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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 26th Nov 2022, 5:33 pm   #41
SiriusHardware
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Default Re: Idiot building a MK14 thread

I noticed someone in Croatia asking him for copies of the scans and I wonder if that is how the Czech replicas eventually came to be. A reminder, Tim has an unbuilt and as yet unscanned Czech replica PCB.
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Old Yesterday, 9:17 pm   #42
ScottishColin
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Default Re: Idiot building a MK14 thread

I'm still collecting parts and waiting for the postie right now. I intend to build in the last couple of weeks of December as I have some time off and work is a bit busy right now.

I can't find a suitable version of the larger capacitor with the legs in the right place (C2) - can someone point me at that please online?

I have 3D printed a camera holder for my ripod to fit my mobile phone in to video what happens - I intend to video the build; I'm not sure how interesting or useful it'll be but I'll give it a go.

Thanks.

Colin.
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Old Yesterday, 9:39 pm   #43
Slothie
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Default Re: Idiot building a MK14 thread

Quote:
Originally Posted by ScottishColin View Post
I'm still collecting parts and waiting for the postie right now. I intend to build in the last couple of weeks of December as I have some time off and work is a bit busy right now.

I can't find a suitable version of the larger capacitor with the legs in the right place (C2) - can someone point me at that please online?

I have 3D printed a camera holder for my ripod to fit my mobile phone in to video what happens - I intend to video the build; I'm not sure how interesting or useful it'll be but I'll give it a go.

Thanks.

Colin.
This is similar to the one I bought although I think mine is 40v for some reason..
Search for 1000uf axial electrolytic.

https://uk.farnell.com/illinois-capa...1000uf%20axial
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Old Yesterday, 9:53 pm   #44
ortek_service
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Default Re: Idiot building a MK14 thread

Quote:
Originally Posted by ScottishColin View Post
>>
I can't find a suitable version of the larger capacitor with the legs in the right place (C2) - can someone point me at that please online?
>>

Colin.
I presume this is the Electrolytic capacitor, in which case you probably need to search for an axial (Horizontal PCB-mount, with leads out of the opposite ends) rather than radial (vertical PCB-mount , with both leads out of the same end).
Although it is possible to mount either the other way round, by extending one lead across the case to the other end (and manufacturers sometimes did this).

You will probably find that modern ones are rather smaller than the original one, but leads may still be long enough to reach / could be extended a bit.
The value isn't that critical, so could use a slightly higher one / higher voltage, if that helps in getting a more similar size one. Equally, a lower value shouldn't be an issue, as this capacitor seems to have been for operation from an unsmoothed (just rectified-AC) DC-supply. Whereas if you are operating it from a decent regulated-DC PSU, it probably doesn't really do much / not really needed.

The MK14's original decoupling was exceedingly minimal / in odd places, and it probably only worked as it operated at a relatively-low frequency. But I believe some of the later replica PCB have enhanced the decoupling.
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Old Yesterday, 11:06 pm   #45
SiriusHardware
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Default Re: Idiot building a MK14 thread

Slothie's issue VI has an easy to remember 14 100n decoupling capacitors as it was observed that the decoupling on original MK14 PCBs was minimal.

Colin, I included a link to a potential part for C2 in a PM to you but perhaps those particular ones have gone? I don't know if this is obvious, but you don't need to find an axial capacitor with a body exactly the same length as the distance between the holes, the body can be way shorter - new / old stock ones always have long leads, and you just crank the leads downwards at the right distance from each end of the body. As long as the length of the capacitor body is not LONGER than the distance between the solder pads it will be OK.

Last edited by SiriusHardware; Yesterday at 11:11 pm.
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Old Yesterday, 11:51 pm   #46
ScottishColin
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Default Re: Idiot building a MK14 thread

Apologies - I've just re-read your message and found the link. I have ordered from there.

Colin.


Quote:
Originally Posted by SiriusHardware View Post
Slothie's issue VI has an easy to remember 14 100n decoupling capacitors as it was observed that the decoupling on original MK14 PCBs was minimal.

Colin, I included a link to a potential part for C2 in a PM to you but perhaps those particular ones have gone? I don't know if this is obvious, but you don't need to find an axial capacitor with a body exactly the same length as the distance between the holes, the body can be way shorter - new / old stock ones always have long leads, and you just crank the leads downwards at the right distance from each end of the body. As long as the length of the capacitor body is not LONGER than the distance between the solder pads it will be OK.
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Old Today, 12:49 am   #47
Mark1960
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Default Re: Idiot building a MK14 thread

You could just 3d print a dummy capacitor, I donít think its needed with any modern power supply.
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