(Topic ID: 243679)

burning questions about EPROMs


By oilspot

9 months ago



Topic Stats

  • 38 posts
  • 8 Pinsiders participating
  • Latest reply 9 months ago by Quench
  • Topic is favorited by 3 Pinsiders

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#1 9 months ago

Let me start by saying that I'm a novice at board work having repaired the MPU in my Gameplan machine and replaced a few components and connectors in a Williams Sys 6. I'm more of a parts changer than technician.
I came into a eprom eraser and burner awhile back complete with a laptop and software to run it. BPM BP1200 programmer running BPWin software. I'm attempting to fix an EBDLE that had the wrong mpu (out of "Hot Dogging") .the mpu had the original 9316 masked rooms and booted but obviously wouldn't work right. So I rejumpered the board for 2732s and downloaded ROM images from ActionPinball, erased my chips, verified they were blank, burned the files onto the 2732s, verified the chip contents matched the buffer and installed the chips and the board and... Nothing. Just one flicker on power up. I've combed over my jumper work and checked it against a couple different sources and it matches up.(and my solder work looks better too) I'be pulled the EPROMs and read them, verifying they match the downloaded file inthe buffer. I burned a second set of EPROMs. Is there a variable in setting up the burner software I'm missing ? If the file on the chip matches the file I downloaded it should work, no? My next step iss to order a ROM set and plug them in to see if it's in the programming or in my board jumpers. I may read the new chips when they come in just to see if they match what I've already done. Ideas?

#2 9 months ago

The BP1200 might be an old programmer but it is a great programmer. Old 2716, 2532 Eproms needing 25V programming voltage; it is no problem for the noisy BP1200. It even is capable of programming the old bipolar proms for the first Bally sound boards for example. We had a few BP1200 here also at work, they are retired now but still hanging here as a back up.

A few things run into my mind what might went wrong.

-be sure to load the files as a binary. Normally, BPwin will recognize the file as a binary. If you want to be sure rename your files as U2.BIN and U6.BIN
-are you using rebranded China Eproms? Or using "originals"?
-your files are corrupted….try another set from another game or source (IPDB.ORG)
-there is an error in the rejumpering of the board. Be sure you removed E13-E15 and E36 next to U2 for example.

#3 9 months ago

Thanks for your response! I'm using old NEC "D2732D" Eproms I got in a bunch of stuff with the burner. Since I couldn't find that exact pn in the dropdown list I tried them as NEC 2732 .there were two choices, I think I picked the first. Then I tries another set as generic 2732 25v. Both verify against the buffer. The files show up in the buffer as .bin files and look like what I'd expect to see when I view contents in edit tab.

#4 9 months ago

when I use a 2732 for a system 6, it is just for one IC. The other two still remain 2716's (the flipper roms). Are you trying to use a 2732 for all three? A little confused at what you are trying to do.

#5 9 months ago

Tip of the hat for the clever thread title.

#6 9 months ago

I'm working on Bally EBDLE with a as-2518-35 mpu.. Replaced three original masked roms with two 2732 eproms

#7 9 months ago

Might be worth posting a clear picture of the MPU board so we can double check your jumper settings.
In any case, this is how I do it for 2732 EPROMs - sorry it doesn't mention what jumpers to remove:

BY-35_After.jpg

#8 9 months ago

NEC2732 (uPD2732D) are fine. They need 25V programing voltage indeed. As long as you choose uPD2732 (or D2732) you are fine. Things go wrong when selecting upD2732A as they are suited for a lower programming voltage - you will probably ruin them in this case.

Check your (jumper) work at your board. It is pretty easy to ruin a trace from pads E1, E2, E4, E6 for example when removing the old jumpers. Maybe you missed a jumper that should be removed.

You can also try another set binaries from another game or another source....

#9 9 months ago

Here's the board....

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#10 9 months ago

A better view of the jumpers left of U2

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#11 9 months ago

U6....

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#12 9 months ago

Ooh my soldering job isn't as pretty as I'd thought under magnification!

#13 9 months ago

What happened with E2 - E6? Is there a short between E2 and the trace in between?

#14 9 months ago

I clipped e2-e6 as per the jumper chart on action pinball.i do see that the chart I followed has e12 going to ground while yours shows to e9. Is e9 also a ground?

#15 9 months ago

I followed the pics on flipperwinkel.nl for jumpering and cross checked it at Actionpinball.

#16 9 months ago
Quoted from oilspot:

I followed has e12 going to ground while yours shows to e9. Is e9 also a ground?

