- Thread starter Yakkers
- Start date
They do
Thanks so much for the analysis, it's nice to know exactly what's going wrong. So, what would I need to do to fix this? Which chip is the text ROM? Would I need to just rerun a jumper wire from elsewhere where they used a resistor, or would I need to order a resistor and add it to the system?
Yeah, I'm considering just returning it as not working and picking up a better made cart. I probably don't want to risk screwing with a crappy conversion and ending up with something that's flakey and also can't be returned anymore.
Who was the eBay seller? Probably worth naming and shaming here so nobody else buys one and gets that level of craftsmanship.
It's a sheep nova cart, yeah. I'm not really interested in shaming though, the seller is sending me another cart and it seems like they might not even want this one back (probably not worth the return shipping) which I would be very grateful for. If I can get it working maybe I'll pick up the stuff to flash Ketsui onto it or something.
I didn't know there were so many types and makers of conversion carts out there, I kind of assumed nobody knew who made any of them and they were all old ones floating around so I never thought twice about just picking up whatever's cheapest on ebay.
Nope.
Like I said in my post. My carts were made by @oneleaf86 when he was active.
And thus as I was originally pointing out. Not all conversions are of the same quality or workmanship.
And finally given the amount of @sheep_nova carts out there running in the wild with no issues, I’ll let y’all make up your mind on that.
sheep_nova
Grand Master
I'll send the replacement to u today.
Thanks!
Thanks!
There are two issues here: Power supply to the chips, and I/O levels. Power supply is relatively easy, you can use a voltage regulator to produce 3.3V from 5V. The tricky bit is I/O: As far as I understand reading signals output by a 3.3V system is no issue on a 5V system (TTL considers everything over 2V "high"), but a "high" produced by the 5V system is over the limit of the 3.3V system. That MAY work fine, or break after a while.
You can use voltage level shifters, and some official boards actually use them.
As for the tile ROM, it is on the same board as the program ROM and ASIC. The program ROM is a socketed EPROM on the boards I've seen (I guess to allow field updates), the tile ROM is a surface mount chip.
Edit, as an example here is IGS PCB-0468-02 GT-A. Sorry, I noticed some small typos, it was late. Unfortunately I lost some source files in an SSD failure, so I can't easily fix them.
You can use voltage level shifters, and some official boards actually use them.
As for the tile ROM, it is on the same board as the program ROM and ASIC. The program ROM is a socketed EPROM on the boards I've seen (I guess to allow field updates), the tile ROM is a surface mount chip.
Edit, as an example here is IGS PCB-0468-02 GT-A. Sorry, I noticed some small typos, it was late. Unfortunately I lost some source files in an SSD failure, so I can't easily fix them.
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sheep_nova carts are decent, and he's always been willing to refund or ship me a replacement when I've had any issues with any PGM carts from him (I've had no issues with any of the three conversions I bought from him).
