Mega-CD Model 1, No Power (Not the fuse)

[PureChaosX]

So as the title somewhat describes, I have a Model 1 Mega-CD given to me by a YouTuber that was basically dead. After quite a considerable amount of research, I found out the F1 Fuse on the power board is usually to blame. I purchased and replaced the fuse, however this doesn't seem to have cured the no power issue.

 

I have looked and looked on both of the boards and I cannot find anything that could explain why there is no power. There are no components blown or missing, no capacitors bulging or leaking. There is no water or electrolytic fluid damage anywhere. There are no traces or vias broken. From what I can see, both the boards are pretty much spotless. I shall try to add a few photos of the boards, maybe someone might be able to see something I missed.

 

FYI, I do not have any testing equipment to hand, so no multi-meters or anything. To be honest, even if I DID have some, I wouldn't even know what I'm looking for. 

 

For what it's worth, I DID fix it briefly, after replacing the fuse. It turned on and stayed on. However, when I turned it off to plug in the SCART lead and turned it on again... it was dead once more. Out of curiosity, I removed the fuse I put in, and soldered in the second fuse (it was a pack of 2). No power, completely dead. 

 

The only life I see in the Mega-CD is when I turn the Mega Drive on, I can see the laser light up for about a second. That means there must be some communication from the Mega Drive to the Mega-CD... at least "some" anyway. So at this point, I'm dumbfounded. Is the Mega-CD dead? Is the circuit that tells the Mega-CD to turn on dead? I honestly do not know what I'm looking for, this is beyond the scope of my ability. Well, I do plan to do a re-cap at some point just because. That I can do.

 

I have made a few YouTube videos about the Mega-CD. Once they're upload, I'll link them here and maybe someone can catch what I missed?

 

Further, if anyone is from the UK and has a broken Model 1 Mega-CD for scrap, I'll buy it off ya, but I can't spare much. Or even just a known working power-board and main board will be good. Anything I can use to test my Mega-CD with.

 

Thanks to all those who read and reply. Replying is not mandatory!

 

[nick3092]

Could also be a dirty connector either on the console And/or the CD unit. I had a model 1 console and CD unit that had maybe a 25% power on rate without removing it and putting it back on several times. 

 

Until I gave both connectors a really good cleaning. I think most of the issue was on the male connector on the console. I hit it with some deoxit D5 and a qtip. It was pretty dirty. So I kept cleaning it over and over until the qtip was fairly clean when done. 

 

To clean the female connector, I like it keep some old gift or credit cards around. I have some heavier card stock paper that I cut slightly wider than the card, fold it over the edge of the card, soak it in some isopropyl alcohol (the higher the %, the better), and run it in and out of the connector. The paper usually gets fairly dirty, so I cut a fresh piece and repeat it till it isn't. Card stock works well since it's thicker and won't shred like regular paper, and the surface is slightly coarse from the fibers giving it a nice scrubbing action. 

 

Let everything dry, and try again.

 

Edit: Also, if you do get it powering on regularly, find someone to replace the caps on the main board with the battery sooner than later. It's not a matter of if those caps will leak, but when. Model 1 CDs, Game Gears, Turbo Duos and Expresses are all guaranteed to have leaky caps.

Edited December 12, 2019 by nick3092

[PureChaosX]

Well, I did give it a bit of a clean with WD-40 since that's all I had at the time. I also used a Magic Eraser instead of fine sandpaper to clean the surface of the pins as well as an eraser... which sometimes works. I also cleaned the female connector on the Mega-CD. Again with WD-40 and a soft brush to get inside the connector. Then used some fine sandpaper on both sets of pins.

 

So I have cleaned them a bit, the best I can without having some of the better cleaning products to hand. And I REALLY need to get some IPA in the future. However, I'll give the connectors a clean again and see what happens.

 

As a side note, upon replacing the fuse today, even though I don't believe it had blown, I DID get it to power on. Until I turned it off again... then it was dead. The fuse still shows as being intact when I test it, so I still do not believe the fuse is to blame. 

[Bruce Tomlin]

On 12/12/2019 at 5:20 PM, nick3092 said:

To clean the female connector, I like it keep some old gift or credit cards around. I have some heavier card stock paper that I cut slightly wider than the card, fold it over the edge of the card

You should try a matte tape like Scotch Magic Tape, I remember that works too. But it would need something thicker than a credit card, maybe even an old junk cartridge board. You probably also want it 2 or 3 layers thick. You can even clean it with a q-tip just like a card edge.

Edited December 14, 2019 by Bruce Tomlin

[PureChaosX]

Had a go at all of these cleaning methods the other day, spent a bit of time cleaning all the connectors on the Mega Drive and Mega-CD. I tried powering it on again the following morning and it actually powered on! So I turned it off and back on again... and it powered on again. I turned it off and connected the CD-ROM drive, and placed it back in the shell. Tried turning it on again and... dead! So maybe cleaning did SOMETHING but it was only temporary.

 

This problem is rather random. Most of the time it won't work, but every now and again.. it comes back to life for a short period. Then just dies again.

[CatPix]

Clean again and maybe try to see if it boots more regularly if you tilt your console.

