How to troubleshoot video problem on 4000T

[videofx]

Anyone know how to troubleshoot loss of video on a 4000T? THe computer seems to boot (I hear it reading the floppy) but no video out the 23pin on board video.
 
I even tried a working Picasso IV in the video slot and no video.
 
I would appreciate nay help!
 
Thanks!

[danbeaver]

What monitor are you using on the 23-pin port?  An A108x is standard troubleshooting gear. The P-IV requires setup with one or two reboots in between.

[videofx]

I am using a sony multisynch monitor. IT was working great one minute then after powering off and powering on I never got the video back. I plugged the monitor into my other Amiga and get video so I know its not the monitor.

[GadgetUK]

Don't know what your electronics skills are like, but if you don't mind getting your hands dirty its worth taking a look at the videos by RetroGameModz on youtube, he's done a couple of 4000 and 1200 videos covering video faults I think.  Knowing the 4000 and 1200 it's most likey the surface mounted capacitors.  Take a close look at your motherboard and look around the capacitor cans for any signs of leakage - if you see anything that looks like leakage that cap will 100% need replacement.

[videofx]

Cheers for that! I will see if I can find the youtube videos. I thought it mught be a cap or a resistor so hopefully the videos will show me where to look

[GadgetUK]

Cheers for that! I will see if I can find the youtube videos. I thought it mught be a cap or a resistor so hopefully the videos will show me where to look

Yes, the most common fault on these 4000's and 1200's (and 600's for that matter...) is the surface mounted caps.  Worth looking at the PCB to see if any have leaked.