Mystery part on Panasonic Plasma P/S TNPA3911

[saddle_au]

I would like a couple of opinions on what part R498 is supposed to be doing.

I needed to remove capacitor C447. But to get it out, I had to remove some other parts that were in the way (there's an overhead heatsink limiting vertical extraction). On locating the pins for R498, I find they are (very obviously) wired together on the PCB. I think the part serves no purpose other than ballast, artificial cost increase or some engineer justifying the time taken on a board. "It took a while because look how complex this is!".

Has anyone seen this before?

[CapLeaker]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

[QUOTE=saddle_au;522218]I think the part serves no purpose other than ballast, artificial cost increase or some engineer justifying the time taken on a board.QUOTE]

you forgot one: Free parts to give away!

[dkneyle]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

I saw just the same situation on a board the other day in the power supply section. I think often the original circuit called for a very low resistor, sometimes used for current monitoring. Then revision changes result in it being changed to a short circuit link. It's the best explanation I've been able to come up with.

[Agent24]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

Design error or maybe it's a spare?

[tw2005]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

I don't know if it was the same board but someone else has reported something similar on a panasonic plasma PSU before. exact same scenario, soldered to the same land

[saddle_au]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

How about:

1) engineering challenge, keep stuffing parts on there until someone else notices.
2) An engineering where's Where's Wally (UK, AUS) game (Where's Waldo US).
3) The power supply was quoted at $X and that's what it will come in at no-matter what.
4) earthing posts for testing (more expensive than a wire link, but hey why not)
5) new storage option for spare parts, get the owner to hold them for you on parts you know will fail
5) Put the part in there to purposely get in the way of a repair
6) 1st April: Put out a service bulletin describing a failure of voltage across it causing massive problems

[Agent24]

Re: Mystery part on Panasonic Plasma P/S TNPA3911

I thought spare initially but a 100 Ohm 5% resistor is not exactly hard to find...

The idea of a ground post is a good one - if they already had heaps of these resistors, it would be easier and maybe even cheaper actually.