Solved Space Invaders test-ROM wich RAM is broken??

[Georgian2]

Hello,
The Test-ROM is giving me this image. How do I know wich RAM is bad? I don't understand the instructions...
https://www.outerworldarcade.com/space_invaders/space_invaders_test_rom.html
I'm having some lines every now and then. So far I found one bad LS08 on the address bus.



TEST-ROM Output:

 

[Georgian2]

2nd ls08 only gave an error when tested at 2.5V, swapped it and no more lines through sprites but test rom still shows this lines?? Something is fishy here.

 

[philmurr]

Download my test ROM from the same site, it beeps as well as trying to print which RAM is faulty.

There's a text file attached which tells you which RAM should be faulty and also explains how the shifter test works.

 

[Georgian2]

Why would this test report an bad ram when the game works stable now? It is space invaders part II (deluxe??) L shape board set.

 

[Georgian2]

Download my test ROM from the same site, it beeps as well as trying to print which RAM is faulty.

There's a text file attached which tells you which RAM should be faulty and also explains how the shifter test works.

I must be doing something wrong. I flashed your test rom V1.1 on an PQ2816 and all I got is this:

The game works fine:

 

[Lurch666]

Which socket are you plugging the test rom in?
And are the eproms you are using for the test rom the same as used in the PCB?

 

[Georgian2]

Which socket are you plugging the test rom in?
And are the eproms you are using for the test rom the same as used in the PCB?

H1. All other eproms are 2716 while test rom is PQ2816.

 

[Lurch666]

Could be that pin 18 of the 2816 is chip enable where it's enable programming on the 2716.
If that's held high then the 2816 might not function properly.

 

[Georgian2]

Never mind. The board is set for TMS2716 and they have different pinout and -5V on pin 21.... I won't bother to make an adapter. Game works.