Model 16 - Power supply - FIRE!

[Tarkie101]

OK, well not quite fire, but smoking.....



From a quick view, from the two rubber wrapped inductors between the 4 electrolytics in a row.

System was operating fine, just took the lid off to measure for a replacement IDC cable. Lucky!

Anyone experienced this before?

Steve

 

[dlightman]

Are you sure it wasn't one of the RIFA's? That one in the far left of your picture to the right of the fuse doesn't look too good.

When they go there's lots of smoke and sometimes a nice bang!

 

[Tarkie101]

The RIFA you highlight has already been replaced.

The smoke was from the vicinity of the inductors as my adrenaline fuels mind actually went into overdrive and looked before i panicked

 

[dlightman]

Gotcha, between C8 and C5 are the two rubber wrapped toroidal coils L1 and L2.

 

[Tarkie101]

Yup, those the babies. They were rather hot. You could feel the heat radiating from that area.

Now, my current thought is i've completely removed two 8" drives from this machine, but not done anything about the load they would normally apply to the PSU.

Should i put one in to at least apply some load to the PSU as the +24v rail for example is probably not loaded.

Thoughts?

 

[dlightman]

I don't know that it has any impact on this occurring (or not) but Frank Durda's 5.25 conversion article said to always leave one of the 8" drives connected to ensure a minimum load on certain power supply voltages.

Personally, with the exception of one special machine, I've replaced my power supplies with Meanwell QP-200D's. Just less grief in general...

 

[pski]

Should i put one in to at least apply some load to the PSU as the +24v rail for example is probably not loaded.

Thoughts?

I always leave one drive plugged in even when not using it to be on the safe side and ensure adequate load. I will disconnect the AC to the Model II drive motors though so they don't continuously run.