STM 4MB RAM UPGRADE

Upgrade your RAM from ST to Falcon.
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stephen_usher
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Re: STM 4MB RAM UPGRADE

Post by stephen_usher »

That looks nice and flat. :-)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
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PhilC
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Re: STM 4MB RAM UPGRADE

Post by PhilC »

Just completed soldering in this upgrade today.

I used round pin headers on the DIP 16 section and then used long header pins inserted through the top to the bottom, soldered both ends and trimmed to length.

I'll give it a test in the morning but don't expect there to be any problems.

Feedback about kit:

Nice upgrade but certainly not for a novice solderer, the old chips will need complete removal and these older boards are very easy to damage if rushed.
If it ain't broke, test it to Destruction.
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exxos
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Re: STM 4MB RAM UPGRADE

Post by exxos »

@PhilC does the shielding fit back in place ?
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Re: STM 4MB RAM UPGRADE

Post by PhilC »

exxos wrote: 24 Nov 2021 17:12 @PhilC does the shielding fit back in place ?
What shielding?
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Re: STM 4MB RAM UPGRADE

Post by exxos »

My fitting..

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PhilC
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Re: STM 4MB RAM UPGRADE

Post by PhilC »

Just waiting for one of these to appear in the store. Just got a rev I stm that I'll be keeping.
If it ain't broke, test it to Destruction.
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Re: STM 4MB RAM UPGRADE

Post by exxos »

PhilC wrote: 27 Nov 2021 12:43 Just waiting for one of these to appear in the store. Just got a rev I stm that I'll be keeping.
Might be after xmas, China didn't solder the header pins, so I can't test them until they soldered on :roll:
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Re: STM 4MB RAM UPGRADE

Post by PhilC »

exxos wrote: 27 Nov 2021 13:09
PhilC wrote: 27 Nov 2021 12:43 Just waiting for one of these to appear in the store. Just got a rev I stm that I'll be keeping.
Might be after xmas, China didn't solder the header pins, so I can't test them until they soldered on :roll:
And getting them straight is a pain in the bum
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Re: STM 4MB RAM UPGRADE

Post by stephen_usher »

You need a jig, or put sockets in an old ST(m) motherboard so that you can pit the pins into that and then rest the PCB on top and solder.

P.S. Maybe sell them without pins? Hmm... then you can't test them. That's a pain.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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Re: STM 4MB RAM UPGRADE

Post by exxos »

stephen_usher wrote: 27 Nov 2021 13:56 You need a jig, or put sockets in an old ST(m) motherboard so that you can pit the pins into that and then rest the PCB on top and solder.

P.S. Maybe sell them without pins? Hmm... then you can't test them. That's a pain.

I've soldered in socket headers in a spare board thinking I can push the pins in and put the board on top, but aligning more than 2 pins even being held in the socket headers is still a nightmare. It took me about 2 hours to do 1 board.

I have some blank PCBs (SMT is on IIRC, just not the chips) if people interested in those I can put them in my store next week. I didn't have time to solder the DRAM so got them done in china.

I did consider selling boards without pins, but I could be selling faulty stuff, which I don't want to do. The first board I did had a short on one of the DRAMs.

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