ToToTEK.COM Forum Index ToToTEK.COM
Help & Support Forum
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Corrupted graphics in Terranigma
Goto page Previous  1, 2
 
Post new topic   Reply to topic    ToToTEK.COM Forum Index -> Copiers and Hardware
View previous topic :: View next topic  
Author Message
ackman



Joined: 01 Mar 2019
Posts: 35

PostPosted: Wed Sep 14, 2022 12:13 am    Post subject: Reply with quote

Hi back,

I tested the memory chips with the multimeter in test/continuity mode looking for shorts connecting the red probe to ground and testing all the legs.

Please, help me out here.. Here are the datasheets of the chips I’m using:

Factory chips https://datasheet.datasheetarchive.com/originals/scans/Scans-95/DSAIHSC00039854.pdf

Extra chips I soldered https://datasheet.datasheetarchive.com/originals/scans/Scans-95/DSAIHSC00039881.pdf

All the measurements are on the same range except for pins 7 (write enable) and 22 (output enable). On the chips I soldered, I got a value of 686 for those pins, whereas the factory chips read 1777-1800.

The chips are almost identical. The only difference is the power consumption in sleep mode, being lower in the factory chips (hence the L in their model number).

Could this mean I have a short on those pins of the extra chips? They are brand new, and I get identical readings on both of them..

Thanks
Back to top
View user's profile Send private message
Mystic_Merlin



Joined: 15 Oct 2007
Posts: 496
Location: Bangkok

PostPosted: Wed Sep 14, 2022 10:51 am    Post subject: Reply with quote

This ram board can accommodate 512x8bit or 1Mx4bit DRAM, this is why you have these pads on the side to choose between both configurations.

Now, the manufacturing of these boards are not the best and you already lifted some pads so I wouldn't recommend too much experimenting either prior to tracing and documenting everything.
Ideally you would want to test with a different ram board, maybe from a Pro Fighter as this one came with some of them and are much more common.

Until then I would suggest testing loads of different games starting from 4M, then 8M, and up see how often it crashes. Also check if one IC gets hotter after some time.
Then you mentioned your unit is PAL. Not sure how compatible DPF are with PAL systems but testing on a japanese SFC could also provide some information.



RAMBoardTop.jpg
 Description:
 Filesize:  167.28 KB
 Viewed:  4326 Time(s)

RAMBoardTop.jpg



RAMBoardBottom.jpg
 Description:
 Filesize:  132.3 KB
 Viewed:  4326 Time(s)

RAMBoardBottom.jpg


Back to top
View user's profile Send private message
ackman



Joined: 01 Mar 2019
Posts: 35

PostPosted: Wed Sep 14, 2022 11:24 am    Post subject: Reply with quote

Mystic_Merlin wrote:
This ram board can accommodate 512x8bit or 1Mx4bit DRAM, this is why you have these pads on the side to choose between both configurations.

Now, the manufacturing of these boards are not the best and you already lifted some pads so I wouldn't recommend too much experimenting either prior to tracing and documenting everything.
Ideally you would want to test with a different ram board, maybe from a Pro Fighter as this one came with some of them and are much more common.

Until then I would suggest testing loads of different games starting from 4M, then 8M, and up see how often it crashes. Also check if one IC gets hotter after some time.
Then you mentioned your unit is PAL. Not sure how compatible DPF are with PAL systems but testing on a japanese SFC could also provide some information.


Thanks for stepping in, Mystic_Merlin.

The DPF is pal (because of the SuperCic I guess). I’m actually trying everything with a Super Famicom, overriding the SuperCic by putting a Japanese cart on top (if not, screen remains black when powering on).

I don’t have any way of getting another memory board to test.

The measurements I took last night (posted above) make me think I got faulty chips from eBay when I bought them (those legs should have similar readings to the factory chips). Important question: Am I wrong in this assumption?

I’m ruling out bad soldering because the very same legs are failing on the “new chips”.

If I’m right in my assumption, I’m thinking on getting two of these cheap replacements https://www.ebay.es/itm/151313013686

Datasheet: https://bg-electronics.de/datenblaetter/Schaltkreise/KM48C512BJ6.pdf

As you can see in the datasheet, they don’t have the same ns speed as the originals (10ns difference). Is this relevant? Or should I buy again the same ones from NEC?

Thanks
Back to top
View user's profile Send private message
MottZilla



Joined: 08 Sep 2004
Posts: 765

PostPosted: Thu Sep 15, 2022 3:08 am    Post subject: Reply with quote

Mystic_Merlin, you photos are of a regular 40 pin Pro Fighter memory board correct? DPF memory boards are 50 pins I believe. I had an issue with my DPF when I first got it where it had a memory board for the regular Pro Fighter in it and while SNES stuff seemed to work ok, Genesis did not. After I got a 50 pin board it all worked fine.

