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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: turbokon on October 23, 2012, 06:04:51 AM
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I have a turbo duo that doesn't hold memory save in its ram. If I turn off the system and power on right away it holds the save. But after a few seconds it doesn't hold. The voltage at pin 24 of the IC drops continually after power off. I have replaced the super capacitors, the diode and the IC ram and still getting the same issue. I've been working with thesteve and I'm running out of ideas on what to check. I have tried two different type of super caps with no differences. Have any body ran into this type of issue before?
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Is it just caps that power the IC for RAM saves? I've never looked in the Duo and always assumed there was a CMOS type battery that did this. Though the cap thing makes more sense, as you can leave a Turbo powered off long enough and everything is lost.
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The super cap is what the duo uses as battery for the IC ram backup. The super caps acts as a battery because voltage is stored and dissipate slowly unlike regular cap.
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It's like something is sucking the voltage after its turn off. I tested the super cap with a battery an it's hold the charges like it should. The orange component is the new super cap I installed.
(http://pic.photobucket.com/bwe.png)
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You know, I was just thinking about asking Steve what the best value is to replace that Backup RAM cap with, and, if it's OK to just put a higher value than before. More farads should be safe and just equal a cap that takes longer to discharge, no? But yeah, the highest value my cap kit came with is 1000 uF, so I wanted to find out if that'd be OK to use.
Yours is a Japanese model I take it ? The cap in question is a square black one, like the one I circled with 5.5 V and 473 written on it, right ??
(http://www.pcenginefx.com/forums/index.php?action=dlattach;topic=13355.0;attach=1318;image)
As far as I know, that is the cap for the Backup RAM, etc. I actually made a thread about this in the mod section because I wanted to know which cap it was and to possibly change it to a 3 Volt lithium battery. I guess the square black box in your PCB is a choke thingy enclosed in plastic.
Anyhow, must pester Steve again! Also, what is the value of this orange super cap you installed? Got it from Digikey or ?
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Yeah its the black block. If you want the part info for a suitable NEC replacement its the following:
part number FMC0H473ZF NEC Tokin America, Memory Back-Up Supercapacitors, THT 5.5V 0.047F
If I remember right anyway...
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It's in Farads? Oh wow, I was REALLY off then in hoping my 1000uF one would work. It really is a "supercapacitor" then. I can see the .047 on turbokon's orange cap there, so you're probably right, but if it's .047 Farads that makes it 47,000uF, so that's quite a hefty cap then!!! Clearly a single order type item off Digikey or something.
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I'm not sure if Digikey carries the NEC issued one, but you can get the "can" type Turbokon purchased both off ebay, Digikey, and elsewhere for cheap.
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The one I used looks exactly like one used on my pc-duo with the same rating except the one on the pce duo is green.
http://bit.ly/TG3f9f
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I think I solved the memory problem too. Last night, I compare this to another duo and found pin 24 of IC ram traces to R544. The duo with the memory problem didn't have res at R544. Found the same res value from a cordless phone and solder it on R544. Voltage isn't dropping rapidly when turn off and memory seems to save. Powered the unit on this morning the save for gate of thunder is still there!! Woot! Woot!
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So a resistor went bad ? How many ohms was it ? I thought resistors were the most least likely of components to ever fail.
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The resistor wasn't there to begin with, odd. However the pce duo I compared it to had it an the smd res value is 470ohm.
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Thought I'd update this, add a new ProTip.
So, it seems judging from console5 that you can replace the super capacitor with a .1F model to double the memory storage time versus the original NEC .047F model!
http://console5.com/store/1f-5-5v-memory-backup-capacitor-for-nec-systems.html
YIKES, THESE ARE RUSTED TO SHIT USED ONES!
