625 Won’t Boot

[mackscb]

I have two 625’s I have been working on. One has a rom103 rev385 icam, the other has a rom206 icam. I have been using the receiver with the rom206 for “practice”. I pulled the bga chips off both receivers and mounted them to bga boards. I have unlocked the rom103 chip.

I used the mod to activate the card slot that involves cutting some of the pins on the card slot. The ird with the rom206 will boot up without the card in it and goes to the acquiring satellite screen. Of course, the other ird that I really want to work won’t boot up.

The disk drive spins up, the tv1 light comes on and after a few seconds, the tv2 and dual mode lights come on as well. At this point I have a black screen. Intermittently, I see a white and black fringe pattern at the far left of the screen, just a little narrow band. The disk drive occasionally makes a sound like it is trying to access something and sometime it seems to coincide with the fringe pattern on the screen.

This will go on for maybe a minute and the screen will go from black to one with just static on it and the tv2 and dual mode lights will go out. After a few seconds the tv2 and mode lights will come back on and the black screen returns.

I pulled the mother board out again today and looked at every square inch of it under a magnifying light, both sides, for solder splatter, cut traces or missing components. I checked that my connections were going to the right places and that the connections were good. I could find nothing wrong. I replaced the mother board and reconnected it, but get the same problem.

Has anyone experienced this symptom and can suggest something I can look for?

[mackscb]

I reversed the mod and got pretty much the same thing. I read another post where someone was having a similar problem and based on his observations, I disconnected the HD connections. I was able to get to a HD error message and then an internal communications error #122. I could also get the menu screens temporarily until the ird rebooted.

I reconnected the card slot mod, double checking the connections and I went around the area where the bga was pulled and touched all the component connections briefly with the soldering iron. Hooked everything back up and still black screen until I put the card in. When I did that, I got the acquiring satellite screen and was able to access the menu screens and was able to check that the HD functions were working OK. Everything was working OK except that the TV2 light would not come on.

I brought the ird in from my shop and hooked it up to another tv. Got the black screen again, whether the card was in or not, and still no TV2 light. Strange. Since the other 625 I have with the same mod works fine, with or without the card in, I’m thinking there may be a bad component or broken internal trace on the mother board. Can anyone suggest how I might trouble shoot this board?

[mackscb]

Based on a tip, I am trying to trace the IO line. Does anyone know where I can get a schematic or could give me some ideas on how to trace it?