ThomasM74's H5 C1 build

[thomasM74]

Hello! Here are my H5 C1 build results and ideas/tips:

Everything arrived safely and fast (EU/East Europe). Info for EU buyers, I was lucky enough to not be charged VAT, but do not take this as guarantee for any EU country.

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One of my first changes during assembly is that I want to have both the DIN13 video connector and a DB15 HD connector, this way I can skip the external adapter in case of VGA monitor. I soldered the wires from below so they don't obstruct the DIN13 connector and the DB15HD socket goes in place of the external floppy connector. Not shown in pictures but I will add an external switch for the lowres/highres jumper.

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Next, I have quite decent soldering skills but definitely no desoldering skills and/or tools. Therefore I did the brutal thing of cutting of the expansion socket from the donor board which allows reuse of the connector (leads are long enough) but only vertically positioned.
Does not bother me because the only reason I installed it is for the test cartridge on first power-on.

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Going on, external connectors, I have no need for external FDD or external ACSI connector. In place of FDD will go the VGA connector and in place of ACSI will go the USB connector from Gotek and the rotary selector.
Floppy drives, I will use two drives, both internally installed. One regular floppy drive, standard PC HD 1,44 drive which (I guess thanks to the GAL chip) works right as is (no mods) and one Gotek floppy emulator. I am using a regular PC floppy cable with one tiny hack: wires 12 and 16 are cut off from the motherboard side connector and are soldered to pin 5 from the (not installed) external floppy connector. PC floppy stays at the end of cable (after the twist) and is by default the first drive and Gotek in the middle (jumpered as S1, before the twist) and is by default the second drive.
Obviously, order of drives can be reversed through the A/B select jumpers on the motherboard.

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Regarding ACSI, I mentioned I do not need the external connector because I plan to install an ACSI SD (or CF) adapter internally. Most probably Pera Putnik's.
Also, I replaced the power supply. Old one was still OK but to eliminate any risk, chose a new one, Mean Well model RPD-60A.

Regarding the H5 C1 platform, no doubt, a great replacement for flaky old STF PCB:

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What I was missing/wished differently are:
- totally missing solder points for audio output for installation of a separate audio socket. Now I can only hack it from the DIN13's pin 1. There is an audio pinheader next to the waveblaster connector but I assume those only carry audio from the wavetable card.
- Crystal oscillator placement, if you put a socket below, it gest quite high no longer fitting under the power supply's metal frame.

The ugly: missing docs ... I agree, most of it is documented here in the forum, in various posts. After a few days of browsing/reading it is possible to get together most of the needed info, yet still not all. I managed to get through and reach a functional state of this new motherboard but not without two days of cursing for reasons that could have been easily avoidable.

So advice for beginners if you do not have a dual TOS decoder, you MUST put a jumper on the "DUAL TOS Low/High" selector pins otherwise not even the external test cartridge ROM will boot.

That's it so far, I'll return with pictures after I manage to cram the floppy and gotek inside the case.

Thomas

[exxos]

Just needs the customary favorite game shot

[Badwolf]

Hello! Here are my H5 C1 build results and ideas/tips:

Looks great. Good work.

BW

[Icky]

What I was missing/wished differently are:
- totally missing solder points for audio output for installation of a separate audio socket. Now I can only hack it from the DIN13's pin 1. There is an audio pinheader next to the waveblaster connector but I assume those only carry audio from the wavetable card.

@thomasM74, great build.

You can just hook off of JP3 if you're looking for a line out for audio

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[thomasM74]

Thanks Icky for advice on the audio connector, missed that.
(there is no indication on the PCB about JP3 and the jumper docu refers to JP3 as a 3 pin header) ... tip for Rev. C2 update silkscreen with "JP3"

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and better later then never:

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[exxos]

Thanks Icky for advice on the audio connector, missed that.
(there is no indication on the PCB about JP3 and the jumper docu refers to JP3 as a 3 pin header) ... tip for Rev. C2 update silkscreen with "JP3"
8_au.jpg

Added a label for C2

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[DoG]

Great job!

[thomasM74]

Thx, for replies and appreciation.

@exxos, future owners of C2 thank you for the audio connector label, just check the numbering, it's reversed.

While these last steps no longer refer to the H5 C1 board itself, I post it here to have continuity:

So far, floppy drive task completed. A regular PC HD Sony drive installed.
Some cutouts required (yellow mark). I always joked that hammer is an IT technicians best tool, in this particular case an angle grinder.

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New handle attached:

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and shorted down to the appropriate length. Cut of an aluminum sheet, at first I was afraid it will be too soft and bend while ejecting but it's not.
Original legs (stands) are too short for a slimmer PC drive therefore new legs installed (flexible plastic pipe cut to required length).

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With case closed, it looks stock, disk insert and eject all good:

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btw, the plastic frame that was originally attached to the floppy drive is now glued to the case. It was no longer possible to attach it to the drive.

Conclusion: was FDD drive worth it or will I need it ? Don't know ... probably no, never, still I like to have a physical functional drive available, just for the sake of it.

I guess there will be just one more post from me in this thread, when I'm done with: find a nice place for gotek's rotary encoder and OLED screen (without cutting case), install the ACSI-CF adapter and reflash the 1.04 ROM to the 1.04 version that has IDE boot modifications included.

[exxos]

@exxos, future owners of C2 thank you for the audio connector label, just check the numbering, it's reversed.

Well spotted!

[thomasM74]

And here it is, the final post of my H5 C1 build ...

I checked several options for IDE, started with Pera Putnik's external ACSI interface, had some glitches due to may DMA chip (his interface worked flawless on a stock 1040ST) so instead of just replacing the DMA chip I took the hard way out ... saw that Pera has an IDE interface schematic for Mega ST and decided to adapt it for the H5.

Fired up Kicad and after two pcb revisions I had a working interface (my first version had a quite stupid mistake, I selected accidentally the wider 64pin socket in Kicad).
The cherry on top is that Pera's IDE interface also includes ROM decoder circuit which works on H5 and now I can boot both lower and upper ROM area - full 1.04 and 2.06 support.

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I designed the IDE interface PCB for both 40 and 44 pin IDE connector, in my case I soldered the 44 connector and plugged in DOM.
From a software point of view, IDE support is via Pera's driver and formatter (available for a small fee).

For the ROM decoder part I needed the ROM2 signal ... my best guess was the pad from the surface mount glue

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Unless there is a ROM2 pin which I am not aware of, would be practical for future H5 versions to put an easily accessible solder point for it.

Next, I needed several switches ... while I hate a drilled case, there was no other option to bring out switches for floppy A/B order select, ROM 1.04/2.06 select, rotary encoder for gotek and one more switch for video auto/force mono jumper

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and that's it!
all crammed in, metal shielding has no longer place (unless I cut off parts of it), ready to be closed with screws and hopefully no need to open it anytime soon again.

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of course I plugged the DOM back in after photo and before closing the lid

If any questions, I gladly answer them.
Until then ... Happy Christmas.