Calling all Namco Classics Collection board owners I need the communities help to help document this.

[GeekMan1222]

Note: This really only pretains to Classic Collection Volume 1 boards.

I am noticing something that I have not seen documented anywhere about the ND-1 ND1 system boards.
I am also not sure if it relates to this odd video distortion issue im having when game volume is turned up to 25 or 50 + % due to what I assume is bad decoupling or power management with the RGB Amplifier. Basically the power amp is kicking noise or pulling power from the video amp ill get dark vertical lines with boomy bassy volume and if you turn the volume up to like 75-100% on the board then its so bad that the video output begins to lose color information too.

Anyways I thought I could be interesting to at least document this. If anything I could maybe reverse engineer the fix they made on the Namco Vol2 board and make a custom mod board to try to do the same mod board on the Classics Vol1 board (seen below)

ANYWAYS

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What I need help with.


- If your board has a bodged on capacitor (attached to the LM1203, see photos below).
Can I get the values from this capacitor?? ( I am thinking this was a field service fix namco gave operators if they called them saying they found something wrong or they did the fix when sent in.)


- If your board has a mod board thats sitting above the Video Amp IC. I would like to document this board so I can repro it potentially. (im just assuming this board to be rare as eff because I only seen one picture of it on the internet, probably a late life board factory fix before they finished the revised board for classics vol 2. )



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Heres the nitty gritty:

If I check the power pins on this LM1203 video amp theres a significant loss in voltage on the rail anywhere from like 3 to 5 volts if i am remembering correctly when the volume becomes bassy/boomy at medium to high volume.
I tried adding my own capcitor to this chip the same way. 100 uf cap seems to make SOME difference but its not a ton and once you push the volume past about 50% the distortions are back again.
I also added a 470 uf cap in parallel trying to just SEE if I can have any kinda of improvements. Its not really the proper engineering way to go about that but I figured why not give it a little shot.


So I noticed early on when I was repairing my Namco Classics 1 that Classics 2 has some differences with the power rail or w/e leading into the RGB video amplifier chip they use. The Classics Volume 1 just has a simple diode and a 47 uf cap to decouple or filter the video amp from the rest of the board. The Classics Volume 2 has a bunch of other stuff added like a inductor a IC (I havent looked up what exactly it is yet) and some extra capacitors.

Im wondering if Namco just really messed up when they first designed these boards and theres power delivery problems with that video amp or its easily susceptible to picking up noise of the power rails. Clearly something was wrong enough for them to make a mod board and then totally revise that portion of the board later.

I have noticed that some boards have a capacitor added to the RGB amplifier bodged on (its installed and positioned the same way on multiple boards I find on the internet IF they have them at all theres not many. Then I found one particular board that has a custom made mod board with Namco silk screening and plastic clip stand offs adding every component that the later revision board uses for its RGB amp for say Namco Classics Collection Vol 2.

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The majority of Classics Volume 1 PCB's I see on the internet including mine.

Bodged on Capacitor of which I have ZERO idea what its value is...

With the offical mod board attached to the PCB. (this board closely matches the additional parts added to the next revision of the board (Example Classics Collection Volume 2)

The next revised version of the board. (Classics Vol. 2) See the design is now miniturized and added into the actual board now\

 

[GeekMan1222]

Realistically im probably just going to go and reverse engineer what they added to the ND-1 rev B board and make that into a mod board its nice to get any feed back if anyone knows anything.

 

[bagheera369]

Checked all 3 copies in my house....none of them have the mod, or the extra cap added to them.

Have never had issues personally, with any audio problems....and the video problems I've had, have been streaky video due to failing caps in the video circuit.

I wish you luck in your quest though!

 

[twistedsymphony]

I don't have this board on mine, but it does have the bodge cap.
I don't recall there being any audio or video issues, at least not since I recapped the all the SMD caps.
I documented the recap here: http://solid-orange.com/2222

However I rarely have need to crank my volume all the way up so if this only happens at higher volume levels I may not have seen it.

Given my bodge cap has the same bends in the same place as yours I'd venture it was a factory mod, not a kit for Ops.

 

[GeekMan1222]

I really appreciate the feed back and input guys.

Symphony I saw your blog post several times and I must have just glanced over the value for that cap apparently. I will definately go check!!

So I did further testing today. The distortions I am seeing I am getting a better idea of the behavior and i'm starting to think this might be part of the reason or the reason namco made these fixes and revisions.

I dont have a second ND-1 board so its difficult for me to just assume all boards have this issue that I have.
However I find it odd Namco added so many components to the 12V power rails close to the video amp in the B revision boards not to mention the mod boards.

