Sega 32X whining coil, audio and video noise

[xwred5]

I assume so. I guess I better practice my SMD soldering...

Oddly my 32x has a sharp IC IR3M03AN verses the schematic On/TI MC34063A. Looking at pictures on the internet, it looks like most units use the Sharp IC. Anyhow, we'll see if this fixes it.

[xwred5]

Okay, so my SMD soldering is hilariously bad-- but after reworking a few resistors I have positive results.

I am discussing the situation with Luke at Console5. Stay tuned.

[xwred5]

So, it's not fixed...

When I was wiggling the hook up wires that used to swap in and swap out the inductor, I noticed that the horizontal lines returned. Wiggling the wires again, I was able to get the horizontal lines to go away, however, I noticed some weird colors in the VF attract screen when there was no horizontal noise.

Wiggling them back to get noise, the noise came back but the discoloration was gone.

I did this a few times and moved the wires. Now I am in a situation where I can't wiggle the wires back into a situation where the noise is gone.

EDIT: Ho-le-crap. I just realized when it was "good" I had the inductor shorted...……. not sure what this means at all. I don't recommend shorting the inductor lol. I just unwound a lot of my toroid, I saw changes, but it was getting to a point where I didn't have much inductance left.

I think my next step is to re-cap this guy... and/or replace TR5.. which they don't make anymore. But it looks like I can replace it with one SB3100 between 4-5 and a 2SB1121 between 1,2,6 then short 5&6 for good measure.

http://www.chipfind.net/datasheet/sanyo/fx401.htm
http://www.onsemi.com/PowerSolutions/pr ... ?id=SB3100
http://www.onsemi.com/PowerSolutions/pr ... id=2SB1121

[maxtherabbit]

TR5 is the dc-dc right? You already did the switching reg and it didn't help I take it?

[xwred5]

IC13 is the regulator/smps IC. I replaced that.
TR5 is the saturating pnp (circuit uses an external switch) and a Schottky diode combined in a package.

If I replace the caps and TR5, there is honestly nothing else effectively left in the power circuit to replace. IC14/TR3 and TR4 look to just turn on the 32x when the 5v rail is detected in the cart slot (i.e. when the Genesis is turned on)

I just ordered a replacement pnp and diode from digikey (what I bought is below.. I'd appreciate anyone reviewing the specs, I never buy semiconductors)

I think I am going to re-cap (lol still haven't done that) before changing TR5. Then I'll try swapping out TR5. If that doesn't work, I'm just going to add some capacitance. I also give myself a reasonable chance of breaking this 32x .

I also tried greatly reducing the inductance of L7 by unwinding a toroid I had. All it did was change the pattern.

Original Chip: http://www.chipfind.net/datasheet/pdf/sanyo/fx401.pdf
"Original Chip" PNP: http://www.amplimos.it/images/2sb1121.pdf
"Original Chip" Diode: https://www.datasheets360.com/pdf/-8578595243261037168

New PNP: http://www.onsemi.com/pub/Collateral/EN1787B-D.PDF
New Diode: https://www.fairchildsemi.com/datasheets/1N/1N5820.pdf (1n5821)

[maxtherabbit]

any news?

[xwred5]

Sorry, I haven't touched in a few weeks. Life has been crazy and I needed a bit of time off of he project.

I’ll try to carve out some time tomorrow evening to at least recap and fully re-assembly and test.

After that I’ll replace the bjt (I have the parts at my desk). I’ll probably do the bjt on a separate day.

[xwred5]

After replacing IC13, Recapping, adding console 5's inductor to the board, and actually putting it back together.

The noise is better but still there.

I am going to swap out his inductor for my recommended replacement. Then I'll try my TR5 replacement... Probably will be next week.

[maxtherabbit]

Yikes, guess bypassing the onboard power section wasn't such a bad idea after all

[xwred5]

Here is my 32x without problems
https://drive.google.com/open?id=1yUJGh ... QtJyS-KJOf

The one with the fixes is OKAY, just not perfect.
https://drive.google.com/open?id=1jkVc3 ... DHFyJMKVTK

Look above the Sega logo and you'll see ripple. The ripple isn't noticeable after YouTube compression.

It is a LOT better than the noise I was getting, but it's still there after the fixes. If this was my only 32x, I'd probably leave it alone, but I'm into the problem pretty deep now.

[maxtherabbit]

Here is my 32x without problems
https://drive.google.com/open?id=1yUJGh ... QtJyS-KJOf

The one with the fixes is OKAY, just not perfect.
https://drive.google.com/open?id=1jkVc3 ... DHFyJMKVTK

Look above the Sega logo and you'll see ripple. The ripple isn't noticeable after YouTube compression.

It is a LOT better than the noise I was getting, but it's still there after the fixes. If this was my only 32x, I'd probably leave it alone, but I'm into the problem pretty deep now.

it's certainly better, but I would still consider that amount of interference unacceptable for any real use

I just wish we could isolate the root cause of this BS

[xwred5]

"Weekly" update:
Swapped the Console5 inductor with a toroid. It's worse, back to horrible. I suspect it's less about the actual inductor then the specific inductance value. There really is nothing with this inductor that should make the situation worse. I've been designing magnetics for like 15+ years, I am pretty sure I can design and spec a buck inductor...