No, E9 is address line A11. I prefer it this way so U2 goes into standby when it's not being accessed. It's also the preferred method on the official PPS site:
http://www.planetarypinball.com/mm5/Williams/tech/bally_read1st.txt

Also, it looks like the through hole at E19 is damaged. Install a wire in the hole and solder the wire on both sides (front and back of the board).

#17 9 months ago

Wow if e19 connects traces on the front and back of the board I think that's it! Going to heat up the iron...

#18 9 months ago
Quoted from Quench:

No. E9 is address line A11. I prefer it this way so U2 goes into standby when it's not being accessed. It's also the preferred method on the official PPS site:
http://www.planetarypinball.com/mm5/Williams/tech/bally_read1st.txt
Also, it looks like the through hole at E19 is damaged. Install a wire in the hole and solder both sides (front and back of the board).

Quench - Interesting on the E12-E9 - I have always just taken it to ground. Noted

#19 9 months ago
Quoted from crazi:

Quench - Interesting on the E12-E9 - I have always just taken it to ground. Noted

I also think it looks neater jumpering E12 to E9. Be sure to use insulated wire though as per my pic in post #7, otherwise using a bare wire jumper comes close to E10.

#20 9 months ago

Switched e12 from gnd to e9, fixed via at e19. Still no boot. Switches in my other pair of roms and still nothing.

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#21 9 months ago

I'll come back to it in a see hours with fresh eyes and look it over some more thanks for a wealth of good information to go on. I know we fixed at least one problem that would have prevented it from booting no matter what chips were in it.

#22 9 months ago

The initial LED flicker on powerup says the board is seeing U6 (parts of) whose initial boot code tells the CPU to switch the LED off. After that point it is failing the ROM checksum test. Might be time to pull out a logic probe and cast your attention at U2.

As Maralb mentioned, download the ROM code from IPDB or PPS incase the ones you got are not faithful.

Hard to tell but there's a small blob on E10 that might be touching your E9 connection:

Jumper_E10a.jpg

#23 9 months ago

I'll give that a try and give the board a detailed inspection tonight. Not quite ready to throw in the towel and buy an mpu board yet!

#24 9 months ago
Quoted from oilspot:

Not quite ready to throw in the towel and buy an mpu board yet!

If the board was working and doesn't have (much) battery corrosion to deal with then there should be no reason it can't be revived.

#25 9 months ago

Just went over the board carefully rechecked all my jumper connections and disconnections and affected thru hole connections, tested across each jumper with my ohm meter to verify the connection. Re burned the roms from ipdb download. Verified good using bpwin. The board is good, the roms are good, it booted before I messed with it, I'm nearing my wits end with this thing and Alltek is about to make a sale. The last thing to try is a professionally burned set of roms for $12 to see if it's in my programmer setup. Meanwhile I'm going back to tinkering on my EM machines.

#26 9 months ago

Pull the ROM chips out and check that you're getting activity on all the address/data/chip enable pins at the U2 and U6 ROM sockets with a logic probe.

You could also consider reverting the jumpers and reinstalling the old original ROMs to see that there isn't some other problem now.

#27 9 months ago

If the OP doesn't mind I have an EPROM question;

I'm looking up the difference between 27CP128 and 27C128.

I found the NSC data sheets and the only really difference I can tell between the two is the 27C has a faster access time and higher power consumption. Max power on the 27C is 360mW vs 55mW for the 27CP

Thoughts? Maybe I just had a bad chip when I tried substitution?

#28 9 months ago
Quoted from gdonovan:

If the OP doesn't mind I have an EPROM question;
I'm looking up the difference between 27CP128 and 27C128.
I found the NSC data sheets and the only really difference I can tell between the two is the 27C has a faster access time and higher power consumption. Max power on the 27C is 360mW vs 55mW for the 27CP
Thoughts? Maybe I just had a bad chip when I tried substitution?

The NMC27CP128 is a strange beast. In fact it is a 27C256 Eprom, and you are programming the last block only - pin 27 is a "block select" which selects the lower or upper half of the array. In a 27C256 pin 27 is the the last a14 addressline.

Important is the programming voltage. The NMC27CP128 is based on CMOS technology and needs a programming voltage of 13volts. When choosing another programming algorithm meant for NMOS Eproms which need 21V a programming voltage you can destroy the chip and maybe your programmer.

Choosing a profile for a ST M27C128 -which needs a 12.75V programming voltage- will probably work fine for the NMC27CP128. You won't destroy anything with that.

