Hello,
I picked up a used JL500/5 and found 4 of the 5 channels working. The 5th channel, the sub section, when hooked up to a speaker has a low distorted full-range sound coming from it, with little effect from the input sensitivity. The speaker has been ruled out, and the external input signal has been ruled out.
One of the internal cards has 1 (the lower one) of the 3 LED's illuminated. I checked the resistance across almost every resistor on this card, particularly the 47k's that Perry mentions to check in this thread: http://www.diyaudio.com/forums/car-audio/216855-jl-audio-500-5-channels-not-working-please-help.html
The resistors are in spec. I did resolder the 47k next to the upper LED's as described in the referenced thread but that did not solve the problem. I will try again to solder, desolder, and add new solder now that the amp is on my bench.
DC voltage is 0 across the left LED (380 mV across the resistor to its left) and 43V across the right one (49V across the 47k resistor to its right). Volts, across the right, not mV, just to confirm since its high for an LED. I double checked both measurements.
Further inspection and resistance measurements of the amp revealed a loose resistor towards the top left section of the amp (R915 popped off when probing it). In fact R910-R915 all look like they have taken a thermal beating but are in spec. In addition, it looks like R800-R805 have been touched up with solder. (pics attached).
The two side-by-side transformers have sticky residue on them (pic attached)
I have not done any additional testing at this point, but I did want to get a thread started for assistance. Thanks in advance.
I picked up a used JL500/5 and found 4 of the 5 channels working. The 5th channel, the sub section, when hooked up to a speaker has a low distorted full-range sound coming from it, with little effect from the input sensitivity. The speaker has been ruled out, and the external input signal has been ruled out.
One of the internal cards has 1 (the lower one) of the 3 LED's illuminated. I checked the resistance across almost every resistor on this card, particularly the 47k's that Perry mentions to check in this thread: http://www.diyaudio.com/forums/car-audio/216855-jl-audio-500-5-channels-not-working-please-help.html
The resistors are in spec. I did resolder the 47k next to the upper LED's as described in the referenced thread but that did not solve the problem. I will try again to solder, desolder, and add new solder now that the amp is on my bench.
DC voltage is 0 across the left LED (380 mV across the resistor to its left) and 43V across the right one (49V across the 47k resistor to its right). Volts, across the right, not mV, just to confirm since its high for an LED. I double checked both measurements.
Further inspection and resistance measurements of the amp revealed a loose resistor towards the top left section of the amp (R915 popped off when probing it). In fact R910-R915 all look like they have taken a thermal beating but are in spec. In addition, it looks like R800-R805 have been touched up with solder. (pics attached).
The two side-by-side transformers have sticky residue on them (pic attached)
I have not done any additional testing at this point, but I did want to get a thread started for assistance. Thanks in advance.
Attachments
![IMAG3498[1].jpg](/community/data/attachments/342/342956-308164aad4d6dcd804f948010b289151.jpg?hash=MIFkqtTW3N)
![IMAG3500[1].jpg](/community/data/attachments/342/342975-fee4037bc37be80a95906b851e072e6c.jpg?hash=_uQDe8N76A)
![IMAG3502[1].jpg](/community/data/attachments/342/342995-0dd65082651c9ea65ec754ddf51d3a23.jpg?hash=DdZQgmUcnq)
The 47k resistors are for the full range channels. Those have nothing to do with the sub channel.
Have the 900 series transistors failed?
If they haven't failed, the resistors were probably damaged when they failed previously.
Have the 900 series transistors failed?
If they haven't failed, the resistors were probably damaged when they failed previously.
Hi deocder
I know that you've checked pretty much all external signal sq, and the sub-woofer driver itself. But don't forget to check the speaker cable for shorting e.g., pos(+) to neg(-) continuity. Even just one small strand of wire making contact with the opposite pole will cause the amp to go into "Fault protection" mode, causing distortion, anemic sq, amp overheating, amplifier thermal protection tripping, warning led glow, etc... it happened to me so maybe, just check. 😉
rigtec, cheers!
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I was able to pull 3 of the 900 series transistors off the board before my iron gave out on me. I've attached the forms for the readings. It looks like these were replaced before. These were labeled IRFZ44R. I believe they all need to be replaced.
I checked the other FET types out of curiosity and it was interesting to see that Q202,Q203,Q102,Q104,Q402,Q403,Q302,Q303,Q406,Q405,Q422,and Q408 are all IRF504
All 900 series FET's are SUP60N06
R910-915 look pretty burned so I'm going to have to replace those.
R800-805 were either replaced or resoldered as there is excess solder and flux residue. (Pic attached)
I'll get a new iron tomorrow so I can keep working.
I have ruled out the bad speaker wire, but thanks for the input.
I checked the other FET types out of curiosity and it was interesting to see that Q202,Q203,Q102,Q104,Q402,Q403,Q302,Q303,Q406,Q405,Q422,and Q408 are all IRF504
All 900 series FET's are SUP60N06
R910-915 look pretty burned so I'm going to have to replace those.
R800-805 were either replaced or resoldered as there is excess solder and flux residue. (Pic attached)
I'll get a new iron tomorrow so I can keep working.
I have ruled out the bad speaker wire, but thanks for the input.
