This order was for a PS1 Mayumi v4 modchip install and a Dual Frequency Oscillator mod. Customer provided an MFO from ConsolesUnleashed, and the Mayumi v4 modchip was provided by Topvint.
On reception and testing the console worked fine after cleaning the laser with a cotton bud and isopropyl alcohol (sign of lens not being clean). On disassembly, a few spots of rust were found. Also, an strange goo was found in the PCB and some of the screw holes. I cleaned the goo and removed the biggest spots of rust before carrying out the mod. The good didn’t seem corrosive or conductive.
The modchip installation went well with all the solder points clear from available instructions
For the MFO, ConsolesUnleashed has not available instructions online, but has instructions for DFO. I followed those instruction to remove one of the SMD resistors and to connect 3.3v, GND, S0 and CLk1. However, this being an MFO, there is a second Clock for the video subcarrier but it isn’t clear where to solder the point to
I tested the console with PAL, NTSC and homebrew burnt discs and all seems fine, both with RGB (SCART cable) and composite. My TV accepts both 50hz and 60hz. I didn’t see any issues with colour on composite, but this might be because my TV accepts multiple region. I also gave the console a wipe with a microfiber cloth and some UV protection 303 liquid.
UPDATE: Consoles Unleashed replied and said:
You will need to look at IC502.
See if Pin 15 IC502 is connected to a 22K resistor which itself is connected to the clock generator Pin 6 IC204.
Trace out the connections and confirm all this.
If it looks correct then the 22K resistor going to Pin 15 IC502 will need removing. Then connect CLK2 pad of the MFO into Pin15 IC502.
Pin 13 IC502 should be the switch just like Pin 157 IC203. S0 of the MFO will control both of these. Maybe Pin 13 IC502 is already connected to Pin 157 IC203. You will need to trace these and make sure.
So I traced back the pins and removed the resistor (2.2K rather than 22K), and connected Clk2 to Pin 15 of IC502. I also confirmed that Pin 157 from IC203 is indeed connected to Pin 13 of IC502. I made the connection and tested the console with the japanese version of Silent Hill using composite. All seems to be working fine:
