wiseman9986
Krauser's Shoe Shiner
- Joined
- Jan 18, 2003
- Posts
- 228
sorry but is there a list of everything i need to do all of these mods to my 138 in 1 i just dont want to forget to order something
Hang on a sec!!!! MagicKey is your problem! Noise filtered out of cart, passes into magic key, and new noise introduced! You might want to add 47pF caps to SDRMPX and SDPMPX lines coming out of the MagicKey.
Hang on a sec!!!! MagicKey is your problem! Noise filtered out of cart, passes into magic key, and new noise introduced! You might want to add 47pF caps to SDRMPX and SDPMPX lines coming out of the MagicKey.
Yes, well spotted - looks like 2 caps missing there - not sure if they are supposed to be bypass spots or what. If its working fine without them don't worry about it, if you want to tempt fate - try putting a 100nF cap into each of those 2 positions and see if anything changes. Chances are you won't notice a difference. When I get time I will follow the traces to see where they connect but it's probably VCC and GND. With regards to voltage drop, yes there is a small difference - especially when using a 2 amp PSU like I did. I see the same small voltage drop as you, from say 5.05 ish with a stock cart to 5.01v on a multicart. Some of the larger chip count carts or carts using encryption also draw more current from what I've seen, eg. KoF 2003.
EDIT: And thanks for the thanks lol =)
I've been using a PSU which outputs 5.3V under load and so far I had zero problems (been playing around for a week).
I've even left it on for 5-6 hours straight and didn't have any issue.
EDIT: I stand corrected. It's 5.3V with no cartridge inserted and 5.2V with the 161-in-1 in.
Thanks, I will report back once I get and add in the regulator. If there is anything else that can be done to the 161 I would be keen to give it a try. I had a look at the electrolytic capacitors and these seem fine IMHO in terms of quality etc. so don't think there is much value in recapping unless they screwed up the values of the caps.
Regarding voltage related issues I am using an arcade PSU (so probably like 15 amps available on the 5V line). While its good to be covered for amps (after all MV-1FZ technical manual states you need 7amps (!)) IMO a key advantage of an arcade PSU is that you can adjust the 5V line, which comes in handy especially if one is using a long or crappy quality jamma harness (high AWG wire). These result in quite a bit of resistance and in turn voltage drop which may mean that a standard 5V PSU may not be man enough to supply 5V by the time it reaches the PCB. I found that anything below 4.8 / 4.9 generally results in pretty unreliable operation - screen blacks out, random resets etc.
PS. just to say that with regard to the two missing caps, my solder pads didn't have any solder on them.