Another sx-1010 Resto

[zebulon1]

The Fuse board (053) looks OK. Transformer is working correctly. Very nice voltage readings! When looking at the Schematic, it doesn't show what voltage from the taps. On some Pioneer schematic's they show the input voltage on the boards. What I am getting at is with the 150 watt bulb you measure the voltage coming into the set, and it's the ratio you use to check the other voltages. How does the PS board look (054) with the 150 watt lamp?

 

[craxx6969]

That is a relief that the fuse board is OK. I did not measure the pins on the 054 board. J was also fixing a laptop for a friend so time was split between both. So u didn't say any thing about the ground issue. Just curious. Late here as well. Need to sleep.

Thanks!

The Fuse board (053) looks OK. Transformer is working correctly. Very nice voltage readings! When looking at the Schematic, it doesn't show what voltage from the taps. On some Pioneer schematic's they show the input voltage on the boards. What I am getting at is with the 150 watt bulb you measure the voltage coming into the set, and it's the ratio you use to check the other voltages. How does the PS board look (054) with the 150 watt lamp?

 

[markthefixer]

It looks like I am missing a ground wire that attaches to the chassis that runs through a resistor then to the a/c input location. Photo attached for clarification.

I wonder what size resistor was used in the ground wire circuit?

2.2 meg red red green. From the white transformer wire to the chassis ground.

as for the REST of this:
100w and 150w dbt glows bright, correct?

and you think the power amps might be commanding the outputs to over conduct? Thus risking them if plugged into the power line directly.

get it glowing on the dbt, THEN measure the voltages across all eight 0.5 ohm emitter resistors on each amp card. You should be easily able to decipher which pins run off the board to the emitters of the outputs on the heat sink (edit: 14, 15, 16, 17 on each channel), use the audio output point (19) for your "black" lead, and probe with the red: while two readings will be negative voltage and two will be positive voltage, we are interested in the magnitude of the voltage.

Just for grins I would like to see what the regulated voltages are (awr-054 pins 8 to 15, 12 gnd) at that same time.

It probably won't help to measure the base voltages of the outputs (pins 10, 13),
BUT it's worth a peek to see if there is anything discernible from them, so read them too.

note for the future me: the power to the collectors of the output transistors comes exclusively through pins 9 (+54) and pin 12 (-54), so a resistor of sufficient wattage could be used to limit the current to the outputs allowing for everything to function well enough so that offending voltage readings can be taken under regulated voltage conditions. Due to the independent nature of the driver stages, the amp will not have DC balance (feedback) without the outputs in place (i.e. railed).

 

[craxx6969]

I will follow the instructions to the letter and post my results.

Yes, both the 100w and 150w bulb glow BRIGHT.. Not even a hint of dimming.
Yes, there were multiple output trans blown due to the previous tech jumping the relay which resulted in the blown diode on the one of the power boards, facing the unit it would be the one on the right(see photo in one of the earlier posts).

thanks MTF! Glad to have the info.

JT

2.2 meg red red green. From the white transformer wire to the chassis ground.

as for the REST of this:
100w and 150w dbt glows bright, correct?

and you think the power amps might be commanding the outputs to over conduct? Thus risking them if plugged into the power line directly.

get it glowing on the dbt, THEN measure the voltages across all eight 0.5 ohm emitter resistors on each amp card. You should be easily able to decipher which pins run off the board to the emitters of the outputs on the heat sink (edit: 14, 15, 16, 17 on each channel), use the audio output point (19) for your "black" lead, and probe with the red: while two readings will be negative voltage and two will be positive voltage, we are interested in the magnitude of the voltage.

Just for grins I would like to see what the regulated voltages are (awr-054 pins 8 to 15, 12 gnd) at that same time.

It probably won't help to measure the base voltages of the outputs (pins 10, 13),
BUT it's worth a peek to see if there is anything discernible from them, so read them too.

note for the future me: the power to the collectors of the output transistors comes exclusively through pins 9 (+54) and pin 12 (-54), so a resistor of sufficient wattage could be used to limit the current to the outputs allowing for everything to function well enough so that offending voltage readings can be taken under regulated voltage conditions. Due to the independent nature of the driver stages, the amp will not have DC balance (feedback) without the outputs in place (i.e. railed).

