Looking for assistance on Pioneer SX-D7000 tuner issue LONG

[saabracer23]

I’m working on a receiver for the buddy of a forum member, as I’m local-ish. The right channel was out and there was distortion in the other channel. Before starting my work as I normally do I went through all of its functions to see what worked and what did not. As mentioned there were issues with output, but aux, phono 1, phono 2 were passing signal. The only other issue I was having was with the tuner. I could faintly hear voices on FM, but had a lot of static. Same with AM. The signal bars on fm would sit at the halfway point regardless of what station I was tuned to. I wrote it off as not having the best antenna and generally having absolutely horrid reception at my home, I probably shouldn’t have. We have to use the internet radio in order to listen to our morning shows. Anyways, I was asked if I could also give it a refresh while I was in there fixing the issues, meaning recap, measured outputs and put new thermal compound down, etc.

I tore it down, did everything discussed, got both channels going with clean output, set bias and offset, set output meters, and went through the testing of it. Aux and phono sections sound great, really great. I still wasn’t able to receive any radio. I bought a proper antenna and still nothing. I compared it to another tuner I have here and while this other tuner has a lot of static, it’s definitely receiving better than the d7000. The best way to describe what I’m getting is motorboating. Both the AM and FM are doing it, though the FM is doing it at a faster frequency.

I figure at this point there is an issue with the tuner section. I see there are other that have had an issue with this receivers tuner and I know someone with this model and he uses an outboard tuner. I go through the power supply and certain points to check voltages as suggested in these other tuner issue threads.

Power supply voltages look good:

Pin 24, 53.76V (supposed to be 54V)
Pin 25, 29.59V (supposed to be 32V)
Pin 21, -55.35V (supposed to be -54V)
Pin 27, -31.53V (supposed to be -32V)
Pin 20, 12.99V (supposed to be 13V)
Pin 29, -20.75V (supposed to be -21V)
Pin 10, 8.61V (supposed to be 8.6V)

Checking pins that were on the tuner board, one seems to be about 5V high, pin 7

Pin 7, 28.97V (supposed to be 24V)
Pin 5, 30.12V (supposed to be 32V)
Pin 37, 8.57V (supposed to be 8.5V)
Pin 34, 13.36V (supposed to be 13V)
Pin 35, 13.36V (supposed to be 13V)

I contact the father-in-law of the owner (he is the one that brought it to me) and let him know that I was able to fix everything that I was requested and that while it sounded good I wasn’t able to get the tuner to work. He talked to his son-in-law and was told that the tuner was working and just had the issues with output.

Bummer... I should have done more testing with the tuner section prior to the work, that was my fault, but I wasn’t receiving anything in my lab.

Im fairly certain none of the work I did would have effected the tuner to make it motorboat and not receive. Since I had the preamp section opened up and had the boards dangling about I made sure to check all of the wiring to make sure none of them broke off, all look good. I was reading about issues with some of the ICs in the tuner section: HA1201, PA3007, PA4006, TC9124AP, TC9123P. I too figured on an IC after measuring voltages and then changed my mind once I saw Markthefixer say he has replaced ICs he thought were bad and had no change.

Everything below I’m going off of this thread
https://audiokarma.org/forums/index.php?threads/sx-d7000-tuner-help.452492/

I have 12V on pin 5 of both of the HA1201

I read there is supposed to be a 10Mhz sinewave on pin 8 of the PA3007, I have no 10Mhz sinewave, just a steady line at 2V.

The person in this thread posted the voltages on his 3007 and they differ from mine which made me think there was an issue. Asterisks are next to the values that I find far enough off of what this other member posted.

