Looks like I'll be getting a Mega ST4 soon

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rubber_jonnie
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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Tue Oct 08, 2019 6:01 pm

Well,I have the Mega, and it's a bit poorly :(

On lifting the PSU out, I found that the Yamaha sound chip was missing. A quick clean of the area shows some via damage, but fortunately nothing too terrible, and eminently repairable.

I'll fit a socket once I've given the board a damn good clean, as it's quite grubby right now and drop in a spare chip.

Next on the agenda will be the PLCC sockets, whuch along with the chips (Just GLUE & MMU, no blitter right now) seem to be heavily oxidised, and some of the socket contacts look a bit wayward, so will need cleaning & tweaking.

The previous owner did say he tried to fit a Blitter, but it still didn't work, and the jumpers are still bridged, so they will need to be cleaned up for now, as I'd rather try to get it working Blitterless to begin with for simplicities sake.

Not yet quite worked out a plan for the keyboard, though I could fit my CosmosEx internally, as it'll give me hard drive (Looks like there is an internal ACSI port already, just need a cable), network and USB for KB and mousage. Only problem there is I'd need to work out some sort of IKBD connector for the CosmosEx IKBD injector.

For interests sake, the mainboard is this model: viewtopic.php?f=55&t=527
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Tue Oct 08, 2019 7:41 pm

Pop your Pak in it once it's fixed, no blitter required then.
If it ain't broke, test it to Destruction.

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Tue Oct 08, 2019 10:28 pm

PhilC wrote:
Tue Oct 08, 2019 7:41 pm
Pop your Pak in it once it's fixed, no blitter required then.
Not a bad idea...

Also considering fitting an IDE interface internally.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sat Oct 12, 2019 1:35 pm

So here it is in all it's glory, as you can see the board is quite grubby:
IMG_20191011_145311.jpg
IMG_20191011_145311.jpg (562.23 KiB) Viewed 61 times
On a positive note, despite the missing sound chip, it does power up and get to a desktop.

Next steps are:

1. Clean the board to remove all the grime. Oddly, the PSU is super clean.
2. Review the damage to the sound chip location, and solder in a socket, repairing any via and pad damage as I go. TBH most of the missing vias on the top are not connected, and the pads on the bottom seem fine.
3. Drop in the sound chip and test.
4. Clean the case and work out what I'll do with the hacked bit at the front where a PC floppy was fitted. It's likely I'll drop in a Gotek.
5. Make a new battery harness for the clock. Currently its missing in action.

I am kind of thinking I may do a permanent CosmosEx install, since there seems to be an ACSI header internally, and it would give me keyboard/mouse options over USB if I can rustle up some sort of IKBD injector. Alternatively I can see if I can make an adapter for one of the spare ST KBs I have.

I may also go down the route of fitting in my PAK permanently and/or an IDE interface since I have 2 beta units to hand and the Mega has the space in the case. Maybe PAK and IDE together?
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Sat Oct 12, 2019 2:43 pm

Would be nice to see if the IDE works with the Pak.
If it ain't broke, test it to Destruction.

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sat Oct 12, 2019 6:21 pm

PhilC wrote:
Sat Oct 12, 2019 2:43 pm
Would be nice to see if the IDE works with the Pak.
Indeed it would.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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rubber_jonnie
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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sat Oct 12, 2019 7:01 pm

Eiffel order enquiries made to Olivier at Gossuin.be. It's inexpensive @€13 + Shipping, so I though why not. It's nice to have options.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Sat Oct 12, 2019 7:03 pm

I got myself two work very well.
If it ain't broke, test it to Destruction.

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sun Oct 13, 2019 10:15 am

PhilC wrote:
Sat Oct 12, 2019 7:03 pm
I got myself two work very well.
Cool :)

I pulled the trigger on the order last night, so hopefully I'll have had a chance to clean the mainboard and install the sound chip by the time it arrives.
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Sun Oct 13, 2019 10:56 am

They did arrive pretty quickly, so youd better get cracking :lol:

Have you got a spare sound chip or would you like me to send you one?
If it ain't broke, test it to Destruction.

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