Is my A1200 b0rked? (Issue w. Sony LCD)

[Nostalgia]

HALP!
 
Sorry about the wall 'o text below, but this really is driving me up the, well - wall.
 
I recently (yesterday, in fact) took delivery of a refurbished A1200 (4GB Flashdisk) from Amigakit. I set it up, RGB to new-ish Sony LCD, and got WB 3.1 installed. All was well - picture looked nice and clear - and I went to get some dinner.
 
10 minutes later I return to the livingroom, and find the screen filled with a black/grey blur - looked like a disconnected cable, but after checking all connections and finding no issues, I tried rebooting. This immediately solved the issue, as the A1200 booted to the WB with no problems.
 
This time I tried staying with the Amiga, watching the screen, and was treated to the same phenomenon: after about 15 minutes the picture started shifting sideways, accelerating until it was nothing but a mass of black with some grey streaks. Instead of restarting, I gently unplugged the RGB from the telly and then re-inserted it - this brought the picture back to normal - for 19 minutes.
 
Since then I've tried leaving the A1200 on and off for a few hours, and the pattern is the same each time: 10-15 minutes of both WB-inactivity and me jiggling the mouse about, and then black screen of death.
 
This is what I know so far:
 
1. A reboot fixes the picture immediately - no need for the Amiga to "cool down"
 
2. Resolution has nothing to do with it - I've tried all res's from 640*512 interlaced to 1280*256 de-interlaced
 
3. It doesn't matter if I use the Amiga or not - it "crashes" anyway
 
4. Two times it has crashed *just* as I jiggled the mouse - although that may have been a simple coincidence
 
5. I'm currently testing it with the RF-cable - hasn't crashed yet (45 mins in)
 
I'm pretty gutted at this, as I'd really been looking forward to playing all my old games again. The Amigakit-bloke seemed quite forthcoming, and I'm sure he'll replace my current A1200 if need be, but I'd really appreciate your thoughts on this all the same.
 
Thanks in advance.
 
Andreas

[Nostalgia]

Cheers guys - the missus is hogging the telly tonight, so further testing will have to wait 'till tomorrow. I'm sorta hoping it's the telly, as I'm looking to buy a new one soon-ish - although the best outcome would obviously be that it just... worked.

[Nostalgia]

Right - tried powercycling my TV, and that brought back the picture just fine. Looks like it IS the sync-issue then - but is this fixable, and if so how?

[Nostalgia]

If a non-15Khz mode (like "Multisync" mode) is stable on the TV, you could probably get away with an Indivision once they come out with another batch, or you could try composite if your TV has the jack for it, awful for Workbench of course but for gaming it could get you through until a new TV comes along. There also have been affordable S-Video adapters if that's an option on your TV.

How does composite compare to RGB for gaming? WB isn't much of an issue, as I'll mainly be using it for accessing WHD Load.
 
It's really strange, because a friend of mine has just tested his A1200 with his Sony (different model, though) and it seems to work just fine.

[Nostalgia]

Just a thought, perhaps you should take your 1200 over to your friends house and see if yours works on his set.
 
The reason I say this is because I don't want you to go out and buy a new TV, only to find that actually, the fault was on the 1200 afteral.

Yeah - I'll probably do this one of these days as well.
 
EDIT: What are odds that it IS the Amiga, do you think? Bearing in mind the powercycle-fix and no issues whatsoever with RF?

[Nostalgia]

And we soak test every A1200 for about two days before shipping to customers. As part of our Quality Control, we have structured Pre Delivery Inspection tests that include testing for many hours on both RGB video and Composite.

So you tested it with RGB, then? Of course the broke-in-transit-option remains, but the package looked in pretty good condition when it arrived. I'll test it on my friend's Sony next (or possibly this Saturday), and if it works then at least I know that the issue is with my TV (or my TV and the A1200).