Instead of wasting $2.29 to buy one from them though, head over to eBay and buy a 5 pack for the same amount of money! If I'm reading it right, as a 1F, not .1F, that should make it last 10x as long! It's a NEC brand to boot!
http://www.ebay.com/itm/High-Light-5-Pcs-1F-Farad-Capacitor-Supercapacitor-NEC-TOKIN-5-5V-HGCA-/191443047755?pt=LH_DefaultDomain_2&hash=item2c92e5154b
This will only cost you $2.33 WITH shipping!!! I just ordered one for my Turbo Duo.
Make sure item is NEW, like this:
http://www.ebay.com/itm/1Pc-1-5F-Farad-Electric-Double-Layer-Capacitor-Super-Ultra-Capacitor-5-5V-C-/371160797535?pt=LH_DefaultDomain_0&hash=item566ae8515f
$2.47+$1.20 S/H = Not bad!
Compare that to the old link turbokon found (http://bit.ly/TG3f9f) with that guy wanting $6.50 for a 5 pack of the .047F model plus $2.25 for the shipping... Bad rip-off and no doubling or more of memory storage time.
Gonna check with Steve on the safety of this, though. A 5.5 Volt capacitor with 10x the capacitance value over the original should simply discharge for a much longer time and not present a problem/risk. NEC not using a higher value than what they did was hopefully just a cost issue and the .047F model simply provided a reasonable amount of memory storage time for the money.
EDIT: The Steve has spoken. The super cap can be as big as you want! Getting a higher capacitance model should merely just equal a longer discharge time and presents no safety issue! It's just a cost issue, but eBay for the win as far as the great deal I linked above!!!
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Thanks for sharing that, just ordered this :)
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Cool, hope it works out for ya! Trick is desoldering that old one off.
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If that's a genuine NEC cap, I'll eat my hat. :-"
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Hmmm, you did make me do a double-take and now I see that they're marked as "used" - didn't catch that before which would explain the pricing. So he's got 30 5-packs left and they're of "used" quality... Where did they come from then I wonder ? Still haven't received my order, will update when it gets here... Just never heard of "used" caps being sold before, that caught me by surprise!
http://www.ebay.com/itm/Technical-Durable-5-Pcs-1F-Farad-Capacitor-Supercapacitor-NEC-TOKIN-5-5V-HCCA-/231397405230?pt=LH_DefaultDomain_2&hash=item35e05c322e
So here's another listing. The seller is claiming "new other" for it.
A new, unused item with absolutely no signs of wear. The item may be missing the original packaging, or in the original packaging but not sealed. The item may be a factory second or a new, unused item with defects. See the seller’s listing for full details and description of any imperfections.
If these caps have never been soldered on to something, then maybe they're trying to say they're used-looking or something. I hope at least that's what's going on here.
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Ah...I didn't see the used, but that makes sense too. I figured it was a Chinese knockoff, no way it could of been 5 New NEC caps at that price.
Nightwolve....you may want to read into Chinese electronic salvage a bit :shock: they're pretty f*cking shady.
Here is a story from fairly recently. I may not be exact, but it was pretty much along these lines.
A arcade dealer bought 1000 hard to find 2.5A MOSFETS from a Chinese vender. After numberous failures he cracked one open and looked at the die. He then cracked open the much more common 1.5A version of the MOSFET and found it had the same die.
Those f*ckers where blasting the cheapos and then rescreening them with the rarer MOSFET numbers and selling them as such.
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thats a common counterfeiting process
your best option is to learn how to sub the parts with more common ones
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Yeah, I'm a little nervous now with that order, but it was only ~$2 and so far I haven't had a problem with any Chinese sellers I bought parts from - this one has a ~98% positive rating. Gonna check the legs as soon as I get them and see if they were soldered on to something... That's weird though, selling "used" caps, I totally missed that shit somehow. I would take just ONE new one at $2-3 bucks and be done with it, I won't need those extras anyway. Anyhow, I'll let you guys know when I get my order what the deal is. Should be here this week.
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Hmm, very interesting. Adding life to the DUOs backup life span would be fantastic. I've lost so many saves on my original RX from 2004. I hate the DUOs backup RAM solution. A battery would have been so much better!
