The latest member of the family

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Maximilian
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Re: The latest member of the family

Post by Maximilian »

How fast are the ram chips on the memory expansion?

Use 100ns or even better 80ns or faster if you do want to place the memorychips on the mainboard.
Make sure the keyboard still fits if you are using sockets.
As I mentioned before, you will not be able to use some expansions (memory expansions and more) after this mod.

Can you show some pictures of JP2 and JP7a?
(if it is already modded for 1mb chip mem and there is 120ns ram on the expansion, this could be a reason for the ram errors)
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rubber_jonnie
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Re: The latest member of the family

Post by rubber_jonnie »

Maximilian wrote: Sun Feb 02, 2025 1:02 am How fast are the ram chips on the memory expansion?


I'll check and post back, but it is a fairly standard 3rd party trapdoor RAM/RTC card so I'd expect the RAM to be a suitable speed.
Maximilian wrote: Sun Feb 02, 2025 1:02 am Use 100ns or even better 80ns or faster if you do want to place the memorychips on the mainboard.
Make sure the keyboard still fits if you are using sockets.
As I mentioned before, you will not be able to use some expansions (memory expansions and more) after this mod.


I think I have 80ns RAM, so that should be fine, but I'm not yet ready to go down that route. I did wonder if the keyboard might be a problem with sockets for the RAM, thanks for confirming it could and I'll test before assembly if I go down that route.

As it happens, RetroLemon are getting stock of the Lotharek 8mb/IDE upgrade that fits under the CPU so it may be unnecessary anyway.
Maximilian wrote: Sun Feb 02, 2025 1:02 am Can you show some pictures of JP2 and JP7a?
(if it is already modded for 1mb chip mem and there is 120ns ram on the expansion, this could be a reason for the ram errors)
I will get some later on, but they appear to be in their factory positions and untouched at the moment.

Appreciate your help, thanks.
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Re: The latest member of the family

Post by rubber_jonnie »

@Maximilian

The trapdoor RAM is 120ns and I have 100ns and 60ns RAM that I can fit on the mainboard if I decide to do so.

Pictures of jp2 and jp7a to follow later.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: The latest member of the family

Post by rubber_jonnie »

stephen_usher wrote: Sat Feb 01, 2025 11:08 pm If there's no RAM there and you're only testing the SLOW RAM addresses then the machine should not crash but the memory test should fail. You are manually testing only 0xC00000 to 0xD7FFFF aren't you?
That memory range is interesting, on the memory map I looked at it didn't say that range so I'll recheck.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: The latest member of the family

Post by rubber_jonnie »

Maximilian wrote: Sun Feb 02, 2025 1:02 am Can you show some pictures of JP2 and JP7a?
(if it is already modded for 1mb chip mem and there is 120ns ram on the expansion, this could be a reason for the ram errors)
JP2 and JP7a:

IMG20250202092202.jpg
IMG20250202092202.jpg (309.33 KiB) Viewed 62 times
IMG20250202092223.jpg
IMG20250202092223.jpg (277.65 KiB) Viewed 62 times
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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stephen_usher
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Re: The latest member of the family

Post by stephen_usher »

JP7 is a red herring as that's purely external real time clock related and isn't connected to the memory sub-system at all.
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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rubber_jonnie
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Re: The latest member of the family

Post by rubber_jonnie »

stephen_usher wrote: Sun Feb 02, 2025 12:42 pm JP7 is a red herring as that's purely external real time clock related and isn't connected to the memory sub-system at all.
Well it's a bit of a moot point anyway as its set to default anyway.

As it goes the RAM card has a jumper connected to there and it can be turned off if required.

The RTC is visible to ATK anyway, so it has to be memory related.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: The latest member of the family

Post by rubber_jonnie »

rubber_jonnie wrote: Sun Feb 02, 2025 8:48 am
stephen_usher wrote: Sat Feb 01, 2025 11:08 pm If there's no RAM there and you're only testing the SLOW RAM addresses then the machine should not crash but the memory test should fail. You are manually testing only 0xC00000 to 0xD7FFFF aren't you?
That memory range is interesting, on the memory map I looked at it didn't say that range so I'll recheck.
No real difference using that range. Crashes quick and has to be rebooted.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: The latest member of the family

Post by rubber_jonnie »

stephen_usher wrote: Sun Feb 02, 2025 12:42 pm JP7 is a red herring as that's purely external real time clock related and isn't connected to the memory sub-system at all.
It was probably meant to be JP3 but that is set as default as below.

IMG20250202150529.jpg
IMG20250202150529.jpg (203.65 KiB) Viewed 37 times
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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stephen_usher
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Re: The latest member of the family

Post by stephen_usher »

rubber_jonnie wrote: Sun Feb 02, 2025 2:38 pm No real difference using that range. Crashes quick and has to be rebooted.
Something is very wrong there then.

Maybe one of the higher address lines isn't behaving correctly somewhere so writing to a location where nothing is supposed to be is changing something at a lower address where something important lives.
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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