Can I use 2 of these modern voltage regulators to replace the two 7805s in a Model 1?

https://www.digikey.com/product-deta...6-5-ND/2259781

I successfully used this voltage regular to replace the 7805 in two Super Nintendos, and they no longer need the heatsink/RF shield in the back now. It improved the video quality on one of them that had horrible video interference. I thought it was the caps but decided to try replacing the 7805 first, and it fixed it! They also don't get hot at all either (hence, no need for a heatsink).

Anyway, will two of these work on a Model 1 Genesis? It'd be great to no longer need the heavy heatsink inside the Model 1 as well as being able to significantly lower the temperature of the Genesis 1 when I have it on for long periods of time.

Technically....yes.... as I tried this once before. Notice I said tried.

Here is the deal. I actually use these DC-DC buck converters in all of my consoles now...minus the Genesis and here is why:

I had two issues when I popped these into the Genesis - 1st and primary issue was the increased noise on the audio line. The main game I tested was Thunder force II. I could hear coil whine in the silence parts where I didn't hear anything before, and worst was that I was getting odd beeps and boops during game play that I knew wasn't supposed to be there.
The second issue. was that some games, especially S&K and Sonic 3 would randomly just lock up for no apparently reason or would suddenly present glitched graphics.

I also have line noise on the my TurboDuo after changing out the 7805s in it with two of these. But it wasn't nearly as bad and didn't present any other issues, so I left those installed. But on my Genesis I ended up taking them out and putting in 2amp rated output 7805 linear regulators in there. These don't run as hot since they are rated for 2amp and the Genesis isn't going to pull near that from each of them. But they still get hot and require the heatsink.

Now in looking at the Genesis schematic, there is something interesting to try on this. On the model 1 the two VRs essentially control different halves of the Genesis system. One of the VRs is mainly for the audio and video output I believe and the other is for the 68k and ram. So...it might be possible to just replace one of these out with a DC-DC converter to lower the temps quite a bit inside without the line noise interference these produce if you just installed it in place of the VR that controls the 68k and ram.

BTW...the model DC-DC converters I used, was the Traco Power brand ones. Pretty much the best you can get and they are totally encapsulated and supposedly have filtering built into them to prevent what I described above. But... not on the Genesis model 1. Again I have these installed in all my other consoles pretty much without any issues. Even my Intellivision has a 7805 DC-DC converter in it and a 7812 DC-DC converter.

Hope that helps? I guess you can certainly try it and it will indeed work and function, but in my case, the audio on the Genesis is pretty much the main reason I love the Genesis so much and hearing that coil whine like sound and other oddness just wasn't worth it.

Oh wow jeez, thanks for that very in-depth explanation of your experience with trying that out. I have two Model 1s, a VA6 that doesn't have an EXT. port and doesn't produce any noises whatsoever during silence, and one of that does have an EXT. port but still doesn't have the HDG print on the top cover (I think it was a Genesis 1 that was bundled with a Model 2 Sega CD). That second one of mine, the one with the EXT. port does produce a some bits of noises during silence but no where near as bad as what you experienced with the new voltage regulators. I guess if it ain't broke, don't fix it right?

Can you explain why that modern voltage regular works so well for the Super Nintendo then? It literally was a night and day fix. My Super Nintendo had very bad video interference, like white lines at the top and very wavy video. Was that perhaps something to do with a 7805 going bad? I put the same modern voltage regulator on another Super Nintendo for preventative maintenance (and so that I can have more room to work with for adding a component video mod) and it didn't seem to do much of a difference on that one, I guess because the 7805 was fine on it.

I don't think I'll be adding the DC-DC converter, seems complicated and my Model 1s work fine anyway. Nonetheless thanks for the reply.

Most likely yes on the first super NES. Chances are the 7805 was going out or basically not producing enough voltage/current for the system. Would explain the odd video. As I said, using the DC-DC converters will work on the Genesis. But I did experience very noticeable audio hum, buzz, etc. Mainly sounded similar to coil whine though and would ramp up on quiet audio sections with lots of white on the screen such as during company logos. But then, maybe it was just this particular Genesis? Forgot to mention, I did this on a va2 HDG unit. I also have a va3 I just got working again, but had planned to basically leave it stock for now as it doesn't seem to generate much heat at all. Same with a va6 I have as well. Not much heat from that one either so I've left it alone for now.

