Oh boy!.....got one!! Sx 1980!!!! Booyah!

One last question......when I got the receiver...it powered ON...and the main (15A)fuse was ok. Hopefully this indicates that my outputs are ok? I am a nervous wreck.......! Need more COFFEE!
 
Ok guys'gals.....I pulled myself together and powered ON on DBT. SSSSSUUUUCCCCCEEESSSSSSS! :banana::banana::banana::banana:
THe 100watt'er went so friggin' bright that initially my heart sank.......then after a couple of seconds.......it dimmed way down.......relay clicked!:banana::banana:

I am doin' the 'gang-nam style' NOW!!!!!:thmbsp::banana:

Now for the real power test..................................................
 
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I tried a couple of times more with DBT.......all looks to be normal. The SS relay clicks about 5 sec. after ON. The speaker relay doesn't click.(speaker 'A' selected)......I am guessing this is normal, until real(230v) power is connected to the unit.....? Please confirm...thanks.
Are there any problems associated with prolonged DBT-use on this unit? I would like to run it about 10min. on DBT............can that be done?
The small current sources don't light up either on DBT........is that normal, Mark?

Otherwise, I'll connect real power and see what happens............
 
I don't know for sure, the power supplies could be starved by the DBT, so :turn the amps to zero idle current, and run it straight. Check the power supply voltages. IF ok, set the dc offset to as close to 0.000v as possible. By then you SHOULD get the click. If not, then we start trying to figure out why not. Check the 5.6 ohm 1/2 W series resistors R210 and R212, I routinely replace these as they are lined up for damage... DO NOT GET CREATIVE AND REPLACE THEM WITH A HIGHER WATTAGE RESISTOR!!!!!!

INSULATE your probe, READING THE POWER SUPPLY VOLTAGES, with that forest of pins, complicated by the slobber joints, a short is very probable on an uninsulated probe.

OTHERWISE

Then back ONTO the DBT, with at least 150 watts and see if it clicks in, iiac it should.

NOW, you can TEST set the idle current to tease out any problems. The bulb WILL get slightly brighter as the idle current is dialed up, and the unit's protection MAY click OUT due to reduced ac voltage - this is NOT a problem...

If the idle current goes very bright quickly dial it back down to zero and STOP -NO EXCUSES - STOP - you are at low altitude and the stall stick shaker is going off like a berserk belly dancer!!

You may not reach idle current, but that's OK, turn iyt BACK down to zero ohms, minimum idle current.

Repeat for the other channel.

WHEN that goes WELL, THEN you can go straight into the line, and set the idle currents for real.

Your tuner will NOT be well behaved, with the apc and tuner being recapped. It will probably not quartz lock, maybe not even come out of mute even with a strong signal. The readjustment of the APC will need a scope.
You MAY get sound, even stereo, but your separation and distortion WILL be at the MOTL or BOTL level until a real realignment is done.
So, even with the messing around you thought you saw, it might not be broke - I WISH you had held off on the recap until we had the tuner sorted out, you squared the difficulty... as it is, that 6.8uf is your loop filter for the stereo decoder, while the 0.56 caps are the coupling between the F8 LPF stereo output and the pa1002a deemphasis amplifier/muting circuit.

These will affect the alignment of your stereo circuits, the vco center point, through separation, and probably pilot rejection. so until they are changed out, don't go for a realignment.
 
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Well done so far Anders. The post above from Mark is CRITICAL for you to understand to prevent immediate and aggravating damage to the 1980.
 
I feel like I was ridding a rollercoaster for a moment reading the last few posts. GLad things are still looking good!
 
Im curious how the tuner does after recap. Concerning alignment that is. Would't be nice to not need this? Time will tell.

I have re-capped quite a few tuners and I never been forced to do an alignment after. I hope it'll work on the touchy sx1980 too.

Your tuner will NOT be well behaved, with the apc and tuner being recapped. It will probably not quartz lock, maybe not even come out of mute even with a strong signal. The readjustment of the APC will need a scope.
You MAY get sound, even stereo, but your separation and distortion WILL be at the MOTL or BOTL level until a real realignment is done.
So, even with the messing around you thought you saw, it might not be broke - I WISH you had held off on the recap until we had the tuner sorted out, you squared the difficulty... as it is, that 6.8uf is your loop filter for the stereo decoder, while the 0.56 caps are the coupling between the F8 LPF stereo output and the pa1002a deemphasis amplifier/muting circuit.

