Update 7805 to OKI-78SR-5 for heat reduction

[SmokeMonster]

I have been going through my consoles and replacing their 7805 voltage regulators with the newer and more efficient OKI-78SR-5. I originally ordered four for my hottest running systems: Sega Genesis (has two 7805s), SNES, and Super Famicom.

The results were dramatic, and all of them pretty much run cool to the touch now. The 78SR-5 doesn't need a heatsink, and there is no change to the AV quality. The sync seems more stable on my Genesis, so it might have had a failing 7805. I have more ordered now for my TG16, PCE, and Duo.

Has anyone else gone this route?

[ClodBuster]

Since I think I'll need to replace the regulators on my Duo anyway, I'll give the swap for the those more efficient parts you proposed a try.

However, the link you've posted leads to a 404 site. EDIT: Thanks for fixing.

[SmokeMonster]

The link should work now. I think Digikey is the cheapest source for them in the US.

There is also a 90-degree angled version (OKI-78SR-5/1.5-W36H-C) that is perfect for TG16 mounting.

[CkRtech]

I have done this on several of my consoles and figured the Turbo Duo was a no brainer. I just haven't done it yet. In fact, a Turbo Duo may benefit the most out of all consoles due to the heat issues it is known for. I may even do a temperature experiment with my unit and take measurements before and after the change and report here whenever I do the mod. One of you will most likely beat me to it.

[SignOfZeta]

...heat...issues...?

[thesteve]

...heat...issues...?

my thoughts exactly

[thesteve]

be aware that the 7805 is rock solid old tech, and may prove more reliable

[SmokeMonster]

...heat...issues...?

SNES and Genesis definitely get toasty but the NEC stuff doesn't seem to be on that level.

[thesteve]

well yes the SNES pushes the 7805 hard, but the other stuff not so much
the 78SR-5 however is a power converter circuit on a board to use as a replacement, but as a much more complicated circuit could prove less robust in practice

[ClodBuster]

On my Turbo Duo, the 7805 thingies got really hot, even so much that you can feel the heat on the plastic cover. A friend of mine who succesfully recapped my Duo even suggested I should replace the regulators with something more efficient.

[Keith Courage]

If it isn't broke don't fix it.

[ClodBuster]

Well my Duo is broken so I've got to fix it anyway.

[SmokeMonster]

I recap consoles that aren't broken all the time. If heat in a console can be completely eliminated using a $4 part, it's worth looking in to.

That said, the negative feedback from thesteve and Keith makes me less enthusiastic about doing this to NEC consoles.

[leonk]

I don't subscribe to "if it ain't broken, don't fix it" mentality.Following this logic people should wait till all the caps in their Duo/TGE leak all over the PCB and rot the traces before doing any sort of preventative maintenance.

Switching power supplies (what this is) have been here since the 80's (unlike the linear 7805 whose been here since the '40s if not earlier). It's a lot more efficient (doesn't waste electricity) and a lot more resilient (can take up to 35V input!) and puts out clean 1.5A of current(which is needed if you use FPGA based devices in your retro consoles - like everdrive)

I noticed that my Sega NOMAD with LCD mod would shut down after 2 hours of usage (using micro surface mount linear transformer) when I put this in there it ran for 8 hours before I just turned it off.

Use it, don't use it, up to you. I tell all my customers about it and they all agree with the extra fee for the upgrade.

[CkRtech]

...heat...issues...?

my thoughts exactly

from the two 7805 near the sound circuit