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 Post subject: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Fri 18, 2019 7:37 pm 
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Joined: Aug Tue 23, 2016 12:59 am
Posts: 90
Location: Western Maryland, zipcode 21722
Pioneer SX-1000TW
FM Stereo Receiver - FET in the FM radio frequency amplifier stage design.

Only During FM Recieve do I hear Loud Popping ( similar to Receive Atmospheric Static Crashes ) occansionally , more predominant after unit major warn-up. This Popping Does Not Occur During Auxiliary Equipment ( CD Player ) Playback and do not notice during AM Broadcast.
Secondly - FM Recieve Audio will ( less occansionally ) drop Audio total output for a millisecond - very spuradic.

Question - Looking for suggestions.
The sound appears to be a Capacitor Defect - very spuradic.

Will completing a Full FM Tuner Alignment Solve These Two Problems or Should I Troubleshoot and try to chase these two errors ?
Your suggestions.

cferry1


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Fri 18, 2019 10:49 pm 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
Have you the experience of replacing the electrolytic capacitors in a 1970s receiver like this before?

Service manuals...
http://www.kallhovde.com/pioneer/sx-1000tw-om-sm.pdf
http://www.kallhovde.com/pioneer/sx-1000ws.pdf


Stay away from an alignment.
:) Greg.


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Sat 19, 2019 3:27 pm 
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Location: Western Maryland, zipcode 21722
Yes.
I could replace the Electrolytic Capacitors.

However, I am concerned that the error is only during FM Receive Operation.


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Sun 20, 2019 8:30 am 
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Location: Mountains of Mourne. Ireland.
If you don't want to replace the electrolytics, try poking components with a plastic chopstick and see if you can locate a dry solder joint.

Also, a close visual inspection of the components will often yield results. Look for signs of overheating - burnt or near burnt.

FM boards are shown in the service manual.

Take note: When poking around a live chassis with chopsticks or the likes, keep your less dominant hand in your back pocket.
This is to stop electricity traveling up one arm and through your chest (heart) and out the other arm.
------------

Otherwise... pull the boards and replace the electrolytics as a first step.

Wire wrapping tools can be found on ebay.
https://www.ebay.com/sch/i.html?_from=R ... 0&_sacat=0

Clean the posts and wire ends with some IPA before re-wrapping.
------------

Use capacitors rated at 35V or 50V (for 6.3V 10V 16V 35V) and 105°C temperature rating.
If the traces begin to lift, your iron is not hot enough - you want to get in-and-out quickly.

Modern day electrolytic capacitors have become so much smaller since the 1960s and '70s
Some of the old μF (microfard) values are no longer common... so choose the next nearest capacitance value, up or down.
... I buy the 50V ones today to replace the old 3V, 6V + 10V

fyi... electrolyitc capacitors rated as 85°C are good enough for transistor radios.

It's foolish to hunt down 3V 6V or 7V electrolytics.

I mark their negative connection on the circuit board with a sharpie and... replace them one at a time, otherwise you can get confused.

For my money, Panasonic... 105°C
FC series
FM series
FR series are all good capacitors.
------------

Before and after soldering...
I clean (and dry) with IPA (isopropyl alcohol) using a small acid brush or an old toothbrush. I use 70% (strength) isopropyl alcohol... mixed 50/50 with regular nail varnish remover (acetone), it leaves no residue.
In a past life I have used Zippo lighter fluid (naphtha) or denatured alcohol in a pinch.

More applicable to modern-day devices...
Adding lead solder to a lead-free soldered joint speeds up the removal process. It lowers the melting point.

If you haven't got a solder sucker...
Image
.. EDSYN DS017 DELUXE SOLDAPULLT

...use fresh solder-wick. (The outer braid of TV coax can be used to soak up the old solder if you are in a jam).

Create a shopping-list... BOM (bill of materials) and post it here for verification, if you wish.


:) Greg.

Edit: the large (snap-in) filter capacitors may be difficult to locate nowadays.
You can replace them with regular through-hole radial ones as seen here.
(no pun intended) lol

Image


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 12:08 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 5414
Location: Sunbury, Ohio 43074
A few thoughts: Don't bother trying an FM alignment for this type of problem... it can only hurt you. I'd also not try a major capacitor overhaul just yet. You might be able to isolate the problem to an area of a board (the FM tuner most likely) by using a hair dryer on low heat, then on just air, to heat/cool certain components. As you get closer, freeze spray can narrow it down to a single part or solder joint. For spot heating, you can just hold a soldering iron CLOSE to a suspect part to heat it up a bit.

