Commodore 1084P no RGB

[protek]

Some time ago, I was donated a nice looking Commodore 1084P, with regards that it had left out the magic smoke. I brought it home and to check whether the flyback was working I connected a source to the composite and I was surprised to see it produce a pristine picture. I later tried out a TTL RGB signal but that just gave me a black image. I know for a fact that it had been connected to an Amiga when the magic smoke had blown, so I gather both analog and TTL RGB are not working. Composite and Luma/Chroma work fine.

I’ve opened it once to check the solder joints but it didn’t occur to me then to look for burned components. Any ideas where to start looking?

 

[Timtheloon]

@roy_bates may be able to help you with this.

 

[roy_bates]

1084P is based on the cm8833 as in the earlier model can you confirm? its basically a phillips

 

[protek]

1084P is based on the cm8833 as in the earlier model can you confirm? its basically a phillips

Yes, it is basically a CM8833.

 

[protek]

Well, I thought I’d give my C128 a try, and lo and behold, I’m getting an image out of the RGBi. I had tried a PC with CGA output and it had not worked then. This monitor just keeps surprising me (positively).

 

[protek]

I guess I need to retry the PC and also the analog RGB.

 

[protek]

Looks like my PC is dead as a doornail. Hence, it didn’t produce a picture.

 

[roy_bates]

well that was uneventfull,there a service manual for this by the way