Yamaha A-960 question

Relay Click Out when pressing "MAIN DIRECT" Switch

Hi Fellows,

At my new A-960 it is the same Issue...

When pressing the Button "MAIN DIRECT" in,
the Power is going down, Relay is switching out.
Power ON Bulb is going off.

On All Inputs, with A/B or without A/B Speaker Switch.
Any Constelation, in any Positions.

I get the Pots and Gliders in great working Order now.
The Checks are done, 10mA Bias both, ~1mV DCOffset, 54,7+B, 1,2V Opto.

So, no DC-Offset is on the Outputs.

I have repaired a nice bunch off Vintage Gear for now,
but this Problem is driving me nuts. Everything seems working fine,
until pressing "MAIN DIRECT" Switch.

There must be some short to Ground, when Bypassing all Tone Controls.

What, when the PRE is bringing DC Voltage? With all Tone Controls in the Path,
the DC Voltage is maybe more less, decrease. Then "directly" switched to the
Protection Circuit kicks the Relay out??

The Only Thing, I not have made bymyself is, replace the Bulbs.
They was replaced before, by the Pre-Owner. No Shorts. Maybe wrong Bulbs?


Help, I need some Advice, what to check!

Best Regards,
Darko
 
Hi Fellows,

At my new A-960 it is the same Issue...

When pressing the Button "MAIN DIRECT" in,
the Power is going down, Relay is switching out.
Power ON Bulb is going off.


Help, I need some Advice, what to check!

Best Regards,
Darko

Hi fellows,

I think this information is what you need...
 

Attachments

  • Service bulletin 05-84.BMP
    93.7 KB · Views: 479
Hi Ecluser,

Thank You for the superfast Answer,
with Attached Service Bulletin Info.

That could be the Answer :)
I never come on this way.


The Thing is not let me found my Freedom,
so I go over to re-check:

- I removed all working (unknown Type) Lamps
- The Relay is no more clicking IN, no Sound
- The B+ Rail 54,7V is without Bulbs only 17V

- I solder 3 new 14V80mA Bulbs in
- Relay is again working well, Sound is comming again.
- NOW: If 1 Bulb is on, 54,7Volts are here
- If 2 Bulbs are on, only 45V are here
- If all 3 are on, Relais is switching out, Bulbs off, only 40V

So, thats a Power Supply Issue!!

I will check Tomorow. Now I know, Iam not crazy and I can go sleep.

:)

Best Regards,
Darko
 
Here is the adjusting procedure for the A960-II, hope it is readable. Incidentally if you take out the balance slider you can open it and with care it can be fixed.
 
The Zener Trick is running well - All 3 Bulbs can be ON, without any Probs..

:tresbon:


Thank You Guys

:music:

Best Regards,
Darko
 
Thank You Sir "ecluse",

:thmbsp::thmbsp:

The Amp is famouse ! Have tested with Dynaudio DIY Project "Profile4"
and Yamahaha NS-1000m. Overall good in Presence and Clarity.

I hope, I can give You also usefull Inputs back on other Units.
-Marantz, -Pioneer, -Sansui, -H/K, -Sony V-Fet, -Sherwood etc.

Thats my first A-960. Last Year, I recap a broken A-760.
I was a little bit impressed, how a little Unit can boost.
Than I decide, to catch one fine Pristine Piece. This Weekend I get the Midrange A-960. The next should be a A-1060.

Tomorrow should land a big Baby. Yamaha CR-1020.
But the most finest is the CA-1010 and the CA-2010.
Big hairy Biests with nice clicking Relays. (if NO Lytics, or NPNs - Issues are Inside the Relay Circuit!)
The little CR-x20 Series are complete: 220, 420, 620, 820.
Also I use from Time to Time the funny-looking CR-1000.

:music:

Best Regards,
Darko
 
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@ Merrylander,

Thank YOU too, for the stunning PDF! Its in very high Quality.
Have no Problems to open and read with Adobe's Reader 8.3.

My Unit is the first Version. Funny Thing: the first A-760 was also a "I".
( From a VIP DJ from Zürich )- not mine.

