SX-1980 Quartz Lock Issues
I have a sx1050 been thinking about getting a high definition tuner for it. Sound quality is superior to analog.
I don't do help by PM. NO ONE else can benefit.
My PM traffic is horrendous - I get more and more tempted to TURN IT OFF. But I NEED it on to fix people's clutches!!!
From Jondubb35 by PM:
This quote below is the most likely answer - get the long qtips to polish the shaft where the ground contact rides.
Try deoxit first, to clean it. JUST WET THE Q-TIP !!!!!! NO MORE!!!! Then you can try wetting with tarn-x, if all else fails, use Brasso polish.
These contacts in the tuning capacitor on the central shaft take up a HUGE portion of my time on a SX-1980 tuner.
BE SUPER CAREFUL TO NOT BEND THE WIPERS!!!!!!!!!!!!!!!!!!
My PM traffic is horrendous - I get more and more tempted to TURN IT OFF. But I NEED it on to fix people's clutches!!!
From Jondubb35 by PM:
Hello-
I have an SX-1980, and recently the FM quartz lock/fine tune section has been acting up. Specifically, a station that has been tuned will all of sudden start cutting in and out and the Quartz lock, fine tune and stereo section lights start flickering. Eventually it stops but it happens every time I use it. I know that’s not a great description, but I’m hoping you might have an idea of what my problem could be. The unit has been recapped and the power supply has been rebuilt. I’m hoping it’s not a power supply problem. Could be that the FM tuner section needs cleaning??
This quote below is the most likely answer - get the long qtips to polish the shaft where the ground contact rides.
Try deoxit first, to clean it. JUST WET THE Q-TIP !!!!!! NO MORE!!!! Then you can try wetting with tarn-x, if all else fails, use Brasso polish.
These contacts in the tuning capacitor on the central shaft take up a HUGE portion of my time on a SX-1980 tuner.
BE SUPER CAREFUL TO NOT BEND THE WIPERS!!!!!!!!!!!!!!!!!!
Jondubb35
New Member
Thank you and I apologize for the PM. Next time I’ll post publicly. But I do appreciate you help. Hope you are healthy and doing well.
QUOTE="markthefixer, post: 13642357, member: 6768"]I don't do help by PM. NO ONE else can benefit.
My PM traffic is horrendous - I get more and more tempted to TURN IT OFF. But I NEED it on to fix people's clutches!!!
From Jondubb35 by PM:
This quote below is the most likely answer - get the long qtips to polish the shaft where the ground contact rides.
Try deoxit first, to clean it. JUST WET THE Q-TIP !!!!!! NO MORE!!!! Then you can try wetting with tarn-x, if all else fails, use Brasso polish.
These contacts in the tuning capacitor on the central shaft take up a HUGE portion of my time on a SX-1980 tuner.
BE SUPER CAREFUL TO NOT BEND THE WIPERS!!!!!!!!!!!!!!!!!![/QUOTE]
QUOTE="markthefixer, post: 13642357, member: 6768"]I don't do help by PM. NO ONE else can benefit.
My PM traffic is horrendous - I get more and more tempted to TURN IT OFF. But I NEED it on to fix people's clutches!!!
From Jondubb35 by PM:
This quote below is the most likely answer - get the long qtips to polish the shaft where the ground contact rides.
Try deoxit first, to clean it. JUST WET THE Q-TIP !!!!!! NO MORE!!!! Then you can try wetting with tarn-x, if all else fails, use Brasso polish.
These contacts in the tuning capacitor on the central shaft take up a HUGE portion of my time on a SX-1980 tuner.
BE SUPER CAREFUL TO NOT BEND THE WIPERS!!!!!!!!!!!!!!!!!![/QUOTE]
The green goop was probably an anti-corrosive, that hasn't aged well.
That said, I reiterate and STRESS, wet the q-tips FAR away from the tuner fins!!! KEEP the fins PRISTINE.
Someday I may look into an anti-corrosive goop to replace it, because that area is SO sensitive to contact quality.
That said, I reiterate and STRESS, wet the q-tips FAR away from the tuner fins!!! KEEP the fins PRISTINE.
Someday I may look into an anti-corrosive goop to replace it, because that area is SO sensitive to contact quality.
I will add to this thread that I had my fun today with tuning up a 1980 FM section. I know someone was in there before me monkeying around.
I noticed that the FM FE mosfet was changed, they did a bad job and lifted traces.
This RF FE can has four screws on the top, but also has two grounding tabs to the pcb which is a PITA. This one was not too bad so I left it alone. A way to test is too ground &/or disconnect your antenna input, mute off, run through the dial listening to scratchy noises (headphones). Sometimes if you go back and forth a few times at one spot, you can hear the noise being reduced, as you wear off oxides and make a better ground contact.
Signal meter was reading "3" on the strongest of signals = Monkey
First thing is to zero the quad detector. No RF muting off, tune to white noise, bottom slug accessed from the bottom plate off.
Minor tweek to a trimmer in the RF FE
In the APC adjustments they say to scope and verify that the 100kHz is present, what they fail to mention is what accuracy it should be set for?
I know if it is off, as in my case, the quartz lock will not work correctly. I monitored the 10kHz, 10x scope probe to a HP 8416A frequency counter and adjusted TC1 for 100K +/-10Hz
They say in the manual that the APC X1 is colour matched to the IF filters?
You will never get the 450mV they state, iirc it was a max of 380mVrms as measured on the Tek DPO. I set it back to what it originally was at ~325mVrms
I did not touch L2, maybe that might have peaked it some more.
So once you get VR3,2 adjusted to 6 & 0VDC spec, it works okay, make sure you test at both ends of the dial.
Pretty good tuner, sensitive, seems to be a bit more selective than the 1250, once it is setup properly.
I noticed that the FM FE mosfet was changed, they did a bad job and lifted traces.
This RF FE can has four screws on the top, but also has two grounding tabs to the pcb which is a PITA. This one was not too bad so I left it alone. A way to test is too ground &/or disconnect your antenna input, mute off, run through the dial listening to scratchy noises (headphones). Sometimes if you go back and forth a few times at one spot, you can hear the noise being reduced, as you wear off oxides and make a better ground contact.
Signal meter was reading "3" on the strongest of signals = Monkey
First thing is to zero the quad detector. No RF muting off, tune to white noise, bottom slug accessed from the bottom plate off.
Minor tweek to a trimmer in the RF FE
In the APC adjustments they say to scope and verify that the 100kHz is present, what they fail to mention is what accuracy it should be set for?
I know if it is off, as in my case, the quartz lock will not work correctly. I monitored the 10kHz, 10x scope probe to a HP 8416A frequency counter and adjusted TC1 for 100K +/-10Hz
They say in the manual that the APC X1 is colour matched to the IF filters?
You will never get the 450mV they state, iirc it was a max of 380mVrms as measured on the Tek DPO. I set it back to what it originally was at ~325mVrms
I did not touch L2, maybe that might have peaked it some more.
So once you get VR3,2 adjusted to 6 & 0VDC spec, it works okay, make sure you test at both ends of the dial.
Pretty good tuner, sensitive, seems to be a bit more selective than the 1250, once it is setup properly.
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Clever.
I was thinking about doing the very thing but wasn’t sure if it would give a accurate reading. And I hadn’t received the probe. Still a few days out.
How did I complete the procedure? Put the trimmer back where it was.