Troubleshooting Harris VTM-4100 fault condition?

[bob_g]

Hi, I'm looking for any troubleshooting info for a old Harris Videotek VTM-4100 rasterizer. The unit was working, one day it just powered up into a FAULT condition (LED lower right front panel was lit) and never got past bars displaying on the DVI output (actually called "bars with motion" in the manual because it also displays a moving pong-like square).

This happens about 30 secs after power is applied. I've checked all the power rails on the internal supply and they're good as well as all green power indicator LEDs on the VTX3340 board.

Also the fans come up full speed then throttle down to an idle (normal) before the FAULT indicator comes on. They all appear to be on.

Are there any other reasons why a FAULT indication would come up. The ops manual pretty much has no information other than the FAULT button (there is no button only an LED) doesnt do anything, and to ignore the LED during a firmware update.

Thanks

[aramkolt]

That's one of my favorite pieces of hardware in terms of vectorscopes/waveform monitors, but yes, I have run across that on both TVM (these contain screens) and VTM, especially if they have composite option in addition to SDI.

I will say that the power supplies like to go bad on these because the XP power brand that they used has some low quality capacitors, so the first thing I do is recap those.

However, just getting stuck at the bars screen I haven't figured out and I gave up on those units (I think I've had 3 or 4 of those). Near as I can tell, they aren't shorted anywhere. My general assumption is that a failing power supply could have caused a voltage spike, something minor goes open or short on the main processing card, or perhaps the firmware somehow gets corrupted. In all cases I've found, the issue is with the main processing board (not an option card) that swapping fixes

[bob_g]

Thanks for the ideas. Yes those power supplies, don't know how many I've replaced on the VTM-420s. Was also thinking it might be a failure on the main board, I did pull out all the option boards, but that didn't make a difference. Also fwiw it pretty much ignores it if you do the cold and warm start button pushes at any point. Was thinking trying a USB firmware update (assuming I could even find the .flu files anywhere), but I think you have to be in a working system to select the firmware file on the USB stick to do the update from, and can't do it from just a power up. But the VTM-4100 is a nice box would like to get it working if possible.

[aramkolt]

Interesting. I thought at one point I might have tried a cold start, but maybe not. If doing that gets past the issue, you'd think it'd be software or setting related since a cold start just resets settings to default, but not sure why it doesn't work on subsequent starts in that case?

[lordsmurf]

Old "pizza box" video gear failing = immediately look at capacitors.

I'm not familiar with the internals of this exact device, but sometimes reseating or reflowing components/chips/etc is needed.

Whatever it is, I'm sure it'll be in the last place you look!

[bob_g]

Those old supplies really did have a run of bad caps. I did scope out for ripple on the DC rails but all looked clean, so starting to suspect some hardware fault possible on the main board. Wish there was a better way to get a readout of the error condition somehow. Thinking while the bars are on during the startup, maybe its not fully operational so would ignore any cold start button pushes but idk. Is the bars display being always on during startup normal until the main screen comes up (which it never does)?