If you want to try and reduce some additional heat and power usage elsewhere, you could get rid of the power supply brick and replace it with a more modern switching power supply. I use a converted gamecube power supply with my Genesis/32x/SegaCD combo.

Quote:

---

Originally Posted by CrossBow

Most likely yes on the first super NES. Chances are the 7805 was going out or basically not producing enough voltage/current for the system. Would explain the odd video.

---

Yeah I kind've figured that by now. I think it wasn't giving the console enough power and it possibly was putting out less much less than 5V. I didn't check with a multi-meter or anything, but at least it's fixed now. Wish I did a before and after video but I didn't know that only changing the voltage regulator would fix it, I thought it was possibly the caps as well.

Quote:

---

Originally Posted by CrossBow

If you want to try and reduce some additional heat and power usage elsewhere, you could get rid of the power supply brick and replace it with a more modern switching power supply. I use a converted gamecube power supply with my Genesis/32x/SegaCD combo.

---

Would this power supply work? It was tossed out at work so I just took it, it works with my NES but I was told that the 12V is too much to safely keep on using it for my NES. I don't know how to change the polarity for the Genesis and all its attachments neither. I've already ordered a 3 in 1 barrel plug for cheap off of ebay, but all 3 plugs would only fit in the Genesis 1 and Sega CD. I'd have to get a Genesis 2 barrel plug from somewhere and rewire it.

http://i67.tinypic.com/10h6d76.jpg

That power supply has the wrong polarity for a model 1 genesis and Sega CD. However, reverse that polarity and this supply has enough amperage to drive a Genesis, 32x, and Sega CD all in one. As for the voltage...I wouldn't worry about that too much. My Gamecube converted supply puts out about 14v without a load. Under load it drops down to about 11.5 - 12v as measured coming into the VRs on the Genesis. Hasn't seem to hurt them yet in well over a year of using it on a near daily basis for well over an hour a day. The NES can use it just fine as well. Polarity doesn't matter on the NES as it inverts the power to what it needs anyway. If anything you are saving it some work by using a DC power supply to begin with.

What you really need to do it plug this into your NES. turn on the NES and then measure the voltage with a multimeter at the VR input leg to see what the actual voltage is coming into the NES.

Now..if you decide to convert this to a trio power supply for the Genesis, then you need to reverse the polarity for two of the 5.5mm plugs for the Genesis Model 1 and Sega CD, and then you need another 2.5mm I think barrel jack for the 32x. But...that jack will need the polarity reversed from the Genesis 1 and Sega CD.

So in a nutshell the power connection to the Genesis model 1 and Sega CD needs to have a negative ( - ) center tip polarity, the 32x or Genesis model 2 needs a positive ( + ) tip polarity on the plug.

Thanks! If I can't convert it as a 3 in 1 for my Genesis consoles, at the very least I will end up just using this for my Hi-Def NES so I would no longer need to fit a fat power adapter into AC sockets.

In case of MD1, one 7805 is for analog stuff, you leave that in, other is for digital stuff which you can replace. In MD2 you'll want to cut some traces and separate analog stuff from digital and use the modern thing for the digital side while 7805 remains powering the analog side. That way there won't be problems with noise in sound and any video interferences.

Quote:

---

Originally Posted by TmEE

In case of MD1, one 7805 is for analog stuff, you leave that in, other is for digital stuff which you can replace. In MD2 you'll want to cut some traces and separate analog stuff from digital and use the modern thing for the digital side while 7805 remains powering the analog side. That way there won't be problems with noise in sound and any video interferences.

---

Happen to know which VCC on the schematic we replace? I'm thinking that VCC1 controls the z80 and the analog stuff related to the audio and vcc2 is for the CPU etc?

Quote:

---

Originally Posted by roadkill

Thanks! If I can't convert it as a 3 in 1 for my Genesis consoles, at the very least I will end up just using this for my Hi-Def NES so I would no longer need to fit a fat power adapter into AC sockets.

