SNES SCART to PVM-2530 too hot

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HDgaming42
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SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

I built a cable to go from SCART to the 25pin DSub on the back of the PVM-2530. PSX and Genesis look great!

SNES tooks waaaay too hot.

Here's S-Video
Image

and now RGB
Image

I opened the SCART cable (bought it from eBay, and works with an XRGB-2+) and it has 220 caps, which I believe is correct.

Any idea what's going on here? Do I need to add resistors? To what lines, and how much? 75? 100?

Thanks for any help--kind of bummed out about it. Amazed I built a cable that works (thanks for the fixes Fudoh!!!) but disheartened my favourite system doesn't work correctly...
fagin
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

NTSC requires 220uf caps
PAL requires 75ohm resistors

You shouldn't need both.
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HDgaming42
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:NTSC requires 220uf caps
PAL requires 75ohm resistors

You shouldn't need both.
Thanks. Any idea why it would look like this? All three of my SCART systems look fine through an XRGB-2+. Two of them look fine direct to my PVM-2530. The SNES is the only system to look like this.

I have a launch model NTSC SNES.
Last edited by HDgaming42 on Sun Feb 17, 2013 3:15 pm, edited 1 time in total.
fagin
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

It's a tad weird. I have two NTSC SFC and they work fine with all my TV's including PVM and BVM's. My scart cabling is capped with 220uf's.

I would have a play myself and remove the caps from the RGB lines and see what that does.
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HDgaming42
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:It's a tad weird. I have two NTSC SFC and they work fine with all my TV's including PVM and BVM's. My scart cabling is capped with 220uf's.

I would have a play myself and remove the caps from the RGB lines and see what that does.
I may come off as an idiot here...but wouldn't that tend to make it brighter? If my soldering skills weren't as abysmal as they are (Fudoh can attest to this!) I'd try it. My fear is once I have them out...I might not be able to get them back in. I can't even get my work to fit in a SCART shell without capacitors! :oops:
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

HDgaming42 wrote:
fagin wrote:It's a tad weird. I have two NTSC SFC and they work fine with all my TV's including PVM and BVM's. My scart cabling is capped with 220uf's.

I would have a play myself and remove the caps from the RGB lines and see what that does.
I may come off as an idiot here...but wouldn't that tend to make it brighter? If my soldering skills weren't as abysmal as they are (Fudoh can attest to this!) I'd try it. My fear is once I have them out...I might not be able to get them back in. I can't even get my work to fit in a SCART shell without capacitors! :oops:
Theorectically, but this is about seeing the effect it has on your set-up, which with what you have told us and with your set-up, appears to be abnormal to me.

You'll probably end up having to remove the caps and replacing them with 75ohm resistors.
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Re: SNES SCART to PVM-2530 too hot

Post by Fudoh »

the weird thing about the photos above is that the 2nd one doesn't show a boosted white level (what you would expect with missing resistors), but it's showing an elevated black level, possibly caused by a remaining DC offset in the video signal. This should be filtered away by the capacitors.

Anyway since the cable doesn't work properly, I would just remove the capacitors and take it from there. Soldering inside a scart connector is easy: first fill up the pins in the question with some tin. Then put the soldering iron to the pin from above and just insert the cable into the liquid tin. Pull away the iron and wait 2 seconds.
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:Theorectically, but this is about seeing the effect it has on your set-up, which with what you have told us and with your set-up, appears to be abnormal to me.

You'll probably end up having to remove the caps and replacing them with 75ohm resistors.
OK. Simply removing the capacitors without adding resistors should show what kind of result do you think? Any ideas? I'll report back here when I do, but I'll be curious afterward awaiting your feedback...
Fudoh wrote:the weird thing about the photos above is that the 2nd one doesn't show a boosted white level (what you would expect with missing resistors), but it's showing an elevated black level, possibly caused by a remaining DC offset in the video signal. This should be filtered away by the capacitors.
Should there be a capacitor on the sync line? I can double check if there is one...
Fudoh wrote:Anyway since the cable doesn't work properly, I would just remove the capacitors and take it from there. Soldering inside a scart connector is easy: first fill up the pins in the question with some tin. Then put the soldering iron to the pin from above and just insert the cable into the liquid tin. Pull away the iron and wait 2 seconds.
I think my problem is I left the exposed wire(s) too long and tinned them. They became inflexible and I can't "curve" them into the shape of the SCART housing.

