1202 ALARM

I was given a broken Acer monitor recently which was powering up but not displaying anything. I took it apart and was surprised to find this, but not where I expected it. The capacitors in the main power supply were fine and the supply was giving out the correct voltages, but for some reason Acer (or whoever made the power board) had decided to use a different manufacturer's capacitors for the part of the circuit powering the backlight inverter and 3 of these had blown. You can clearly see the top of the capacitor has been pushed up and evidence of leaking electrolyte in the 'hot-cross bun'. This looked like an ideal candidate to test my new capacitance meter I got on Amazon and received (from China of course) only last week. The capacitor is marked as 1000uF, so let's see what it is actually doing now. Oh dear, only 230uF and probably on it's way to a dead short. Unfortunately one of the other ones looked like it had exploded and had shorted ...

I've been fiddling about with a 40" Samsung LCD television today. I was given this free because the power board had packed in. The previous owner had attempted a repair by replacing the 'Bad Caps' (i.e. blown electrolytic capacitors, Google that one!), but the de-soldering and soldering was a bit ropey looking so I tidied that up and replaced 2 of the capacitors myself as one didn't look right and the other was the wrong value. I managed to find a schematic diagram online for the board (Hansol SIP400B), which was helpful in identifying the capacitor values. Anyway, I put it back in the TV and powered it up and all the voltages coming off the board are correct, but all it does is click. This is the result of a relay on the board switching the circuit from  standby to power on. The red LED on the front panel lights and the set is receiving IR signals from the remote control. This is really frustrating, but as 95% of these boards suffer from Bad Caps, I might just...

I got this dead Finilux 32-inch LCD TV from Chris on Freegle. The power board was doing nothing, no voltages, so I took a good look at the capacitors and 6 of them were bulging and suspect. Raiding the spares box, I found replacements for all 6 capacitors and upped the voltage rating on 4 of them just to be on the safe side. Re-assembled the television and it is working like new. Here it is running off a Raspberry Pi Kodi box via HDMI playing a music video on Vimeo. Picture quality is excellent.