Hey guys
I have this jp04 psu http://www.joyoaudio.com/en/product/show_248.html, opening it up i've found a T0-220 type LM317 regulator installed improperly in a SOIC spot on the PCB. There is no bolt holding it, so it's free standing. I've included a pic of the close up view. It looks like that area of the board was altered looking at the excess solder present on the green smd components, also do you guys know what these green components are?
I can replace that regulator with the smd format LM317ND but what bothers me is the heat it would generate. That regulator is used for the 12v/18V/switchable outlet with 100mA. The transformer secondaries for it is rated 20V, 0.15A. The rest of the secondaries are 10V, 0.15A for the 100mA outlets & 10V, 0.3A for the two 250mA outlets. In the pic you can see a LM217 chip soic form with no heat sink, while the two lm317 have it i think. There is a hole under all these lm217 which i noticed when i had the whole thing apart.
So if i change it to the correct format would i need a heat sink for the soic package present underneath, cause there isnt a copper pad that acts like one. What i'm worried about most would be the heat dissipated could make the pads desolder or something, because at 12V there will be more heat compared to 18V setting. Alternatively, can i drill a hole on the enclosure & have the present regulator bolted down & use wires to connect the pads to it but will it affect its functioning since the middle tab would be then grounded right?
I wasn't sure if I should place this thread in the Power subforum, so sorry in advance for that, mods please move it to appropriate section if necessary.
Regulator chip size subbing, but is heat sink necessary?
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Hanky-
- Breadboard Brother
Update:
I tried subbing in an soic version of the lm317. It works to a point but overheats & shuts down. At 12V and 45mA or 65mA draw don't remember exactly but it quickly shuts down in about 5 secs. My guess is that mod is factory installed, they should have used the kind that can be seen towards the top, those would have worked and had a heat sink pad on the pcb. Joyo will probably revise the board and include proper type later on i suppose, since doing it manually is a waste of time for them anyways.
I added three leads and connected the original regulator, that way the pressure is off the pads if the regulator were to be bent, as it does when trying to remove those wires on top of it to the switch connections. I also tested it under load and it works and doesn't shut down but it does generate heat alot, luckily i don't have any 12V or 18V pedals so on idle heat won't be a problem.
So if anyone is considering getting this beware of this issue & if the 12V outlet isn't working then the first thing to check is if that regulator is connected or broken off the pads.
I tried subbing in an soic version of the lm317. It works to a point but overheats & shuts down. At 12V and 45mA or 65mA draw don't remember exactly but it quickly shuts down in about 5 secs. My guess is that mod is factory installed, they should have used the kind that can be seen towards the top, those would have worked and had a heat sink pad on the pcb. Joyo will probably revise the board and include proper type later on i suppose, since doing it manually is a waste of time for them anyways.
I added three leads and connected the original regulator, that way the pressure is off the pads if the regulator were to be bent, as it does when trying to remove those wires on top of it to the switch connections. I also tested it under load and it works and doesn't shut down but it does generate heat alot, luckily i don't have any 12V or 18V pedals so on idle heat won't be a problem.
So if anyone is considering getting this beware of this issue & if the 12V outlet isn't working then the first thing to check is if that regulator is connected or broken off the pads.