Case considerations

[msknight]

Now that I have the mechanical keyboard, the zeddy isn't going to fit into the original case.

I've been thinking about this... https://uk.rs-online.com/web/p/instrument-cases/0503616

The question I have is about the heatsink from the voltage regulator. ... the motherboard will be mounted on studs, so I was thinking of putting two bends in the metal plate, to bring it down to the case, and thus route heat to the case itself... thus making a larger heatsink.

Am I onto something here, or am I just being bonkers, as usual

[Paul]

I would consider to replace the 7805 against a switching regulator like Recom or Traco and get rid of the heatsink because those don't produce heat.

[msknight]

I would consider to replace the 7805 against a switching regulator like Recom or Traco and get rid of the heatsink because those don't produce heat.

You're talking to someone who only knows the very basics of electronics.

If you can point me at a link for something to buy... preferably on e-bay as RS, etc. need minimum postage ... and some instructions on how to make the change, I'd be very grateful.

[Lardo Boffin]

If you just want one then search for Murata on here:

https://www.retroleum.co.uk/

It comes up for the Spectrum but works fine in the zeddy. Will find a photo of one fitted.

Edit - you will need to bend the outer pins out slightly otherwise it might be too tight a fit.

[Paul]

You're talking to someone who only knows the very basics of electronics.

Thanks for the Info. Please excuse my poor english.
This requires desoldering of the 7805 which is attached to the heatsink (or otherwise round)
First you unscrew the heatsink and put it aside. not needed anymore.
The value of the old 7805 is near zero, so don't hesitate to break it.
Best you can do is cut the legs as close to then Black housing as possible and throw away the 7805.
The cutting can be done with with a side cutter, but a scissors can also be used.
Then heat the soldering iron and with it you can melt the solder of each of the three pins and pull out the pin with a pincer or a pair of tweezers.
If there is still solder in the holes you need to clean them with desoldering braid.
After this you can solder in the new device. Lardos link already has the correct orientation (the one for horizontal mounting) of the pins so soldering this in should be easy.
Cheers
Paul

[1024MAK]

See also my topic on the DC/DC converter / switching regulator here

Mark

[msknight]

Thank you all very much!

Can't wait to get stuck in to this! Getting rid of the heat sink will make re-casing the zeddy much easier.

[1024MAK]

The type we are talking about are a direct replacement for 7805 type series pass regulators.

Series pass regulators discard excess voltage by converting the excess power to heat, hence the need for a heatsink.

DC/DC converter / switching regulators use switch mode technology, they are normally better than 85% efficient and produce very little heat. They also reduce the power consumption from the 9V (nominal) power input.

Mark

[msknight]

Retrolium has some Murata direct replacement, but the shop isn't open until Jan.

I've found the Recoms on Farnell...
https://uk.farnell.com/recom-power/r-78 ... dp/1793143
...but I'm having a problem finding those caps. The ones which I have are small brown circles and I don't know what they're maximum voltage is... I doubt it would be safe to use those, so I've been trying to find the ones you're using Mark. It's a small nightmare trying to navigate a mini-dropdown nightmare when, if you're like me, it's just so confusing.

Michelle.

[msknight]

And here's the other one... with the Recom having an output of 5a, does that mean I can use a larger power supply and run the PiZero and possibly a 5v fan inside the case?