Problem NMS-8245 2+, black screen

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By Caliostro

Expert (74)

Caliostro's picture

11-06-2021, 19:32

what should i include in the rom?
to which addresses?
Cbios_basic
Cbios_main
Cbios_sub?

By Pentarou

Champion (375)

Pentarou's picture

11-06-2021, 19:53

I think for an MSX2 you would need (at least) basic+main.
I've never tried building a config from scratch, I used a pre-built image on the Ω, so can't offer much help.
But if I were you, I would build a 64KB MSX2 ROM image and test in OpenMSX (8245 machine) to check if the structure is correct.

I suppose you already tried refitting the original ROM (if it's still in your possession), but have you also checked if the service jumper (SI1?ST1?) is in the correct position?
And what does exactly mean " I tried to remove the TMS2793 chip" ? ;-)

By sdsnatcher73

Paragon (1975)

sdsnatcher73's picture

11-06-2021, 22:06

You can still go MSX1 with CBIOS for the test. No need to worry about anything just flash the 32kB ROM like jipe said before (although he meant original MSX1 ROM but the same applies to CBIOS)

By Caliostro

Expert (74)

Caliostro's picture

11-06-2021, 23:00

something happens, I turn on - black screen, I press the reset button and this appears
[img][/img]
P.s.jumper st1 is in position 1-2 ... what is it for?

By Caliostro

Expert (74)

Caliostro's picture

12-06-2021, 19:07

I tried to replace RP5C01 too, nothing new ... soon, this MSX is going to live in landfill

By sdsnatcher73

Paragon (1975)

sdsnatcher73's picture

12-06-2021, 19:26

Are you sure your VRAM is good?

By Alexey

Guardian (3118)

Alexey's picture

12-06-2021, 20:08

Caliostro wrote:

I tried to replace RP5C01 too, nothing new ... soon, this MSX is going to live in landfill

Come on, donate it to someone for the cost of shipping. Or sell as defective. Don't throw away the history!

I have the same problem with one of my 8235. RAM is good, VDP is good, ROM is good, but something else blocks computer from starting. Philips diagnostics ROM shows yellow screen (video bus problem). Trying to identify where the problem actually is. The VDP doesn't output RGB, SYNC and doesn't get INT from the CPU for some reason.

By Caliostro

Expert (74)

Caliostro's picture

12-06-2021, 22:00

VRAM is good...
I changed everything, I'm left alone:
C311C
74LS04N
7416N
74LS14N
Can any of these prevent it from starting?

By Caliostro

Expert (74)

Caliostro's picture

13-06-2021, 01:26

which rom diagnostics?

By Alexey

Guardian (3118)

Alexey's picture

13-06-2021, 12:38

https://download.file-hunter.com/Technical/Hans%20Otten/STCM...

Write this ROM image to W27C512 chip and put it into the main ROM's socket.

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