Trouble with my Pioneer SX-626

Ryan Abelman

New Member
Hey everyone!

So I just joined and already have questions for the group. I got a Pioneer SX-626 receiver from Goodwill last year. I had it serviced at a local shop here in Los Angeles. I don't think they did a very good job. The lights were dim and not all worked. Then the other day, the dial cord snapped when I stupidly spun the knob too fast. Ugh! So I thought I would try my hand at fixing both issues myself. I have never done anything like this before, so I wanted to give it a shot. I took the case off and saw that the indicator lights were either still missing bulbs or burnt out. The backlight bulbs lighting up the tuner was even more strange. Rather than using normal fuse bulbs, they soldered in little tiny lights. So I was going to desolder it and put fuse bulbs back in (LEDs this time). Then I was going to try to record the turn. Then this happened... This morning I went to take out one of the old burnt out indicator bulbs so I can get replacements. I then turned on the tuner again to check which bulbs were out and it wouldn't turn on. Did I somehow short something? DId I destroy this thing? Any advice or guidance would be greatly appreciated. (I have the service manual already and have watched several videos so I think I am capable of changing the bulbs and the cord myself. But this power issue might be beyond my comfort level.) I am bummed because I really like this receiver.
 
You may have shorted the lamp wiring. Check the fuses.

I don't remember offhand, but I'm pretty sure that there are at least 2 internal fuses, in addition to the three you can check from the rear panel (it is not likely to be the protection fuses).

Before replacing a fuse, make sure you have not shorted or opened a circuit while messing with the lamps.
 
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Well, replacing a fuse is easy. Make sure it has same amperage rating and equal or greater voltage rating. I would guess they are fast blow types. But as I said, first carefully examine the area in which you were removing bulbs to assure no shorted connections, loose wires, bare ends, etc.

While the problem could be unrelated, logically the most likely cause is something that you did when removing bulbs/messing with lamp wiring.

Good close-up pics might be helpful.
 
Ok... this might show my level of ignorance on the topic, but how do I verify that it is a fuse issue and not a shorted connection, loose wire, bare ends, etc.? There is a lot going on in there and I am not 100% sure how it "should" look to know if anything other than a blown fuse is the culprit.
 
A blown fuse is a secondary issue. It was caused by something (usually by a short circuit).

The receiver worked before you made changes. It does not work now. So, first check all the fuses, with power off. Normally, you will see that the thin wire in the fuse is broken and/or the fuse is blackened if it has blown...but not always. Ideally, you would use an ohmmeter or the continuity test function of a multimeter to check the fuses and confirm if they are good or bad.

But as I said, a blown fuse is a symptom...not the primary problem. You have to tell more about precisely what you did before the problem occurred. And as I said, some good close up pics of the area in which you were working before the problem would be helpful.

Pics will also help to determine what mods were done to the tuner display lamps. I'm guessing that these mods are involved with your current problem. Someone probably converted them to LED prior to the availability of "drop-in" LED fuse bulbs. This would have involved dropping the voltage with resistors.
 
First off, let me say thank you so much for helping me. I clearly am new at all this.

Here's what I did. Last night I took the case off to see what was going on. I noticed the two areas that I wanted to work on. 1. Burnt out bulbs and 2. Broken dial cord. Looking at the bulbs, I saw that they were not the normal fust bulbs but were little tiny lights that were soldered to both sides of each fuse holder. I tried to pry them off but I didn't want to break the fuse holder so I decided to desolder and moved on to issue 2, the dial cord. I unwound it and was left with it attached to the dial pointer in the little clips there with a little bit of glue. Using an exacto knife, I scraped off the glue enough to get the broken cord out. I then took the dial pointer and the frame that it slides on off to get to the indicator bulbs. I set the dial pointer and frame piece aside, but I think it was resting on some of the internal components when I turned on the stereo to see what bulbs were out. I think that the metal from the frame touched something it shouldn't have and that might have done me in. I have the service manual and not exactly sure which fuse to check so I guess I will check them all???
 
Yes, check all...although if it is a fuse it will most likely be one of the internal fuses,, or perhaps the single AC fuse on the back panel.

Hopefully just a fuse blew, and saved other components from damage.
 
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Replacing the dial cord will be a challenge. It is too bad that you removed it; splicing one in is easier than full replacement. The manual should have instructions.
 
I would guess that whoever modified the lamps put in LED bulbs, and resistors. To revert back to fuse bulbs (LED or incandescent), the resistors will need to be removed. Hopefully the fuse holder mounts for the bulbs can still be used. Again, pics would help to know what is going on in this regard. Can you determine if the bulbs used were LEDs?
 
Ok... Here are some photos. I also tested the three fuses in the back. They are all fine. I hope there are some fuses inside! Otherwise, I fear I destroyed this thing!
 
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OK...I can see that someone installed resistors in the lamp circuits so they could install LED bulbs. To go back to fuse bulbs, you will need to use desoldering braid to remove the wires and resistors between the ends of the fuse holders. I can't tell from the pics, but it appears that you will be able to still use the fuse holders after removing that stuff, and any solder on them.

The other fuses - if there are others - are in the interior, but I don't remember where. I would assume underneath, so you will need to remove the bottom of the case. They are probably on the power board, near the transformer.
 
This is very helpful! Thanks!!!

The fuse bulbs I was going to put in are LED fuses. Does that mean I can just take out those silly lights they put in and then just pop in these fuses? (Boy do I owe you! I see why it says you are a "super member"! Ha!)
 
This is very helpful! Thanks!!!

The fuse bulbs I was going to put in are LED fuses. Does that mean I can just take out those silly lights they put in and then just pop in these fuses? (Boy do I owe you! I see why it says you are a "super member"! Ha!)


Yes, the LED fuse bulbs have small resistors built into them. That's why they are so popular....the lamp circuits do not have to be modified (with resistors to drop the voltage) to use them. I would guess the modifications to your receiver were done before these LED fuse lamps were being produced...they've only been around for a few years.

So it appears that you are getting power to the lamp circuits...but I assume the receiver is still "dead"? To be clear, you are getting nothing from the speakers? What are you using for an input (CD player, etc)? Are you sure that the speaker switch is on, that the selector is set to the correct input, and the tape monitor button is not on?

NOTE: Don't try to use it with it disassembled.
 
Once again, you are correct! I took the bottom off and sure enough spotted a fuse. Pretty sure it is blown. However, I have never seen this before. It is inside a plastic tube and soldered to other parts. Is this a simple desolder and resolver a new one? What is the purpose of the plastic tube? Can I just snip this one off and resolver a new one on without have to desolder it first? Thanks!!!!
 

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Oh... I should have mentioned this... No lights are working still. I was using a flashlight to make the photos better to see for you. But still no light. No sound. I turn it on and it is like the unit is unplugged. The only input is a turntable which is obviously not connected at the moment. I did plug it in to the back of the unit and saw that it was getting power. So the receiver is able to transfer power to the input device but seems to be a problem elsewhere. (I think the fuse mentioned above.)
 
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