Sharp Twin Famicom help

[dommie]

It took me a bit, but between calibrating the head and adjusting the motor speed I got my Twin Fami to load disks.  Now the next problem:

When it sits a while, I'm ok at first to play disk games.  But as the unit heats up and, like if I'm playing a game for like 10 minutes or so, if the disk has to load or anything like that the unit just powers down by itself.  It's as if some type of fail-safe switch was triggered.  Then, I have to wait a few minutes with the power off before I can try it again or else it just shuts immediately off if I try a disk.

Any idea what's causing this or how to fix it?

[133MHz]

Overheating you say? The 7805 voltage regulator IC contains thermal protection which shuts down the output if it gets too hot because of overloading or similar faults. The disk drive consumes the most power in a Famicom system, so it makes sense.

First things first: Where are you from? Do you have the original AC adapter for your Twin Famicom?

[dommie]

I live in the U.S.  I'm not sure if the power adapter is original.  It's a bit oblong shaped and has a green led light on it.  Specs on it are AC100-240V~  50-60Hz 40-70mA for input.  Output specs say max DC 9V, max 1000mA.  The power adapter was made in Taiwan.

Is this the original power adapter for the Sharp Twin?

[133MHz]

Is this the original power adapter for the Sharp Twin?

No, it's not. It's a universal AC adapter for video game systems. I bet it's smaller and lighter compared to the older AC adapters.
It should work fine as long as its polarity is center positive (the Twin is the opposite of the regular Fami).

If I'm correct about your AC adapter, it could be the adapter that's shutting down because of overload and not your Twin, since those new adapters have an all-electronic design with several protection mechanisms. Old school AC adapters were just a bunch of metal that overheated and caught fire if something went wrong .

[dommie]

I noticed on the back of the Twin that it says 7.6V.  Since my adapter is 9V, could this be the problem?  Also, any place I can get a proper adapter that'll work without overloading my Twin?

This problem may also explain why it was working fine in Japan when tested before it shipped here to me in the U.S.  Going from 100V AC in Japan to 110 in the U.S. may have been the last straw for that universal adapter.

[133MHz]

I definitely recommend getting a bulky, heavy, old school AC adapter for your Twin, but it's not going to be easy to find. The regular Famicom AC adapter is not compatible - unless you open it up and reverse the internal leads. The NES AC adapter... don't even THINK about it! It's a Famicom killer .

Try online or at electronics stores around you. Ask for a 7.5 to 9VDC, 800 (or more) mA positive tip polarity AC adapter.
Ordinary multi-output AC adapters might also work fine if their build quality is decent and if they're set up correctly.

[dommie]

do you think this will work?

http://www.ecrater.com/product.php?pid=3710457

[133MHz]

500 mA might work for your Twin, but it's the bare minimum. You might run into the same problem you're facing now, or the adapter could overheat and burn out. Look for one with a higher mA rating .

[dommie]

I picked up a 7.5v 1000mA power supply.  It's actually a variable ac adapter with a switch to change between a bunch of different volts between 3 and 12.  That should do the trick, aye?  1000mA wouldn't trigger the same issue, would it?

[133MHz]

1000 mA is perfect. Remember to set the polarity switch to + .

[dommie]

Awesome, thank you!  I can't wait to get home from work and test it out.  I'll post an update later.

[dommie]

Everything works a-ok!  Thanks for all the help!