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General Stuff(tm)

Blogs & guides and tales of woo by forum members.
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JezC
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Re: General Stuff(tm)

Post by JezC »

@stephen_usher Looks like it might be time to update that list of machines in your signature... ;)
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stephen_usher
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Joined: 13 Nov 2017 19:19
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Re: General Stuff(tm)

Post by stephen_usher »

Hehe
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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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

Looks like the TI 99/4A has bad 4116 display RAM.

When I very first turned it on it was OK for a couple of seconds and then more and more of the display became corrupt and stayed corrupt in that way when power cycled. Not surprising. 4116 RAM is notoriously bad.
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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agranlund
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Re: General Stuff(tm)

Post by agranlund »

stephen_usher wrote: 12 Mar 2022 19:28 IMG_2617.jpg
The TI 99/4A is in mint condition with not even a hint of a fingerprint on the aluminium.
Wow!! Just like new :)
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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

Well, pulled the machine apart this morning and replaced the bad video DRAM.

One chip was obviously bad with the output being a few millivolts. Replaced that and things got a bit better. One other chip was behaving slightly strangely when viewed on the 'scope so replaced that and...

IMG_2619.jpg
IMG_2620.jpg

Happy machine! :-)

My experience with the Memotech MTX helped here as it uses the same graphics sub-system so it was obvious to me what the fault was.
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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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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

And this afternoon checking out the Mac LCII as much as I can without being to re-cap the power supply (which is mostly dead) as Sod's law states that in my large stash of capacitors I have none which match those in the power supply.

So, rigged up the bench power supply for 5V. All fine as far as I can tell.

IMG_2622.jpg
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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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Location: Essex

Re: General Stuff(tm)

Post by rubber_jonnie »

That TI is really nice :)

As for the LCII I had an LC475 a few years back and ended up getting rid of it as I just didn't have enough space, and now honestly wish I hadn't!! It's a scenario that's played out a few times for me over the years, and I'm happy to finally be over it!!

That is an impressive and very nice haul :mrgreen:
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: General Stuff(tm)

Post by stephen_usher »

I'm going to be giving away the TI. I'd never use it for exhibitions and the two games carts are awful arcade clones.

After that power test on the LCII I noticed that a couple of the surface mount caps had belched their guts, so I had to clean up the electrolyte.

I've got a full set of the surface mount caps on order now, along with a full set of the power supply low voltage side ones. They should arrive on Tuesday.

The LCII isn't fastest machine on the planet. It was definitely a Low Cost machine. Only 4MB of RAM on board. I'll have to find out what sort of SIMMs it takes.
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.
User avatar
rubber_jonnie
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Location: Essex

Re: General Stuff(tm)

Post by rubber_jonnie »

stephen_usher wrote: 13 Mar 2022 17:49 I'm going to be giving away the TI. I'd never use it for exhibitions and the two games carts are awful arcade clones.

After that power test on the LCII I noticed that a couple of the surface mount caps had belched their guts, so I had to clean up the electrolyte.

I've got a full set of the surface mount caps on order now, along with a full set of the power supply low voltage side ones. They should arrive on Tuesday.

The LCII isn't fastest machine on the planet. It was definitely a Low Cost machine. Only 4MB of RAM on board. I'll have to find out what sort of SIMMs it takes.
Lovely caps!! Apple seemed to have a particular talent for putting crappy caps in their machines of this era.

I think what I liked about the LC was the form factor, it's really neat. I actually acquired a number of LCs, the 475 included, from a school that had a huge pile in the basement. I knew a guy who worked there, and he said I could take what I wanted, so I think I took the LC475 and another 3 machines, plus matching CRTs. I really regret getting rid of them, and though the 475 had its own specific set of problems, it was a nice little machine, and the CPU looked glorious in all its ceramic finery!!

I may try and find another 475.

The TI is one of those machines I say 'I want one of those' and when it comes to the crunch, I get other stuff instead. I always remember going to Liverpool with my parents, and one of the department stores had the TI along with Ataris and Commodores, and I always thought it looked fab, but it was just too expensive, hence why I ended up with an Atari 600XL in the end.
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: General Stuff(tm)

Post by stephen_usher »

Yeah, the TI is quite limited. It's got a very tiny amount of built-in RAM which rather hobbles the 16 bit processor. It was really designed with cartridges in mind, the BASIC is just a place holder.

The LC475 is really sought after as it's the fastest of the m68k Macs and the motherboard can be fitted into a Mac Color Classic.
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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