Help diagnosing Pyle Receiver PTA66BT with burned resistors

[SluggerB]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

OK, I soldered the 2W resistor in. With chips A-E & the power LED connected (F, G, and the CD IC disconnected), I read 6.23v across it.

I soldered back in the resistors to connect up chips F & G. With chips A-G & the power LED connected (CD IC disconnected) I read 7.66v across it. The VCC+ of chip F & G were around 5v each (A-E are ~10v)

I soldered back on the resistors and all the other components connecting the CD IC to the board, and read 11.70v across the new resistor. I took out my thermometer and the temp seems to stabilize at 137F-139F degrees. Certainly to hot to touch for more than a second, but I saw no white smoke and no burning resistor smell.

Now here is where I earn my idiot reward. I was checking the fan, and I disconnected it to the board and connected the ends to a 9v battery, and it spun. So I thought maybe somehting is wrong with the board not turning it on, how about I just wire it right to the main power supply going into the unit? Nothing bad could happen by dumping 120 AC into a small 12v DC fan, could it?

So yeah, now I need a new fan. And annoyingly its a 60mm fan and all I have on hand are 80mm fans, and even more annoyingly the unit is like 75mm tall so I can't fit an 80 in there as a replacement. Sigh

So I'm ordering a new 60mm fan, I don't want to run the unit for a long time without the cooling fan attached, so while it's back together I have not extensively tested it yet. When I get the new fan in and run it through it's paces I will let you know what happens.

[budm]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

OK, I soldered the 2W resistor in. With chips A-E & the power LED connected (F, G, and the CD IC disconnected), I read 6.23v across it.

I soldered back in the resistors to connect up chips F & G. With chips A-G & the power LED connected (CD IC disconnected) I read 7.66v across it. The VCC+ of chip F & G were around 5v each (A-E are ~10v)

I soldered back on the resistors and all the other components connecting the CD IC to the board, and read 11.70v across the new resistor. I took out my thermometer and the temp seems to stabilize at 137F-139F degrees. Certainly to hot to touch for more than a second, but I saw no white smoke and no burning resistor smell.

Now here is where I earn my idiot reward. I was checking the fan, and I disconnected it to the board and connected the ends to a 9v battery, and it spun. So I thought maybe something is wrong with the board not turning it on, how about I just wire it right to the main power supply going into the unit? Nothing bad could happen by dumping 120 AC into a small 12v DC fan, could it?

So yeah, now I need a new fan. And annoyingly its a 60mm fan and all I have on hand are 80mm fans, and even more annoyingly the unit is like 75mm tall so I can't fit an 80 in there as a replacement. Sigh

So I'm ordering a new 60mm fan, I don't want to run the unit for a long time without the cooling fan attached, so while it's back together I have not extensively tested it yet. When I get the new fan in and run it through it's paces I will let you know what happens.

So those Voltages are for the 180 Ohms 2W for the V+ only? No change in the reading for the 180 Ohms for the V-, correct?

"I took out my thermometer and the temp seems to stabilize at 137F-139F degrees."
So if room temp is 70F then temp rise is 69F (about 20c rise), so that is way below the handling spec of two Watts resistor.
According to the chart for 2W with power dissipation of 0.76W (11.70V on 180 Ohms, 37.50 % of power rating ratio), the temp rise is expected to be
50c (122F), so the resistor is cooler than expected since temp rise is only 69F.. less rise than using 1W dissipating 0.76W.

[SluggerB]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

So those Voltages are for the 180 Ohms 2W for the V+ only? No change in the reading for the 180 Ohms for the V-, correct?

Yes. I didn't check voltage on the V- cause I didn't add anything back onto it.

So if room temp is 70F then temp rise is 69F (about 20c rise), so that is way below the handling spec of two Watts resistor.
According to the chart for 2W with power dissipation of 0.76W (11.70V on 180 Ohms, 37.50 % of power rating ratio), the temp rise is expected to be
50c (122F), so the resistor is cooler than expected since temp rise is only 69F.. less rise than using 1W dissipating 0.76W.

The room was about 64 degree that I was working in. So about a 76F rise. But that's still less than 122F. I also mounted the resistor about as far above the board as the legs would lift it.

[budm]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Yes. I didn't check voltage on the V- cause I didn't add anything back onto it.

The room was about 64 degree that I was working in. So about a 76F rise. But that's still less than 122F. I also mounted the resistor about as far above the board as the legs would lift it.

"But that's still less than 122F" Do you want to see 122F temp rise instead?

Well, it is good that the measured temp rise is not 122F, if it is then the resistor will be 191F!, the lower the measured temp rise you see the better.

[budm]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

BTW, can you get a hold of Oscilloscope and know how to use it?

[SluggerB]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

BTW, can you get a hold of Oscilloscope and know how to use it?

That would be a no and no.

Replacement fans showed up, tonight I install the new fan, button everything up, and run the unit for 30 minutes straight and see if it holds up. If it passes that test it's back to the owner on Saturday.