#29 9 months ago
Quoted from MarAlb:

The NMC27CP128 is a strange beast. In fact it is a 27C256 Eprom, and you are programming the last block only - pin 27 is a "block select" which selects the lower or upper half of the array. In a 27C256 pin 27 is the the last a14 addressline.
Important is the programming voltage. The NMC27CP128 is based on CMOS technology and needs a programming voltage of 13volts. When choosing another programming algorithm meant for NMOS Eproms which need 21V a programming voltage you can destroy the chip and maybe your programmer.
Choosing a profile for a ST M27C128 -which needs a 12.75V programming voltage- will probably work fine for the NMC27CP128. You won't destroy anything with that.

Question: The National Semiconductor Corp lists the NMC27CP128 as a 16k x 8 part, is this correct? I can scan in the sheet and e-mail, I don't wish to clutter up the OP thread too much.

I'm looking to replace the factory installed 2.3V code with 2.4V downloaded from IPDB but the factory chip is 27CP128 and I'm looking to substitute. 27C256 should work if I double up the file size yes? Load it in the upper and lower section of the 27C256?

#30 9 months ago
Quoted from gdonovan:

Question: The National Semiconductor Corp lists the NMC27CP128 as a 16k x 8 part, is this correct? I can scan in the sheet and e-mail, I don't wish to clutter up the OP thread too much.
I'm looking to replace the factory installed 2.3V code with 2.4V downloaded from IPDB but the factory chip is 27CP128 and I'm looking to substitute. 27C256 should work if I double up the file size yes? Load it in the upper and lower section of the 27C256?

NMC27CP128 is listed as a 16k8 part. You can use a 27C256 also (in Data East games in socket 5A). You can double up the image OR you can load the 16kB image with an offset in a 32kB buffer -> start/loading addres/offset $4000.

#31 9 months ago
Quoted from MarAlb:

NMC27CP128 is listed as a 16k8 part. You can use a 27C256 also (in Data East games in socket 5A). You can double up the image OR you can load the 16kB image with an offset in a 32kB buffer -> start/loading addres/offset $4000.

Thank you, I will let you know how I make out tonight.

#32 9 months ago
Quoted from MarAlb:

NMC27CP128 is listed as a 16k8 part. You can use a 27C256 also (in Data East games in socket 5A). You can double up the image OR you can load the 16kB image with an offset in a 32kB buffer -> start/loading addres/offset $4000.

Bad chip I think, worked perfect the second time with a different 27C128.

Thank you for your help again!

#33 9 months ago
Quoted from oilspot:

Just went over the board carefully rechecked all my jumper connections and disconnections and affected thru hole connections, tested across each jumper with my ohm meter to verify the connection. Re burned the roms from ipdb download. Verified good using bpwin. The board is good, the roms are good, it booted before I messed with it, I'm nearing my wits end with this thing and Alltek is about to make a sale. The last thing to try is a professionally burned set of roms for $12 to see if it's in my programmer setup. Meanwhile I'm going back to tinkering on my EM machines.

No offense, but the soldering is so bad on those jumpers, who knows what's going on.

#34 9 months ago

Ok, I went back and neatened up some of the grotty looking solder work and went around the eprom sockets with a logic probe (more on that later) assuming that the board jumper work is fine, which I'm increasingly confident it is, I'd like to review my operation of the eprom programming system. The replacement eprom chips should be arriving anytime which will help in determining what's going on, but for future work I'd like to learn what went wrong this time. Following is a series of pics of my computer screen while setting up to program a 2732 eprom.

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#35 9 months ago

Of course, this is between removing the 2732 from the eraser and blank checking it, and verifying the finished eprom against the buffer contents. Lather, rinse repeat for the U6 rom file. Most of it is pretty straightforward, the one screen that concerns me most is the "data pattern" box where file type and other variables are adjusted. I selected "binary" each time from the drop down list.

#36 9 months ago

I created testroms for these boards which also provide you the possibilty to test the accessabiltity to socket U2. It can give you some more insights. Send me a PM with you email address if you would like to try them.

#37 9 months ago

Update- new ROM chips came today from Actionpinball. Popped them in and the board now boots and game basically acts like EBD. It has many other issues like the sound not working along with numerous electromechanical problems with playfield but the light at the end of the tunnel is in sight, and it's flashing green!. I'd still like to figure out why the roms I burned failed though.

#38 9 months ago

Try reburning those ROMs a couple of times (say about 3 times) without erasing between reburns, i.e. to top up the cell programming.

One of my cheap programmers programs 2716 EPROMs and it verifies them ok, but they don't work when put into use and other programmers show a fail on that verification. When I reprogram 3 times on the cheap programmer without erasing between reprograms, they then work ok. This is an (algorithm?) issue with my cheap programmer not the 2716 chips.

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