Always-on Pioneer SX-1980

[akaslutz]

First thread!
I picked up an SX-1980 recently. I've been enjoying it as well as my wife (neighbors get routine Josh Grobin concerts when I'm at work) for a few months now. A couple of weeks ago my wife facetimes me when I'm abroad on business and shows me turning on and off the power switch but the unit stays on. When I got home, I unplugged, sprayed lightly some DeoxIT, waited then plugged back in - the switch functioned properly. Fast forward several weeks and the condition returned. Tried DeoxIT again but no luck, the unit is on constantly. I haven't plugged it back in since and fear unplugging repeatedly as an alternative for a switch will do more harm than anything. Anybody dealt with such a condition? Suggestions for a troubleshooting path?

Side note: I picked up the SX and a set of HPM100's for $2000... in 2017!

 

[Skylab]

When you say you "sprayed some deoxit lightly" into the power switch - did you take the cover off of the unit and get the deoxit into the switch mechanism itself? If you just sprayed a little into the opening of the faceplate, you probably didn't do anything.

One suggestion I can offer, as a longtime owner (and fan!) of an SX-1980: with the unit UNPLUGGED, vigorously cycle the power switch on and off at least 50 times, rapidly. Then plug back in and turn on. If the power switch functions as normal, it's very likely a dirty switch issue. If it does not, it probably isn't (although it could still be).

Also, if your 1980's power supply board hasn't been rebuilt by someone who really knows what they are doing, it will need to be. This is the one Achilles heel of the 1980. The PS boards will eventually fail from overheating unless they are modded/upgraded.

Good luck - I had my 1980 fully recapped/restored by Mattsd and it's been working flawlessly for years of daily use, and I love it!

 

[akaslutz]

Thanks Skylab. I found the root cause by tapping this relay with the handle end of a small screw driver:



One light tap and the relay clicked and the unit functioned properly. I cycled the power switch multiple times with success.

Now my fear is how long until the next time the relay sticks if I do nothing? I'd like to solve the problem and that appears to address the relay. Anybody replaced this relay? Is there any sense in popping the cover (possible / effort in futility?) and reworking the internals like cleaning contacts? My gut tells me to replace the but there are a ton of a lot smarter, more experienced resources in AK that always seem to a better and perhaps a deeper systemic answer.

Curious to know what the best next steps are?

Thanks.

 

[markthefixer]

Not a simple answer. The 48v version of this relay isn't readily available. The 24v version is: 653-LY1-0-DC24
Thus the board has to be rewired slightly to use this one.
Pulling the board to do this relay replacement, no less the voltage change, without doing the rest of the board rebuild doesn't make sense.

 

[akaslutz]

Thanks markthefixer. I'm ok with not-simple. Would PS board removal and sending for the 24v mod and rebuild to a reputable resource be sensible?

Speaking of reputable resource, would asking for suggestions for a reputable local (Bay Area) resource be taboo? I'm thinking long term when / if I need to get the receiver serviced either by need or want? I've seen the concerns in other threads of shipping this monster.

 

[Skylab]

Certainly not taboo to ask for a good service tech. The only one I happen to know on the west coast is http://www.pacificstereo.net/ - he does great work, not sure if he is norcal or SoCal. Like most of the good ones he isn't cheap or quick, but he is good.

I personally had AKer Mattsd restore mine and he did a fantastic job. But he is in Ohio.

 

[akaslutz]

Thanks Skylab, appreciate it. I've dropped a line with pacificstereo.net, thanks.

I've been geeking out on AK incessantly only being a new member trying to catch up but have found a lot of good SX-1980 threads / forums. I followed a few gurus, who seem to congregate in the Midwest, and found one thread where txturbo made a PS board from scratch but as a project fit for first class production release. The gurus were indeed impressed. I'm seeing if there's a list to getting one of those.

 

[markthefixer]

Thanks Skylab, appreciate it. I've dropped a line with pacificstereo.net, thanks.

I've been geeking out on AK incessantly only being a new member trying to catch up but have found a lot of good SX-1980 threads / forums. I followed a few gurus, who seem to congregate in the Midwest, and found one thread where txturbo made a PS board from scratch but as a project fit for first class production release. The gurus were indeed impressed. I'm seeing if there's a list to getting one of those.