 

[zebulon1]

ME too!!

 

[craxx6969]

Here are the results of the readings, 2.2 meg from white to chassis ground, completed (used clear shrink wrap to protect the resistor

Voltage Readings..

While on dbt, 150 watt bulb, unit on, bulb glowing bright.
AWR-054 board Black lead on Ground,
Red lead on Pin
8 = 5.06vdc
9 = (-4.56)vdc
10 = (-19.45)vdc
11 = (-7.34)vdc
12 = black lead on this pin
13 = 12.32vdc
14 = 19.33vdc
15 = 8.15vdc

Measuring the AWH-032 board
Black lead on pin 19
First board is the right board (facing the unit)
R32 goes to pin 17, -196.2mv
R30 goes to pin 16, -305.3mv
R31 goes to pin 15, 294.7mv
R29 goes to pin 14, 199.2mv
~~~~~~~~~~~~~~~~~
Second board is the left board facing the unit
R32 goes to pin 17, 0v
R30 goes to pin 16, 0v
R31 goes to pin 15, 120.4mv
R29 goes to pin 14, 120.7mv
~~~~~~~~~~~~~~~~~
Right board measuring pins 10 & 13 with red lead, black lead still on pin 19 (no instructions to change to a different pin or chassis ground
Pin 10 = 13.88v
Pin 13 = (-.404v)
~~~~~~~~~~~~~~~~~
Left board measuring pins 10 & 13 with red lead, black lead still on pin 19
Pin 10 = 13.86v
Pin 13 = (-11.58v)

If any readings look funky or if I misunderstood the instruction, I will redo the readings

Just an FYI, the receiver is stone cold, no heat from any components/heat sinks..

Thanks
JT

2.2 meg red red green. From the white transformer wire to the chassis ground.

as for the REST of this:
100w and 150w dbt glows bright, correct?

and you think the power amps might be commanding the outputs to over conduct? Thus risking them if plugged into the power line directly.

get it glowing on the dbt, THEN measure the voltages across all eight 0.5 ohm emitter resistors on each amp card. You should be easily able to decipher which pins run off the board to the emitters of the outputs on the heat sink (edit: 14, 15, 16, 17 on each channel), use the audio output point (19) for your "black" lead, and probe with the red: while two readings will be negative voltage and two will be positive voltage, we are interested in the magnitude of the voltage.

Just for grins I would like to see what the regulated voltages are (awr-054 pins 8 to 15, 12 gnd) at that same time.

It probably won't help to measure the base voltages of the outputs (pins 10, 13),
BUT it's worth a peek to see if there is anything discernible from them, so read them too.

note for the future me: the power to the collectors of the output transistors comes exclusively through pins 9 (+54) and pin 12 (-54), so a resistor of sufficient wattage could be used to limit the current to the outputs allowing for everything to function well enough so that offending voltage readings can be taken under regulated voltage conditions. Due to the independent nature of the driver stages, the amp will not have DC balance (feedback) without the outputs in place (i.e. railed).

 

[HVHiFI]

Power supply seems proportionately low on all power rails, possibly the DBT still limiting the current. Something seems up with that left amp board.

 

[craxx6969]

Agree the left board seems wacky. Will wait for further instructions.

Power supply seems proportionately low on all power rails, possibly the DBT still limiting the current. Something seems up with that left amp board.

 

[HVHiFI]

The outputs and drivers are OK?

 

[craxx6969]

Brand new, On Semis and new drivers based on the recap list. All trans and caps replaced . The left board stv-3 adjacent to q9(not attached to the heatsink) has been worked on. I do have a photo of it. I'll post it IF necessary

Unit has never been off the dbt.

The outputs and drivers are OK?

 

[markthefixer]

Were ALL resistors on the amp boards checked with one leg raised when you found destroyed transistors?

This amp is funny, the driver stages for the PNP outputs and the NPN outputs are COMPLETELY separate.

Please detail all replacement parts on the amp cards. Just grab the replacement parts list and delete those that are still original.

Also are you sure that both idle current pots are adjusted to zero ohms.
And the offset pots about centered in their rotation?

I really want to get the amps powered up with the outputs current limited (sort of a dim bulb just for the outputs).

Do you have some ~ 250 ohm to 2k ohm, 5+ watt resistors laying around? I probably do.

Otherwise some 20 to 50 ohm resistors, say 1/4 to 1/2 watt.
The outputs would be removed.
DC feedback would be restored by substituting the (same value) resistors between the base drive wires (10,13) and pin 19. 10 to 19, and 13 to 19.
This will establish a feedback connection to a voltage point halfway between +0.6v and -0.6v so the amplifier can be powered up with minimal damaging currents flowing. IF it smokes the little resistors, there is a fault with a driver stage, as there is much more than a 1.2v difference between pnp and npn base drive..

 

