Roland tr-505 EPROM programming question

Gnizi · July 20, 2011, 01:03:10 AM

Greetings,
I'm wanting to switch out my EPROM from my circuit bent 505 and need help...
I have a 505 with switchable EPROM (currently I have 2 chips, original 505 and one with custom sounds) made by an aquaintance in japan. There is an apparatus on the 505 with a lever that sets and releases the chip.

Now I'm aware I need a EPROM programmer, EPROM chips and a computer. But am totally lost at this point....
Can anyone help me?
Any help is greatly appreciated.
Thank you!

Circuitbenders · July 20, 2011, 01:27:23 AM

whats the code on the custom sound EPROM?

Gnizi · July 20, 2011, 07:21:47 AM

Thanks for replying cicuitbender

The code says:

JAPAN 9730
0017EE0
PGM 3.5V
HN27C301AGI-15
.....

Circuitbenders · July 20, 2011, 11:10:07 AM

You're looking for a 27C301, any numbers before or after that aren't relevant. They are obsolete but you can still buy them from ebay secondhand. The 27C1000 seems to be identical.

http://www.ebay.co.uk/itm/160618159397 for 10, which is mysteriously roughly the same price as getting one or two.

Annoyingly this EPROM doesn't seem to be supported by the standard Willem Programmer, which is what i'd use for burning just about everything similar. I might be wrong about this so it'd probably be a good idea to check it out, but the 27C1000 or 27C301 don't seem to appear on any supported device list for the Willem that i can see.

This seems to support the 27C301 but its getting a bit pricey http://www.ebay.co.uk/itm/160554620185

I guess what you'd have to do is read one of the EPROM's you have and work out exactly what format it is. Then load the file into an audio editing program and create a new file with exactly the same layout and file characteristics, but with different sounds. Then try to burn a new EPROM with that file.

Alternatively you could get an Akai S20 for about £60 which you could load any sound into easily and which produces better sounds than the TR505 when bent anyway!

Gnizi · July 21, 2011, 11:58:37 PM

interesting

Thank you.
I think I will pick up these chips:
http://www.ebay.co.uk/itm/10-pcs-Hitachi-27C301-HN27C301-UV-EPROM-HN27C301AG-1M-/270785953912?pt=LH_DefaultDomain_0&hash=item3f0c19c078#ht_500wt_1156

seems to match the criteria above.

also that writer is costly....i will keep researching and see if i can find something more affordable.
taking the akai bending concept sounds divine, but i need to learn more on circuit bending...quite frankly i dont even know where to begin to start circuit bending. its basically a primordial version of the mpc right?
thanks so much for helping me with this, man. i goto buy the equipment first and follow your instructions, i think i might have problems with writing the new sounds on the chip...but will report back to you with progress if you dont mind..
thanks again!
peace

Gnizi · July 22, 2011, 06:21:03 AM

i emailed the seller on ebay asking whether it would be compatible and this is what he said
"It seems that 27C301 is compatible with 27C1001, so you can replace yours with 27c1001 which is supported. Regards, Ken"

hopefully he's being honest but idk...
the price difference between the two you suggested is around $10.00. i already purchased 10qty of 27c301s so i think i might just purchase the top853.
btw i cant seem to find 27c301 on the top853 ebay listing...are they abbreviated? and are the 27c1000s, and 27c1001s supported on the top853 programmer?
sorry if im asking alot of questions but i appreciate the help.
thanks agian!

Circuitbenders · July 22, 2011, 11:22:27 AM

The 27c301 is definately on the listing fior that programmer as being supported, except its down as HN27C301,P27 in the EPROM-HITAVHI section, which i assume is meant to be HITACHI.

I think the 27C1000 is different to the 27C1001. Both are supported by that programmer though.
Having said that, you could be entering a nightmare world here:
http://www.neo-geo.com/forums/showthread.php?177628-Source-for-27C1000-or-alternative&s=28736add9525db6783d482307e3a984d

I'd stick with the 27C301 and hope for the best.

Gordonjcp · July 24, 2011, 08:13:45 PM

IIRC the chip used in the TR-505 has a funny pin layout, but I can't remember exactly what the difference is. I bought a 505 specifically to do a ROM swap over two years ago and still haven't even started it ;-)