——— His ———— Mine

Pin 1 6.33V ———- 6.33V
Pin 2 6.33V ———- 6.34V
Pin 3 6.41V ———- 6.31V
Pin 4 6.73V ———- 6.23V
Pin 5 12.9V ———- 13.35V
Pin 6 .367V ———- 2.02V ***
Pin 7 1.33V ———- 2.02V ***
Pin 8 .365V ———- 2.02V ***
Pin 9 4.5V ———- 4.95V
Pin 10 0V ———— 0V
Pin 11 0V ———— 1.4V ***
Pin 12 0V ———— 0V
Pin 13 2.97V ——- 2.4V
Pin 14 3.05V ——- 2.65V
Pin 15 12.5V ——- 12.72V
Pin 16 .026V ——- .015V
Pin 17 6.33V ——- 6.30V
Pin 18 0V ———- 0V

I have taken a video of the issue and if anyone would like me to email that video to them I can.

Any assistance would be greatly appreciated!

Thank you,
Dan

 

[Ylli]

Just taking a quick peek at it. You say the issue is on both AM and FM? The outputs of the AM and FM sections are combined and fed into pin 1 of Q8, PA 4006A. Since it is common to both AM and FM, I'd start looking there.

Have you got any test equipment beyond a DMM?

 

[saabracer23]

Just taking a quick peek at it. You say the issue is on both AM and FM? The outputs of the AM and FM sections are combined and fed into pin 1 of Q8, PA 4006A. Since it is common to both AM and FM, I'd start looking there.

Have you got any test equipment beyond a DMM?

Thank you much, I’ll take a look around Q8 tomorrow. I have an oscilloscope that measures up to 100 MHz, signal generator, and some smaller things like peak atlas esr meter, peak atlas transistor/diode tester, and lcr meter. Not sure how much those last things will help out.

Dan

 

[Ylli]

'Scope out pin 1 of that PA4006A and see if there is audio there. If it looks like there is audio there, you could lift the positive end of C67 and/or C68 and jumper from Q8 pin 1 to the (now floating) positive input of C67 and/or C68. Audio should pass through. that would confirm a problem with Q8.

 

[saabracer23]

'Scope out pin 1 of that PA4006A and see if there is audio there. If it looks like there is audio there, you could lift the positive end of C67 and/or C68 and jumper from Q8 pin 1 to the (now floating) positive input of C67 and/or C68. Audio should pass through. that would confirm a problem with Q8.

I don’t think there is audio there. Regardless of which station it’s on I get this basically. Looks like distortion sitting at 7.33V



I scoped the output of a cd and this is what I got. This is what I want to see.



I looked at C67 and C68. It looks like the service manual has C68 (or is that 58) wrong. It shows three with positive facing the same way and the last one positive is facing the other way. The actual board is marked two one way and two the other. This should be correct as I replace a cap as soon as I pull it, no removing multiples and then replacing. So in the two I have marked in red, is the top C68 and is that C58 below?




If I switch over to AM this is what I measure at pin 1, just a 7.60V



Thank you again,
Dan

 

[Ylli]

OK, hard to believe both the AM and FM tuners quit at the same time. So what else is common? Power supply or something with the synthesizer perhaps. You seem to have covered the power supply voltages, lets see if we can confirm the synthesizer. Find pin 61 on the tuner board. Nothing should be connected to it, it's basically a test point. Connect a voltmeter to it. Pin 60 is the associated ground. With the unit set to FM @87.5 MHz, the voltage should be 6 V. At 108 KHZ, the voltage should be +20 volts.

 

[saabracer23]

OK, hard to believe both the AM and FM tuners quit at the same time. So what else is common? Power supply or something with the synthesizer perhaps. You seem to have covered the power supply voltages, lets see if we can confirm the synthesizer. Find pin 61 on the tuner board. Nothing should be connected to it, it's basically a test point. Connect a voltmeter to it. Pin 60 is the associated ground. With the unit set to FM @87.5 MHz, the voltage should be 6 V. At 108 KHZ, the voltage should be +20 volts.
View attachment 1614704 View attachment 1614705

Looking good there.
87.55 MHz (won’t got to 87.5 exactly) sitting at 5.90V
108 MHz sitting at 19.96V

Dan

 

[Ylli]

OK, well it looks like we will have to look at each tuner (AM/FM) separately - let's continue with the FM section. Glad you got that scope. Those PAxxxx chips do not seem to have much if any info on line. Will have to guess at the internals based on the surrounding circuitry. .

