Genesis Power Base Converter only reads Sega Cards

[Cmherndon79]

Recently got a console lot in, with everything advertised as "not working".  One of the items in that lot was a Sega Genesis Power Base Converter.  Thought it odd this wouldn't work at all, as the Genesis has the hardware built in for SMS support. 

 

Inspected the cart connectors and cleaned them, no issues there.  Installed the converter and tried Shinobi and I indeed got a black screen.  I know the cart works, as that lot also came with an SMS that i fixed by replacing the 7805 voltage regulator and used that cart to burn in the system after.  Tried reseating the cart multiple times, but no change in behavior.  Screen is always black when powered on.

 

Next, I removed the Shinobi cart and I tried a Sega Card, Spy vs. Spy, which I'd also just used on that SMS I repaired and it worked fine in the Power Base Converter. Removed the Sega Card and tried the cartridge a few more times, but always black screen.  So, it seems to be fine with a Sega Card, but not with a cartridge.

 

Opened it up and not a lot going on inside.  No visible damage.  Not much going on inside either, got a few electrolytic caps, that I haven't tried replacing yet and a Sega chip, 315-5342 that i can't find  much information about.

 

Anyone ever run across something like this?

 

Thanks!

 

Edit:

 

Other information:

 

This is a Model 1 non-TMSS Genesis the Power Base Converter was tested on.

Edited December 11, 2020 by Cmherndon79

[Cmherndon79]

Figured while I had the thing disassembled already, I'd go ahead and swap out the 2 47uF and 1uF electrolytic caps.  No change however.

[Cmherndon79]

More updates:

 

Cut one end of the diode and resistors and measured/tested those and they're in spec.  Soldered those back down.

 

Hit the SMS cart slot portion with WD40 contact cleaner, and then used a credit card wrapped in an old sheet to scrub the contacts.  Followed up with 99% isopropyl and the same CC and sheet.  Then installed a cartridge and removed 5 times.

 

No change.

 

Pulled out a few more cartridges to test.  I found that Outrun, Alien 3 and Space Harrier will boot at least 1/4 of time, some nearly every time.  Found the Alien Syndrome will never boot, just like Shinobi. 

 

Went back and did more extensive power testing on Spy vs. Spy on the Sega Card and I found that it also won't boot up perhaps one out of every 10 attempts. 

[BillyNY]

I recently got Shinobi and tried it in my Power Base Converter. I cleaned the contacts in the cartridge and it would boot up roughly 10% of the time. I got a replacement cartridge from the eBay seller. I had pretty much the same luck with that one too. I have 5 other Master System games and they boot up 100% of the time. Then I read in a forum that someone has the same problem with R-Type. He turns on the power with Power Base Converter in but no cartridge, then inserts cartridge straight in (try not to go in on a slant), presses Reset, and it works every time. So I tried that with Shinobi. It doesn’t work every time but it boots up a lot more often than before. I’m still trying to figure this out. I just got the replacement cartridge yesterday. 

[Om_Rom_Rom]

I had R-Type and found that it was the only game of 5 others I had (inc. Hang-On card version) that wouldn’t always work. I ended up selling R-Type, but more recently bought Shinobi in excellent condition and am having the same problem as I did with R-Type. 
 

Both Shinobi and R-Type are FM-enabled games. I believe, based on what some other people have said elsewhere online, that FM-based games seem to have problem booting up on the Master System Power Base Converter. Sometimes they work, sometimes they don’t.

 

I’ve found that if I play some games and then try them afterward they’re more likely to work. They also 100% work if I put them in the cartridge slot when the console is already powered on and then press reset, but I do not recommend that as it is not healthy for the console. 
 

Seems odd that the community hasn’t already got a definitive answer on this with full breakdown of issue, as so many people over the years would have had this combo of system / games. 

[zylon]

Bios issue with the Genesis, and a difference between that, and the SMS 1. Those two games in particular, us a byte from RAM to detect if card or cart being used, then looks for the FM use. Nothing in the Genny bios has that function, and sometimes, it temporarily disables the z80.

The file I linked, is one someone sent me some time ago, that patches this for R-type and updates the checksum. Supposedly, carts with the "Sega for the 90's" sticker, are far more likely to work, being the SMS 2 was the new model. The PB contains a small "boot rom", which may not always be working.

This post explains the little program on that IC. I don't have a file to have someone flash you one, but you've an idea where to look and ask now.

 https://web.archive.org/web/20190403192608/http://www.smspower.org/forums/14084-PowerBaseConverterInfo#73874R-Type-SMD-patch.ips

 

Another trick for some games, was to hold in the "pause" button while booting.

Edited July 17, 2023 by zylon