The 900 series FETs are the power supply transistors for the sub channel. Q405, 406, 422 and 408 are the output transistors for the sub channel.
Ok, so next step is to check those output transistors and replace the 900 series resistors and transistors. Are there any other things I can check at this point?
Would bad supply transistors cause the two LED's on the card to not illuminate?
Would bad supply transistors cause the two LED's on the card to not illuminate?
You need to confirm that the drive circuit for the sub FETs is OK. You'll need to clamp all of the other FETs to the heatsink to protect them while testing the drive circuit.
You shouldn't have 3 cards with LEDs lit and one without. Are the two adjacent LEDs out?
Did you re-solder the connections on the 47k resistor for those LEDs?
You shouldn't have 3 cards with LEDs lit and one without. Are the two adjacent LEDs out?
Did you re-solder the connections on the 47k resistor for those LEDs?
When I test the drive circuit, does that assume I have removed all 800 series transistors? Do I need to send I signal through the input to test the circuit? Or am I just going off of the LED's on the cards?
I went ahead and re-clamped the remaining transistors to the sink. Powered the amp and found the same LED lights on and off as stated in the original post (two adjacent LED's out on one card). I had previously re-soldered the 47K resistor. The LED's look a bit burnt as well. I know they can't take 43 volts....they may never light up again. I've attached a pic of both the ones that look burnt and ones that do light up.
I went ahead and re-clamped the remaining transistors to the sink. Powered the amp and found the same LED lights on and off as stated in the original post (two adjacent LED's out on one card). I had previously re-soldered the 47K resistor. The LED's look a bit burnt as well. I know they can't take 43 volts....they may never light up again. I've attached a pic of both the ones that look burnt and ones that do light up.
Attachments
![IMAG3576[1].jpg](/community/data/attachments/348/348503-53413040e9926809ba68e3292ed9b39f.jpg?hash=U0EwQOmSaA)
![IMAG3575[1].jpg](/community/data/attachments/348/348525-7691b5937f676e950f90234f44ba51d2.jpg?hash=dpG1k39nbp)
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The Mouser 696-SML-LX1206GC seems to be a good replacement for the LEDs on the driver boards.
The 800 series FETs can remain in the amp.
You don't need to drive a signal into the amp.
You will measure the DC voltage on the 3rd leg of the driver transistors for the 900 series FETs. Set your meter to DC volts and measure the voltage on the 3rd leg of Q901 and Q902. Don't let your probe slip.
The 800 series FETs can remain in the amp.
You don't need to drive a signal into the amp.
You will measure the DC voltage on the 3rd leg of the driver transistors for the 900 series FETs. Set your meter to DC volts and measure the voltage on the 3rd leg of Q901 and Q902. Don't let your probe slip.
Solder a 1k resistor from the 3rd leg of the two driver transistors to the third pad of one of the 900 series FETs.
Measure the DC voltage on the 3rd leg of the driver transistors again.
Move the resistor from the 3rd pad of the 900 series FETs to the center pad of the 900 series FETs and measure the DC voltage on the 3rd leg of the driver transistors again.
Post the four voltage readings that you get.
Measure the DC voltage on the 3rd leg of the driver transistors again.
Move the resistor from the 3rd pad of the 900 series FETs to the center pad of the 900 series FETs and measure the DC voltage on the 3rd leg of the driver transistors again.
Post the four voltage readings that you get.
It appears that there is a problem with the Q900/901 pair. When you order parts, order several 2SB1260s and 2SD1898s.
To remove these, apply additional solder to the tab and enough to bridge the legs together. Heat the tab for a few seconds then quickly move to the legs. It should readily slide off of the pads.
To remove these, apply additional solder to the tab and enough to bridge the legs together. Heat the tab for a few seconds then quickly move to the legs. It should readily slide off of the pads.
Alright, ordered 20 IRFZ44R's, 20 47 ohm resistors, 8 led's, 10 2SB1260's, and 10 2SD1898's from Mouser. Should all be here by Friday. I will follow up then. Thanks!
I will receive the 47 ohm resistors and IRFZ44R's today. Is it safe to replace the resistors today? I assume I should wait on the IRFZ44R's until the drive circuit tests properly.
The LED's and other transistors will arrive tomorrow.
The LED's and other transistors will arrive tomorrow.
All the parts have arrived and I am about to replace the Q900 transistor marked UY (KTC4379) with 2SD1898 and the Q901 transistor marked WY (KTA1666) with the 2SB1260.
I will then:
Aslo, I am having a very hard time soldering anything on this board. I have tried 2 soldering irons, first my Weller TC201T with a #7 tip which I thought died, and now my Hako936. I have it set to 650 degrees. It takes forever to get the solder on the board to flow, even when trying to apply additional solder to the joint. Solder melts just fine when applied to the tip. Is this typical with this board? Do I need to try yet another iron?
I will then:
Aslo, I am having a very hard time soldering anything on this board. I have tried 2 soldering irons, first my Weller TC201T with a #7 tip which I thought died, and now my Hako936. I have it set to 650 degrees. It takes forever to get the solder on the board to flow, even when trying to apply additional solder to the joint. Solder melts just fine when applied to the tip. Is this typical with this board? Do I need to try yet another iron?
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