[craxx6969]

First? = No, only those that were close to the fried q11 transistor.
List will be forthcoming. Answering from my bed at the present time.
Idle current pots at zero
Offset were set at the middle
Do not have those resistors in possession. I would have to check at the local ratshackfor the 5% I have 1/4 watt resistors in various values. Will need to check on exact value.
So i would need a total of four resistors of the same value to simulate the outputs.
10-19 and 13-19 on each amp board.
Will list the parts not replaced on the amp boards.

Sounds like I need to lift one leg of each resistor on both amp (032) boards first and post the results?

thanks!

Were ALL resistors on the amp boards checked with one leg raised when you found destroyed transistors?

This amp is funny, the driver stages for the PNP outputs and the NPN outputs are COMPLETELY separate.

Please detail all replacement parts on the amp cards. Just grab the replacement parts list and delete those that are still original.

Also are you sure that both idle current pots are adjusted to zero ohms.
And the offset pots about centered in their rotation?

I really want to get the amps powered up with the outputs current limited (sort of a dim bulb just for the outputs).

Do you have some ~ 250 ohm to 2k ohm, 5+ watt resistors laying around? I probably do.

Otherwise some 20 to 50 ohm resistors, say 1/4 to 1/2 watt.
The outputs would be removed.
DC feedback would be restored by substituting the (same value) resistors between the base drive wires (10,13) and pin 19. 10 to 19, and 13 to 19.
This will establish a feedback connection to a voltage point halfway between +0.6v and -0.6v so the amplifier can be powered up with minimal damaging currents flowing. IF it smokes the little resistors, there is a fault with a driver stage, as there is much more than a 1.2v difference between pnp and npn base drive..

 

[markthefixer]

checking amplifier board resistors first is the best use of time, r23 on through the drivers to the edge of the amplifier schematic.

the high power resistors I would loan you (via USPS), but I hope that it doesn't come to that point in troubleshooting.

anything around q11 (q7 Q9 and everything around them) is suspect.

when we get regulated voltages t the board, the first thing we will check is +/- 1.8v at R23, R24 to see if the bias string is behaving.

 

[craxx6969]

The resistors will be checked and results posted for each board. A few of them were already replaced(around q11).

Thanks

checking amplifier board resistors first is the best use of time, r23 on through the drivers to the edge of the amplifier schematic.

the high power resistors I would loan you (via USPS), but I hope that it doesn't come to that point in troubleshooting.

anything around q11 (q7 Q9 and everything around them) is suspect.

when we get regulated voltages t the board, the first thing we will check is +/- 1.8v at R23, R24 to see if the bias string is behaving.

 

[craxx6969]

Right board (AWH-032 D) as looking from the front of the unit, this is a multi-voltage unit. It does not have a diode where D1 is located. Instead it has a resistor which I will call R 0. It has thrown all the next resistor numbers off (not the values). I started on the side that has the bottom wire labeled 7. There are two resistors that are to the right of that pin. Again in the schematic that I have the first component is listed as D1. My unit is NOT like that as the first component is a resistor that I’ll call R 0. The components that were NOT replaced are all the resistors except those listed below, the green caps and the tan ceramic flat caps as well as the STV-3 diodes. The right board is the one that had the blown Q11. If you need a photo of the board, let me know and I can upload one. I will be working on the left board tonight and tomorrow. It is a real pain to get at some of the resistors but I will get it done.

R 0 – 47.1k
R5 – 46.8k this is the second resistor going from my right going to my left as listed above. As all the rest are in that same direction.
R6 – 91.7 ohm, this is the third resistor from my right
R2 - .385m
R1 – 3.252k, fifth resistor from my right
R9 – 15.91k
R10 – 15.91k
R11 – 1.276k
R12 - .569k
R13 – 55.6k
R14 – 222.4ohm
R19 – 1.005kohm
R15 – 48.9ohm
R18 – 5.55k
R16 – 47.6ohm
R39 – 1.200k (new resistor)
R40 – 1.201k (new resistor)
R38- 2.729k
R37 – 2.704k
R33 – 22.5ohm
R35 – 2.26ohm
R34 – 22.3ohm
R36 – 22.5ohm
R17 - .472k
R32 - 000.7ohm
R30 - 001.3ohm
R28 – 4.69k
R27 - 4.74k (new resistor)
R25 – 17.84k
R21 – 32.92k
