REPAIR GUIDE - TurboDuo/PC Engine Duo: Total capacitor replacement chart

[nodtveidt]

What's with the hideous watermark? Got a clean version?

[Platinumfungi]

I hate watermarks too, but I feel that the time I have invested is worth one.  It's just so people don't try to pass it off as their own work.  I don't think it hinders the chart but I'm open to constructive criticism.

[nodtveidt]

Do you think you could email or PM me a clean version? I'd like to have a printout of it for my binder, but the watermark just bugs me, heh.

If not, then well...I'll do something else.

[Platinumfungi]

Well I could try and lighten it a bit more if that would help you out?  Don't print one off yet though as I have just added an edit yesterday that I found some more info I missed on my chart and will more then likely have separate charts for the US and the PC Duos very soon. 

Edit - Chart updated and the water mark has been slightly lightened.

[Platinumfungi]

Just added some more info. Let me know if you need anything else or have questions.

[SNKNostalgia]

Here is one thing though. Would it be a better idea to replace the caps that function for the CD-Rom drive first and then buy a Hop M3 laser if there still is a problem with the disks reading?

Also, what caps function for the CD-Drive? I find it funny how Duo-Rs use the same exact drive but different board layout with less functioning issues. It must be a cap issue, or just how the controller part works for the CD drive.

[Turbo D]

My U.S. duo pcb has both those insulated wire holding legs and is missing the ceramic disk capacitor. Also, it has that one part on the bottom with the pad, like the pc engine. Do you think my U.S. duo is earlier or later model?

[Platinumfungi]

SNK -  Unfortunately I don't know which caps regulate which areas of the system.  I'm new to working on NEC systems so I had been following D-Lite's suggestions on the audio replacement. I still had issues so I decided to randomly replace two at a time and then test. I eventually replaced two that got my cd audio going only to find it gone again later. I continued to have problems until I replaced one other specific cap and then it seemed fine. I can point out the three caps that most effected my PC Engine's audio but it could just be that those caps were going bad on my system and might not be of any use to anyone else.  I was going nice and slow and charting my results but unfortunately I'm fixing this system for someone else and so my deadline came up and I had to hurry along.  I'd love to have a chart that shows which caps relate to which part of the system if anyone/everyone could figure it out....

Turbo D - So....perhaps it's not the difference between US and PCE but an earlier or later model eh?  Sounds like we should both check the model numbers and compare.

I edited my post slightly to try to figure out what the real reason is for the differences on the pcbs.

[Turbo D]

The model number on my U.S. Turbo duo pcb is "L61-I-280IY." The serial number on the plastic case is "28011731A." It says under the serial number that it was manufactured August 1992.

[SNKNostalgia]

My Duo is a March 93 model and resembles the typical US model. Serial 33000254A. Will look at the PCB later on, playing my system right now and really far into Legendary Axe.

[Platinumfungi]

The PC Engine Duo from the pics:

PCB # - L31-4-2804B
Serial # - 28008251B
CD-ROM # -02920618
No sticker on the bottom for manufactured date.

The US Duo from the pics:

PCB # - L61-2-3107AV
Serial # - 31024101A
CD-ROM # -02921107
Manufactured - January 1993

[agt_dale_cooper]

Holy Bananas, Nat quoted this original posting.

Yes, Red Ghost, this is the one I wanted to see the volts updated on...[and, as long as I've got everyone's attention by necroposting this, both this chart AND the Express charts are WORKS OF ART according to us folk who like to repair stuff and both deserve to be stickied...how does one access this functionality?  I see the buttons at the bottom of the main page, but.........?]

[Special Agent Dale Cooper (http://en.wikipedia.org/wiki/Dale_Cooper) adds his name to the list of folks who have appreciated your efforts....]

[Platinumfungi]

Holy Bananas, Nat quoted this original posting.

Yes, Red Ghost, this is the one I wanted to see the volts updated on...[and, as long as I've got everyone's attention by necroposting this, both this chart AND the Express charts are WORKS OF ART according to us folk who like to repair stuff and both deserve to be stickied...how does one access this functionality?  I see the buttons at the bottom of the main page, but.........?]

[Special Agent Dale Cooper (http://en.wikipedia.org/wiki/Dale_Cooper) adds his name to the list of folks who have appreciated your efforts....]

Hey thanks

It's nice to hear someone finds it useful. When I first posted it a few people gave comments, but I didn't know if many people were actually using it/finding it useful.

I'll see if I can update it in the next few days. I'm going out of town till New Years soon, so if you don't see it updated in the next week, I'll get it done early January.

I've also thought about making charts for the other NEC systems, but I think they would be of less use as the Duo and Express (and variants) are the most problematic it seems.

[nick3092]

Hey thanks

It's nice to hear someone finds it useful. When I first posted it a few people gave comments, but I didn't know if many people were actually using it/finding it useful.

I used it to do a total cap replacement on my US Duo as well, and it was a lifesaver.  Just printed it out, and laid it on the workbench next to me.  Only question I have though, unless I'm missing something - the key has a 3.3uf cap listed, but I don't see it marked anywhere on the board.  Where is it?

[Necromancer]

Only question I have though, unless I'm missing something - the key has a 3.3uf cap listed, but I don't see it marked anywhere on the board.  Where is it?

Right below the laser and above a pair of 22uF caps.