Identify a burnt & disfigured IC chip on power board of DVD player

Question

Hi,

Recently the DVD player heard a loud ping and loss of power to it. I removed the cover of that player found the power panel with fused & IC chip burned. I can't identify the chip due to the numbers being burned . I would like to seek your assistance in identifying the chip for replacement. Thank u.

michaelkellett · Answer

It certainly looks like a mains to DC converter - the optocoupler and transformer rather confirm it. Your next step should be to trace out the complete circuit and draw a schematic of it - it looks like a single sided pcb so it shouldn't be too hard. Mark up the component values on the schematic and post it here. It will be much easier to find the regulator chip type. Then test all the components you can - as Doug says the chip failure may have been caused by something else. Alternatively look for a replacement board: This looks promising but not currently available: https://www.amazon.in/Voltage-Player-Power-Supply-Circuit/dp/B00MJVKBRA Here's another: https://uk.dhgate.com/product/1pc-ac-dc-universal-5v-12v-switching-power/421056711.html?f=bm%7cGMC%7cpla%7c1670763299%7c… MK

michaelkellett · Answer

Sorry Doug, I'm missing something here. I can find the data sheet for the DK1203 and it's a flyback mains to low voltage regulator for optocoupled feedback in an 8 pin DIL package as I'd expect. I can't see where the S1701 fits in. MK

dougw · Answer

It looks like that chip was exposed to very excessive voltage and current (as in mains power) so there may be other problems that caused this failure. Check if this is a power supply card (between power input and other circuit boards. - These other cards may provide insight into what voltage is used) If it is a power supply card, this might be a voltage regulator IC. If it is a regulator, it is probably a switching regulator (if it is linear it might be a NJM78LR05BD) Trace the components connected to the chip to see if they are typical of a switching regulator. You may need to look through datasheets of 8 pin dip regulators to see typical circuits. There are only about 15 (8 pin dip) regulators out there, so it may be possible to figure which it is by comparing with their reference designs. If it isn't a power supply, try to figure out its function.

14rhb · Answer

npsp I would also go with michaelkellett suggestion to try one of these boards as they are so very similar in components and layouts. Probably they are re-works of an original board design - either by the same company, via sold IP rights or plain clones. Some of the images will show their IC values; e.g. DK1203

michaelkellett · Answer

The good way to do it would be to power up the DVD player with a couple of suitable bench type power supplies and measure the current - that's what I would do but if you don't have the gear then that isn't an option. You could buy a spare part from the original manufacturer - if they are interested (or ask them for a service manual). Or you could punt $8 and see if it works Your choice. MK

michaelkellett · Answer

You would only get a problem if the DVD needs more current than the power supply is rated for.

Once you install the board you can check the supplies with a meter.

There is still a risk that fault in the DVD caused the power supply to fail - the only way to check this would be to power up the DVD using other supplies but they should really by lab type supplies with meters and current limiting. If you don't have access to these then just turn the new supply on briefly and turn it off if the DVD doesn't work. Do be very careful to get the right voltages onto the DVD pins (I expect you know that !).

MK

Identify a burnt & disfigured IC chip on power board of DVD player

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