N64/NES Weird Display

Sharkspine · 30 Aug 2023 at 18:50

Hello

I apologise if this isn't really the right place for this but as you all seem technically minded I thought I'd try.

I own a Sony Trinitron CRT. Plays SNES, Mega Drive, PS1, PS2, original Xbox, Saturn with no issues at all for many years.

My TV has one scart socket which accepts AV and RGB and so I switch between the two depending on the requirement.

It used to play my NES and N64 no issues too until I got them out of storage this year.

The NES displays a very dark image and the colours are strange. The clouds in Mario are Black for example. Almost like the colours are inverted.

The N64 is very dark too and on Mario 64 Marios skin is a dark brown.

I've tried different leads and power packs with both, same result.

I borrowed a cheap LCD off my neighbour, hooked both the N64 and the NES up and they are fine. Colours and brightness are all as you expect. I used the same consoles, leads, game carts.

So the issue is the TV. But that plays every other console nicely. I even hooked my BBC Micro and Amiga 500 up to it and they look lovely.

What could be causing the issue for those two consoles? Could there be a setting in the service menu or does it sound purely hardware?

Thanks again for reading and take care,

Ryan

Zaf · 30 Aug 2023 at 19:50

I think the NES and N64 are the only consoles you’ve mentioned that do not support RGB, and assuming you connected the BBC and Amiga over RF.

It could be an issue with the composite pins on the Scart socket on the back of the tv maybe.

I’m only clutching at straws here but I would visually inspect the socket and try clean it if you can to see if that makes a difference.

Others on here are much more clued up on these things, but worth a shot while you wait.

Good luck in solving it!

Nemiyen · 30 Aug 2023 at 20:56

I'd say what Zaf said is right. Scart can do RGB, composite and S-video. Unless the NES and N64 have been rgb modified, they'll be outputting composite. I'd say the pins for composite on your scart port are damaged or not working correctly.

It's wither that or you may be able to manually select composite from the video menu. Most tvs will just auto select it somehow but you might be able to manually select it on some tvs.

The pins used for composite are at the slightly angled side, not the straight side (hard to describe haha) so look for any damage to those holes on the TV. You might notice the hole is wider than the rest which is stopping the pins connecting correctly.

Sharkspine · 30 Aug 2023 at 21:38

Thank you both for your responses. Much appreciated! I shall take a look and see what I can do. Damaged or dirty composite pins does seem a good hunch.

Just for clarity: N64 unmodded. Computers were connected via RGB.

Zaf · 30 Aug 2023 at 22:52

Sharkspine said:
Thank you both for your responses. Much appreciated! I shall take a look and see what I can do. Damaged or dirty composite pins does seem a good hunch.

Just for clarity: N64 unmodded. Computers were connected via RGB.

The N64 will be using composite over the scart cable then rather than RGB, these are pins 17 - 20. Does the front of your TV have composite inputs? If that works the issue is definitely with the scart socket or maybe the encoder on the PCB.

Sharkspine · 31 Aug 2023 at 14:16

This morning I connected the N64 via my TV's front yellow phono jack and the issue remained. No difference

I also connected both the N64 and the NES via RF and the issue was there via that method.

So the fault doesnt appear to be isolated to the scart socket if at all.

So definitely not consoles or cables. Definitely TV. But not the scart socket itself.

Zaf · 1 Sep 2023 at 00:26

Very odd! Do your other consoles work over composite and RF too?

It’s very strange that its isolated to the N64 and the NES

Zaf · 18 Sep 2023 at 08:09

@Sharkspine did you ever get to treat bottom of this?

Sharkspine · 10 Oct 2023 at 00:03

Zaf said:
@Sharkspine did you ever get to treat bottom of this?

Hello

Sorry for belated response. Have been busy tracking down a local repair person. Not easy.

Left it with a reputable gentleman at the weekend who phoned me this morning.

He has cleaned it up, resoldered some connections on the scart and generally gave her a good check up and has isolated the problem to the RGB 'CHIP' (I can't remember exactly what he said)

He said theres a specific part of the chip which has failed. Basically the non RGB signals are not being processed. He sent me a photograph of the chip and identified the part at the top which needs repairing or replacing. This is what is written on the chip:

SAA549BPS/ 014 (This is the part)
72700741
02 10P TEXT
PHILIPS 1994
INTEL 1980
bSS9744M1X

Does anybody know what that part is precisely? May help tracking it down?

He says if we can find it he can repair it.

He also suggested using a VCR as a passthrough/signal converter?

Thank you for any help!

Zaf · 10 Oct 2023 at 01:04

You could try posting on here as this seems like a similar problem - https://forum.allaboutcircuits.com/threads/sony-crt-no-video-only-audio.170594/

Have you tried searching for the service manual?

Haze · 10 Oct 2023 at 10:14

Jus

Sharkspine said:
Hello

Sorry for belated response. Have been busy tracking down a local repair person. Not easy.

Left it with a reputable gentleman at the weekend who phoned me this morning.

He has cleaned it up, resoldered some connections on the scart and generally gave her a good check up and has isolated the problem to the RGB 'CHIP' (I can't remember exactly what he said)

He said theres a specific part of the chip which has failed. Basically the non RGB signals are not being processed. He sent me a photograph of the chip and identified the part at the top which needs repairing or replacing. This is what is written on the chip:

SAA549BPS/ 014 (This is the part)
72700741
02 10P TEXT
PHILIPS 1994
INTEL 1980
bSS9744M1X

Does anybody know what that part is precisely? May help tracking it down?

He says if we can find it he can repair it.

He also suggested using a VCR as a passthrough/signal converter?

Thank you for any help!

buy another n64?

Look on ebay for console only, as you already have cables ect

Sharkspine · 10 Oct 2023 at 13:07

Yes. Been perusing it.

It's a BE-4A chassis. Model is KV21 3TU

I've found the part in the manual with the nearest name to that in the photograph and it appears to be a Semi-Conducter.

Zaf · 12 Oct 2023 at 16:01

Did he say if it was the chroma jungle IC? I've just had a quick look at the schematics and it could be this. I'll be honest and I'm no expert by any means, but I think you are going to really struggle to find a drop in replacement. I would seriously consider selling it on as spares or repairs and buying another CRT.

GeX · 13 Oct 2023 at 16:09

Haze said:
Jus

buy another n64?

Look on ebay for console only, as you already have cables ect

The TV is the issue, not the N64.

Rather than trying to source the part, if you're not keen to use a VCR or similar then (what I would do) you could RGB mod the consoles

Kit : TW RGB - N64 | oldskoolconsoles

N64RGB Mod Kit with Deblur by Tim Worthington Some ntsc models may require the fine pitch DAC adapterCheck to see if you have a MAV-NUS or AVDC DAC chip These are the latest v3 boards. I stock good quality shielded RGB scarts here The best RGB mod kit available for the N64 As Featured on...

www.oldskoolconsoles.com

Kit : RGB - NES (All models) | oldskoolconsoles

Tim Worthington NESRGB Version 4 Mod kit for the following models: Frontloader Famicom av Toploader / NES 101 Famicom twin Original Famicom (you need the p/a board as well) Version 4 with new features: Controller reset and pallette toggle function Functional de-jitter option Diagnostic LEDS...

www.oldskoolconsoles.com