For sale on eBay, search under "sx-1980" . Relay is already done, and there are installation instructions. seller stereomax is our txturbo.

 

[akaslutz]

For sale on eBay, search under "sx-1980" . Relay is already done, and there are installation instructions. seller stereomax is our txturbo.

Fantastic, thanks! I've only seriously looked at AK for a couple of weeks now and admit AK is creating a junkie! - work and wife be warned.

Question that might be a re-direct to another thread: I've seen in several thread voltage measurements of various pins on the PS board... I took some measurements and would like a review for a sanity check if my PS is of any concern... would you know a thread that lists the pins and process to check PS board voltages?

Here are my measurements (receiver with bottom cover removed, on it's side, tuner / volume knob on the bottom, volume knob 1 click. Fluke 117.):

Pin Value
17 +82.7
9 +36.85
14 +12.97
16 +7.83
15 +4.82

18 -84.8
11 -36.92
8 -31.57

 

[QSilver]

I think they look pretty reasonable.... if I'm correct? Some look to be a little high.. only a little... but that could be because the 80V regulators are both 2-4V over 80... That will at least throw the 30V regulators off....

IIRC....
5V for part of the tuner?
8V for some of the lighting
13.5V for the tuner again
-30V for the meter board
+/-34V for pre amps
80V for references for other regulators and power amp driver stage...

Pin Value Voltage Rail
17 +82.7 80V
9 +36.85 34V
14 +12.97 13.5V
16 +7.83 8V
15 +4.82 5V

18 -84.8 -80V
11 -36.92 -34V
8 -31.57 -30V

 

[akaslutz]

Guys, sorry for all the wet behind the ears questions ,but I'm trying to find a thread on the process for simply checking DC Balance(called in the Service Manual, same as DC Offset so popular on AK?) and Idle Current. I have the .pdf Service Manuel and maybe because I've been up 20 hours now, the wording in the Service Manual is throwing me. I get test between two pins and check voltage. I'm looking for a thread that says check between pin A and pin B. Then pin C and pin D.

Severely doubting my English skills, I checked both ways I interpreted how I read the manual and would like to find out if I should pursue adjustment. I'd like to compare data or have it interpreted, good or bad.

Measurements, in DCV, Fluke 117 DMM, receiver mounted normally, on for 20 minutes, volume zero setting, I've adjusted nothing:

DC Balance, numbers are pins:
17 to ground = 0.297
17 to 32 = 0.043
32 to ground = 0.340

Idle Current,
24 to 10 = 0.011
24 to 25 = 0.046
25 to 39 = 0.011
10 to 39 = 0.041
23 to 26 = 0.046
23 to 11 = 0.020
11 to 38 = 0.037
26 to 38 = 0.014

 

[akaslutz]

Crud, wanted to add: should I simply have started a new thread?

 

[larryderouin]

Put some mini Grabbers on your Fluke. If you don't have any, get some before working around the 1980. When you don't need mini grabbers, insulate the +(RED) probe except for the extreme tip. Slips happen and this helps prevent less than Bay area PC cussing. Unless you live in an area with a lot of retired shipyard workers, then it's OK to cuss, swear, etc..
(L) means LEFT CHANNEL. (R) means Right Channel. Not the Left side and Right side of the amps. Read the pins as noted in the manual. Page 33 Figure 10-1.


(DC BALANCE)
For VR1 +(RED) probe on pin 17 and -(BLACK) on Chassis ground (use alligator clip on probe)
For VR2 +(RED) probe on pin 32 and -(BLACK) on Chassis ground (use alligator clip on probe)
voltage to be 0.0V DC within + or - 3mv. Adjust as needed.

(Idle Current)
For VR3 (LEFT CHANNEL) connect +(red) to pin 24. -(black) to Pin 10. Check for 30mv (or at least 20mv to 40mv) Adjust as necessary to get 30mv

For VR4(Right CHANNEL) connect +(red) to Pin 25 and -(black) to 39. Check for 30mv (or at least 20mv to 40mv) Adjust as necessary to get 30mv

Adjustment. The pots will probably be very touchy, so be prepared for that. Just barely twitching on the tool will move the voltage a good amount. Once you get the voltages set and the appear stable, Check and re-adjust after 10 minutes. And that's it for adjustment. The rest of the checks are just to make sure the rest of the amp is behaving(both of them).