[SluggerB]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

"But that's still less than 122F" Do you want to see 122F temp rise instead?

No, I was saying it's less than 122F, which is a good thing.

[SluggerB]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Final update: I installed the new fan, plugged in a speaker, connected to my phone's Bluetooth, and played about 30 minutes of music. I kept the thermal probe resting on the new 2W resistor and it held steady at 137-139F the whole time. I reassembled the unit, gave it one last test run, and I'm calling it fixed. It goes back to the owner on Sat.

Again huge huge huge thanks to budm for all the help, I've learned a ton and had a blast! Here's to the next one!

[petehall347]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

59.4444C sounds lots better than in F ... if the owner is happy that is what matters . if it comes back graft in a better power supply for that circuit and maybe add a fuse or 2 .

[budm]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Final update: I installed the new fan, plugged in a speaker, connected to my phone's Bluetooth, and played about 30 minutes of music. I kept the thermal probe resting on the new 2W resistor and it held steady at 137-139F the whole time. I reassembled the unit, gave it one last test run, and I'm calling it fixed. It goes back to the owner on Sat.

Again huge huge huge thanks to budm for all the help, I've learned a ton and had a blast! Here's to the next one!

Thanks for the follow-up.

[PMan976]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

I tried following this as best as I could and I am probably missing something.
I have a unit that has the exact same issue with that resistor burned up. Does anyone happen to remember what was the cause?

[budm]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

It is due to failed Voltage transistors, read post 41 and lots after that.

[PMan976]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Thank you budm, I replaced all of the blown transistors and also upgraded the Resistors to 3 watt. The unit is working great now. Your input was most helpful.

[snoozr]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

I also had this same issue. I replaced the transistors and used the 2 watt resistor. Any idea what would cause distortion in this unit. I'm using bluetooth but can not turn the sound up very much due to distortion.
Thanks. By the way I think budm deserves an award for most patient member

[dragonmas]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

May be a day late and a dollar short but I took a pta66bt-A good working and either pulled and tested every active component made pictures took voltage readings dl data sheets.I used these findings and am in process of repairing same model unit with blown 180 ohm 1 watt resistor.

Every d716/2SD716(30-35 watt)(2SD718)(35-40 watt) checks good Collector( pin 2)(base pin 1)(emmiter pin 3) and c-b is .55 ,c-e reads OL(infinity or open) b-e OL using black lead(reference) on Fluke 77 diode check. Voltage on 7805(input 29v output is 5.02)voltage drop of 180 resistor toward speaker connection =24/31 180 toward the front is -24/-31.KIA4558p(op amp) pin 4 -11.9 pin 5 is =11.9.Connection(ribbon cable) from main board to ps board 5v=5v +v=11.9 -v=-11.9.These readings are from the good working unit only difference is the power tx's they are 2SD718(35-40 watts) waiting on the 180's. and op-amp.Can not find anything dead shorted on the bad PS board on the bad unit.

[Flacooo1]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Hi everyone and thanks for those that are helping on this tread I Know is kind of old now, I have some help not the real fix just some help, the burned resistor is NOT 180ohm I have 3 units 2 pta66bt one brand new and one burnt that i purchase off ebay for $25 and one brand new pta44bt that stopped working but with warranty, so I sended the pta44bt to pyle and they in fact fixed I don't want to open the unit and see what they did to it but i can confirm they put a bigger resistor same ohm but 2w and it looks like the 3 caps next to it are bigger in size I don't have pictures of that one from inside since I did not opened but i do have pictures from the pta66bt new unit and burnt unit, on the burn unit i put a 2w 100ohm resistor and it did smoke as well so next is to check transistors and see if i can upsize the caps

[dragonmas]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Have repaired about 4 burnt resistors units. None have had fans running. Bought new unopened 66bt.It's fans not running. Traced 12v+ line of fan back to 47ohm-66ohm b647 have 32 Vdc on emitter and base and nothing on collector which appears to feed the 12vdc to the fan?
Any suggestions?

[dragonmas]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

My $3.50 fix for non-operational fan.

[dragonmas]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Neat it up some

[EZabala]

Re: Help diagnosing Pyle Receiver PTA66BT with burned resistors

Hi everyone and thanks for those that are helping on this tread I Know is kind of old now, I have some help not the real fix just some help, the burned resistor is NOT 180ohm I have 3 units 2 pta66bt one brand new and one burnt that i purchase off ebay for $25 and one brand new pta44bt that stopped working but with warranty, so I sended the pta44bt to pyle and they in fact fixed I don't want to open the unit and see what they did to it but i can confirm they put a bigger resistor same ohm but 2w and it looks like the 3 caps next to it are bigger in size I don't have pictures of that one from inside since I did not opened but i do have pictures from the pta66bt new unit and burnt unit, on the burn unit i put a 2w 100ohm resistor and it did smoke as well so next is to check transistors and see if i can upsize the caps

Hi, i have the same problem. I found that is you move to switch to 220V instead of 110V and connect to 110V, the system work great. I don't know how it's work, but it's working great.