Comments

 

• 

  Juan Miguel
  November 28th, 2023 at 7:08 PM

  Reply

  Could you provide the diagram for the 27C64 adapter?

• 

  Jani
  November 28th, 2023 at 7:20 PM

  Reply

  Hi,
  2764 and 27C64 has same pinout, the latter is CMOS which draws less power.
  Regards
  Jani

Pablo Sufan

December 15th, 2018 at 5:49 PM

Reply

Genial, lo probaré en el atari.

cliff ruszin

December 22nd, 2018 at 5:36 AM

Reply

hi .i hope yocan help me .i have an 85 bmw 325e 2.7 5-sspeed ..i have an eprom problem …24 pin needs to be installed on a 28 pin socket …can you help mey

• 

  Jani
  December 29th, 2018 at 3:00 PM

  Reply

  Hi Cliff,
  I don’t have any experience in chiptuning(?) cars, I would recommend you to check for any BMW related forums.
  Drive safely 🙂
  Regards
  Jani

Jesper

February 17th, 2020 at 6:28 AM

Reply

Hi Jani,

Love your site! 🙂

I just started soldering and try learning to read schematics etc. to be able to bring back life to 2 dead C64’s.

1) I have seen a few sites where these adapters don’t have the 4.7k resistor but most sites do have the resistor in their schematics. Why do we need it?

2) if I have a bunch of 27128’s and don’t care to switch between two kernals – is it possible then to just leave out the switch?

Kind regards
Jesper

• 

  Jani
  February 17th, 2020 at 10:05 AM

  Reply

  Hi and thanks 🙂
  1) The resistor ensures the state of a signal. I recommend to google for “pull up resitor” and “pull down resistor” for more detailed information.
  2) You can use a 27128 and fill the eprom twice (64K+64K) and it doesnt matter which bank it starts in. However, good practise is forcing either bank (low is easier, no resistor needed), otherwise you may have the signal floating. With that said, you need to burn only one of the 64K banks, just make sure you know which one you choose to hardwire :).

  Short and simple answer: Fill up the eprom twice, and use the 2364 to 2764 adapter schematic instead :).

  Good luck with your repairs !

Ruudi

April 4th, 2021 at 2:57 AM

Reply

Hi Jani,

really a very good and interesting site!

One remark: the 2364 Adapters shown above will only work inside C64, but not with some earlier CBM computers, as MOS aka CSG built several different versions of 2364 (and earlier 2332..) ROMs, using different Chip select polarities and even sometimes more than one CS pin (like some other MOS chips like 6522 also does…)

So maybe you should include a short warning that these adapters are only for the kind of 2364 used in C64 machines with negative active /CS logic 2364 derivates.

best regards,

*Ruudi*

• 

  Jani
  April 5th, 2021 at 4:56 PM

  Reply

  Good point, thanks for the information. Clarified information about that 🙂