A strange case of no RGB.

[soop]

I have 2 PC engines, both PAL modded (one working one not) which I removed the PAL modulator for, and then stuck in an IFU 30.  Even though I can see a voltage coming out of the expansion port, they both give no signal.  After replacing two missing transistors on one, I poked around with a multimeter, and found a bad cap (replaced to no effect) and noticed one was missing an oscilator.

Now I know it's a bit of a stab in the dark here, but I'm wondering if there's something fundemental you change when performing a PAL mod?  It can't be something on the RF modulator itself, and the one with the oscilator has the same hz as a working engine (although it could be bad I suppose).  Really at a loose end on this one!

[SuperDeadite]

Well in the worst case, couldn't you just tap the RGB from the chip?  Never tried this, but couldn't you just lift the chip's RGB pins, then connect them to the expansion port's pins directly?  Totally bypassing the NTSC/PAL encoder completely?  Would probably need to cut the port's pcb traces as well.  This is just a theory but I see no reason why it wouldn't work.

[soop]

Well in the worst case, couldn't you just tap the RGB from the chip?  Never tried this, but couldn't you just lift the chip's RGB pins, then connect them to the expansion port's pins directly?  Totally bypassing the NTSC/PAL encoder completely?  Would probably need to cut the port's pcb traces as well.  This is just a theory but I see no reason why it wouldn't work.

That's a really good idea.  With my level of soldering, it couls also go horribly wrong, as it's a lot more fiddly.  But this is an awesome worst case scenario, potentially saving a PCE here.  Both were boxed (with non matching serial numbers) and both were cheap enough that I can live without them...

But also one of them is melted a bit around the RF socket, and it could be the perfect candidate for portableizing too (since I dread actually taking a dremel to a fairly good condition one). Still need a working RGB amp to make it a standalone console of any kind though.

In the interest of clarity, can someone tell me where and what actually changes from the chip to the expansion port?

*edit* perhaps just connecting the composite sync will show me whether it will work or not?  I'm not sure how the RGB will be changed.  Although cutting the trace is a tad permanent.

*edit2* Oh yeah, clever clogs here, going by the old "big blobs of solder are usually ground" tapped the ground of the multimeter on the power input, and got nearly 12v off of everything (or -12v, can't remember).  will this have killed anything?  Seems alright now...