive stops working, does not even show up on EmuTOS at boot screen.
- without floppy, CE_DD does not come up
- CE has been checked working on my 1040STe

i tried

- checking my board for shorts
- new cable from ASCI port to CE
- connecting from US DMA connector to CE
- PLCC and DIL CPU
- jumpering IC6 like Paul did

any ideas would be highly appreciated!

20191211_190943.jpg

[exxos]

I have had similar problems to that with the original machines, but mostly it just turned out to be no pullups I think.. but the H4 has them anyway..

https://www.exxosforum.co.uk/forum/viewt ... =17&t=1015

Might be worth re-soldering the SIL arrays ?

[btl]

Hi,

thank you for the hint, Exxos, i did reflow my pullup networks, checked they are the correct ones
and correctly positioned it made no difference, though.

Looks i got it running, anyway. As a last resort i wanted to try my Link 2 with a known good SCSI drive.
In its box, i found the original connector cable of my CosmosEx, et voilá, FDD and CE can be connected both.
Now i just needed to upgrade teh CE Firmware to match the new image on the Raspi SD card and i'm back in the game.

The faults were clearly on my side, H4 working (with the IC6 bridged out) with DMA and FDD!

[exxos]

Glad you got it fixed :)

I think all these DMA issues relating to "external hardware" will be a thing of the past once Trudie makes it into production :)

[exxos]

in the meantime, last resistors are in. R3 and R4 were tricky, they go through the plastic frame of the MIDI ports...

Can you post a image of this issue then I can correct it on the REV F layout :)

[PaulJ]

in the meantime, last resistors are in. R3 and R4 were tricky, they go through the plastic frame of the MIDI ports...

Can you post a image of this issue then I can correct it on the REV F layout :)

I believe I had the same issue. It depends on the MIDI sockets the donor board has. The MIDI sockets that are on the board I used to get the 19 pin D connector were different and didn't have the extended squares on the base. Hard to believe the leads fit right through the holes. :dualthumbup:

8888.jpg

[exxos]

I believe I had the same issue. It depends on the MIDI sockets the donor board has. The MIDI sockets that are on the board I used to get the 19 pin D connector were different and didn't have the extended squares on the base. Hard to believe the leads fit right through the holes. :dualthumbup:

I have moved the resistors on the next revision..

It also looks like the PSU feet slot needs moving to the left fractionally ?

[btl]

It also looks like the PSU feet slot needs moving to the left fractionally ?

On my build it fits exactly.
Cheers,
btl

[btl]

Hi there,

i just had some fun running Notator (with Dongle in ROM port) and was playing some demo songs via MIDI.
Input seems to work as well. Not sure if someone reported MIDI as tested and OK before, so i do here.

[Icky]

@btl - great MIDI is working. We should create a topic on what has been tested and reported as working as I think everyone who has an H4 working has been testing different things.