When I get the chance I might trace out my board to have a schematic. Unless someone has already done it.
Back to top
View user's profile Send private message
Mystic_Merlin



Joined: 15 Oct 2007
Posts: 496
Location: Bangkok

PostPosted: Thu Sep 15, 2022 10:15 am    Post subject: Reply with quote

MottZilla wrote:
Mystic_Merlin, you photos are of a regular 40 pin Pro Fighter memory board correct? DPF memory boards are 50 pins I believe. I had an issue with my DPF when I first got it where it had a memory board for the regular Pro Fighter in it and while SNES stuff seemed to work ok, Genesis did not. After I got a 50 pin board it all worked fine.

When I get the chance I might trace out my board to have a schematic. Unless someone has already done it.


Indeed, I know it's odd but I recall some DPF had a regular PF mem board. Thanks for confirming it's at least working on the SNES side. I would bet the pinout on the 8x(1Mx4bit) pads on the DPF mem board matches one of a PF mem board.
Some PF ram boards used 8bit ICs in conjunction with 74HC138 and the DPF has 2x74HC139 next to the 50 pins ram slot to accommodate different ram configurations.
Back to top
View user's profile Send private message
ackman



Joined: 01 Mar 2019
Posts: 35

PostPosted: Thu Sep 15, 2022 5:45 pm    Post subject: Reply with quote

MottZilla wrote:
Mystic_Merlin, you photos are of a regular 40 pin Pro Fighter memory board correct? DPF memory boards are 50 pins I believe. I had an issue with my DPF when I first got it where it had a memory board for the regular Pro Fighter in it and while SNES stuff seemed to work ok, Genesis did not. After I got a 50 pin board it all worked fine.

When I get the chance I might trace out my board to have a schematic. Unless someone has already done it.


If you get the chance to get your board out of storage, you couls measure pins 7 and 22 (output enable) on all the chips to check if you get the same readings in all of them.

So far, 4, 8, 12, 16 Mb roms run ok on both systems. 24 Mb just ok on Super Famicom. None of the chips is overheated.

Regarding the chips I posted above: do you think they will work together with the ones the copier came with?

On another note to Mottzilla: I ran the Genesis DPF memory tests that you got from here https://gendev.spritesmind.net/forum/viewtopic.php?f=2&t=690&sid=8ce153b3fec9d11aacc446279c32eafa and they pass, but the copier still fails with Super Famicom 32Mb and Genesis 24Mb roms.

Thanks for the help
Back to top
View user's profile Send private message
MottZilla



Joined: 08 Sep 2004
Posts: 765

PostPosted: Sun Sep 18, 2022 2:04 am    Post subject: Reply with quote

It was over 10 years ago, but it seems I expanded Gunstar Heroes to 32 megabits, filled the extra ROM with data from UMK3, and fixed the checksum to perform a 32 megabit check. There may be some existing 24M and 32M games that actually have a checksum test, I just can't say for sure without examining them.

It will probably be atleast a month, maybe two, before I can look at my DPF unfortunately. But if I remember or am reminded I will. When you say measure those pins, measure what exactly?

If we're lucky maybe we can design a new RAM board.
Back to top
View user's profile Send private message
ackman



Joined: 01 Mar 2019
Posts: 35

PostPosted: Sun Sep 18, 2022 9:27 pm    Post subject: Reply with quote

MottZilla wrote:
It was over 10 years ago, but it seems I expanded Gunstar Heroes to 32 megabits, filled the extra ROM with data from UMK3, and fixed the checksum to perform a 32 megabit check. There may be some existing 24M and 32M games that actually have a checksum test, I just can't say for sure without examining them.

It will probably be atleast a month, maybe two, before I can look at my DPF unfortunately. But if I remember or am reminded I will. When you say measure those pins, measure what exactly?

If we're lucky maybe we can design a new RAM board.

With the multimeter in test mode (continuity/diode), connect the red probe to ground leg of the chip and the black probe to the pins to measure. This will give you a read in the multimeter, which is very low on the chips I soldered compared to the factory chips.

I wish we can design a new ram board!
Back to top
View user's profile Send private message
MottZilla



Joined: 08 Sep 2004
Posts: 765

PostPosted: Mon Sep 19, 2022 10:00 pm    Post subject: Reply with quote

There shouldn't be anything stopping someone from making their own new RAM board. It could use DRAM, PSRAM, or SRAM. All that really matters is that the rest of the machine can read and write to memory as intended.

But atleast then you could use some newly manufactured memory instead of relying on decades old memory chips.
Back to top
View user's profile Send private message
ackman



Joined: 01 Mar 2019
Posts: 35

PostPosted: Thu Dec 15, 2022 10:47 pm    Post subject: Reply with quote

MottZilla wrote:
It was over 10 years ago, but it seems I expanded Gunstar Heroes to 32 megabits, filled the extra ROM with data from UMK3, and fixed the checksum to perform a 32 megabit check. There may be some existing 24M and 32M games that actually have a checksum test, I just can't say for sure without examining them.

It will probably be atleast a month, maybe two, before I can look at my DPF unfortunately. But if I remember or am reminded I will. When you say measure those pins, measure what exactly?

If we're lucky maybe we can design a new RAM board.

Mottzilla, Could you take a look to your DPF memory board?
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    ToToTEK.COM Forum Index -> Copiers and Hardware All times are GMT
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group