Display issues with MFX 40 column basic

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davesnowdon
Posts: 20
Joined: 01 Oct 2023 21:54

Re: Display issues with MFX 40 column basic

Post by davesnowdon »

I've got some 4116 chips from retroleum.co.uk. They appear to be TMS4116-15NL so according to http://www.primrosebank.net/computers/m ... txvram.htm they should be fast enough.

I'm reading through the service manual and also http://www.primrosebank.net/computers/m ... repair.htm and http://www.primrosebank.net/computers/m ... _fault.htm
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gunrock
Posts: 276
Joined: 28 Oct 2020 21:17

Re: Display issues with MFX 40 column basic

Post by gunrock »

Good luck!
Steve G
Danish Memotech MTX 512, MFX and loving it
davesnowdon
Posts: 20
Joined: 01 Oct 2023 21:54

Re: Display issues with MFX 40 column basic

Post by davesnowdon »

Victory!

I ended up replacing 3 4116s. I tried checking for overheating chips but didn't feel any obvious differences. I ended up grounding pin 14 of each VRAM chip in turn via a 15 ohm resister and found 3 with dodgy bits. De-soldered those, fitted some sockets and it worked first time with the replacement 4116s.

Thanks Dave and everyone else for the help and encouragement!

Wishing you all a Happy New Year!
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Dave
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Joined: 11 Aug 2012 18:16
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Re: Display issues with MFX 40 column basic

Post by Dave »

Happy New Year to you too.

Great stuff - well done!
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1024MAK
Posts: 785
Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: Display issues with MFX 40 column basic

Post by 1024MAK »

What he ^ (Dave) said.

Well done 8-)

Mark
:!: Standby alert :!:
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Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Autumn is here. Bye bye summer 2024...

Not as many MTXs as Dave! :lol:
stephen_usher
Posts: 341
Joined: 27 Nov 2016 19:58

Re: Display issues with MFX 40 column basic

Post by stephen_usher »

4116 chips are always dodgy!
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