Discussion in 'Pioneer Audio' started by Oscar23, Mar 25, 2017.
Ok then I can get that in spec have it at 6mv right now
The idles are supposed to be 25mV's on full power.
You can check them on the DBT for movment. Adjust the trimmer and watch the voltage rise and fall when turning the trimmer.
If it moves smoothly and is adjustable, turn the trimmer fully CCW to the min mV reading. Once you plug into the outlet and apply full power the idles can be set to the final voltage reading (25mV's)
The idle will not move out of 0 still grrrrr. Ok i have the 32 d version of the board with stv3 (not 3h) one of them was blown i replaced it with a uf4004 diode and the other stv3 with one as well. Could this be the problem.i read on another post that there replaceing them with 2 uf4004 should i put a second one on each
I think the STV3 is best replaced by two UF4004 diodes in series. There are numerous posts by expert members on this and different opinions on what is best. I'm not an expert! However, I think that just one diode in each STV3 position would not prevent bias adjustment, I'm thinking there is still some other problem.
Take an image of the amp board so we can see what version you have.
If the STV diodes were open the outputs would of smoked.
There is something not connected or is in backwards.
It could be a open trace.
If the amp is balanced the pre stage is good, the problem is with the idle adjustment located in the driver stage.
If one of the two STV diodes is mounted to the heatsink, compare readings from the good amp on the pins where they connect to the board.
Report your findings.
Here is a pic of the board the stv3 mounted to the heatsink is brand new so should be good (I got a bunch of these when buying out a repair shop) the out puts were replaced before I will check those pins again when I get home from work.I'm going with the open trace they were cooked when I started
Just kills me I know I'm real close to getting that going
I'm surprised at how scorched the board is around R27 & R28. But then, I looked again at your photo in post #9, this thread, that shows the backside of this area and the severely burned trace from the emitter of Q10 (2SA740). I think that trace leads to D8 and to wrapping post 13, which connects to the output transistors on the heat sinks. You've replaced the outputs, are you sure they are (still) good?
Maybe you've done this, but I'll suggest re-checking the area of the damaged trace and the pinouts of your new transistors, as well as every component that connects there. When I rebuilt my 1010, I found it confusing looking at the component side of the board, and working in cramped quarters on the backside (the foil side). The foil traces don't show in the service manual copy I have, because it is reproduced so badly that there is no guide for working on the foil side. Combine working on the backside of a board with no guide and installing transistors with different pinouts, man, this was nerve-racking! I had to recheck every component installation against the schematic to make sure I was installing correct pinouts.
I think this is from something Markthefixer posted. To check the 1010 outputs, try doing ohmmeter test across the terminals of the big (filter) capacitors, the red meter lead connected to the red wire(s) on one of the BIG capacitor's terminals, and the black meter lead connected to the orange wire(s) on the other BIG capacitor's terminals. Then swap the meter leads around (red/black) and repeat. If zero ohms both ways, the output transistors are shorted.
What is the good amp reading?
Be really careful with those alligator clips don't move them with power on!!!! (Just a reminder).
I know I have it running now both side are 25mv idle and offset was 03.0 mv sounds great the repaired side actually sounds better then the other side. The was one leg on a transitor not soldered in the 538 now to rebuild the other side so it sounds the same
That board was cooked really bad I did the best I could but I account the one side being better because we'll everything is BraND new
It does look stressed.
I don't have a board with that mod standard here. Thinking of sending you one.
It's not impossible to replace the entire board. The biggest drawback is the "F" pins on the top and bottom of the board. I'll desolder them and remove the pin wire wrap and all. The two solder contacts of the "F" are slightly bent together and can damage the board when being removed, even if the pin is desoldered completly. Who cares about the bad board? But after you have the pin removed you will have to massage the pin to mate to the new board, which hopefully you took your time removing the pins from.
The second board is no where near as bad as that. That board acaully caught fire when i started it. Some one had worked on the board before a few of those wires were mixed up. It was sold to me as a servced unit. NEVER BUY A "SERVICED" UNLESS YOU THE PERSON WHO SERVICED IT.
Well I'm back recapped the other amp board and been running for a few days sounds so sweet. When I press the dimmer all the lights go off and the function lights are out they worked before. I changed the fuse inside (f13) the power supply was rebuilt ( before I got the thing more great "serviced" work) I noticed to caps in backwards c10,c12 I already fixed those.
I rebuilt the protection board and now my left channel is humming and no music right side is fine it comes out of protection,bias is 0 and offset is 54v no idea what has happened
If you don't mind. Use the terms Pioneer uses for the amp adjustments:
DC Balance (Offset) should be near zero volts.
Idle (Bias) should be 25mV's
Your seeing 54v's? That means the amp is railed to one side.
What did you do to the protection board?
Check C3 and C4.
I changed c1,c2,c3,c4,c5,c6
Q4,q5 with ksc1845
The right channel is perfect.
The DC balance is 54 volts and the idle current is 0
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