42 pin EPROMs

[GadgetUK]

I've got a cart with sound glitches which will need 1 or 2 replacement chips in the form of EPROMS. I've got a couple programmers but neither will accommodate 42 pin chips that it uses.

Does anyone know if EPROMs can be programmed in two passes? Say lower 256Kb with relevant address lines connected, then rewire MSB address line to do the upper 256Kb, or is there some internal state bit to dictate programming has already been done?

Assuming I can't find a way around the problem, would anyone in Europe mind programming one or two 42 pin chips for me - cost obviously?

 

[HeavyMachineGoob]

Are you sure that's 256Kilobits and not Kilobytes? If your ROMs are 4Mbit (256KB x2), couldn't you just get away with a 40pin EPROM and seat the chip one row of pins down from the socket's pin 1?

 

[GadgetUK]

Are you sure that's 256Kilobits and not Kilobytes? If your ROMs are 4Mbit (256KB x2), couldn't you just get away with a 40pin EPROM and seat the chip one row of pins down from the socket's pin 1?

The chips on board ATM are 42 pin. One is 1 megabyte (not bit) and the other is 2 megabyte. Or 512Kb (16 bit) and 1Mb (16 bit) depending on how you look at it. So, yes I need to use 42 pin chips =\

 

[bustedstr8]

You can use 40 pin eproms if you piggyback and tie a LS139 to all the /OE

 

[GadgetUK]

You can use 40 pin eproms if you piggyback and tie a LS139 to all the /OE

Not really sure how I would do that as there's no space really to piggy back so many chips.

There is enough room on the board to mount another 512Kb chip though, so if I am lucky the 1Mb chip is faulty and I can possibly split the 1Mb image over 2 chips.

If anyone can program 42 pin 1Mb and 2Mb chips please let me know. Dont mind paying for the EPROMs, postage and a little for doing the job for me.

The game is The King of the Monsters 2. It's definitely a V ROM issue. I need to work out which chip it is first. I should be able to dump current contents by feeding +5v / ground into the upper address lines whilst attached to programmer. That way I can do 2 dumps for the 1Mb and 4 dumps for the 2Mb and join the images then compare to emul working copy.

 

[shadowkn55]

It sounds like you really enjoy this kind of tech stuff. You should really invest in an eprom programmer that supports 42 pin eproms. You'll save yourself a lot of headaches and guess work.

 

[HeavyMachineGoob]

If you don't mind buying from china, you can buy an appropriate EPROM and have it programmed by this site:

www.buyicnow.com

 

[ne7]

Just get these, I've used mine to fix loads of busted carts -
http://www.ebay.co.uk/itm/MCUmall-C...in-adapter-4-willem-programmer-/310345927515?

http://www.ebay.co.uk/itm/MCUmall-C...ASH-PICECU-AVR-Chip-Programmer-/310531715847?

Totally worth it in the end and the programmer is miles cheaper now too (about 1/2 the price I paid!)

 

[Hitokiri]

I have the ADP-054 adapter and a Gq-4x proggramer, I could program the eproms for you, but I live in chile...

 

[GadgetUK]

If you don't mind buying from china, you can buy an appropriate EPROM and have it programmed by this site:

www.buyicnow.com

Wow, I didnt know they did that! I've used them before OK. I will use them for now, and then when i've been paid again at XMAS I will order what shadowkn55 has recommended. It's annoying i've spent a bit on 2 other programmers over the years not realising I would ever need anything more than 40 pins. The Willems looks good though.

EDIT: Just ordered buyicnow.com - $13 shipped for both programmed, can't be bad!

 

[mainman]

Read my words, buy a programmer that supports 42 pins natively.

 

[GadgetUK]

I have the ADP-054 adapter and a Gq-4x proggramer, I could program the eproms for you, but I live in chile...

Thanks for the offer =) I've sorted it now so no worries.

 

[GadgetUK]

Just get these, I've used mine to fix loads of busted carts -
http://www.ebay.co.uk/itm/MCUmall-C...in-adapter-4-willem-programmer-/310345927515?

http://www.ebay.co.uk/itm/MCUmall-C...ASH-PICECU-AVR-Chip-Programmer-/310531715847?

Totally worth it in the end and the programmer is miles cheaper now too (about 1/2 the price I paid!)

Thanks, this is what I will look to buy =)

It sounds like you really enjoy this kind of tech stuff. You should really invest in an eprom programmer that supports 42 pin eproms. You'll save yourself a lot of headaches and guess work.

Thanks, I will get one soon =)

 

[ne7]

if u get stuck along the way just bung me a PM \o_

 

[GadgetUK]

if u get stuck along the way just bung me a PM \o_

Thanks! I've already ordered from that website above, so will see how I get on - you never know they might not verify them, or give me chips that have failed the verify... Time will tell!

 

[GadgetUK]

Just an update... I fixed my King of Monsters 2 cart. Ended up replacing the 1Mb chip, and sticking with the original 2Mb chip that was already on there.

I did a video on the repair (link below). One thing I forgot to video which I did afterwards was to measure resistance between ground / vcc and each O (data / output) pin and I found a low resistance between vcc and the dodgy O pins. Interesting thing with this was that it wasnt a typical 'bit state change' type failure - must have been pull up resistor faults or something similar and one chip was affecting the other (seemingly).

Also worth noting - for people wanting to use buyicnow with pre-programmed chips, think twice. The 1Mb EPROM they sent me wasn't right, it had 3 bytes changed state from the original file I sent them. They have told me they've shipped out a replacement but they've been pretty 'sharp' in their email reply stating how much I 'might owe them' regards chip and postage if the replacement they send still shows invalid checksum.

It has put me off using them at all tbh. I had a few 68000 chips off them previously which i've yet to get working - suspected faulty. And even the 2Mb KOM2 chip they sent I think has at least 1 bad byte, or the chip is glitchy because occasionally I get one note on title intro not quite right. I will be replacing the 2Mb chip again, or at least verifying it / re-prog with my new Willems programmer.

Thanks for the sound advice on the Willems - it's great! A little slow but it's fantastic otherwise.

 

[HeavyMachineGoob]

Also worth noting - for people wanting to use buyicnow with pre-programmed chips, think twice. The 1Mb EPROM they sent me wasn't right, it had 3 bytes changed state from the original file I sent them. They have told me they've shipped out a replacement but they've been pretty 'sharp' in their email reply stating how much I 'might owe them' regards chip and postage if the replacement they send still shows invalid checksum.

It has put me off using them at all tbh. I had a few 68000 chips off them previously which i've yet to get working - suspected faulty. And even the 2Mb KOM2 chip they sent I think has at least 1 bad byte, or the chip is glitchy because occasionally I get one note on title intro not quite right. I will be replacing the 2Mb chip again, or at least verifying it / re-prog with my new Willems programmer.

Thanks for the sound advice on the Willems - it's great! A little slow but it's fantastic otherwise.

For a long time, BuyICNow has been pretty reliable (or at least, since 2012). As of late, myself and many others have reported issues with incorrect data. It's not that bad though, usually they send off good chips. If you have a problem, ask for replacements.