Luke at Console5 mentioned to me that changing the timing cap (C85) helped someone. So... I went on Digikey and bought these two. The thru-hole part is there because I suck at soldering (eh, I'd give myself a 6 out of 10). I bought two of each.

https://www.digikey.com/product-detail/ ... ND/8572594
https://www.digikey.com/product-detail/ ... ND/3725990

If these don't work, I am going to swap out the bjt/diode package, for real. I've had those parts for like a month. I am reluctant to because once I do that as I consider it a major "point of no return".

It's also like 90-100 degrees in my garage where I solder, if it's not cooler this weekend, I am going to push the project out a few weeks.

Feel free to add any recommendations....
- Done: Recapped (Console5 kit)
- Done: Changed the buck inductor.. a lot. (L7)
- Done: Replaced the switcher IC (IC13)
- Next Step: Replace the timing cap (C85)
- Next Step: Replace the BJT/Diode (TR5)

[xwred5]

Welp I got home from a business trip early today...…. I replaced both C85 and TR5.

The good news is it powers on.
The bad news is that the problem is still there, maybe worse, who knows.
I also lifted a pad from TR5... I had the diode mounted radially on the SMD pads and bumped it putting the shield on... I was able to jumper it.

- Done: Recapped (Console5 kit)
- Done: Changed the buck inductor.. a lot. (L7)
- Done: Replaced the switcher IC (IC13)
- Done: Replace the timing cap (C85)
- Done: Replace the BJT/Diode (TR5)

Edit: I was probing it... and she's dead jim. A probe slipped and I think I fried a 32x chip from the surge. I get genesis pass thru, and it regulates to 5V, just nothing when a 32x cart is put in.

Consider me tapped out

[maxtherabbit]

Welp I got home from a business trip early today...…. I replaced both C85 and TR5.

The good news is it powers on.
The bad news is that the problem is still there, maybe worse, who knows.
I also lifted a pad from TR5... I had the diode mounted radially on the SMD pads and bumped it putting the shield on... I was able to jumper it.

- Done: Recapped (Console5 kit)
- Done: Changed the buck inductor.. a lot. (L7)
- Done: Replaced the switcher IC (IC13)
- Done: Replace the timing cap (C85)
- Done: Replace the BJT/Diode (TR5)

Edit: I was probing it... and she's dead jim. A probe slipped and I think I fried a 32x chip from the surge. I get genesis pass thru, and it regulates to 5V, just nothing when a 32x cart is put in.

Consider me tapped out

ouch, I'm sorry dude

[xwred5]

Eh it’s no problem, I got this 32x cheap “broke”. I’m just disappointed that nothing fixed it. I should spend a bit more time debugging my unit, I just have a bad feeling it is major.

Considering the shielding, soldered on jumpers and hot glue in the oem unit, who knows. My good 32x might have the same ripple but everything is more tolerant.

If I run into another cheap broken unit, I’ll pick up the project again. Hopefully the data and steps taken help someone.

[xwred5]

The Ebay gods accepted the blood sacrifice of my last 32x and bestowed upon me a $26 shipped "as-is" 32x with AC adapter.

I am torn if I should bother debugging this anymore (could swap motherboards...) or try to design a new power board. I have never made a converter.. or a PCB... I am familiar with both, I just don't design either. I have a copy of EAGLE.

Based on what I've seen, I think a ~300kHz 10W 5V buck taking 8-14VDC in, CCM if possible. Probably can tie the input/ground to the CMC and the output to the inductor (would have to remove the inductor and solder to one of the holes). I might need to lift C85/the IC to connect to the circut that enables the buck on the 32x when the Genesis is turned on. I was actually probing this part of the circuit when my probe slipped and shorted the Common mode choke....

Speaking of my destruction, Luke at Console5 recommended that I take my "dead" 32x and try a 32x CD game... I'll try that "soon", I'm traveling all week for work and have weekend commitments.

[maxtherabbit]

Probably can tie the input/ground to the CMC and the output to the inductor (would have to remove the inductor and solder to one of the holes).

You can do exactly that - that's how mine is running now, just dumping 5VDC to the "output" leg of the inductor and putting ground to wherever - no modification to the turn on circuit necessary

[forde]

I have a 32x (blue coil) with the same problem of whining coil and video problems to the point it made the image grey with a lot of interference. I recapped it and tried to resit the coil without cushion and at first it was fine but the noise remained and the video problem appeared and was so bad it looked like it wasn't properly channel tunned.

I read in another thread a guy who said that putting hot glue around the coil can dampen the noise and give some isolation to it, so I teared the plastic and put some hot glue on the copper directly, then I bended the near capacitors and resistors to move then away from the coil and put some cushion rubber I usually put on the fans of my computer to reduce the vibrations. Now the noise is much less than before and only audible if you are close to the 32x in a silent room, so a huge improve in that, also the video problems where reduced to a much bearable level and doesn't appear everytime, now looks like some sort of interference of a mobile phone in old tvs.

So since I could reduce the problem a lot, I need further advice to go on. I don't know about electronics, so I need someone to tell me if my proposals are good or not. I thought of walling the coil with some metal from the shielding or other piece of metal, maybe covering that wall with tape or some plastic to avoid shorts. Also I thought of move the near elements (capacitors, resistors) a little further away with a bit of wire and do some room, maybe tearing down some of the shield and put them there properly insulated.

Thanks.