Anyone have a Pioneer SK-550?

[monchito]

well the seleniod has its use if not they would have not used it but on the sk-95 and the 61,71,31, and the 900 they all use the same deck so it does need the selenoid for the songfinder and autorepeat so the deck has a small board on the deck itself with has the transistors for the seleniod plus a couple of microswitches thats why i thought it might be simular even though i did not think it had the autorepeat or songfinder feature......

 

[Superduper]

Ramon. That is true. If you read my other post more clearly, you'll see that I mentioned that the solenoid is used for initiating autostop during the music search. But right now, it's probably more important that the deck does not lock up, which is what happens when the solenoid engages but won't release. So you are right, disconnecting the solenoid will result in the music search feature being not-operational but at least the deck won't lock up, and you can play, FF, RW and record normally. Of course ideally, fix the issue causing the driver transistor to switch on will fix the problem properly.

 

[monchito]

well once you get her up and running let us know how it goes for you those 550 are really nice and hard to come by

 

[Gluecifer]

Awesome Norm!! Your work is greatly appreciated!

I'll attempt to locate and disconnect the solenoid on the weekend then. I don't mind not having music search, like you say, it's the basic deck functionality that is the main thing!

Thanks again, really marvellous work on your behalf!



Rock On.

 

[monchito]

glue there you go man so now you know once you get her running let us know if not i will be waiting send it down this way

 

[Gluecifer]

Well, I took mine apart. Had a look around the mech, manually rotated the wheel a few times to get it into neutral, and then powered her up.

Much to sheer amazement everything started working. All the decks functions, including the music search, are going like clockwork. I let it run for a while, and apart from a bit of hum when the deck isn't going in the right channel (any ideas?) it's all rockin! I really have no idea what I did, apart from manually rotating the deck, but I'm very happy regardless.

How long this will last, I don't know however, and as I couldn't find the solenoid you mentioned, Norm, I'd reallllly appreciate a photo of it or instructions of where to find it, whenever you get around to doing yours.

Been a lucky day on the blasters today, I also slipped while adjusting the head azimuth on my C-126F and snapped a wire off the tape head a while back and I got that all resoldered and fixed up today.

So it's been a winning saturday!



Rock On.

 

[monchito]

you did good glue and the selenoid should not be hard to find in the deck mostly they sit on the outer corners of the deck plate and you will see 2 wires going to it it has a small coil shape a plunger or a plate

 

[Gluecifer]

Ohh I know that thing! I'm learning even more today then!

I thought that contraption was related to recording!

thanks heaps Ramon!



Rock On.

 

[Superduper]

Hey Glue, that solenoid is in the rear of the deck mechanism. When activated, it locks the function slide levers and prevents manually stopping the FF or RW modes. When I had mine apart, I could get the solenoid to deactivate by touching or slighly tapping on the power transistor that is secured at the heatsink directly behind the tape mechanism on the left side. Touching the large capacitor and the transistor could cause sufficient change in capacitance to cause this to happen. I suspect that this is the transistor that is powering the solenoid but I don't want to guess. Anyhow, if it's all working, then congratulations. However, if it locks up again when it's all reassembled, will it present a problem disassembling it once more?

BTW, the hum you are experiencing is tyically a symptom of an ungrounded head cable shield. Since you broke the leads, maybe it's related. Also, you may want to clean the record bar (the long bar mounted on the PCB). If it has poor connection, it could manifest like an ungrounded cable. Of course hum could also be evidence of an issue in the amp or preamp. If that is the case, re-capping the box would usually take care of it.

 

[blu_fuz]

For such a simple looking box there is a lot going on in the cassette area. I hate that there aren't quick connectors on all wires, just makes working on these more frustrating.

You guys gave such great directions to open the door that I got mine in less than 5 minutes .

But now I need to get the heads down on mine too and I don't understand the "wheel cranking" you guys talk about. Can any of you describe what I need to do? Thanks a lot for the help!

 

[BMoney]

The flywheel. You gotta crank (turn) it to get the heads down.

 

[blu_fuz]

FOUND IT! haha

Just learning so bear with me .


Well I got my SK-550 pretty much DOA. Just powered up.... sometimes . I knew this from the auction though.


So, for some reason everything but the cassette works now . Loose wire perhaps - I dunno.....


I am getting rewind only on the cassette, The light for the music search #1 is on and the dolby NR light is on.
Also I see a small brown diode looking thing that has electrical tape around it that looks like it pulled out from the board somewhere, so I gotta find where that goes. Pics soon, hopefully.

 

[blu_fuz]

Here is the little diode thing (located to the right of the cassette deck):

 

[Superduper]

That's a capacitor. I can see that it's clearly cracked, probably from excessive flexing. My guess is that the other leg is soldered to a grounding tab on/near the cassette area.

 

[blu_fuz]

Yeah, it is all cracked up and the wire is in a position pointing towards the cassette deck. I did unscrew a ground eye from the bottom right corner of the cassette deck case and can't seem to find it now, so it probably did fall off and is laying in the box somwhere..... Why would they have a capacitor on a ground strap?

 

[Superduper]

To shunt RF and EMI interference to ground.

 

[BoomboxLover48]

Very nice thread from almost 6 years ago!

 

[Ghettoboom767]

I have 2 SK-559's,one deck works very good except when it auto stops,then you just have to hit stop twice then open it then I just have to click play like twice and away it goes,all works.
But my silver 559 is a different story,some moron tried to repair the deck and put a mound of solder in one place so I'll just get a whole different deck mechanism for it.

Now I have a SK-750 and it is in the no heads go up syndrome. It did work for a while,I spent 2.5 hours yesterday and it at least isn't stuck in spinning flywheel mode.
This deck isn't fun and it's a somewhat abused box but I'm slowly restoring. Sound is great on 750!
But need new belts and a diagram for proper belt routing. Had to use counter belt to replace 1 broken one.
I can get it to FF sometimes but that's about it.

If anyone has a photo of belt routing in 750 let me know.
I think I may have a bad solenoid myself.Will try again when new belts come and routing,I think I can figure it out but would feel better if I knew for sure.

Funny I've fixed SK-71,95 decks but this one seems tougher.

 

[BoomboxLover48]

I have 2 SK-559's,one deck works very good except when it auto stops,then you just have to hit stop twice then open it then I just have to click play like twice and away it goes,all works.
But my silver 559 is a different story,some moron tried to repair the deck and put a mound of solder in one place so I'll just get a whole different deck mechanism for it.

Now I have a SK-750 and it is in the no heads go up syndrome. It did work for a while,I spent 2.5 hours yesterday and it at least isn't stuck in spinning flywheel mode.
This deck isn't fun and it's a somewhat abused box but I'm slowly restoring. Sound is great on 750!
But need new belts and a diagram for proper belt routing. Had to use counter belt to replace 1 broken one.
I can get it to FF sometimes but that's about it.

If anyone has a photo of belt routing in 750 let me know.
I think I may have a bad solenoid myself.Will try again when new belts come and routing,I think I can figure it out but would feel better if I knew for sure.

Funny I've fixed SK-71,95 decks but this one seems tougher.

You fixed it?
Gained lots of experience with those Pioneers..

I have worked on up to 750..in the boombox series.

It is so tricky

 

[Ghettoboom767]

No not yet,750 I have has been abused. When I get belts I'll tear into it again no test solenoid as heads won't go up and tape light won't function as it won't go into play mode.