NES vertical artifacts after cuted 4th pin CIC pal ver

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rafalnir
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NES vertical artifacts after cuted 4th pin CIC pal ver

Post by rafalnir »

Hello,
I have a question about nes, that is, did somebody have that before the removal of the lock (cut off 4th leg) was the console functional, there are vertical artifacts after cutting? I have resoldering vram and no changed. Could the chip itself broke? Nes reset works. Damage, according to me, arise by additional power supply in systems because before by cutting off this 4th leg, I checked the operation of nes and it was ok. Then I disconnected the power supply from the nes but how to the nes still hold power. Maybe someone had one already? I replaced ppu from good nes and still have artefacts.
Last edited by rafalnir on Thu Jun 17, 2021 12:50 am, edited 1 time in total.
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

It's more likely you damaged some capacitor when you were reaching in to cut the 4th pin of the CIC.

I don't think your PPU is damaged.
rafalnir
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Joined: Fri Jun 11, 2021 4:17 am

Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Sun Jun 13, 2021 1:12 pm It's more likely you damaged some capacitor when you were reaching in to cut the 4th pin of the CIC.

I don't think your PPU is damaged.
Maybe, but I touched only 4th pin and this PPU in my second nes had artefacts but other becouse they are diffrent not vertical.
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

Could you share a picture of the artifacts now? Feel free to upload it to the forum here.
rafalnir
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Sun Jun 13, 2021 4:18 pm Could you share a picture of the artifacts now? Feel free to upload it to the forum here.
Yes, please.
Attachments
Artefacts vertical removed 4th pin CIC
Artefacts vertical removed 4th pin CIC
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

That's the "open bus" pattern. Somehow neither NES-internal NT RAM nor the cart CHR ROM are ever being enabled.

Try touching your fingers to PPU pins 38-25 while it's operating. You should see the image change.
https://wiki.nesdev.com/w/index.php/PPU ... escription

While your NES is off, and with a cartridge inserted, check whether 74HCU04 (U9) inverter pin 6 is connected to PPU RAM (U4) pin 18.
rafalnir
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Joined: Fri Jun 11, 2021 4:17 am

Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Mon Jun 14, 2021 9:26 am That's the "open bus" pattern. Somehow neither NES-internal NT RAM nor the cart CHR ROM are ever being enabled.

Try touching your fingers to PPU pins 38-25 while it's operating. You should see the image change.
https://wiki.nesdev.com/w/index.php/PPU ... escription

While your NES is off, and with a cartridge inserted, check whether 74HCU04 (U9) inverter pin 6 is connected to PPU RAM (U4) pin 18.
I tested and when touched pins ppu 38-25 nothing happends and pins 6 u9 and 18 u4 are connected.
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

You said you replaced the PPU. Could you check whether all the pins are making good contact?

There aren't a lot of things that could possibly cause the symptoms you're seeing. PPU A13 (pin 25) goes to the cartridge, where it should enable the CHR ROM. PPU A13 also goes to the inverter (pin 5), where it becomes PPU /A13 (pin 6), and that goes to the cartridge (pin 58), which almost always connects it back to the mainboard (pin 57) where it then goes to the PPU-internal RAM (pin 18).

Do you have any test equipment more than just a multimeter?
rafalnir
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Joined: Fri Jun 11, 2021 4:17 am

Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Mon Jun 14, 2021 10:27 am You said you replaced the PPU. Could you check whether all the pins are making good contact?

There aren't a lot of things that could possibly cause the symptoms you're seeing. PPU A13 (pin 25) goes to the cartridge, where it should enable the CHR ROM. PPU A13 also goes to the inverter (pin 5), where it becomes PPU /A13 (pin 6), and that goes to the cartridge (pin 58), which almost always connects it back to the mainboard (pin 57) where it then goes to the PPU-internal RAM (pin 18).

Do you have any test equipment more than just a multimeter?
I soldered std dil40 under ppu and this artefacts I has before changed ppu only after cuted this 4th pin. I dont have oscyloscope only multimeter. I checked capacitors near to ppu and blue has 0,5uF and ceramic has 202uF.
In good nes this blue has 1.3uF. Maybe this blue is damage?
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

rafalnir wrote: Mon Jun 14, 2021 11:14 am In good nes this blue has 1.3uF. Maybe this blue is damage?
instead of 0.5uF? I mean, probably. NESes are pretty old. But I don't think it's relevant to the symptoms you're seeing.
rafalnir
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Mon Jun 14, 2021 11:24 am
rafalnir wrote: Mon Jun 14, 2021 11:14 am In good nes this blue has 1.3uF. Maybe this blue is damage?
instead of 0.5uF? I mean, probably. NESes are pretty old. But I don't think it's relevant to the symptoms you're seeing.
No, instead 1.3uF becouse in my second good nes is 1.3uF on this capacitor. I dont now what more is wrong.
lidnariq
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by lidnariq »

Regardless, I don't think it's relevant to the symptoms you're seeing.

If your multimeter has a logic tester mode, check if PPU pin 25 (A13) is going both high and low when powered. Then check if 74HCU04 pins 5 and 6 are also. Finally, check if PPU RAM pin 18 is also.

If it doesn't have a logic tester mode, but can either measure frequency or volts AC, for all of the above signals, check if frequency is around 670kHz or VAC is more than 1V.
nocash
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by nocash »

Any chances that you have cut the wrong "4th leg" on the wrong chip?
And it's having cut, or after cutting, not having cuted, or after cuted (unless you have decorated the mainboard with cute pussycat stickers).
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rafalnir
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Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

nocash wrote: Mon Jun 14, 2021 4:24 pm Any chances that you have cut the wrong "4th leg" on the wrong chip?
And it's having cut, or after cutting, not having cuted, or after cuted (unless you have decorated the mainboard with cute pussycat stickers).
I did cut this 4th pin in CIC 10 times on the other nes pal and ntsc, always without problem:-)) This time is for me suprice with this artefacts after cuted this pin.
rafalnir
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Joined: Fri Jun 11, 2021 4:17 am

Re: NES vertical artefacts after cuted 4th leg CIC pal ver

Post by rafalnir »

lidnariq wrote: Mon Jun 14, 2021 3:45 pm Regardless, I don't think it's relevant to the symptoms you're seeing.

If your multimeter has a logic tester mode, check if PPU pin 25 (A13) is going both high and low when powered. Then check if 74HCU04 pins 5 and 6 are also. Finally, check if PPU RAM pin 18 is also.

If it doesn't have a logic tester mode, but can either measure frequency or volts AC, for all of the above signals, check if frequency is around 670kHz or VAC is more than 1V. Its too low under 1V and where is problem means which part?
My multimeter has't logic tester mode but today I check VAC on this pins. I checked and ppu 25 has 0.02V, pin 5 74HCU04 has 0.02V and pin 6 has 0.01V, to same pin 18 PPU RAM 0.01V. Its too low under 1V and where is problem, means which part? AC adapter is ok becouse working with my second good nes without problems.
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