+ and - below indicate which probe +(RED) and -(BLACK) goes where.

Check them as follows;
23 + & 11 - (LEFT SIDE)
26 + & 38 - (RIGHT SIDE)
18 + & 16 - (LEFT SIDE)
31 + & 33 - (RIGHT SIDE)
These should closely mirror the V4 and V3 voltages of about 30mv. NO OTHER CONNECTIONS to be made. You could end up with either a smoking pile or a very large doorstop.


Your earlier readings from post #11 I edited out the junk voltages (you were checking either + to + or - to - which aren't of any use.
You got the 2 idle current readings (marked with *) and 2 of the 4 secondary voltages (Marked with **). Take the other two as marked with ? after the = BEFORE ANY ADJUSTMENTS.
Use this list as a template and paste in your new voltages for all BEFORE ANY ADJUSTMENTS so Mark can see how healthy the amps are.

Idle Current,
Primary readings
* 24 to 10 = 0.011
* 25 to 39 = 0.011
Secondary Readings
** 23 to 11 = 0.020
** 26 to 38 = 0.014
** 18 to 16 = ?
** 31 to 33 = ?

Then copy the format again and repost the new Voltages after adjustment.

I would suspect that the secondary voltages will straighten out and follow the idle current primaries as you increase the voltages on VR3 and VR4.

Go slow and methodical. The 1980 is a gold plated PITA when it gets cranky. And as far as "stupid questions" The only STUPID QUESTION is the one you DON'T ASK! We've all BTDT, got the T'shirt, and a few have read the book vs the movie. So don't feel that a question is stupid because you don't understand something. ASK AWAY! especially with the 1980. Ask 1st, get the answer, THEN PROBE! You don't want a doorstop that weigh's 70#'s. So go only as fast as the answers here.

A lot of us work too so answers may be a bit slow at times. Give it 24 hours at least.

 

[akaslutz]

Put some mini Grabbers on your Fluke. If you don't have any, get some before working around the 1980. When you don't need mini grabbers, insulate the +(RED) probe except for the extreme tip. Slips happen and this helps prevent less than Bay area PC cussing. Unless you live in an area with a lot of retired shipyard workers, then it's OK to cuss, swear, etc..
(L) means LEFT CHANNEL. (R) means Right Channel. Not the Left side and Right side of the amps. Read the pins as noted in the manual. Page 33 Figure 10-1.


(DC BALANCE)
For VR1 +(RED) probe on pin 17 and -(BLACK) on Chassis ground (use alligator clip on probe)
For VR2 +(RED) probe on pin 32 and -(BLACK) on Chassis ground (use alligator clip on probe)
voltage to be 0.0V DC within + or - 3mv. Adjust as needed.

(Idle Current)
For VR3 (LEFT CHANNEL) connect +(red) to pin 24. -(black) to Pin 10. Check for 30mv (or at least 20mv to 40mv) Adjust as necessary to get 30mv

For VR4(Right CHANNEL) connect +(red) to Pin 25 and -(black) to 39. Check for 30mv (or at least 20mv to 40mv) Adjust as necessary to get 30mv

Adjustment. The pots will probably be very touchy, so be prepared for that. Just barely twitching on the tool will move the voltage a good amount. Once you get the voltages set and the appear stable, Check and re-adjust after 10 minutes. And that's it for adjustment. The rest of the checks are just to make sure the rest of the amp is behaving(both of them).

+ and - below indicate which probe +(RED) and -(BLACK) goes where.

Check them as follows;
23 + & 11 - (LEFT SIDE)
26 + & 38 - (RIGHT SIDE)
18 + & 16 - (LEFT SIDE)
31 + & 33 - (RIGHT SIDE)
These should closely mirror the V4 and V3 voltages of about 30mv. NO OTHER CONNECTIONS to be made. You could end up with either a smoking pile or a very large doorstop.


Your earlier readings from post #11 I edited out the junk voltages (you were checking either + to + or - to - which aren't of any use.