I though my Mega-CD had issues until I cleaned the connector and used a ruler on the female connector to slightly push the pins more out (you do'nt want to pull them out too much or they will bend when mating the console to the MCD).

Since then it had been working MOSTLY flawlessly (mostly, because while it's a Japanese modle with an "universal BIOS" it only mean that it doesn't care if it's mated with an Euro Megadrive; unlike what you could read on some sites, you can only play JP games on it unless you change the BIOS chip, which I have yet to do).

Apparently it's very finicky with connection quality.

Edited December 14, 2019 by CatPix

[PureChaosX]

I gave them a clean again, I think this is the third time in two days. Also used fine sandpaper and Brasso again. The contacts have come up quite clean but the Mega-CD still refuses to power on. And I've tilted the console in every direction possible, still with no power on.

 

I did try to push the pins out a little bit, but one or two popped out so I had to pop them back in again. I think they're as far out as they can go. Other than that, I've pretty much exhausted all I can do without a spare power-board and mainboard I can use to test with. I do plan to re-cap the mainboard at some point, and install a fresh battery. Maybe new capacitors will help. Ah well... one for the Giving Up pile for the time being.

[PureChaosX]

OK, so after many days of working on this, I seem to have finally got it working... mostly by tapping the fuse on the mainboard (not the fuse on the power-board). Whether this was just a coincidence or not, no idea. But if the fuse is on it's way out, I'll need to replace it.

 

The fuse is covered in black though, so I can't read the ratings. Is the same as the fuse on the power-board, as in 1.5a?

[nick3092]

2 hours ago, PureChaosX said:

OK, so after many days of working on this, I seem to have finally got it working... mostly by tapping the fuse on the mainboard (not the fuse on the power-board). Whether this was just a coincidence or not, no idea. But if the fuse is on it's way out, I'll need to replace it.

 

The fuse is covered in black though, so I can't read the ratings. Is the same as the fuse on the power-board, as in 1.5a?

There is no fuse on the main board. I can't find a great picture of the PCB right now, and mine is not in an easy place to get to and open up right now. But I suspect the part you are talking about is labeled FB, possibly FB4 from a picture I found. That is a ferrite bead, if I'm not mistaken.

 

If tapping it makes a difference, I would suspect a bad solder joint that is making intermittent connections. If that's not the case, I'm not really sure why tapping it would make a difference. Or how to determine a proper replacement part if needed. 

[PureChaosX]

Hi, you are correct that it's labelled FB, but it's in fact FB17 and not FB4. If you see my photo above, it's on the far left under capacitor C52.

 

It's a small green component, like the power-board fuse, but it looks a little bit bigger. Though I think I will have a look at the solder joints and possibly re-flow them just in case it is a dry or cracked joint. Couldn't hurt.

[nick3092]

Yeah, it may look kind of like a fuse, but it's not. According to the service manual, this is the description for FB17. 

 

BEADS INDUCTOR FBAO'IVA600VI3-00

 

Skimming the schematics, I don't see a FB17 though. But this service manual seems to be a mix of European and Japanese info. Half the manual is in English, and half in Japanese. They have a drawing of the board, and they indicate what I saw on a different picture, that it's FB4. Which if I go back to the parts list, FB4 is listed as "not used". So I think it's an issue with the manual. The part number on your PCB ends in 8952, and the notes in the manual have a part number ending 8015. 

 

Anyway, ferrite beads/inductors are typically always inline with the voltage or signal that they are filtering. So a faulty connection would stop the voltage or signal dead.

 

Looking at the schematic and assuming FB17 is the same as FB4, it appears to be filtering the voltage to the connector right next to it (for VCC2). Which I believe is the ribbon cable to the laser. I'm no expert on the SCD, but if that's the case, it seems odd that the entire unit wouldn't power up if the laser is unresponsive due to lack of power. Plus the ribbon cable does also have two other voltage lines, M VCC and VCC. And I'm not sure how VCC2 factors in.

[BBZ149]

This problem is none of the above!! You have a broken track from either C41 that has damaged a trace to IC4 or C43 that has damaged a track to IC2 or even under C43, or could also be a bad Trace from C48 thats damaged a trace to FB17! You need a powerful Microscope to repair these and good soldering skills!! I repair these all the time! RetroRepair@gizmosltd.co.uk

 

 

[BBZ149]

Opsss, just noticed the original post posted after waiting for Account authorisation!

 

Dead or stuck on the Boot screen is probably Acid damage from a leaky Capacitor! Dead if not the fuse is more likely C41 leaked and damaged track to pin 20 under the ROM or C41 damaged track to FB4. Could also be Cap C43 that's leaked and damaged Track to IC1 pins 153 - 155 which normally causes the CD to be stuck on the Logo Screen. Either way you will need a powerful Microscope and good Solder skills! repaired so many of these and have the equipment, even built a nice Interconnect to test Boards while powered up ?

 

Weller WR2 De-solder Station makes easy work in replacing Bios ROMS.



Built a nice test Loom  makes testing a lot easier!

 

Here's the latest badly Acid damaged CD I managed to bring back to life again after major damage repair ?

 

Edited April 12, 2021 by BBZ149