These will affect the alignment of your stereo circuits, the vco center point, through separation, and probably pilot rejection. so until they are changed out, don't go for a realignment.

MTF is correct. You may get away by recapping tuner but there will be at least subtle difference. I recapped my SX-780. Works good but do sense for some reason it needs realignment. I recapped my SX-1250 tuner too and it works but when I hooked my Sansui TU-717 to the 1250, it blew away the SX-1250 by a large margin. So that being said, my 1250 tuner really needs realignment. Just some consideration to watch out for. That's why many have discouraged recapping tuners unless you have a way to get them realigned.


EDIT: I also forgot to mention that I also recapped my Fisher 201 tuner as well the rest. Well, the tuner is WORSE. It'll pick up good on close to specific frequency and the rest is almost silent. Some receiver will get finicky if not all.
 
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I changed the tuner Electrolytic caps on both my SX-780 and the SX-1050, one at a time, I even wrote down the cap number on the old one in case they changed something for the worse, I could swap them back in place. Between each cap I listened to the FM and AM radio sections, playing with the tuner, grabbing weak and powerful stations after each cap, and noticed no sonic difference or difference on how the stereo lamp operated, dial indication etc.

I repaired and recapped my SX-1050 first. I recapped the Tuner board after recapping all the other boards making sure it was working well, figuring that I would get it aligned anyways. While I was replacing the Tuner board caps, I did all the grey CEA's at once, fired it up, and the AM/FM Tuner worked exactly the same as before. So I started to replace each Orange CEANL type cap one at a time, then starting it and checking the tuner afterwards. (Note: I wrote the cap number on each removed cap so that I could reinstall it if it adversely affected the Tuner) The only cap that made any perceptable difference in the way the tuner reacted was C51. Previously, when a station was tuned in for best stereo light and sound, the Tuner indicator would be off to the right, after the new cap was put in, it reads almost dead center! I measured the original cap at 1.32uF, spec is 1uF. After replacing all the electrolytic caps, the sweet spot for the stereo operation in FM mode seems to be a bit broader. AM seems unchanged. The FM dial indication reads about 2 ticks low compared to the actual station, (same as before the recap). AM is perfectly aligned. AM radio works very well, too, I have an external antenna for AM, i like to listen to far away stations at night while working in the garage.

After experiencing no real change in the radio operation in the SX-1050 tuner recap, I decided to redo the SX-780 tuner after recapping the main board. Also did it one at a time, marking each old cap for reinstallation if needed. Again absolutely no audable/visable change I could hear on the SX-780 as to stereo lamp operation, ability to tune weak stations, dial accuracy, AM operation, etc. If anything, I think I notice less hum on AM radio, but that could also be due to the recapping of the rest of the unit.

I know it's not recommended practice to change them, and I'm not recommending that anyone else changes theirs unless they plan on sending it out for alignment, just relating my experience with two of my Pioneers!

Maybe anderslober will get lucky with his SX-1980, too! :smlove:


Note: I still want to get the SX-1050 professionally aligned, just need to find a tech within 100 miles or so, I'd prefer to drop it off in person, not ship it. If anyone knows a good shop in SoCal, please PM me!
 
Wow...a lot of good info......I have re-capped many tuners.....to me, performance, sensitivity and sound have gotten better in all cases. I just leave all the small pots alone and change the caps to spec. Maybe the touchy sx1980 is different!? We shall see......I hope it works out.
Today, initially I will power ON with 200watt bulb on DBT......to see if I can get the speaker relay to click................if I can, then I'll start dc-offset/idle current setting and voltage measurements...........maybe MUSIC today too!!
 
It ain't over 'til its over! Mark...you were right again....I took out R210/212...they both were different resistors and measured in the Mega-ohms. I changed them to brand new 1/2w 5.6 ohmers..........DBT'ed........bright and dimmer(not as dim as before)....and the SS relay doesnt click now. What could this be? Or is it normal? I measured at the 'end' of R102...it was 27.8v.........for the relay to connect it needs 48vdc.......is this correctly understood?
I changed nothing except the 2 resistors.

Edit: All the voltages on the pins are OK when measured on DBT. They are of course slightly lower......but they are all there.
 