I will be waiting for the report once they arrive. :-k
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Le Steve offered a diode with lithium battery mod/solution if you'd like.
You need:
1) CR3032 Lithium battery holder for 2 batteries
2) 2 CR3032 Lithium coin cell batteries
3) 2 standard diodes
CR3032 batteries are 3 Volts each, so together they would be 6 Volts. The positive/+ side would connect to 2 diodes facing outward which would connect the + tap on the motherboard, negative of the holder to the negative/ground of the motherboard, easy enough (where the super capacitor is now!).
The 2 diodes give you a slight voltage drop so the batteries provide 5 Volts afterwards, and the diodes' one-way direction prevents 5 Volts going back towards the batteries when the system is turned on which would cause a recharge situation, and hence damage.
Unless you wanna buy those $11 rechargeable lithium batteries though that come in the CR3032 size, this is one route. A rechargeable would make it easier.
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Someone needs to try a FeRam in the Duo.
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I missed that too NightWolve, hmmm...we might be getting Chinese scraps ](*,)
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Yeah, sorry about that. It was unexpected for caps (that idea of used ones being sold) and my eyes just went passed that detail.
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Le Steve offered a diode with lithium battery mod/solution if you'd like.
You need:
1) CR3032 Lithium battery holder for 2 batteries
2) 2 CR3032 Lithium coin cell batteries
3) 2 standard diodes
CR3032 batteries are 3 Volts each, so together they would be 6 Volts. The positive/+ side would connect to 2 diodes facing outward which would connect the + tap on the motherboard, negative of the holder to the negative/ground of the motherboard, easy enough (where the super capacitor is now!).
The 2 diodes give you a slight voltage drop so the batteries provide 5 Volts afterwards, and the diodes' one-way direction prevents 5 Volts going back towards the batteries when the system is turned on which would cause a recharge situation, and hence damage.
Unless you wanna buy those $11 rechargeable lithium batteries though that come in the CR3032 size, this is one route. A rechargeable would make it easier.
Wait...what?? Steve is currently offering this mod? That sounds awesome!
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That is one of his ideas so in theory the save state should last as long as say a SNES cart with those batteries. He hasn't done it for anybody, I had just asked him if you could convert it to battery style. I would trust the rechargeable ones more though cause diodes aren't 100% at one-way electron flow control but I guess 2 are good enough since that's how it probably is right now for all carts with regular lithium batteries soldered on. I did notice my Zelda cart still had a save stored so they can last well over 15 years.
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Im sure even if they are used, at least 1 of them should work, if not, it was only a few $ :lol:
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OK guys, really bad news... I got scammed - he's a scammer... The epic failure here was the decision to use iron/steel instead of aluminum for the metal body of the capacitor. These are not just used, they're badly corroded/rusted from sitting around too long as well, possibly in a very high humidity environment... This is a bit of debacle - I wouldn't use any of these... I'm gonna leave the f--ker a negative review... He should've used a screenshot like I'm posting below to tell the truth as to exactly what condition they're in, how "used" is used, etc...
Damn bastard, look at this shit, like they've been sitting in salt water for ages:
http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_133010.jpg
(http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_133010.jpg)
http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_132707.jpg
(http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_132707.jpg)
F--k am I supposed to do with that when you couldn't in good conscience trust ANY of them ? The top end of the steel body at parts is corroded/rusted inward (AKA eaten away!) so they're surely headed for leaks... He seriously expected possible reuse for these ? I haven't tested them as I don't care if they work, they're not trustworthy by appearance alone!
Compare to the photos he's using to sell these ??
http://www.ebay.com/itm/High-Light-5-Pcs-1F-Farad-Capacitor-Supercapacitor-NEC-TOKIN-5-5V-HGCA-/191443047755?pt=LH_DefaultDomain_2&hash=item2c92e5154b
He's a f--king scammer!! He told you they're "used" but compare the "marketing" photos he used to what I got in the f--king mail!!!
