Original Clock Repaired?

[dn010]

I was able to finally complete the transfer of a good working VDF display on a bad board, to my good clock board which had a bad VDF display. After a bit of work, the VDF comes on and works great, I can adjust the time, etc. with no issue. However, I notice that the underside of the board gets pretty hot, particularly under the large resisters that are located under the display. I only had a half assed working clock for about a week when I first got the car so I am not sure - is this heat normal? This is also of course only when the display is on/key on; if they clock is plugged in but the key is not on, no parts feel hot.

Cheers,
Dan B.

[Mario]

That is normal. There's a filament inside the VFD that needs a regulated current - there are two power resistors on the PCB that drop the 12V to an acceptable voltage for the filament. As a result, the two resistors dissipate the extra power as heat.

[dn010]

Thank you for your reply. So when you say it's normal, they are supposed to get HOT, not warm, correct? When I say hot, I mean it was getting a little uncomfortable holding it on my skin but it did not get to the point I'd get a burn from it. I just want to specify because I really don't want to melt or destroy anything if there is something wrong.

[Mario]

Yep, quite hot! Certainly too hot to touch if you were touching the actual resistors themselves.

[dn010]

Well, that's awesome then - clock fixed! Thanks for the reply.