The AU-X1 is, like, so hot right now.

Looks like you haven't worked on the Driver modules yet - failure to be able to set bias (or DC offset) is very likely to be 2 x 390 Ohm resistors per driver that are probably fusibles - because they seem to take a beating and go near enough open - mine were up in the ~200K area. :)

These are R36 & R37 (near TR13 & TR14). ;)
I'm pretty sure he replaced those John, at least I think that's what he did....We all told him about those at the beginning of the thread......I think those modules have been out.
 
Looks like you haven't worked on the Driver modules yet - failure to be able to set bias (or DC offset) is very likely to be 2 x 390 Ohm resistors per driver that are probably fusibles -
Cheers John - these were replaced.

Can you explain how you have your power supply set up?
Mines pretty simple Kev - 230v wall outlet thru to a DBT with a 100W (240V) bulb in it, then to my 2000w stepdown, which is set to 100VAC.

One idea I had was to set the stepdown to 120VAC, (its selectable between 100-120VAC), taking into account a voltage drop, this could give me enought "headroom" to get the speaker relays to click, while also keeping the DBT in-circuit.
 
I think you might need a higher wattage bulb, I used a 120watt, and with that, the amp would run, and the bulb was dim, say down at around 10% at a guess, only just glowing.
I cant remember how much it dropped the voltage unfortunately.
But I would have thought 100 would do it.
 
I used a 100W but I can't remember if I got speaker relay activation or not, thinking about it now I think probably 'not' but then I never check for audio output on DBT. I would have been happy enough to see the bulb dim down, even if the speaker relays didn't close. :)

The thing you Do need to have working is the Soft Start relay - definitely change bulbs to get that working - assuming no very bright bulb showing. ;) You can check for 'normal' bias setting reaction under those circumstances, and also same for DC offset, if you can find a spot to measure at.
 
OK - thats promising.

I will need to try again - it could simply not be coming out of protect as the offset is too high. Once I get new trimmers in, I can test that theory......
Connect the power LED up so you can see if it stops flashing when it powers up just so you know for sure. Remember the LED is DC so it has to be the right way round...I know you know that but gotta make sure we are all on the same page...
 
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This test point usually does not work. For whatever reason Sansui stopped wiring the point to measure the F-2775 voltage.

The SM actually recomends measuring the voltage from the bottom of the unit by attaching multimeter probes directly to the emitters of output transistors 701 and 703. Just attach them before the resistors, or rather, on the resistor leads that directly contact those emitters.
 
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This test point usually does not work. For whatever reason Sansui stopped wiring the point to measure the F-2775 voltage.
Thanks Ronito - looks like the best place to take the DC and bias readings in that case is from underneath the power modules.

Cheers
 
Regarding lack of sound. Is the "Power Amp Operation" selector (and this has happened in the best of families) switched to "integrated"? If not, make certain it is.
 
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Regarding lack of sound. Is the "Power Amp Operation" selector (and this has happened in the best of families) switched to "integrated"? If not, make certain it is.
Yup - its on that setting. I need to wait till the trimpots arrive (1 week) before having another go at this....
 
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This test point usually does not work. For whatever reason Sansui stopped wiring the point to measure the F-2775 voltage.

The SM actually recomends measuring the voltage from the bottom of the unit by attaching multimeter probes directly to the emitters of output transistors 701 and 703. Just attach them before the resistors, or rather, on the resistor leads that directly contact those emitters.
The test points on all four of my units were wired wrong at the factory all you need to do is move the white wire (18) to the other side20170427_104155.jpg of the op and they will work as they should leave the black wire(17) in place..In this pic the white wire was on the left and I moved it to the right now the tps work..
 
Yes!

I wanted to mention it, but since you were the one to figure out the rewiring to make that test point "live" I thought it only proper that you get as much credit for this discovery as possible.

Thanks Willy6!!

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The test points on all four of my units were wired wrong at the factory all you need to do is move the white wire (18) to the other side
Ok - because I am a bit slow and dont want to muck this up.....can you please confirm?

That the white wire you show moves from its current pin 18 to the empty hole at pin 15? Is this correct?

My board IS wired the same way as you show in your pics too.....
 
My understanding is that the white wire only - needs to be moved from the 4.7ohm to the 0.33 ohm resistor, as in the picture in post #55 - leave the crimped stake pin where it is in the driver PCB.
 
My understanding is that the white wire only - needs to be moved from the 4.7ohm to the 0.33 ohm resistor, as in the picture in post #55 - leave the crimped stake pin where it is in the driver PCB.
Thanks John - I got it now. I'm moving the wire at the "resistor end" rather than swapping any pins at the "board end."
 
Actually you move the white wire from the 0.33ohm resistor to the 4.7ohm resistor..
Don't quote me on that though it could be the other way around as I haven't been under the hood of an X-1 in over a year..
 
Don't quote me on that though it could be the other way around as I haven't been under the hood of an X-1 in over a year..

Yes, it is the other way round, the TP are for bias current adjustment which must be done across the emitter resistors. Therefore the white wire mustn't connect to the 4.7 ohm resistor as they are in turn connected to the bases of the OP transistors. Thus the white wire must go to the 0.33 ohm cement resistor, and emitter of the OP transistor. ;)
 
Yes, it is the other way round, the TP are for bias current adjustment which must be done across the emitter resistors. Therefore the white wire mustn't connect to the 4.7 ohm resistor as they are in turn connected to the bases of the OP transistors. Thus the white wire must go to the 0.33 ohm cement resistor, and emitter of the OP transistor. ;)
Ya i wasn't sure if I had switched sides with that wire in the pic yet or not since it was taken with my phone camera over a year ago..
 
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