R22 – there is none, it is a solid wire link
R23 – 2.236k
R31 – 0.5ohm (this is a new resistor)
R29 – 0.5ohm (this is a new resistor)
R26 – 17.88k
R24 – 2.236k
R20 – 1.003k
R8 – 100.1ohm
R7 – 100.1ohm
R3 – 63.4k
R4 – 82.1ohm
R41 – 10.2ohm
R42 – 10.1ohm


thanks

The resistors will be checked and results posted for each board. A few of them were already replaced(around q11).

Thanks

 

[craxx6969]

Right board (AWH-032 D) as looking from the front of the unit, this is a multi-voltage unit. It does not have a diode where D1 is located. Instead it has a resistor which I will call R 0. It has thrown all the next resistor numbers off (not the values). I started on the side that has the bottom wire labeled 7. There are two resistors that are to the right of that pin. Again in the schematic that I have the first component is listed as D1. My unit is NOT like that as the first component is a resistor that I’ll call R 0. The components that were NOT replaced are all the resistors except those listed below, the green caps and the tan ceramic flat caps as well as the STV-3 diodes. The right board is the one that had the blown Q11. If you need a photo of the board, let me know and I can upload one. I will be working on the left board tonight and tomorrow. It is a real pain to get at some of the resistors but I will get it done.

R 0 – 47.1k
R5 – 46.8k this is the second resistor going from my right going to my left as listed above. As all the rest are in that same direction.
R6 – 91.7 ohm, this is the third resistor from my right
R2 - .385m
R1 – 3.252k, fifth resistor from my right
R9 – 15.91k
R10 – 15.91k
R11 – 1.276k
R12 - .569k
R13 – 55.6k
R14 – 222.4ohm
R19 – 1.005kohm
R15 – 48.9ohm
R18 – 5.55k
R16 – 47.6ohm
R39 – 1.200k (new resistor)
R40 – 1.201k (new resistor)
R38- 2.729k
R37 – 2.704k
R33 – 22.5ohm
R35 – 2.26ohm
R34 – 22.3ohm
R36 – 22.5ohm
R17 - .472k
R32 - 000.7ohm
R30 - 001.3ohm
R28 – 4.69k
R27 - 4.74k (new resistor)
R25 – 17.84k
R21 – 32.92k
R22 – there is none, it is a solid wire link
R23 – 2.236k
R31 – 0.5ohm (this is a new resistor)
R29 – 0.5ohm (this is a new resistor)
R26 – 17.88k
R24 – 2.236k
R20 – 1.003k
R8 – 100.1ohm
R7 – 100.1ohm
R3 – 63.4k
R4 – 82.1ohm
R41 – 10.2ohm
R42 – 10.1ohm


thanks

The resistors will be checked and results posted for each board. A few of them were already replaced(around q11).

Thanks

 

[zebulon1]

craxx, Could you take pictures of the procedure when using MTF's resistors; to check the feedback system.

 

[craxx6969]

Right board (AWH-032 D) as looking from the front of the unit, this is a multi-voltage unit. It does not have a diode where D1 is located. Instead it has a resistor which I will call R 0. It has thrown all the next resistor numbers off (not the values). I started on the side that has the bottom wire labeled 7. There are two resistors that are to the right of that pin. Again in the schematic that I have the first component is listed as D1. My unit is NOT like that as the first component is a resistor that I’ll call R 0. The components that were NOT replaced are all the resistors except those listed below, the green caps and the tan ceramic flat caps as well as the STV-3 diodes. The right board is the one that had the blown Q11. If you need a photo of the board, let me know and I can upload one. I will be working on the left board tonight and tomorrow. It is a real pain to get at some of the resistors but I will get it done.

R 0 – 47.1k
R5 – 46.8k this is the second resistor going from my right going to my left as listed above. As all the rest are in that same direction.
R6 – 91.7 ohm, this is the third resistor from my right
R2 - .385m
R1 – 3.252k, fifth resistor from my right
R9 – 15.91k
R10 – 15.91k
R11 – 1.276k
R12 - .569k
R13 – 55.6k
R14 – 222.4ohm
R19 – 1.005kohm
R15 – 48.9ohm
R18 – 5.55k
R16 – 47.6ohm
R39 – 1.200k (new resistor)
R40 – 1.201k (new resistor)
R38- 2.729k
R37 – 2.704k
R33 – 22.5ohm
R35 – 22.6ohm
R34 – 22.3ohm
R36 – 22.5ohm
R17 - .472k
R32 - 000.7ohm
R30 - 001.3ohm
R28 – 4.69k
R27 - 4.74k (new resistor)
R25 – 17.84k
R21 – 32.92k
R22 – there is none, it is a solid wire link
R23 – 2.236k
R31 – 0.5ohm (this is a new resistor)
R29 – 0.5ohm (this is a new resistor)
R26 – 17.88k
R24 – 2.236k
R20 – 1.003k
R8 – 100.1ohm
R7 – 100.1ohm
R3 – 63.4k
R4 – 82.1ohm
R41 – 10.2ohm
R42 – 10.1ohm

thanks

In between other things that needed to be done, here is the readings for the left board. I replaced al the transistors, all the caps, the diodes EXCEPT the STV-3 and of course I replaced the trimmer resistors with bournes and they are the correct values with the correct settings. There was a typo on the right board value for R35. I placed a decimal point in the wrong spot. The value is 22.5 ohms.

