G4 QuickSilver 733MHz - No video signal and no USB

Welcome, Toni!

First, What kind of monitor and how is it connected? Apple sold "ADC" monitors (info here) that ran power, video and USB over the same cable. The presence of an ADC monitor will affect recommendations. If it is an Apple monitor, get a lens and strong light and look for a model number on the back so we can b sure whether or not we're fighting ADC issues. Serial numbers for Apple monitors of that generation all stated with "M" or "A" followed by a four-digit number.

On older Macs resetting the power management unit (PMU) was recommended to wake up non-responsive USB ports. This Apple article is old but still available: Resetting PMU on Power Mac G5, Power Mac G4, Power Macintosh G3 - Apple Support

⚠️ When resetting the PMU, give it ONE SHORT PUSH (under one second)! DO NOT press and hold like required for older PowerMacs than yours. "Press/hold" can make a right mess of your PMU-equipped computer.

USB expansion cards were always a "some work--some don't" expedition. I used a MacAlly UH-222 in a G3 powermac with great success but finding workable drivers may be dicey today. The later UH2-225 was also good. Sonnet cards were on the good list to.. Basically you are looking for one with an NEC chipset. Look at the largest IC chip on the card--If NEC is silkscreened on that chip it will probably work. If it is not marked or is marked "OPTI," put that one down and keep looking.

At this point I don't think we can be sure adding a PCI expansion card is the sure cure. Let's figure out if you have an ADC display that is messing with your USB bus, and see if the PMU reset helps wake up your ports.

I firmly believe the nVIDIA Model P40 is the original Display Adapter / Graphics Card .

Could very well be. It looks like it has Apple part numbers (format: 000-0000). Normally an after-market card is festooned with the brand and model. Can you get a picture of the ports? There should be one VGA and one ADC. An ADC connector looks like this:

I've not done flashing. The link I sent about "All things PPC" has some vid card and flashing info. My recollection is that ATI cards were easier to flash than Nvidea models. Flashing most commonly requires a Win computer with compatible expansion slots. The flash is done while the card is installed in the PC, then the card is moved to the Mac.

Thanks for the followup.

I would pull the graphics card from the QS and clean its contacts, and also brush out its slot with a non-conductive, non-static brush. I use brushes with natural bristles and wood handles--think "pastry brush." When you reseat the card, go in and out with it a few times to scuff any residual corrosion off the contacts. Also make sure the card is still seated fully and level after you reinstall any retaining screws. Sometimes tightening retined screws can cause one end of the cad to lift from the slot.

If the computer has been off wall power for an extended time (more that about 15 days), I would replace the logic board backup battery--most people call that the "PRAM" battery. On that model it's a long shot but worth at try at this point. You need a battery with these specs:

https://eshop.macsales.com/item/NewerTech/BAA36VPRAM/

That one is new to me but I'm better at ATI cards than nvidea. A quick web search for nvidea p40 turns up hits but they look newer than what could ship in a G4, and there is no mention of Mac compatibility.

I'll be out most of the rest of today so try some more googling for the card name. Also, if possible, post an image of the card--that might be the most helpful step at this point.

I've not had success in learning more about the nVidea P40 but thought you should have this link in your Quicksilver toolkit:

http://www.jcsenterprises.com/Japamacs_Page/All_Things_PPC.html

The site belongs to a former contributor here who is a a genuine PowerPC expert. There are links to additonal gfx card articles at the bottom of this page:

http://www.jcsenterprises.com/Japamacs_Page/Graphics_Cards.html

Some user-updated cards that can appear in used PPC Macs like yours may be "Flashed" cards that originally shipped with firmware for PCs not Macs. That site also discusses this. It's possible that someone installed a PC-based card without flashing to Mac ROM or the flashing was not properly done. Those units got upgraded a lot when users found the original gfx cards underpowered for newer apps and games (usually games).

It is this one, powered by ATI but branded "Club." It is only 128MB VRAM, so is very much early 90s but still more VRAM than the stock cards that shipped in the QS (32 and 64MB):

http://www.gpuzoo.com/GPU-Club_3D/Radeon_9250_-_CGA-9258TVD.html

Apparently that site has full specs for a LOT of old video cards. Bookmark it.

It is based on the ATI Radeon 9250. I am an idiot when it comes to flashing but, if a 9250 can be flashed, so should this one be. search for "ATI 9250 flash to mac" and see what you get.

The round port should be S-video, thus the "TV" in the model number.

EDIT: As Limnos points out, flashing is not a sure thing. It usually requires a PC and there are many different versions of flashing software in the wild, most written by hobbyists.

MY old G4 MDD has the AGP ATI Radeon 9000 Pro 64MB and it'a a good card. A lot of those are on the used/pulled market as people pulled them to install more robust cards. That would be a very workable card--they are usually cheap, and already have the Mac ROM.

Here's a 9000 Pro that claims to have been pulled from a G4:

https://www.ebay.com/itm/ATI-Radeon-9000-Pro-64MB-AGP-Graphics-Card-109-99700-00/283332543845?epid=1300287421&hash=item41f7ef8565:g:dzgAAOSwiE1cEstl:rk:36:pf:0

That is the correct battery