Hello all, I have been using my GQ-4X to program 27C801 chips and just recently got a batch of 27C128 and 2764 chips. The 27C128 seem to program just fine, but the 2764 doesn't. The chip is actually labeled "M2764A2F1" and my GQ-4X has a couple options. When I set it to 2764 is tells me to "apply external power" which I take to mean attach an ac adapter. I decided to ignore it and program anyway(just to experiment) and it seemed to work. But when i put the game in my nes I just get a gray screen. When I set it to "M2764A" and try to program I get this error: "Write failed, Address=0x000000, Buffer=0x38 Device=0xFF" The chip says "PGM 12.V", so I plugged in my 12v adapter and still got the same error. Do I need to get exactly a 12.5V adapter? Thanks so much for any help. - John
GQ-4X is takes a 9V adapter that is centre positive 200mA or more - at least that's what my one says. Just to rule out the basics, you blank checked the chips before flashing right? I remember a while back @Bad_Ad84 helped me with my GQ-4X. He's a wizard at these things - if he's about I'm sure he'll advise!
http://assemblergames.com/l/threads/help-with-eprom-programmer.56820/page-2#post-816009 But yes, check polarity of the adapter, also check it actually works (got a multimeter?) It certainly sounds like the device is blank, but its not programming it - likely due to missing programming voltage.
Ok, so I'm going to go get a 12.5v adapter today. Can I go higher than that, or will that harm my programmer? Also, should I be setting it for the 2764 or the M2764A?
Update: I plugged a 15v adapter in the gq-4x and still no luck. I try selecting 2764 and it says it programmed TV chip, in fact, I read it and it had the right file. I selected the M2764A and it still won't program, the chip is still blank. Also. I'm using golf as my donor, if that helps at all.
The power supply is 9v, not 12v. The higher programming voltages are generated internally with a dc-dc boost converter (steps up voltage). M2764A is the right one, setting it to 2764 is likely a generic algorithm. Are you saying it writes correctly with 2764? if so, just use that. But as per my comment in your previous thread - algorithm issues are fairly common with the GQ-4X and support is pretty slow to fix them.
Yeah, it seems to write correctly with the 2764, I can't get the M2764A to write at all. So why do I keep getting the gray screen? I'm using dip sockets to test these, maybe that's why? Should I just solder them directly to the board?
THE BOARD WAS BACKWARDS!!!! I feel so stupid, and rightfully so. I have been using a bare nes test board in a top loader. The snes repros I made have the chips face the back of the console, I figured the same for nes. So I got it working. Thank you guys so much for the help but you can't cure stupid.
