[dfwarden]

Thanks, Aether. It helps to hear that someone else struggled, too. It appears my choice has been made easier by the fact that there are no more DIY boards available 🙂

I am lucky in that I was able to get an assembled board from the waiting list as an insurance policy in case my DIY efforts failed. I had hoped that my DIY success would mean that assembled board could be sold at cost to someone, but no such luck.

Perhaps I’ll try again someday if the DIY boards come back in stock. This time I’ll know to build the power lines/regulators first and test all of them before adding the ICs.

[dfwarden]

Like an idiot, I ripped up a bunch of FPGA pads as I was cutting off the FPGA legs. Too much lateral pressure, should’ve pushed straight down. Debating if I should order DIY board #3 or just accept the premade board. I really wanted to be able to say that I built this kit.

[dfwarden]

This story has gotten very strange. After cleaning the board with alcohol and testing various points for connectivity, the board suddenly started working long enough for me to flash 0.74 with a USB Blaster. I started to add the remaining connectors (re-testing after each one) and after adding the audio the board no longer booted.

I tried putting U14 from the old board on U12 of the new board and with the output legs raised I still read about 1.35v. I even tried putting U14 from the new board on U12 and got the same result, which surprised me because U14 on the new board works fine. The only explanation I can think of is that the FPGA is now so damaged that something about it caused the a working regulator to fail even with the output legs raised.

At this point I don’t have any other ideas but to accept your diagnosis of bad TLV70012s from Mouser US and probably busted FPGA. Is there a way to tell for sure if the FPGA is gone?

Do you have any advice on making sure the replacement U12 is working correctly? If I only connect the 3 input pins, should I read 1.2v? Should the presence of the FPGA, regardless of if the U12 output pins are connected, affect the output of U12?

[dfwarden]

My equipment is probably not as good as yours. I’ve got a decent iron (Hakko fx-888) with a fine tip for the SMD bits but I haven’t had great success with my MG Chemicals wick or SRA #80 flux pen. Perhaps I just need to improve my technique – I’m going to try to give your wick advice a try. Probably the weakest link in my chain is I only have up to 4x magnification, and even through that lens you can only on a small area.

This project also motivated me to improve my equipment. I worked my way through various console RGB mods with an entry level iron and no magnification, lighting, or flux. What a difference having decent gear makes!

[dfwarden]

Apologies for the late reply… I did figure out that I had a bridge somewhere in the left row of pins on the TVP7002 (presuming the LCD side is “top”). I more or less destroyed all 3 chips tracking that down since I don’t have a clean way of removing them. (I might need to bite the bullet and invest in hot air.)

I got a fresh board and my second attempt was better in that all the voltage regulators are connected correctly and outputting the correct voltage, but I must have a problem somewhere else because the LEDs don’t turn on and the LCD backlight is very dim. I saw marqs gave some good suggestions on “LIGHTS ARE ON, BUT NOBODY’S HOME” that I am going to investigate before I start a new topic asking for help.

[dfwarden]

I also took the plunge on the DIY kits. I have slightly more soldering experience having also done the NESRGB mod, but certainly not with such small SMD components.

Out of curiosity, did you know about https://www.niksula.hut.fi/~mhiienka/ossc/diy-v1.5/assembly_tips.txt? I’ve found his recommendation for 300C and connecting opposite legs on the ICs first (to achieve good alignment) before drag soldering the other 2 rows to be excellent advice. I also struggled to remove solder from IC pins and my side to side motion resulted in more than one bent pin that was tedious to fix. I found it was easier to control the flow of solder to the legs by using a very fine tip and only putting enough solder on the tip to go a 4-6 pins at a time. Maybe with more practice I could have used a larger tip and done the whole row in one drag like he recommends.

I was able to get the board fully assembled, but discovered that all but one of my voltage regulators have a pin with an incorrect connection to ground. Hopefully I just have a small bridge on the ICs that needs to be cleaned up as I’m still very new to the art of diagnosing malfunctioning circuits.

Best of luck with your second attempt.

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