You got the 2 idle current readings (marked with *) and 2 of the 4 secondary voltages (Marked with **). Take the other two as marked with ? after the = BEFORE ANY ADJUSTMENTS.
Use this list as a template and paste in your new voltages for all BEFORE ANY ADJUSTMENTS so Mark can see how healthy the amps are.

Idle Current,
Primary readings
* 24 to 10 = 0.011
* 25 to 39 = 0.011
Secondary Readings
** 23 to 11 = 0.020
** 26 to 38 = 0.014
** 18 to 16 = ?
** 31 to 33 = ?

Then copy the format again and repost the new Voltages after adjustment.

I would suspect that the secondary voltages will straighten out and follow the idle current primaries as you increase the voltages on VR3 and VR4.

Go slow and methodical. The 1980 is a gold plated PITA when it gets cranky. And as far as "stupid questions" The only STUPID QUESTION is the one you DON'T ASK! We've all BTDT, got the T'shirt, and a few have read the book vs the movie. So don't feel that a question is stupid because you don't understand something. ASK AWAY! especially with the 1980. Ask 1st, get the answer, THEN PROBE! You don't want a doorstop that weigh's 70#'s. So go only as fast as the answers here.

A lot of us work too so answers may be a bit slow at times. Give it 24 hours at least.

---------------
Thanks Larry,

UH OH! - Haste makes waste. I adjusted DC BALANCE after logging off last night and adjusted DC Balance then adjusted VR3 and VR4. Data from last night session:

17 to ground: 0.001
32 to ground: 0.000

24 to 10: 0.032
25 to 39: 0.002 !!! Virtually no change from full CCW to full CW on VR4. Full CW got me 0.002. VR4 bad?

23 to 11: 0.041
26 to 38: 0.002
18 to 16: 0.038
31 to 33: 0.003

I have to admit, I have been using the receiver at just a couple of volume clicks (way less than 1 watt on the meter(have not adjusted meters, no 1 kHz* signal generator). Very little heat from either heat sink, however, whatever heat there is, the left side sink feels slightly warmer.

(*cool, I typed kHz all lower case and this site auto-corrected...I don't recall if Word or Excel does that)

Appreciate the assist in all this from everybody. This thread drifted from the original issue....should this be a new thread?

 

[zebulon1]

Don't work on the set if fatigued. It will only cause trouble and alot more work.
There is no hurry to get this set up to speed. The patient time spent is rewarded in spades.
Give time for others to respond.
So far so good!

 

[larryderouin]

You got problems on the Right Channel. I wouldn't run it until Mark comes back and verifies it. A non functioning bias circuit is not something to FU*& around with. Especially with a 1980!!! Leave it OFF!!!

Actually as it's the same unit and it's evolved into this it's OK. No sense in starting a new thread.

 

[akaslutz]

You got problems on the Right Channel. I wouldn't run it until Mark comes back and verifies it. A non functioning bias circuit is not something to FU*& around with. Especially with a 1980!!! Leave it OFF!!!

Actually as it's the same unit and it's evolved into this it's OK. No sense in starting a new thread.

Thanks Larry, and Zebulon. I'll leave it off and stare, no worries... I have a 1250 sitting next to it. And a few 1080's.

 

[akaslutz]

Ugh... been trying to catch up on YEARS of posts from several gurus on AK. I realize I should have stuck more into long term memory than basic P=IE type stuff in the early college years. I spend a lot of time working with suppliers on their operation and manufacturing process as an overall system. It's cool to see "system" applies everywhere in life, including inside of the SX-1980 where one section or one simple component in a section can really affect the overall system. My eyes are bloodshot on the weekend reading threads deep into the night. I'm convincing my wife in the morning this is a good mistress for me.

 

[larryderouin]

You'd be surprised at how much comes back from the nether reaches of "that Gray crap between your ears" as my dad puts it. The more you research the more you start to remember. Honestly, I'd find something a bit easier to fix 1st and work your way up to the 1980. You can always sell the lesser stuff to finance the next project, all the while reading up on everything you can on the 1980 (bookmark them as you read them so you have an index of 1980 threads).

 

[petehall347]

i find putting on a shelf until ready works . thats if i can ever find it again .