Since the tuning voltage follows the selected frequency and is near specification, I would assume the local oscillator is running. There appears to be quite a bit of gain ahead of the PA3007, so let's put the scope on the input of Q7 (pin 8) and see if we can see any of the 10.7 MHz IF. Should also see 10.7 MHz on the quadrature coil, Q7 pins 1 and 17. Be sure you are tuned to a strong FM station.

Another path to investigate... You mentioned that you may be able to hear the FM (and AM) signal *very* weak in a background of static. Perhaps something is in a 'mute' state. I'll have to stare at the schematic a bit.

Got to ask, have the switches all been cleaned?

 

[saabracer23]

OK, well it looks like we will have to look at each tuner (AM/FM) separately - let's continue with the FM section. Glad you got that scope. Those PAxxxx chips do not seem to have much if any info on line. Will have to guess at the internals based on the surrounding circuitry. .

Since the tuning voltage follows the selected frequency and is near specification, I would assume the local oscillator is running. There appears to be quite a bit of gain ahead of the PA3007, so let's put the scope on the input of Q7 (pin 8) and see if we can see any of the 10.7 MHz IF. Should also see 10.7 MHz on the quadrature coil, Q7 pins 1 and 17. Be sure you are tuned to a strong FM station.

Another path to investigate... You mentioned that you may be able to hear the FM (and AM) signal *very* weak in a background of static. Perhaps something is in a 'mute' state. I'll have to stare at the schematic a bit.

Got to ask, have the switches all been cleaned?

It’s hard, well impossible to get a strong station. When you hear the talking you can tell that it’s talking, but can in no way make it out. It’s off way in the background. Pretty much all of the frequencies I go to the bars look like this.



Hard to see really, occasionally I’ll get to a frequency that will flicker the stereo lamp.

On pin 8 of Q7 all I get is a steady 2.5V.


On pin 1 and 17 of Q7 I get a steady 7V.


All switches and pots have been thoroughly cleaned with deoxit and finished off with CorrosionX.

Dan

 

[Ylli]

Put that scope in 'AC' coupled mode and get the sensitivity down into the 50 mV/div range. Check again, Q8 pin 1, Q7 pins 8, 1, and 17.

Looks like things are pretty accessible. Check DC voltages as listed on the schematic from Q7 back towards the antenna. Could also try to work backwards with the scope, keeping it in the low mV AC ranges.

 

[saabracer23]

Put that scope in 'AC' coupled mode and get the sensitivity down into the 50 mV/div range. Check again, Q8 pin 1, Q7 pins 8, 1, and 17.

Looks like things are pretty accessible. Check DC voltages as listed on the schematic from Q7 back towards the antenna. Could also try to work backwards with the scope, keeping it in the low mV AC ranges.

Alright, got the scope into AC coupled mode and took some measurements.

Pin1 of Q8


Pin 1 and Pin 17 of Q7


Pin 8 of Q7



I measured all of the voltages on the pins of Q7 and Q8. There were a few discrepancies.

Q7 PA3007
Pin 11, schematic shows 0.6v and I’m reading 1.36v

Q8 PA4006
Pin 18, schematic shows 0.1v and I’m reading 5.005v in fm and 6.2v in am

Pin19, schematic shows 6.9v and I’m reading 5.01v in fm and 12.7v in am

Pin 25, schematic shows 3.9v and I’m reading 2.9v

Did some measuring of voltages on the board and looks like I’m missing some voltage.



According to the schematic just over from Q7 there is a transistor, Q15 I think it says marked in red(difficult to read) that is supposed to have 4.9v on the emitter and 5.5v on the base. I have 0v at both points.

Dan

 

[Nakdoc]

Look at the tuner block diagram. Is T2 common to both AM and FM? I'm failing at remembering the pioneer part number for the filter that failed in many different models. ATF??

