Since the retrofixes INTV RGB is out of stock, if I were to build the one with the 2 ICs SN74AC32 and 74HCT244N,
do you recommend 1/4W 5% resistors, or is there a benefit of higher W and/or 1% tolerance?
As far as I can tell, the Retrofixes mod is not out of stock : https://store.retrof...kit-coming-soon
I wondered too about the tolerance of the resistors but doubt it has much impact. The mod from Turkey uses 5% while Retrofixes uses 2%.
What I find more interesting is the resistance values these mods are using. Looking at the photos of the resistors on the boards (eBay retro_mood, retrofixes.com and eBay v3*mod) I have done my best to tabulate the resistance values chosen and compared them to what Joe Zbiciak (Intellivision Wiki) recommends.
The standouts for me are that the Retrofixes mod doesn't use a 51K resistor. The value is a hard to tell from the photo but as far as I can tell it is nowhere near 51K. Could this be what causes some to have oversaturated colours and jail bars I wonder?
Secondly, both RetroMood and Retrofixes use differing resistances instead of the 22Ω resistor. Joe does state in his design that some people may experience colour shift near the top of the image and that tweaking the 22Ω resistor higher has been found to alleviate the problem (via a potentiometer). So, my guess is that in their testing the 47Ω and 27Ω worked best for them with their particular test setups. BUT, based on Joe's statement, wouldn't it be best to replace the 22Ω resistor in these boards with a potentiometer so that images can be optimised after the install.
The variations around the 660Ω resistor are within tolerance and are likely to have negligible effect on the output image.
What I would love to see is a board design that includes a potentiometer instead of the 22Ω resistor AND a place to install an optional 2000µF capacitor between +5V and GND which has been reported as helping solve smearing of bright areas. Anyone?
Edited by Ikrananka, Wed Aug 22, 2018 9:48 AM.