(Topic ID: 88915)

Black Knight rom positions

By boydsc331

5 years ago

Topic Stats

  • 9 posts
  • 5 Pinsiders participating
  • Latest reply 5 years ago by Pepse25
  • Topic is favorited by 2 Pinsiders


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2014-04-26 16.40.12.jpg
2014-04-26 16.39.55.jpg

#1 5 years ago

hello can anyone tell me how these black knight roms should go on the mother board ? i have 2 blue flipper roms labled 1 and 2 i think those are in the right positions and i have 2 that say black night rev3. one says D800 and the other says E000 i think. the tags are coming off and theres a glass window on each. does that make it an eprom ? and also looking at the board as it is mounted in the back box which side do the notches go on ? the left side? i see no markings on the socket or board. oh ya its a sys 7 board. and should all the dip switches on the top left corner of the board be in the of2014-04-26 16.39.55.jpg2014-04-26 16.40.12.jpgf position ? thankyou

#2 5 years ago

Well, you do have the roms in the proper sockets for the most part. The Flipper ROMS take up IC20 and IC17, the game roms taking up IC14 and IC26. The real question is do you have the right ones in the right sockets?

Flipper ROM 1 goes to IC20, Flipper ROM 2 goes to IC17. You have these right.

Your game roms are a different story. You apparently have L-3 Roms, and with out the label indicating which one they are, I'd have to figure out which game rom has D800 checksum. However, I cannot find any L-3 checksums, all I have are checksums for L-4, and Google isn't helping me at all. If I can figure out how to generate some, I can figure out which position has D800 checksum and where it goes. Right now you just have to guess and try; the flipper roms are in the right spot so it'll either work that way, or work after you swap the white roms. I'll keep digging for checksums and let you know what I come up with. Someone may have an old checksum list lying about.

Here are the positions as they are on the board since they're not marked.

IC26 (Game Rom 0)  IC20 (Flipper Rom 1)
NOT USED                IC17 (Flipper ROM 2)
NOT USED                IC14 (Game ROM 1)

The white chips with the glass windows are in fact EPROMS. It was recommended that most of the original PROMS be changed to EPROM, both for game and flipper rom data. The Flipper ROMS tend to survive if they're not pulled out; but the game roms have undergone several revisions. If yours say rev 3, the lastest for Black Knight is L-4. It might be worth looking in to a new set.

Those sockets don't have notch, but there's a little dot near the sockets which shows where pin 1 should go; they also align in the same direction as the PIA and CPU; so they're installed correctly.

I don't seem to recall the dip switches doing much of anything on a System 7 board, I believe that was a throwback to the system 3 software which did not have a computerized adjustment/audit/diagnostic system; you used to have to flip indvidual bits and insert them in the CPU. I will double check on this as soon as I track down a good copy of the System 7 reference manual.

Post edited by dewdude82: tried to blockquote the IC positions

#3 5 years ago

ok thankyou dewdude82 for the in depth reply. i tried the game roms in both sockets and still have 2 solid leds and a "0" showing on the display on the board. so i have bad roms or problems elsewhere. voltages on the board or there +5 and +12. so i may just send the boards out , or maybe buy a rom set if that doesnt work then send them in. if A rom is installed upside down and powered on i assume it ruins the rom ? this may be my problem also

#4 5 years ago

EPROMs are instantly destroyed if installed upside down. (you reverse the voltage typically). Masked ROMs tend to live, but are suspect for later failure.

Looking at your board as in your pic...

top right is IC20 flipper rom1. 2716 or masked rom
mid right is IC17 flipper rom2. 2532 or masked rom.
bot right ic IC14 game rom 1. 2716 or masked rom
top left is IC26 game rom 0. 2716 or masked rom.

Remove everything but a known good CPU and a test rom or known good flipper roms. If you still locked up... time to figure out what is stopping the CPU from running. Bad IC sockets, reset, clock generator, buffers, etc....

I think i see corrosion in your pics. If so your IC sockets are going to be suspect. Those single wipe RN sockets dont hold up to corrosion very well. If you pry an used IC socket housing off i bet you find corrosion.

#5 5 years ago

Yes. If you install an EPROM backwards, it will destroy the chip. I *have* seen cases in the field where they've survived. But if you think you may have blown one up, then it might be best to get a new set. Although that's no guarantee it'll fix your board. Those white sockets tend to be bad and need to be replaced.

The 0 with both LED's just indicates the thing isn't booting.

#7 5 years ago
Quoted from johnwartjr:

Sys7CPU.jpg 131 KB

ima yell at you for using header pins that are too short on the interconnet =P

#8 5 years ago

That photo was shot at least 8 years ago, before GPE had the longer ones remade.

I now replace all header pins on sys 3-7 including the longer interconnect pins.

#9 5 years ago

To answer the rom location, they are in the correct position and facing the correct way.
would never hurt to have the latest release.
IC14 : Game Rom 1 : E000 - E7FF
IC26 : Game Rom 2 : D800 - DFFF

dewdude82: check byte for the "game roms" is at the last location of the chip
only difference between the release of L3 and L4 is in Game Rom 2,
(which the checksum is only looked at during the diagnostics)
Game Rom 1 : L3 - hex E4 | L4 - hex E4
Game Rom 2 : L3 - hex 25 | L4 - hex 28

Agreed a place to start could be to check for bad connections/roms/reset circuit/corrosion...

hope this assists.

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