 

[Ylli]

Q15 I think it says marked in red(difficult to read) that is supposed to have 4.9v on the emitter and 5.5v on the base. I have 0v at both points.

Q16. It's a buffer for the "AM Stereo" output port. It may not have any voltage applied in FM mode. See what you get set to AM.

Scope pictures sure don't seem to be showing anything other than noise. When looking for the 10.7MHz IF signal, speed up the trace to 0.1 uS/div if it will go that fast.

Please check:
Q6 pin 5, DC voltage + look for signal with scope
Q5 pin 5, DC voltage+ scope
Q57 drain, DC voltage
Q2 collector, DC voltage

Q7 PA3007
Pin 11, schematic shows 0.6v and I’m reading 1.36v

Locate board pin "56", it's in the middle of the board. I think it is a mute in/out test point. Temporarily ground that point and see if you get an real audio.

If it is not too difficult, could you humor me and lift the + end of C67 or C68 and jumper it to Q8 pin 1? See if you get real audio of of one of the channels. AM and FM.

Nakdoc, thank you for dropping in. The more ideas the better. T2 is the FM detector quadrature coil. Shouldn't affect AM.

 

[saabracer23]

Look at the tuner block diagram. Is T2 common to both AM and FM? I'm failing at remembering the pioneer part number for the filter that failed in many different models. ATF??

Here is the block diagram if it helps us in any way, and thank you so much for contributing, really really appreciate it!

Q16. It's a buffer for the "AM Stereo" output port. It may not have any voltage applied in FM mode. See what you get set to AM.

Scope pictures sure don't seem to be showing anything other than noise. When looking for the 10.7MHz IF signal, speed up the trace to 0.1 uS/div if it will go that fast.

Please check:
Q6 pin 5, DC voltage + look for signal with scope
Q5 pin 5, DC voltage+ scope
Q57 drain, DC voltage
Q2 collector, DC voltage


Locate board pin "56", it's in the middle of the board. I think it is a mute in/out test point. Temporarily ground that point and see if you get an real audio.

If it is not too difficult, could you humor me and lift the + end of C67 or C68 and jumper it to Q8 pin 1? See if you get real audio of of one of the channels. AM and FM.

Nakdoc, thank you for dropping in. The more ideas the better. T2 is the FM detector quadrature coil. Shouldn't affect AM.

You are correct, when on AM Q16 has the appropriate voltages.

Sped the scope up to 0.1uS/div and can go faster if you need, up to .002uS/div. here are the new pics of Q7 and Q8

Pin 1 of Q7 some form of sine wave, second pic is a .1uS/doc as requested



Pin 17 of Q7


Pin 8 of Q7


Pin 1 of Q8




On Q6 pin 5 I read 12.03vdc and scoped


Q5 pin 5 I read 11.92vdc and scoped



Q2 collector I read a fluctuating 1.6vdc to 2.2vdc

Q57 I have 0vdc on the drain.


I lifted the positive of c67 and c68, as I mentioned previously c68 is marked incorrectly in the manual. That have positive facing away for Q8 and it’s facing towards on the board. I really with they would have marked the board as the manual is very difficult to read. I’m guessing c68 is the on top of the two below marked in red? So the one right below c67?



Anyways I lifted the positive of both and jumpered the positive lead of each to pin 1 on Q8 and still just a bunch of static, motorboating, and very faint voices. When I mean faint I mean you can hear the higher frequencies and tell it’s a human, but that’s about it. So no change really.

Dan

 

[Ylli]

Q57 I have 0vdc on the drain.

That's interesting. Are you sure you were on the drain? Should be about 12 volts on the right side of R30, and about 9 volts on the left side.

Looking at pin 1 Q7, it looks like the quadrature detector is trying to lock on to noise. But looking at pin 8 of Q7, there does not appear to be any signal there.

Pin 5 of Q6, DC voltage OK, but see no 10.7 MHz signal.
Pin 5 of Q5 DC voltage OK, no signal.
Reconfirm the drain voltage of Q57 by measuring on both ends of R30.

