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I've got two TIs with the same ailment. Black screen on power on with the unending tone. Both occurred in relation to an F18A mod (but I would guess the F18A is not the cause) and I was wondering if anyone had some brilliant advice that could save the day, or advice in avoiding future tragedy. Story Time - Not for the faint of heart, you have been warned. Beginning this year I got the urge to start playing with my TI-99/4A again, my TI had been sitting idle and collecting dust for a few years ever since it's TV went away. It was a stock TI, no expansions apart from the speech; and I was really interested in improving it to explore the community offerings. I read about this fabulous modification called the F18A that completely overhauled the TI's video out. It didn't seem too difficult, so I ordered one as soon as they came available and waited patiently. After a time I received the magic F18A and dutifully opened my TI, removed the VDP, and installed the F18A. I then dremeled some holes for the VGA cable and snaked it to the back of my console. Shield, attach, close up, power on, total victory! Everything seemed to work without complaint and I was playing Tunnels of Doom on my computer monitor the same evening. What followed were some good times, a month or so of vintage happiness. It was not to last. A few weeks ago I powered on my TI so I could continue one of my latest Quests for the King. Black screen, blaring tone. As near as I can tell this was a spontaneous failure as nothing had changed - the system hadn't been opened since the F18A and it had powered on fine the evening before; no new expansions or cable changes. The internet informed me this dreaded error could mean virtually anything wrong with the system. I opened the system and did the only diagnostic steps I could handle. I replaced the original VDP and tried to power on. Nothing. Tried putting the F18A back and powering on. Nothing. I started re-seating the GROMs and clock chip. As I gently pried and lifted the first GROM it suddenly flipped 180 and attacked me, impaling my poor finger. I quickly deduced the reason, I had snapped off two of the pins. Disaster. Nonetheless, I carried on to see if any change in the system state could be discerned from the re-seating. The TI was unmoved by my efforts and continued with the black screen and harsh tone. As I was working with the TI motherboard, and under unremembered circumstances. I took hold of the keyboard ribbon cable to attach to the motherboard and instead had it come away in my fingers. Catastrophe. The keyboard ribbon cable had sheared off from the solder points on the keyboard. I sadly realized that my efforts had probably already killed my patient, I honestly am not equipped or knowledgeable enough for computer surgery, and should no longer indulge in this pointless torture. I resolved to visit eBay and order another TI. A scan of ebay revealed that TIs generally would cost $50 after shipping. I decided to go ahead and order a lot of 2 that were both claimed to be working but were missing some accessories (only 1 power supply and no RF) and one was missing keycaps. I bid, I won, and I waited. Yesterday the TIs have arrived. I verified that they were indeed functional as stock units (although the busted keycap one seemed to have some video issues). I set about opening the better of the pair to transplant my F18A. Unscrew, open, unshield, pry. Everything proceeding smoothly I gently pried up the F18A from it's old host and I let out a cry of genuine anguish. One of the pins was gone (nothing else bent or damaged that I saw, just cruel fate), the F18A had been wounded in this latest action. What follows is my descent into pure madness and unmitigated stupidity. Faced with the missing pin, and desiring to install the F18A in the fresh patient IMMEDIATELY, I resolved to solder a replacement pin to the F18A board. Now some background, in years past some fool gifted me a inexpensive soldering iron as they knew my interest in vintage computing and thought I would find the tool useful. This tool would become a murder (of my poor TI) weapon. I have no training or formal education, and my past successful efforts with the tool have been only to solder wires together. A pin isn't that much different from a wire though? Of course not. So I cut a pin from a bit of discarded electronics I had laying around and proceeded to attempt to solder it to the board. What followed was an hour of trembling hands, cursing, fiddling, and jabbing a hot iron at the little board to try and get the pin to stick and not be crooked. Each passable attempt ended in failure, resulting in a black screen (but accompanied by the TI's lovely startup chirp). These efforts were interspersed with periodic sanity checks with the original VDP which I would insert to verify that I had not inflicted fatal injury. This continued until finally a measure of success. Video, but not that which brings joy, but a hideous abomination that shrivels the soul. The system powered on, but showed a title screen that was corrupted. The colors were wrong, the characters were garbled. Further desperate action improved nothing: from garbled screen, to blank blue screen, to black screen, to F18A ready screen, to garbled screen; round and round till I resolved myself and admitted defeat. However, the drama still had one final cruel twist of fate. I placed another F18A order and replaced the original VDP. Only this time instead of the grainy title screen I was greeted by doom's horrible screech. Black screen, blaring tone. Panic. I tried replacing the F18A. Black screen, blaring tone. Re-seat all the socketed chips. Black screen, blaring tone. Swap power supplies. Black screen, blaring tone. To my shame it seems I have killed another patient. Now I confess my eyes have shifted to my last misshapen TI to perhaps harvest its organs to fuel my mad designs. One potential slight glimmer of growth, I have decided to err on the side of wisdom and solicit my betters, and prevail upon their wisdom to see if there is any way I may undo this horror, or at least advice that I may prevent another one. Well? What say you? TL;DR - I am an idiot. Due to botched install+repair I'm soliciting help/advice in fixing my TIs. Black screens, blaring tones.