Then I buy the Manuals for this Version.
Next Week I have found a "A760 II"... :scratch2:

Best Regards,
Darko
 
I just acquired an A-960 and this thread has been very helpful to me. Thanks to Merrylander's instructions, I was able to perform the idle and offset adjustments, except I think I did it with the volume at max. Well, actually I know I did. Having no Owner's Manual, I was not familiar with way this volume knob is marked and so followed the instructions literally (i.e. volume at 0). It was only after I hooked it up and engaged my speakers that I just about had a heart attack. :eek:

Luckily, I had only static from the tuner coming through (and only for a second or so) and there doesn't seem to be any damage so far. But after I finished panicking about my NS-1000s, I felt really stupid. :stupid: And this, just after feeling accomplished for having actually serviced a piece of electronics. In fact, this was the 1st time I'd ever even used a multimeter. (I made sure to read up on the process and watched a couple of videos online today 1st).

My question, though, is what is the effect of having done the adjustments with the volume at Max (0) instead of at Min (infinity)? Do I need to go back in and do it all again? The amp is working and doesn't seem to be overheating, but I'd like to be sure.

Plus, I'm curious as to why it is important.

Also, does anyone have a copy of an owner's manual for this model they might scan and post? I found the service manual, which I used, but no O.M. Apparently, I need one more than the average bear.
 
Asha,

My bad I should have written "Volume at minimum" but if you had no input it probably made no difference. It is mainly when adjusting DC offset having any signal come through would confuse you.
 
No problem at all Merrylander. It was only my ignorance that led me to misunderstand the instructions. And if it weren't for you, I wouldn't have been able to attempt the adjustment at all.

So, I went ahead and remeasured today with the volume at minimum this time (good practice!). All the measurements still looked pretty good, but I did bring the right channel idle down a little bit more. (Could it have wandered off that quickly?)

In addition to the adjustments yesterday, I took the time to do a thorough cleaning with the front, top and bottom off, polish the face and realign the knobs. All the lights work, so I didn't have to try the zener diode fix, which I was worried about. (Good thing, too, as that is still beyond my current skill level.)

The amp looks great and the colored lights are kind of cool, though I still think I prefer the look of the CA/CR series. The black and silver is a visual match for my NS-1000Ms, but I'm not sure it is the best sonic match. I’m still getting used to it and playing with room tweaks, etc., but most of the sound seems to come out of the upper and mid register through the 1000s with this amp and it might not be not driving the bass quite enough. I think I like a more full, enveloping and balanced sound. But, this could be the fault of my sources, too, as they are all digital right now and not of high quality. (I'm waiting on delivery my 1st TT, so that will change soon.)

However, the amp is far better than I expected and I am enjoying it. And, the price was much more reasonable than what the 1010s seem to go for lately, especially considering it sold on ePay. In fact, I think it might be kind of a sleeper. I know I'm pleasantly surprised.
 
no sound or lights......

I just got a a-960, but its not working. I read on another site(thevintageknob) that if the LED for the power button isn't lighting up then nothing will work? It will light up the mm or mc red led, but nothing else.

I only found one fuse (250v 12amp IIRC...pretty sure its good, because i get no red mm/mc light with it pulled) are there others, or is this led most likely the problem.....if so what do i do to fix(or bypass to check?) the led(sorry noob).

thanks for any help, -K


EDIT: also what program do i need to view the scematics etc that have been posted earlier in this thread?
 
@ Weasel ,

Hi There -
Hows the Snow Quality in Kalkaska?

Here In Switzerland, You can easy break a Leg, or Two,

while seddle out the Car.


Ok, What exactly is the Relay doing, after Switching ON ?
Do You can hear a "CLICK" ? ( Relay ).

:scratch2:
 
Hi
Hoping that someone is still watching this thread.
I have an A-960 II on the bench. No signal from the left channel.
The power switch light is out, am looking for a 14.5 v 80Ma (from what I have read). I have cleaned all of the pots and switches a few times, and have tried both aux and tuner inputs with the same result. I have also tested both A & B speaker outputs with speakers with the same results.
Any clues? I do not have a schematic, and am not sure what I would do with it if i did.
Thanks in advance
Glen

Sorry, right channel is out.
G
 
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See if you have signal going to the input section of both power amplifier channels. It will tell you if the problem is within the power amplifier section or before this stage.

What test equipement do you have?
 
A favorite on these amps is the ^%$# balance control. The contact wipers are fastened to a plastic part by slipping the holes in the wiper over two plastic protrusions then hitting the protrusions with a hot iron. You can take the control apart and gluing the wiper to the plastic with cyano-acrylate glue.
 
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See if you have signal going to the input section of both power amplifier channels. It will tell you if the problem is within the power amplifier section or before this stage.

What test equipement do you have?

I have an analog multi meter. I will send a picture of it along tomorrow. I am on the road for 24 hours. I will need direction on tracing the signal that you speak of. Thanks
G
 
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