~~~~~~~~~~~~~~~~~~~

Left board (AWH-032 D) as looking from the front of the unit, this is a multi-voltage unit. It does not have a diode where D1 is located. Instead it has a resistor which I will call R 0.

R 0 – 46.6k
R5 – 46.9k this is the second resistor going from my right to my left as listed above
R6 – 91.5 ohm, this is the third resistor from my right
R2 - .399m
R1 – 3.330k, fifth resistor from my right
R9 – 16.08k
R10 – 15.93k
R11 – 1.285k
R12 - .558k
R13 – 56.9k
R14 – 219.4ohm
R19 – .993kohm
R15 – 47.7ohm
R18 – 5.52k
R16 – 47.8ohm
R39 – 1.189k (new resistor)
R40 – 1.194k (new resistor)
R38- 2.705k
R37 – I broke one lead from this one so was unable to test, a new 2.7k will be installed
R33 – 22.2ohm
R35 – 22.6ohm
R34 – 22.6ohm
R36 – 22.8ohm
R17 - .476k
R32 - 1.3ohm
R30 - 000.7ohm
R28 – 4.81k
R27 - 4.74k
R25 – 17.89k
R21 – 32.70k
R22 – there is none, it is a solid wire link
R23 – 2.195k
R31 – 0.F
R29 – 0.F
R26 – 17.89k
R24 – 2.137k
R20 – 1.004k
R8 – 100.8ohm
R7 – 100 ohm
R3 – 63.3k
R4 – 82.4ohm
R41 – 10.2ohm
R42 – 10.2ohm


To Zebulon1, I will photo the procedure if MTF gives me a green light. Sounds fairly simple but it will be nice for any future AK'rs having a similar issue.

 

[craxx6969]

FYI,

I have the resistors soldered back in place and replaced the ones that were out of specification.
The resistors that were out of spec were the 0.5 ohm ceramic wire wounds. I did order some 250 ohm 10 watt wire wounds from Mouser which are scheduled to arrive on Wed. Once they have arrived, I'll put together the jumpers/resistors, photo the set up and then wait for MTF to answer a question that is lingering in my mind. Which is on dbt or raw?

I have the outputs out and the connectors taped off to prevent them from touching any of the chassis or pcbs. I also have the slots that are around the bottom pins of the 032 board taped off as well.

 

[craxx6969]

Rec'd the wire wound 250 ohm 5% resistors today. Waiting to find out if the receiver is on the dbt or raw when the resistors are hooked up.

Thanks

JT