1 reply to this topic

[Dirty Harry]

Hello I am new here, please forgive me if I am posting this in the wrong section.
Recently I bought a mint condition Coleco Telstar Pong machine, the ad said, as is where is, and because of its condition I decided to buy it. When I tried it all I managed to get was this on my TV screen. I have taken it apart and cleaned everything several times, re-soldered up any bad spots and there was still no difference. I tried batteries and multiple AC adaptors with no luck. Also I am using a new coaxial adaptor that works fine with all my other systems so there is no problem there. Anyone know what could be causing this?

sorry for the bad quality picture I had to hold my finger over the flash just to get something that looked decent.(the redish lights are the house lighting not the game)
Here is what type of machine it is

Edited by Dirty Harry, Sun Jan 9, 2011 8:37 PM.

[simbo]

you have a filled buffer for video but for hsync signal nothing
vsync is ok {this is what a pitcure looks like if hsync isnt right}
hsync and vsync are usualy mixed together in a logic ic
this is the way older 4-8 bit machines work
as hsync and vsync are usualy generated in different areas of there chipset
{or single ic}
the picture and its framing is correct but the display isnt
becouse the hsync isnt there
i assume it uses a modulator and rf signal to tv
having never seen one or held one.. used one or owned this unit

i would sumise its one of the ic's inside has come loose
or moreover these older pcb like pong and other bat and ball are single sided pcb
that use TI controllers

with solders on one side only
i recon its either
a dry joint around the hsync to the sync combiner logic comes from the video ic.?
or a bad coupling capacitor usualy a low value electrolytic that has dried out like a bad battery

can you open the unit carefully
and take a macro photo of the top and bottom of the pcb
i think here pictures speek volumes