On another note I'm going to redo my VGA-->DB25 anyway as I've got an audio hum I'd like to banish.
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

I think you're missing the point. We may be past the point of expecting what it will look like with any given mod, so we need to start playing with it to see what it will do.

No cap is needed or should be on the sync line.

Audio hum on your other lead is probably a bad ground.
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:I think you're missing the point. We may be past the point of expecting what it will look like with any given mod, so we need to start playing with it to see what it will do.

No cap is needed or should be on the sync line.

Audio hum on your other lead is probably a bad ground.
OK. Just hoping for some guidelines as it seems I'm able to eek out 1/2hr per week on this endeavor. I understand what I'm seeing is unusual--I guess we're outside the scope of normal, so there's no "predicting" what will happen.

There is a cap on the sync line. Should I just remove that one first and see what that does before removing all the others? Here's a few pics of the cable as is (no grounds on audio or RGB it seems. is that normal?)

Image
Image
Image
and here's the cap on sync (video I assume):
Image
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Re: SNES SCART to PVM-2530 too hot

Post by Fudoh »

Should I just remove that one first and see what that does before removing all the others?
seems like a good idea
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HDgaming42
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

I'm confused.

So I removed the capacitor from sync. No visible difference.

I proceeded to remove the caps from R, G, and B.

No difference! WTF?

Like Fudoh remarked--it looks weird because it's not "hot" in the manner I would expect it to be.

Ideas? Add 75ohm resistors to RGB (I will have to buy these). Anything else?
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:Audio hum on your other lead is probably a bad ground.
The SNES doesn't buzz, so I guess my Genesis cable is constructed worse than the hack jobs I've come up with! :lol:

My SNES serial number is UN10343021 if that matters. I don't believe I have the required screwdriver to open it up to see if there's anything crazy going on inside...
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

From your photo the R,G & B caps appear to be the wrong way round. The Sync cap looks the right way round.

All caps should be - to scart pin + to wire (back to console).

Is my photo deduction correct (it would certainly explain what Fudoh mentioned)?
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

fagin wrote:From your photo the R,G & B caps appear to be the wrong way round. The Sync cap looks the right way round.

All caps should be - to scart pin + to wire (back to console).

Is my photo deduction correct (it would certainly explain what Fudoh mentioned)?
I wish I'd taken better photos. All the caps are off now--not sure how they were originally. I will try to rewire them tonight (7 hrs from now or so) if I get the chance with the caps positioned as you're described. What you're saying makes sense--if they were wired incorrectly perhaps that's why removing them had no effect...

odd that the XRGB-2+ didn't seem to care...

And would I be adding a cap back on the sync line, or not?

Thanks!
Last edited by HDgaming42 on Mon Feb 18, 2013 8:25 pm, edited 1 time in total.
fagin
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

I would leave the sync cap off.
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HDgaming42
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Re: SNES SCART to PVM-2530 too hot

Post by HDgaming42 »

SUCCESS!!!

You have some eagle-eyes there fagin! Reversing the incorrect capacitors fixed the issue! SNES looks great! I can finally enjoy my SNES in full RGB the way it was meant to be played--on a CRT. :D

Put the caps back on RGB but left it off the sync. Works a treat.

A big thanks to Fudoh and fagin for their help in this matter. I wasn't sure I'd be able to fix this given my lack of soldering skill but to be honest it wasn't that bad. Now that I've got the proper technique, really, if you mess up you can always re-do it!

:D :D :D :D
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Re: SNES SCART to PVM-2530 too hot

Post by fagin »

Awesome! :mrgreen:

It amazes me the amount of shit cables being sold. Another guy on this forum is having a similar issue with connecting his 360 to an arcade cab...... the wiring on the cable is about as much use as tits on fish imo. Again... another retail cable. :shock:


Anyway.... glad we could help you and that you have bust your soldering cherry! :wink:
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