color problem on spc-800

Page 1/2
| 2

By Caliostro

Expert (74)

Caliostro's picture

05-05-2021, 12:02

Hi, I have an annoying problem on a spc-800:

I tried to replace the VDP, the RF module and I replaced all the electrolytic capacitors, but it doesn't change...
Please don't say the problem is vram :x

Login or register to post comments

By Grauw

Ascended (9904)

Grauw's picture

05-05-2021, 12:08

Caliostro wrote:

Hi, I have an annoying problem on a spc-800:

I tried to replace the VDP, the RF module and I replaced all the electrolytic capacitors, but it doesn't change...
Please don't say the problem is vram :x

(Fixed image link.)

It doesn’t look like a VRAM problem to me. The screen contents look fine, but there is an issue with the colour encoding.

By Caliostro

Expert (74)

Caliostro's picture

05-05-2021, 12:08

thanks, what was I wrong?

By Grauw

Ascended (9904)

Grauw's picture

05-05-2021, 12:11

You needed to link to the actual image, not to the page that contains the image. On ibb, there’s an “embed codes” tab at the bottom, where you can use the BBCode one.

About the issue you’re seeing, it doesn’t look like a VRAM problem to me. The screen contents look fine, but there is an issue with the colour encoding, which points to the circuitry on the path between the VDP and the video output.

What video connection are you using, composite video?

By Caliostro

Expert (74)

Caliostro's picture

05-05-2021, 12:17

Yes
ok, this is good news already, I try to follow the leads from the vdp ..

P.s. sorry for my english, i use google translate

By Grauw

Ascended (9904)

Grauw's picture

05-05-2021, 12:36

Caliostro wrote:

P.s. sorry for my english, i use google translate

No problem, of course Smile.

By Caliostro

Expert (74)

Caliostro's picture

05-05-2021, 12:42

[img][/img]
there are only those resistors, then the signal goes to the RF module
[img][/img]

By Grauw

Ascended (9904)

Grauw's picture

05-05-2021, 12:53

Maybe there is an issue with the LVA510 encoder or the components around it?

By Pencioner

Scribe (1421)

Pencioner's picture

05-05-2021, 12:55

In many cases with MSX1 computers the problem is with LVA510 encoder... i had two computers with bad video (missing color, one was missing red, other was missing blue) and after LVA replacement it was good again. I would suggest to try to replace it first and see

By Grauw

Ascended (9904)

Grauw's picture

05-05-2021, 12:58

If you search the forum for LVA510 you will also find a number of threads related to discolouration.

By Caliostro

Expert (74)

Caliostro's picture

05-05-2021, 13:25

Amazing, i found the problem, MB to RF module cable, it is not broken, all cables are good, but if I change it, it works perfectly.
edit: 1 oxidized pin

Thanks for your help

Page 1/2
| 2