From your description, the problem has some connection to heat, so it should be fairly simple to localize this way. Going on a capacitor jihad will introduce a few hundred other variables... I'd hold off on that for now.

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 12:24 pm 
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Joined: Jul Mon 26, 2010 8:30 pm
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Location: Annapolis, MD
Ask 10 people and get.........

A few years ago, I overhauled THREE Pioneer receivers from the 70s. After a bit of reading about electrolytics from that era, I decided on the "shotgun" approach-----ALL electrolytics were replaced before power-on. Also, all the other typical inspection of solder joints, checking resistors, etc.

All three sets worked perfectly after all this + alignment.

I don't remember if I had wire-wrap in those three---or somewhere else. Regardless, If I find 50 year old wire-wrap joints, they get soldered.

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"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 12:29 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
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Location: Sunbury, Ohio 43074
roll the dice. :). Sometimes it comes up 11, sometimes snake eyes. :shock:

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 12:52 pm 
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I have been mostly successful with the "shotgun" method, but I certainly don't advocate it for everyone. I'll spare you the gory details of the cases where 20:20 hindsight suggested a different approach....:)

_________________
-Mark
"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 1:03 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 5414
Location: Sunbury, Ohio 43074
I hear ya .... I suppose if I were selling or keeping vintage (70s) stereo equipment it might be different. But all I'm doing right now is acting as a hired gun for a local stereo shop. For basically beer money lol. The marching orders are "just fix it" .... so restorations that involve replacing 100 capacitors are out of the question. All the customer wants is it 'fixed' so I swallow hard, and just fix it.

I completely agree however, that the shotgun approach is definitely not for everyone. The novice would be much better served to first get their system working, and THEN start wholescale capacitor replacements where they can check it as they go, basically. To be successful at the shotgun approach, you'd have to assume that the one doing the work is capable of finding any errors that they introduce, such as a wrong value electrolytic, one installed backwards, some wire broken etc ..... and that's a stretch for most begineers. misspelled, but it looks like it fits. I invented a new word (beginner engineers = begineers)

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 1:22 pm 
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Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26908
Location: Annapolis, MD
Barry H Bennett wrote:
I hear ya .... I suppose if I were selling or keeping vintage (70s) stereo equipment it might be different. But all I'm doing right now is acting as a hired gun for a local stereo shop. For basically beer money lol. The marching orders are "just fix it" .... so restorations that involve replacing 100 capacitors are out of the question. All the customer wants is it 'fixed' so I swallow hard, and just fix it.

10 years ago, I had no intention of trying to fix electronics for customers. After moving to the DC/Baltimore/Annapolis sprawl, I discovered a significant demand, and restoration jobs trickle in regularly. The best jpbs are the sets that have been in the family for some time and are being fixed for their nostalgic value. I don't accept any work other than a complete refurbishment and, so far, I'm getting away with it.

Remembering the 100s of little electrolytics in those Pioneers, I wondering how that episode compares to the German sets that come in regularly. Sometimes I wonder if I'm the only one around here that will take on a German radio......that doesn't seem plausible

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-Mark
"Measure voltage, but THINK current." --anon.


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 Post subject: Re: Pioneer SX-1000TW FM Tuner Errors
PostPosted: Oct Wed 23, 2019 3:42 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 5414
Location: Sunbury, Ohio 43074
^5 to that ..... I had no intention of ever getting back into HiFi service either... so much for the best laid plans. But now I have the first right of refusal ... I can REFUSE if I want lol. And I will, if it stops being fun. I kinda like that they don't do restorations on these.... they limit that to what we do here on the forum... namely vintage tube stuff. He's got a tech there that handles that stuff. Fine with me. Most of it is huge living room furniture size consoles etc which I'd turn down anyway.

And first and foremost, I do NOT have to deal directly with the customer. That is worth a lot of $$$ to me ... been there, done that, won't again.

So I replace the fried power supply pass transistor, a few caps, and a few panel lamps, and move on to the next one. Occasionally an output stage. So far, none beyond repair. Some of these things are selling for $1,500 - $2,000 so I probably could make a good buck restoring them if I were so inclined. I am definitely NOT so inclined. I've got a warehouse full of antique tube type test gear calling me ....

:D 8) !!!

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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