So for one I tested this PCB on my egret 3 when I first fixed it and the audio gain to video distortion level wasn't super bad but it was there. When I put the board in my Madonna cabinet it got a bit worse where say you cant set the volume higher than 25 to 50% with out seeing distortion.

However tonight was very very interesting because I tested the board out on my buddy @Cage4296 's Candy 26 and you could not even have the volume more than say 5 or 10% turned up on the PCB before SERIOUS distrortions would start to show...

When we tried it on his NNC using a Jammafier there was zero issue at all period no distortion you could crank the volume to max on PCB or the cab. (Mind you this uses a power amplifier but its eliminating the speakers power draw from the board basically..

I think the speaker impedance or speaker power draw from the audio amp is pulling down the 12V rail on the video amp or some oddity involving the speakers and amp.
I checked the voltages again at Cage's house and on the candy 26 the 12V rail was spot on at the jamma edge but when you tested the power pins on the video amp it was as low as 11.23V and was not stable at all. This is similar to what I saw weeks ago when I tested on my Madonna. If you checked the 12V rail anywhere else around the PCB it was at 12V or very very close to it and mostly stable.

My board is totally recapped though as well. Im not using SMD cabs though (yeah I know.. its just what I had on hand) its not outside the realm of possiblity that maybe the amp is damaged or the video amp. Its too early for me to make too many assumptions outside of being curious.

I am not sure what to think of this yet but i'm documenting it anyways.

I should add as well someone on KLOV mentioned this exact same issue in passing on a post about another issue with his ND-1 board but it was never discussed past him bringing it up..



PS I'll try to get a video clip of what it is im talking about since I got some footage recently.

 

[twistedsymphony]

I pulled out my NCC Vol 1 board the Capacitor is a 470uF 16V

putting the board in my E29 and cranking the volume all the way up I do see some minor pulsing with the beat of the music to the overall brightness of the image, I only really looked at the menu and it was more noticeable with the darker background than the brighter foreground. Had I not been looking for it I might have assumed it was intentional. it does start to appear at 50% volume (just barely) and gets more intense the higher the volume goes. but I'd say on my board/cab I probably wouldn't have even really noticed at full volume unless I was looking for it. and most of the time I'm maybe playing around 30% volume so it's not something I would have normally seen.

really it felt like the background was dimming just slightly on the more bassy drum hits of the music and not anything more dramatic than that.

 

[Phil Bennett]

Interesting! Recently I helped fix a Namco Classics Vol. 2 for a friend which had no video. The video amp's 12V supply had dropped to 5V. This seemed odd as I thought it would be supplied by the JAMMA 12V rail. Turns out the video amp has its own 12V supply generated by an LT1109A DC-DC converter, which had failed. Now I know why it's there

 

[GeekMan1222]

Interesting! Recently I helped fix a Namco Classics Vol. 2 for a friend which had no video. The video amp's 12V supply had dropped to 5V. This seemed odd as I thought it would be supplied by the JAMMA 12V rail. Turns out the video amp has its own 12V supply generated by an LT1109A DC-DC converter, which had failed. Now I know why it's there

OH! that is really interesting!

I was wondering if that little IC was a DC regulator or something I just like I said had not bothered to look up the part number yet off my NCC Vol 2. Very interesting.

I actually tried with a 470 35v cap by its self yesterday but it also made no real difference on my Madonna.

So I suppose I may look into reproducing namco's factory fix mod board here.
Im gonna try to find a manual too maybe theres specific mention that the speakers need to be a certain impedance or something??

Heres a small video from yesterday I made to document the behavior on my friends cabinet which has had the MOST dramatic of all 3 cabinets it did this with.

View: https://youtube.com/shorts/l7UwvXmQ6rM?si=5tb4nyTPKPVtz3SD

 

[twistedsymphony]

The mod board looks like a pretty simple circuit do you have any higher resolution pictures of it or pictures from different angles?

 

[GeekMan1222]

The mod board looks like a pretty simple circuit do you have any higher resolution pictures of it or pictures from different angles?

I dont if what I can see is anything Im pretty sure is nearly the same components as what the production Vol2 board uses including extra added traces for some of those wires going off to places.

Furthermore if all it really is is a 12v dc to dc power supply then I can probably fashion a mod board using an off the shelf module and break it out that way. Something to that effect maybe.

 

[tcdev]

Just happened to have retrieved my NCV1 PCB from the shed this afternoon, for a completely different purpose.

Mine has the bodge cap on 10B as well, though I can't read the value either (probably stuck in the goo).

FWIW I need to measure the XIN/XOUT frequency on the YGV608 (pins 42,41 respectively). I don't suppose anyone has measured this already and has this information at hand? It either going to be 49.152MHz or a division of. TIA.