By the looks of the PCB, it's toast. Probably, at some point, somebody wired it wrong and fried it. However, the part shouldn't be too hard to replace as they were never exactly rare.

You're dead on there I think. I pulled a similar part from another machine and connected it to the case in question, and the display did function correctly for a time, but then started to heat up and fry before my very eyes. On closer inspection it looks like someone has messed around with the wiring at some stage.

I guess I need to get me a multi meter and learn how to use it instead of doing any more half arsed experiments.

Thanks for the reply, I guess I'll just keep an eye out for a replacement.

Looks like someone applied a 12v line on that 5v input. They fried the crap out of that resistor.

Even using a meter won't tell you the value of that resistor since it cooked. It probably bumps a 5v down to 3.3v. If it feeds a regulator it may of took that out as well. since the trace on the board has burned away.

badmofo wrote:

I have a shameful habit of taking unwanted hardware to my local recycle center and, while the attendant isn't looking, browsing other people's discards and often coming away with more things than I arrived with.

That ain't shameful. I used to do that all the time! Needless to say, I've gotten some pretty good stuff out of it. 😁 (though my friends tend to do a lot better than I do for some reason 🤣)

They always do. Then again, the farthest I'll go with garbage hunting is if I happen to spot something on the curb.

An update on this - eBay to the rescue once again.

I found this 4-pin to 2-pin adapter to replace the dodgy one I suspect caused the burnout previously:

http://www.ebay.com.au/itm/160639806633?ssPag … 9#ht_500wt_1180

And I found a similar looking LED unit here:

http://www.ebay.com.au/itm/170439216583?ssPag … 9#ht_500wt_1180

Time will tell if the screw holes match the case but I'm sure I can make it fit regardless.

Questions:

- Can someone confirm that the molex adapter above should deliver 5v? The PSU lists the red cable as the 5v rail.

- What are people's experience with these Mhz displays, specifically the way in which the case interacts with the motherboard? The case has a turbo switch, a turbo on/off indicator (single led), and this LED display - but there are only 2 wires? A 'turbo switch' wire, which obviously connects to the turbo switch jumper on the motherboard. And a 'turbo LED' wire, which I have plugged into the turbo LED jumper on the motherboard. This all works fine.

But what tells the LED display to alternate b/w HI and LO (or 66/33, etc)? As you can see on the unit pictured above, it has a TSW jumper, but if I plug the case's turbo switch wire into that, then what's controlling the turbo option on the motherboard?

Thanks for any help.

Yeap, the red on is the 5v rail. But I don't think the original connector is to blame for a problem like that. If the power supply is bad, probably every 5v rail might be faulty. In my opinion, that is not the issue here. I believe someone connected the 2pin cable at the wrong place, and fried the circuit (been there done that....). Just to be sure, check the voltage using a multimeter.

OK thanks for the reply, I will get a multimeter and test it. I could easily switch the PSU out for another one I have but it's a nice clean one, so I'd prefer to use it if possible.

The reason I suspected the connector is that - by looking closely at the molex plug - I could see a cut section of wire sticking out of the 12v (yellow) rail. So one possibility (in my mind) is that the connector was dodgy from the factory, the computer was turned on and fried the resistor, someone investigated and rewired the adapter but it was too late, the damage was done.

The case itself looks almost brand new, so perhaps it was returned to the store and sat in the back room for all these years, before finally being dumped at the recycler. Who knows. Anyway it's a nice case, I'll post some pics here if I get it up and running.

Before plugging in the new one get a picture of it and post it up. Can give you the value of the resistor by the color codes on it.

Thankyou, I will do.