NES System Help
Sold an NES. Got shipped back. Buyer said the game would work fine for a couple minutes then the entire system would shut off. Well I had never heard of that so she sent the system back since I didnt experience this when testing it and selling it. I always have a system on for atleast 10-20 minutes on going through the process of testing a game and controller.
Low and behold. Yes this is exactly what it does. I had to unplug it and plug it back in after a few seconds and it worked again for a couple minutes.
I have ruled out a short in the AC.
Edit: I left the system in the on position after it went out and after 5 or so minutes it came back on, but then goes back out
Anyone know what the problem is here?
Low and behold. Yes this is exactly what it does. I had to unplug it and plug it back in after a few seconds and it worked again for a couple minutes.
I have ruled out a short in the AC.
Edit: I left the system in the on position after it went out and after 5 or so minutes it came back on, but then goes back out
Anyone know what the problem is here?
Comments
Originally posted by: MrPete1985
Sounds like maybe the 7805 is overheating or on its way out, I would replace that first, it's super cheap
totally my thoughts.
Originally posted by: Faxanadude
help a noobie. Where and what is the 7805?
These are found in most of the retro consoles. Often screwed into the heat shield because they get hot.
They take power from the power adapter (leg 1) and output (leg 3) to a clean 5v. If it gets too hot it will shut off.
Plus they do weird things when they are going bad. Like not outputting 5v and giving 4v.
Honestly removing these and testing these require tools like Multimeter and a desoldering unit.
If you have a multimeter I can guide you.
Originally posted by: Faxanadude
So it is like a capacitor chip?
Originally posted by: Faxanadude
So it is like a capacitor chip?
It's a voltage regulator, it takes the 9 volt input and steps it down to 5 volts for everything in the console.
Originally posted by: mkiker2089
If you switch to using a 5v DC unit will the 7805 run cooler? I've heard that theorized and that you save a miniscule amount of power.
I doubt it. Or not enough to matter. The 7805 is receiving DC regardless of the adapter. That's the job of the rectifier.
Then again another thought occurs to me. Cut out the 7805 and rectifier and use USB to power the NES. Any USB adapter would work fine.
Originally posted by: mkiker2089
It seems odd to me that most electronics (or so it seems) run off about 5 volts but power supplies are often 9v.
Then again another thought occurs to me. Cut out the 7805 and rectifier and use USB to power the NES. Any USB adapter would work fine.
Well nearly all electronic devices have or need regulators.
Otherwise you have an unregulated power source and will damage sensitive components like ICs.
The overall goal is to stepdown from the 120v wall outlet.
Technically you could run USB 5v to a NES motherboard. But most USB ports/chargers would lack proper amps.
Though what do we gain from this?
Anyway this thread is getting off topic I think.
Switching power supplies do save power over the transformer bricks from the 80s; look up vampire draw or https://en.wikipedia.org/wiki/No_load_power
but yeah not a big deal.
Also modern USB phone chargers are able to output 1.2 A which is greater than the 1A that the stock 7805 is. So a 1.2A output USB power adapter should work just fine
As for USB power, moving the power supply off board would be more for longevity. It will remove heat from the console, keep you from needing a special adapter (assuming you add a mini-usb port) and allow you to bypass the rectifier and 7805. As for USB bricks, they are all at least 1amp now with 2amp energy efficient models becoming the norm.
I think Gametech was the one designing a new power supply as a hobby. I can't remember what his results were.
Anyway, yes the topic is derailed but the OP got his answer. I changed all my power bricks to DC ages ago but I didn't go the extra step to getting 5v. I kept them all at 9 since I wasn't sure about Sega consoles or the Sears Arcade 2. I'd bet they are all 5v internals though.
Originally posted by: AaronE
If you feed the 7805 5V DC it will run cooler than 9V DC/AC. As retrofixes mentioned the bridge rectifier makes it all DC prior to getting to the 7805 anyhow... but I think it was missed that mocker2089 said 5V DC and not just DC.
Switching power supplies do save power over the transformer bricks from the 80s; look up vampire draw or https://en.wikipedia.org/wiki/No_...
but yeah not a big deal.
Also modern USB phone chargers are able to output 1.2 A which is greater than the 1A that the stock 7805 is. So a 1.2A output USB power adapter should work just fine
Actually the 7805 needs atleast 7-8 volts to operate. It will not pass 5v through.
Switching power supplies are nice. There is even Switching regulators that have the same footprint as the 7805. I have installed a few. You can pop one in and remove the heat shield. Runs cooler and more efficient.
I think that would be the best alternative vs custom USB ports etc.
There are many options out there. It boils down cost/time/reward
Originally posted by: mkiker2089
I was thinking that most of the heat comes from the conversion. The older chips created a great amount of heat just reducing the power. Using a 5v DC power supply should make the rectifier and 7805 both pretty much just pass power through with almost no heat.
As for USB power, moving the power supply off board would be more for longevity. It will remove heat from the console, keep you from needing a special adapter (assuming you add a mini-usb port) and allow you to bypass the rectifier and 7805. As for USB bricks, they are all at least 1amp now with 2amp energy efficient models becoming the norm.
I think Gametech was the one designing a new power supply as a hobby. I can't remember what his results were.
Anyway, yes the topic is derailed but the OP got his answer. I changed all my power bricks to DC ages ago but I didn't go the extra step to getting 5v. I kept them all at 9 since I wasn't sure about Sega consoles or the Sears Arcade 2. I'd bet they are all 5v internals though.
That would not work with the original parts inside. You would need to remove all those internal parts and build a new power amp or somthing to accept 5v. But yes lower heat would be great for the console.
The most common "modern" low heat power system is switching regulators. As stated above. replaces the 7805, runs cooler and more efficient. But needs 9v or more to operate.
https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf
Originally posted by: AaronE
odd a lot of 7805s say they work down to an input voltage of 5V if you look at the data sheet. Like this one works between 5V and 18V
https://www.fairchildsemi.com/dat...
You are reading it incorrectly. They are stating potential output from different 78xx models they produce. Not inputs. Input voltage will always be higher than the output voltage.
Trust me I do this stuff for a living.
Input requirements are around 1.5x higher than output.
78XX 5v-24v.
7805=outpts 5v
7808 = 8v
7812 = 12v
7824 =24v
Originally posted by: mkiker2089
It seems odd to me that most electronics (or so it seems) run off about 5 volts but power supplies are often 9v.
Then again another thought occurs to me. Cut out the 7805 and rectifier and use USB to power the NES. Any USB adapter would work fine.
a USB powered nes would be intresting lol.
Originally posted by: mkiker2089
It seems odd to me that most electronics (or so it seems) run off about 5 volts but power supplies are often 9v.
Then again another thought occurs to me. Cut out the 7805 and rectifier and use USB to power the NES. Any USB adapter would work fine.
a USB powered nes would be intresting lol.
Unless I'm mistaken, bunnyboys AVS will be USB powered.
Originally posted by: Jerbilly
You know, this problem could stem from an inverted rotary balance on the ol' banus.
Exactly what I was thinking...
Originally posted by: Jerbilly
You know, this problem could stem from an inverted rotary balance on the ol' banus.
tell me more about this banus
thanks for he help everyone. Ill look into it with the information provided
Originally posted by: quest4nes
Originally posted by: Jerbilly
You know, this problem could stem from an inverted rotary balance on the ol' banus.
tell me more about this banus
Why, it's the main sprocket off a ten gear wanking machine!