---

The Hi-Def NES suggests removing the 7805 since the HIDef NES has a switching regulator built into it to power the NES with. In other words, installing a HI-Def NES will convert it to a switching regulation circuit. You can still use either the regular NES power supply or a Genesis Model 1 1602 PS..either will still work since the inverter or rectifier I guess is still used initially before powering the Hi-Def NES.

Quote:

---

Originally Posted by CrossBow

The Hi-Def NES suggests removing the 7805 since the HIDef NES has a switching regulator built into it to power the NES with. In other words, installing a HI-Def NES will convert it to a switching regulation circuit. You can still use either the regular NES power supply or a Genesis Model 1 1602 PS..either will still work since the inverter or rectifier I guess is still used initially before powering the Hi-Def NES.

---

Yeah I already had the Hi-Def NES kit installed on my NES, it no longer uses the 7805 but instead uses its own regulator on the kit as you said. The power adapter in the picture works just fine. I'm also aware that I can still use the original AC adapters, but they're old and not cheap. I'd rather use a new power adapter that won't go bad on me. I've had at least 3 official AC adapters go bad on me dating all the way back to the '90s; 1 NES, 1 SNES, and one Genesis 1 AC adapter.

Bump,

Does anyone know which voltage regulator is digital and which is analog? If I’m powering mods with clean voltage, I would think ideally I’d want to hook it up to the digital one, replacing that voltage regulator with a 1.5a version for headroom, as to not chance adding interference to the analog circuitry.

Edit:
From looking at the schematic, it appears on a va3 model 1 that’s the 7805(1) powers the 68000 where as the 315-5364 and the z80 is powered by the second 7805.

I guess I’ll replace the first one with a 1.5a to give headroom and power my overclock. And I’ll use the second voltage regulator to give clean power to my rgb bypass.

By digital you mean a DC-DC converter right? I'm sure this would work fine in theory but then I was using 1amp versions of the Dc-DC converters. I've since changed out both of my 7805s to 2amp linear versions and the overall system runs much cooler with no lockups anymore and nice clean audio as well. Well, except that I think there is something wrong with the audio connection portion of my HDRetrovision cable as I notice there is static coming in that is very audible all of a sudden from the right channel only. I recapped the entire Genesis about 3 or 4 years ago so that should be good and have redone the audio out lines several times. It only seems to do it with the 32x attached and if I use the audio through the HDretrovision cables.

Still I've got Dc-DC converters still on hand but tend to only use them in older consoles now as they seem to benefit the most using them.

The stock voltage regulators are linear, no? I have a 7805 replacement and a 7805 1.5a replacement I plan on putting in with some fresh thermal paste. I read somewhere on this forum that using dc-dc causes audio static.

Do you have a Sega cd to test the audio in another manner?

Quote:

---

Originally Posted by ironnick23

The stock voltage regulators are linear, no? I have a 7805 replacement and a 7805 1.5a replacement I plan on putting in with some fresh thermal paste. I read somewhere on this forum that using dc-dc causes audio static.

Do you have a Sega cd to test the audio in another manner?

---

I tested my va2 model 1 with dc-dc converters in both 7805 regulator spots and had audible noise on the line that wasn't present before along with strange audio anomalies during gameplay that was especially evident with TF2.

the original 7805 regualtors in the Genesis I believe are already 1.5 amp output versions. I ended up changing mine out as part of a troubleshooting a video issue that was only present from the Sega CD side of things during FMV and some other video specific from the Sega CD when the system had been on for about 30min. Mainly bad sparkles or snow all over the image. I have a video that demonstrates this on my YT channel here:

https://youtu.be/LMS6E46EhUo?list=PL...8p82wKYNRj2Hom

I eventually figured out that with the 32x attached plus the sega CD, plus the mods I have in my genesis, that apparently the VRs were working too hard and generating too much overall heat causing the video issues. Cooler running 7805s took care of it thankfully.

But back on topic, I haven't tested it but it would seem plausible that you can at least install a DC-DC converter in place of the 7805 that only controls the main CPU logic, and leave the 7805 in place that controls powers the z80, 1034, 2612..etc and that should at least reduce the overall heat in side by about 50% since the heatsink only has one 7805 to dissipate the heat from and not two of them. I just haven't tried it since I installed the newer linear 7805s in mine.