Information about the TG-CD's 11VDC power supply.

[kid_rondeau]

Hey kids!

I recently bought the TG16+CD for sale in another discussion board.
I got it mainly as a backup in case I run my current system into the ground, but it came with all the accessories, including the AC adapter. Many of you out there know that it's basically impossible to find this particular adapter, and no one seems to manufacture an 11-Volt power supply that would be a good substitute.

Well, a few years ago I wrote a short essay about my discovery that although the AC adapter says 11VDC, MY adapter actually puts out 15.3V. I thought I might have a faulty adapter, but my new one measures 15.7V!

My point is, if you are looking for an adapter for your TG-CD, just look at Radio Shack (or online...) for a +15VDC power supply with a max current draw of 1200mA and an interchangeable tip. Kinda like this one:

Edit:
[DEAD LINK]

I think the correct one is "N" but I could be wrong.


I'm unsure about the current loading because testing that is more involved than testing voltage. I plan on researching that in the near future. So I obviously can't guarantee successful performance. I mean, if worst comes to worst, you'll blow a fuse in the power supply; your system will be fine.


Additionally, please don't bring up the idea of the "extra" 4.5V being used to compensate for "circuit loading"...I promise you that AC adapters are supposed to put out the nominal voltage.

[2X4]

Isn't it a little shy on the amperage?  I mean it is (puts out 1 amp, turbo+cd needs 1530mA), but will that do any damage?  Don't get me wrong, it would be sweet if this works, but not so sweet if it burns up something that hard to replace.  I don't know a lot about this stuff, i'm just asking.

[kid_rondeau]

Well, it may be a little shy on the milliamps...see, the essay I wrote strongly suspected that NEC may have deliberately swapped the Volts/mA numbers as a proprietary measure (like, 11VDC and 1.53A => 15.3V and 1.1A...same numbers, just reversed).

That charming salesman who works at TZD told me in an email that he talked to *his* boss who talked to some dude in Japan who actually helped *design* that particular power supply, and said no no no, they would never deliberately do such a thing.

In today's post I was planning on 1100mA max, but I said 1200 just to be safe.

Tell you what: sometime in the next few weeks I'll do a proper current test on both adapters while booting up the system, starting a CD game, playing a music CD, playing a chip game, etc. I'll record the highest number I see, and come up with a final value.


Seriously, I've been wanting to do this for years. The idea that an 11V adapter would be so bloody difficult to find never made sense to me. Plus, it could mean the difference between life and death for thousands (well, okay...hundreds) of TurboGrafx CD systems!

[2X4]

This will be interesting.  If they didn't "deliberately do such a thing," it makes me wonder why he would say "deliberately" instead of just saying, "no, we did not do that, the rating is such and such as labeled."  At any rate, I don't get why they used such an f'd up power supply. Perhaps you are right.  I think I may just test mine as well! 

[guyjin]

Here's hoping you don't destroy it 

[grahf]

You guys are reading WAAAAAYYY too far into it. Everything inside these systems runs at 5v. They use your average run of the mill, dime a dozen LM7805 type linear power regulator. This is connected to a heatsink. You need at least 7.~v input to produce a stable 5v output. Most power adapters are at least 10v to compensate for power fluctuations (your 110v a/c wall socket).

You can feed up to 30v into most 7805 varients. What happens? The extra voltage is turned into heat. If the heatsink isnt big enough, the LM7805 will shut down after a while (they are internally protected). Worst case is you'll fry the 7805 and/or the system fuse. 9v, 10v, 11v, 15v, doesnt matter. The important thing is the adapter provides enough amperage, and polarity is correct.

[SignOfZeta]

Worst case is you'll fry the 7805 and/or the system fuse. 9v, 10v, 11v, 15v, doesnt matter. The important thing is the adapter provides enough amperage, and polarity is correct.

Did I hear someplace ages ago that PCE GT's lack some of the regulation that a PCE has? Maybe I imagined that. Maybe it was only on the battery side of things.

Either way, frying a 7805 isn't exactly good news for most people, and Duo R/RXs don't have fuses in them so I'd stick with smaller voltages when it comes to things like this. From my experience when a PCE's power supply isn't keeping up current-wise the drive slows down (access, not actual CD speed) and the display dims when accessing the CD.

[2X4]

As I have said, I don't know much about this stuff.  But I went ahead and put my brick adapter to the test.  I only tested the voltage, but sure enough, it kicks out about 15.4 volts.  It will be interesting to see what kid comes up with for amps, but at any rate, you can go ahead and grab a 15V adapter if you need a replacement.

[nodtveidt]

So then, 9V should be more than adequate, because even with lower power, say 110V, it should reduce fine. A 9V output is going to be 13:1 based on a 117V supply (which is the accepted AC standard and a good average) so even at a low 110V, you're still going to get ~8.5V (we usually get 123V here, so it'd be ~9.5V). However, I read that the 7805 requires an input voltage of at least 10V, since the varience of input of a 78XX voltage regulator has to be between 5V and 30V over output (meaning a 10V-35V supply). Perhaps that's the real reason for the 11V rating...if the 7805 regulator requires a +5V minimum input over output, 11V is more than enough (even if the line voltage is low). Maybe that's not the case with this particular make though? Who knows...

[grahf]

The 7805s only require a little over 7v to get a stable 5v output. However most things usually come with at least 10v adapters since wall voltage in your house fluctuates and is not always 110v.

[nat]

Hey, cool, I'm on vacation for two weeks and when I come back we have a new forum. ROCK ON! (Too bad it will take me 96.3 days to read all the new messages.)

I did similar tests to kid's years ago, and came up with the following adapter as a viable replacement:

Radio Shack part number 273-1779
12V adapter, output 1500mA (which is close to what the original outputs)
Tip "N" is the correct tip.

I've used these adapters for years with the TG-CD decks and the work great. I've also pointed countless folks in their direction as a replacement option.

[nodtveidt]

Okay, I ran a little test with a power supply I found kickin around the house. 12VDC, 1000mA. Powers the TG16 deck itself and is able to run the detachable CDROM unit just fine. However, it won't power on the whole unit assembled. I don't know if this is because of insufficient power (previous posts make this seem unlikely; it should power on just fine but not run software) or if the base unit is broken (very likely). I also noticed just today that the unit I got back from D-Lite is NOT the same one I sent him; the one I sent him had screwdriver marks in the side where I tried to pry the sucker open...this one doesn't have them, and has other scratches that didn't exist in the one I sent him.

[nodtveidt]

Today we picked up a Cat. No. 273-1775 AC adapter from Radio Shack (12V, 1.5A). This is closer to the spec of the original adapter. The "N" type barrel is indeed correct, that's the type I picked up and it fits the core unit, the base, and the detachable drive perfectly, no wobbling. Again though, no power to the base...I really think it's broken.

Anyone got an extra gamebit they're willing to sell me?

[grahf]

Cmon, every self respecting video game nut should have their own gamebits, tri-wing screwdriver, and hammer . Just spend the 5 bucks, you'll surely use it again in the future.

[nodtveidt]

Picked one up the other day on ebay. Should be here by the end of the week...here's hoping.

Gonna fix this unit, then fix my broken Genesis model 1 unit, then attempt to repair my PS2 as well. Wifey really wants me to get into console repairs and mods...