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read voltages on both sides of r102, THEN measure R102 ohms if the resistance from pins 1 to 2 is infinite ohms (open/off power switch).

Then measure DC resistance across coil.

I am slightly disappointed that you did not check all the resistors on this critical board before you applied power. There should be no "cross your fingers and throw the power switch" - it should be as inevitable as falling off a log. ESPECIALLY with the amounts of power available to circuit faults.

The DC resistance and required energy is probably higher for this relay than the originals. I will need all the numbers I asked for in order to recalculate a resistance.

I REALLY would appreciate being able to SEE what all the regulated voltages are, ESPECIALLY if we have further troubleshooting (i.e. no ss relay click)
 
Mark....do you want all the measurements while on dbt?

You are right.........I should have checked those 2 resistors........

The DBT goes bright then dim.......so still no major shorts........
 
R102-----63,2v in.......27.2v out.
Pin1/2 both measure 27.2v. Mark...my sx1980 is an 'S' model....so pin 1 and 2 are jumpered. They do not go to the power switch(gray/orange wires) like in 110 volt models.

I measured R102 out of circuit...it measured 3.31K......

Why did the SS relay connect before? Was it because the 'OL' R210/212 was 'blocking' voltage and 're-routing' it through the relay?
 
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63.2 in is way too low - it should be 99 to 106 volts.

MEASURE the voltage ACROSS R210 and 212 - that means one dmm lead on EACH side of that particular resistor. That will allow the calculation of current being drawn.
Then shut it down.

YOU DID DISCONNECT IT FROM THE DIM BULB TESTER BEFORE TRYING TO READ r102 VOLTAGES AND POWER SUPPLY VOLTAGES?

REPEAT THE BELOW:

i don't know for sure, the power supplies could be starved by the dbt, so :turn the amps to zero idle current, and run it straight.
edit - this means run it without the dim bulb tester, plug directly into the wall


check the power supply voltages. If ok, set the dc offset to as close to 0.000v as possible. By then you should get the click. If not, then we start trying to figure out why not.

Otherwise

then back onto the dbt, with at least 150 watts and see if it clicks in, iiac it should.

Now, you can test set the idle current to tease out any problems. The bulb will get slightly brighter as the idle current is dialed up, and the unit's protection may click out due to reduced ac voltage - this is not a problem...

If the idle current goes very bright quickly dial it back down to zero and stop -no excuses - stop - you are at low altitude and the stall stick shaker is going off like a berserk belly dancer!!

You may not reach idle current, but that's ok, turn it back down to zero ohms, minimum idle current.

Repeat for the other channel.

When that goes well, then you can go straight into the line, and set the idle currents for real.
 
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Mark...I measured while on DBT. Thats why it is low..............

HUH....you mention R210/212.........aren't we measuring R102?

So, you want me to apply full power? Is that wise? I mean, even though it does go 'Bright then Dim'....................
 
we are done with r102, yes full power WITH THE IDLE CURRENT TURNED TO MINIMUM.

Bright to dim is GOOD. STAYING bright or going bright QUICKLY is BAD. brightening with idle current being turned up is ok.

OTHERWISE

Then back ONTO the DBT, with at least 150 watts and see if it clicks in, iiac it should.

NOW, you can TEST set the idle current to tease out any problems. The bulb WILL get slightly brighter as the idle current is dialed up, and the unit's protection MAY click OUT due to reduced ac voltage - this is NOT a problem...

If the idle current goes very bright quickly dial it back down to zero and STOP -NO EXCUSES - STOP - you are at low altitude and the stall stick shaker is going off like a berserk belly dancer!!

You may not reach idle current, but that's OK, turn iyt BACK down to zero ohms, minimum idle current.

R210,212 was looking for current load on transformer, don't need since on dbt

this is my LAST post on this tonight. I keep on getting sucked in instead of getting sleep.

that's why there are long EXPLICIT instructions. Please pay close attention to them. The information density is very high in them. PLEASE reread them a few times so I don't have to repeat them verbatim some more... :dunno:
otherwise :gigglemad
 
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Mark....get some sleep, man! Don't worry....we'll get it fixed.....just small sniggles(I hope)........I will try a full power test..................with idle current fully counter-clock-wised on both vr3/vr4..................
 
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