(http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/SuperCap.jpg~original)
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Look on the bright side...at least there wasn't a severed child finger in there as well :)
.....but ya, sorry to see you got boned. Chinese salvage people are all underhanded a$$holes for the most part.
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That's bullshit. I'd file a not as described claim, for the worst ebay can do is reject it.
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Ouch. Least it didnt cost you much, but a headache...
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Yeah, I reported it to eBay already. F--ker needs to show you the badly rusted condition of these in the FIRST IMAGE YOU SEE!
I took one apart to see what's going on inside. You have a black, circular module that seems OK, and it works by flat metal contact on opposite sides for positive and negative terminals, etc. The steel body cap had been compromised with a rusted hole, but yeah, that black fluid-filled module seems OK. Nonetheless, who knows where this thing has been, to hell and back in deep sea diving or whatever the hell! Wouldn't put this shit in my Turbo Duo, it's the principle of the matter.
http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_151813.jpg
(http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/IMG_20150204_151813.jpg)
https://www.greatplainselectronics.com/products.asp?cat=165
(http://www.greatplainselectronics.com/prodimages/EEC.html)
Part#: CERS-1.5F-5V
The first item for sale there is a Panasonic 1.5 Farad supercap for $3 - an interesting candidate for a new one. Nothing as good as that so far on eBay. Am considering it.
Tried a checkout - you're looking at $3.86 in S/H in USA, so total would be $6.86... You need to be in state make a big order of several items to justify that, sucks when you're only looking for one item at time...
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OK, here we go. This is "NEW" and 1.5 Farads, so more capacity!
http://www.ebay.com/itm/1Pc-1-5F-Farad-Electric-Double-Layer-Capacitor-Super-Ultra-Capacitor-5-5V-C-/371160797535?pt=LH_DefaultDomain_0&hash=item566ae8515f
$2.47 + $1.20 S/H
That's more ballmark for what I'm willing to spend now.
This is an interesting version:
http://www.ebay.com/itm/2PCS-4-8V3F-4-8V-DZP-8X30mm-ELNA-CYNACAP-DZP-4R8D305-Farad-Super-Capacitor-/171470122617?pt=LH_DefaultDomain_0&hash=item27ec6a6e79
Bigger, look like batteries, are at 3 Farads. Would last a long time. One should be able to fit them... But the 4.8 Volts max breakdown rating is a bit too low, should be 5.5 Volts.
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To Brraap and anyone else, with the report and negative feedback I left for the seller, he offered a full refund with forfeit if I agree to remove the feedback, so I got my money back which will go towards a *new* capacitor... So FYI. Time wasted, but problem solved!
These 5 junk steel cans are going in the garbage where they belong - don't care if some work or not, if they look like they've been to hell and back, in deep sea diving equipment or whatever the f--k, no thanks! I love my Turbo Duo too much to put this kind of garbage into it!
I told the guy he needs to put up photos that reflect reality, but I doubt he'll change anything in future listings. Anyway, that's that...
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That first link wont work easily, 20mm lead spacing on it.
NightWolve don't be a cheapass and treat your Duo like the Queen she is....not some trashy whore.
For $3 more you can get a quality cap for it and not another China POS.
This is a beautiful console worth $200+ and your pinching a few bucks over a cap that may live longer than you.
NightWolve, I am only telling you this because I love you....and all NEC hardware for that matter :wink:
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Heh-heh. I'll still be looking when I get a chance. That first one is a Panasonic but the seller is in the US so S/H kills it. If I can find that on eBay with better spacing, that would be good.
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I have a few of these super caps. I only had to change couple of systems. Hit me up if you need one.
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Mine will be going in the garbage when they show up. I will leave negative feedback as well.
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I have a few of these super caps. I only had to change couple of systems. Hit me up if you need one.
Thanks Shawn, but you bought the exact matching capacitance of the original at .047 farads... A 1.5 farad model has ~32 times (1.5 / .047) more capacitance and should last A LOT longer, that's why I checked with Steve about how big you can go! Yours is very, very puny in comparison my friend! :P