 

[saabracer23]

That's interesting. Are you sure you were on the drain? Should be about 12 volts on the right side of R30, and about 9 volts on the left side.

Looking at pin 1 Q7, it looks like the quadrature detector is trying to lock on to noise. But looking at pin 8 of Q7, there does not appear to be any signal there.

Pin 5 of Q6, DC voltage OK, but see no 10.7 MHz signal.
Pin 5 of Q5 DC voltage OK, no signal.
Reconfirm the drain voltage of Q57 by measuring on both ends of R30.
View attachment 1615535

Sorry after sitting there an looking at it I was measuring the wrong device. I should measured on the top of the board. That’s what you get when you go to measure from the back side.

So I’m getting about 9.5v at the drain. Sorry.


Dan

 

[Ylli]

Hmm, maybe we should move to the AM side. I still think it is something common and approaching it from a different direction might be helpful.

Start by putting it in AM mode tuned to an active station around 1000 KHz and checking the DC voltages on the pins of Q14, the HA1138. You have already checked the voltages on Q16. Then look with the scope:

Pin 10 should be audio. Set the scope at 1 ms/div and the vertical as needed to see the signal. If we have audio here, STOP.
Look at pin 3. This would be the Local Oscillator. Scope at 1 us/div, vertical as required.
Pin 13 is the IF output at 455 KHz. Scope at 2 us/div.
Pin 15 is IF input. the signal may be too low there to see.

I found this on the NTE1494, which is supposed to be a replacement for an HA1138.

 

[saabracer23]

Hmm, maybe we should move to the AM side. I still think it is something common and approaching it from a different direction might be helpful.

Start by putting it in AM mode tuned to an active station around 1000 KHz and checking the DC voltages on the pins of Q14, the HA1138. You have already checked the voltages on Q16. Then look with the scope:

Pin 10 should be audio. Set the scope at 1 ms/div and the vertical as needed to see the signal. If we have audio here, STOP.
Look at pin 3. This would be the Local Oscillator. Scope at 1 us/div, vertical as required.
Pin 13 is the IF output at 455 KHz. Scope at 2 us/div.
Pin 15 is IF input. the signal may be too low there to see.

I found this on the NTE1494, which is supposed to be a replacement for an HA1138.
View attachment 1615663

It won’t tune into a station, even with an external AM antenna. Regardless of where it’s at the voltages didn’t change.

Q14

Pin 1: 11.73v
Pin 2: 2.737v
Pin 3: 11.8v
Pin 4: 11.81v
Pin 5: 4.77v
Pin 6: 9.49v
Pin 7: 1.97v
Pin 8: 0.895v
Pin 9: fluctuates 0.12-0.4
Pin 10: fluctuates 3.59-3.7
Pin 11: 4.214v
Pin 12: 13.2v
Pin 13: 2.72v
Pin 14: 2.68v
Pin 15: 2.686v
Pin 16: 0v

I took a couple pics of each pin.

Pin 10





Pin 3



Pin 13



Pin 15 is pretty low, 20.0mV is as low as the scope goes.



Thank you again!

Dan

 

[Ylli]

What do you mean 'won’t tune into a station'? You mean no usable audio out or it won't stay on a given frequency? What I am seeing on the scope on pin 10 could be audio. Have you got anything that you could use to 'listen' to pin 10? Some high impedance headphones, or you could jumper it with an RCA cable to another amplifier.

You mentioned you have a signal generator. I assume this is an audio signal generator and not an RF signal generator?

This is becoming a real head-scratcher.

 

[Ylli]

Looking at the video you emailed, and the pin 3 pix above, I am wondering if the frequency synthesizer is actually locked. Let's look at the tuning voltage (Circuit board pin 61) with the scope. Try AC coupling, DC coupling, various vertical gains, and various sweep speeds - the voltage on that test point should be a rock solid straight line (unvarying DC voltage). If there is any ripple, or varying voltage, I want a picture of it.