REPAIR GUIDE - TurboDuo: Sound Fix

[grendelrt]

This is one of the first times I have heard of the RX having sound problems, they are usually problem free.

[grahf]

Its still possible that they are bad, even though they are not the usual faulty type. It cant hurt to change them if you have the ability.

[avkooi]

I changed the two capacitors "after" the op-amp, like D-Lite wrote. The problem of the fading sound-level is over now. But there is still a lot of electrical noise from the audio-out. It sounds like a bad contact, but that can not be the problem, because I checked and cleaned them.

So my next plan is to change the capacitors on the pre-amp side as well. I'll let you know what the effect will be!

[grendelrt]

Sounds good, I was thinking of changing those out myself.

[_joshuaTurbo]

I hate to necropost but I have a story.

I have a Duo(US) that seems to have (or had) the #2 problem.  The games load up just fine, but the CD music/sounds don't work at all.  I had even tried using just a regular compact disk.  I think it was an amorphis CD to be exact. And on the Music player it shows that the CD is playing, but I still would get no sound.

This was around last summer(2005) when I was just getting totally frustrated with this!  In 2003 I had a DUO totally blow out on me, it wouldn't even spin the CD.  So instead of going out and seeking my 3rd Duo, I decided on emulating.  Now while I love what they'v done with ME and HUGO, It just isn't the same.

So I was telling one of my buds about some of the problems I've had with the DUO and just last night, say around 8pm we  got together and I pulled out the ole DUO from storage and booted it up.  I put in Lords of Thunder, and boom, NO sound.  the built in sound effects where ok, and the game was playing just fine.  

Then just for the hell of it we played around with some HuCards (BattleRoyal, Bomberman, and Sonic Spike)  after about 2 hours of gaming a couple more people came over, and they were asking about some CD and SCD games, and I regretfully told them that the Duo lense had burned out.  SO just for the hell of it I tried Lords of Thunder again and when I hit Run, all of the SUDDEN the most rockin' soundtrack EVAR in a video game came thrashing out my Surround Sound!!!!

My friends told me I looked like I saw a ghost.  I was in shock, the friggin thing was WORKING!!  We went on to play Dungeon Explorer II, Fatul Fury Special, DracX, and Lords until around 5am!

Every single game worked like a charm!  I cannot explain it. Then I read this:

I let it run for a while and this seems to fix the problem.

Holy CRAP!!! So does anyone else have issues like this?  Where you can just let it 'warm up' and then it runs well?


So I'm going on about 2 hours of sleep, and while my wife is at the store, you guessed it I'm playing some more DUO..\

LONG LIVE THE DUO!!!!!

Now with the above problems I posted above-(The #2 Problem) will the solution that D-lite posted fix that if it gets worse?  Or should I go with the other fix that I saw in another thread about replacing the lense?


TurboSage

[guyjin]

The duo has 1337 self-healing skillz...  

[grahf]

turbo_sage, replacing the caps should fix it completely. Sometimes bad capacitors will start to work a little if you let them "warm up". For example on most of the TurboExpress and GT portables with the low sound issue, if you play for a while the sound level will gradually rise.

Unfortunatly its just common for capacitors that were manufactured during that era to be notoriously bad. Not just NEC consoles, but a LOT of other electronics (many many automotive ECUs for example).

[Platinumfungi]

I realize this topic has not been active in quite awhile but I have the exact same audio issue with my Duo R.  I have located caps C604 and C610 for replacement but I am not sure which other caps relate to the audio.  If anyone can give me any input I'd really appreciate it.  I can send a digital pic if needed.  (or post the pic if someone can tell me how to)

[Michael Helgeson]

If you feel completely up to it,when in doubt replace all old caps on the pcb. Good japanese caps manufactured these days are much more solid then the ones from early 90ies. Its more of a shotgun method but if the problem can be fixed by replacing the caps then replacing all of them is a sure fix,and in the process your buying your system more life with newer caps.

[Platinumfungi]

True.  I might just do that if replacing the two caps doesn't fix it completely.  Is there any company/brand of caps that are of higher quality then others?  I just bought mine at Radio Shack but if there are better ones then I'd gladly buy those. 

[Michael Helgeson]

The Radioshack ones are fine overall in quality. I never ran across a defective one when purchasing from there. But I tend to only buy 220uf caps there for Genesis s-video mods.

http://www.partsexpress.com/webpage.cfm?WebPage_ID=329

I think most of the caps they sell are manufactured by Xicon which is supposed to be reliable. As far as japanese caps go,you will know if they are made in Japan,they usually say Japan on them. Panasonic has a line of caps they sell under the TK series. They tend to be surface mount and are very reliable. I don't know if they will cover everything you need but I'm sure you can find them on Digikey somewhere.

[Platinumfungi]

Excellent. Thanks for the info!

[Michael Helgeson]

Let us know if it fixes your problem.

[raven1280]

I bought a duo from GUITARMAS that had the sound issues. I had to end up replacing all the caps on the board. Alot of them had leaked. Wasnt to hard to do. Now I have great audio from the cds!

Raven

[grahf]

Its good to know people are taking the time to fix their Duos. Nice work.