nashou
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Post by nashou on May 5, 2019 20:32:22 GMT -5
So I measured that pin and the other pins 17, on that board and 10 and 17 on the "B" board all the other pins measured in the mV's whilst the pin you asked me to measure came in at - 5-6 VDC. Can you clarify this sentence. I am not getting a clear picture. Oh Sorry. The pin you asked me to remove from board "A" I see on the schematics comes from the Control amp . So looking at the schematics, I found other pins similar to pin 10 you asked to remove that also come from the similar circuit on the control board( 4 identical circuits one for each channel). So, On that board "A" there is a pin 17 that also comes from the control board to a section similar to where pin 10 goes. That pin measured in the mV's at the Amp board. So on the other amp board "B" that is mirrored board of the one that is suspect "A", I also measured pin 10 on that board and that was in the mV's as was pin 17 which both come from the control board to a similar spot in the control board circuit. there are 4 similar circuits one for each channel on the control board. So if all channels are similar they should behave the same I assume. So three voltages to the associated pins are in the mV's while pin 10 is 5 or 6 VDC So pin 10 from Amp "A" goes to control pin 9 And pin 17 from amp "A" goes to control pin 8 On amp "B" pin 10 goes to control pin 7 pin 17 goes to control pin 10 Make sense? lol   |
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Post by mastertech on May 5, 2019 20:45:40 GMT -5
Ok, that is what I thought. Just needed verification.
I use to unwrap those connections all the time when I use to work on these older units. I just figured it would be easier then removing components just too see. But if you would rather remove components then you can remove C1 and R1 and test the output line and see if you still have the 13.4v..
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nashou
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Post by nashou on May 5, 2019 22:59:22 GMT -5
On Amp board or Control amp board?
But now I see why you removed wire, I'll try that tomorrow.
Nashou
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nashou
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Post by nashou on May 6, 2019 19:07:56 GMT -5
Ok, that is what I thought. Just needed verification. I use to unwrap those connections all the time when I use to work on these older units. I just figured it would be easier then removing components just too see. But if you would rather remove components then you can remove C1 and R1 and test the output line and see if you still have the 13.4v.. Ok this is why your the Mastertech and I am not. I removed that pin by flexing the board a bit and heating the pin connection and pulling it out. Once removed I first measured to see if the 5 vdc was on that pin(10) , nope!! it was gone ! not what I expected. So on to pin 4 and the voltage was still there about 14 now. So whats next? If i have to remove any parts off that amp board It will require me to probably remove the entire amp assembly and that will most likely end any more voltage testing as i don't think I'd be able to fire it up that way.  |
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Post by mastertech on May 6, 2019 19:38:30 GMT -5
Yeah, I figured it might of been voltage feeding back from the amp section. So looks like you will have to pull that amp and test all parts in that section. It may be a bad cap or transistor or diode. Happy hunting. LOL.
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nashou
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Post by nashou on May 6, 2019 20:09:34 GMT -5
Yeah, I figured it might of been voltage feeding back from the amp section. So looks like you will have to pull that amp and test all parts in that section. It may be a bad cap or transistor or diode. Happy hunting. LOL. Gee, thanks!!! |
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nashou
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Post by nashou on May 8, 2019 6:37:05 GMT -5
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nashou
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Post by nashou on May 8, 2019 17:07:50 GMT -5
Ok for the 2SD357 i'll use a KSC2690AYS .
For the 1415 i replaced with a KSC3503D but the 2SC1451 was the hat type with a round heat sink added , will the KSC3503D need a heat sink as well?
Nashou
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nashou
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Post by nashou on May 8, 2019 18:43:04 GMT -5
Another issue, Bending the board back and forth and not removing a part off the heat sink I snapped those leads. Guess what those part are!!!  !!! STV-4H varistors !!! Unobtainable as of now!! I read that stinging 4 UF1004 diodes together and encasing them in epoxy connected to a Wire ring will work. Crap no one has them and if they do , like eBay, they want big money. I might try to grind some of the potting away from the case and see if I can solder the wire to the leads . Crap! Learning more every day . Nashou |
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nashou
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Post by nashou on May 8, 2019 20:11:44 GMT -5
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nashou
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Post by nashou on May 15, 2019 20:33:49 GMT -5
Crap!!!!!
Well no go, put amp module back in fired it up and no go. Saw some slight smoke from some where. So I have to pull the module back out and start checking part.
The heat sink got hot fast and I had the unit plugged into a power monitor and that went up to 800 watts!! SO something is a miss. I only had it on for a few seconds.
Might have been enough to do more damage but I think the outputs are ok, they all measure the same on both halves .
What next ? Ugh this sucks cause its a pain to get those wires off the board.
I checked all resistors on that board too. Changed all caps while I had it know I did those correctly.
Only thing is the transistors . Im pretty sure i am suing the correct replacements .
nashou
Nashou
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nashou
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Post by nashou on May 16, 2019 17:47:47 GMT -5
well I had Q2 installed wrong, but checked Q4 and Q6 and they measured fine, as did the output tranny's while in circuit.
Is that why I got 12 volt on the emitter of Q8?
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Post by mastertech on May 17, 2019 10:57:07 GMT -5
So what is the status now? Working or not?
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nashou
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Post by nashou on May 17, 2019 14:12:35 GMT -5
So what is the status now? Working or not? Haven't put it back to gather yet. Got tired and didn't want to screw up again.  Nashou |
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nashou
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Post by nashou on May 18, 2019 20:05:45 GMT -5
Status is Relay clicked !!! Small mV's on pin 4 and pin 22 !! Yes!!!
Ugh can't believe I put that transistor in wrong, thank god it didn't blow the main outs.
Haven't hooked up speakers yet so not sure how it sounds.
One thing I checked when I removed the good transistors is that the hFe's were mostly much lower than the new parts. Hope that won't over drive
anything.
Taking a break for tonight. will hook up audio tomorrow night I hope. Suppose to be nice out finally and need to get out on my Moto Guzzi !!!!!
Nashou
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!!! STV-4H varistors !!! Unobtainable as of now!!
