wedanced
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San Francisco

I opened my model 1 to clean it, check on the capacitors, and figure out if I wanted to perform any mods on the unit and was confused by what I saw. I can't seem to find a picture of the circuit board that matched mine and the unit board is labeled in a strange way.

Typically the model 1 boards are labeled "IC BD M5 USA" with a revision number like VA2, VA3, VA4, etc. Mine doesn't include a VA labeling at all and has some additional text just below it that I haven't seen anywhere else. Does anyone have a clue about what's up with my unit and what revision it is?

https://www.dropbox.com/s/ml6izylnt0zq2 … y.jpg?dl=0

Last edited by wedanced (Nov 22, 2020 5:24 am)

Orgia Mode
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Sea of Souls

Can you get a different link to the image?

wedanced
Offline
San Francisco
Orgia Mode wrote:

Can you get a different link to the image?

Sure thing! Thanks for taking a look.
https://imgur.com/gallery/yyYxGdp

Orgia Mode
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Sea of Souls

I believe it is a VA6.
Comparing it to photos and chips here: https://segaretro.org/Sega_Mega_Drive/H … _revisions
If you read the label on your I/O chip, does it read "513-5433?" Thats the big square chip on the right. Just below it you can read "315-5402: VA5, 315-5433: VA6"
It doesn't seem like USA got a VA5, so I am very certain this is a VA6.

wedanced
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San Francisco
Orgia Mode wrote:

I believe it is a VA6.
Comparing it to photos and chips here: https://segaretro.org/Sega_Mega_Drive/H … _revisions
If you read the label on your I/O chip, does it read "513-5433?"

Confirmed! It looks like a VA6. I had a hunch it was some kind of va6.x because it has the TMSS but was thrown off because of the labeling and not knowing what chips were what. Thank you so much!

Do you know why it has that "Ru^ GX 211-VO" and "9208"? I don't think I have ever seen it on any of the other motherboard revision photos I have seen. Maybe a factory stamp or something?

Orgia Mode
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Sea of Souls

I've seen that on a lot of parts. I can't say where off the top of my head tho. The 9028 probably has to do with production date.

I just googled that the RU probably means "The "Recognized Component Mark" is a type of quality mark issued by Underwriters Laboratories. It is placed on components which are intended to be part of a UL listed product, but which cannot bear the full UL logo themselves.[6] The general public does not ordinarily come across it, as it is borne on components which make up finished products."

You can see it on the "PC BD MD2 VA0 USA" as well.

chipmonkey
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You have the extension port on it. Does the case have "high definition" on it?
If so you have the best version.

Last edited by chipmonkey (Nov 23, 2020 8:16 am)

wedanced
Offline
San Francisco
Orgia Mode wrote:

I've seen that on a lot of parts. I can't say where off the top of my head tho. The 9028 probably has to do with production date.

I just googled that the RU probably means "The "Recognized Component Mark" is a type of quality mark issued by Underwriters Laboratories. It is placed on components which are intended to be part of a UL listed product, but which cannot bear the full UL logo themselves.[6] The general public does not ordinarily come across it, as it is borne on components which make up finished products."

You can see it on the "PC BD MD2 VA0 USA" as well.

Thanks for filling me in! I was going nuts trying to figure it out. I appreciate you taking the time.

chipmonkey wrote:

You have the extension port on it. Does the case have "high definition" on it?
If so you have the best version.

It does have the HD labeling. I am glad to hear it is considered the best version. I have been comparing the stock sounds between the different revisions I come across.

TBH for recording, I have been finding the model 2 with the 3/4 boards sound better than the model 1 VA6. The model 1's Yamaha YM2612 chip is distractingly noisy because of the exaggerated ladder effect caused by its bit conversion. I prefer not to have the extra distortion. The integrated YM3438 found in model 2s are really clean in comparison though their amps vary in quality.

Last edited by wedanced (Nov 24, 2020 12:51 pm)