Anyone have a Pioneer SK-550?
Posted 23 October 2009 - 02:14 AM
Hopefully, someone here owns one of these and can help show me how to "slim-jim" the door open.
Posted 23 October 2009 - 05:41 AM
Will get some pix for you and post here within the next 24 hours.
Posted 23 October 2009 - 08:57 AM
Posted 23 October 2009 - 12:11 PM
Posted 23 October 2009 - 07:57 PM
norm- i had the same problem, i think i actually used a thin butter knife from the top to flip up lock, once i respun the flywheel, it took it off perma lock and no more problems since then.
whoa...... I was thinking this was gonna be hard to photograph because I expected the latch to be at the top left corner, which was where I was concentrating my efforts. Couldn't do much better blind. Now I think I stand a much better chance getting it opened! Thanks a bunch blahblah, THAT is much helpful.
Unfortunately, the latch looks deeply recessed so I don't think this is gonna be easy by any stretch of the imagination. I can't see how you would get a butter knife into that location with the door closed though.
Posted 23 October 2009 - 08:01 PM
Posted 23 October 2009 - 09:33 PM
Thanks for saving me taking mine apart Blah. Good luck Norm, I hope you can work it all out
and we all get our tape mech's working properly. I know with mine it only happenedwhen it
was put into record mode, if that's any help.
Hope the mystery can be solved as this is a really great radio that deserves to be put into full rotation.
Posted 24 October 2009 - 01:36 AM
The image was a little too small for print (I printed it out to have it next to me as I tried to rig something up but no success.) While it looks fine on screen, when printed, the resolution was really poor.
Could either of you guys get me a larger photo or other angles? The problem is from the angle of the shots, it's really hard to tell and estimate the measurements for me to bend my jig. Photos can be deceptive. Is the latch about reel disk height? Also, how deep from the front of the cassette door would you estimate I would need to bend my rig to catch the latch? Maybe I'm missing it entirely (too shallow) or maybe I'm too deep -- it's really hard to tell since the spring wire I'm using is really stiff and rubbing all over the place. This thing has been bugging me like forever and I really hate to snap that door since I'm pretty sure there is no parts units available. I hardly see any of this model at all, as it is, in any condition.
Blah Blah, you must've had great luck. The thin butter knife thing from the top just doesn't seem possible unless the knife is like razor blade thin and can zig and zag too. Also, it seems like from the top, you would be pressing the hook down and not hooking it up. Oh well, gonna take a break now before I get too tempted to smash it apart.
One final question. If all else fails, I might consider cutting an access hole at the bottom, do you guys think the capstan flywheel will be visible so I can spin it if I cut a hole below the tape mechanism?
Posted 24 October 2009 - 03:53 AM
Just got mine open. It was locked up entirely, heads were engaged and none of the buttons were doing anything.
This was my method.
Get something like a butter knife with a reasonable flex and run it under the left edge of the door and up. You need to make the door flex a bit so a bit of force is required. When you wiggle it right you'll catch it on the clip that holds the door front in place and you'll be able to slide it up and off.
I found that now I could get access to the reel spools I just got a flat tip screw driver wedged between the spool and reel so I can manually turn them. This eventually got it into neutral with the heads disengaged and everything opens and shuts as it should.
Mine's still rooted, however, and won't get any further.
Here's some pix:
Hope this helps, Norm. If you need more of anything else specific let me know.
Posted 24 October 2009 - 02:05 PM
A couple of questions: If I understand you correctly, the goal is to try to slide the door cover off the metal frame and not undo the spring latch, right? If so, what is the purpose of the butter knife? Is it to hook the door clips and if so, then why are we only working on the left side? It looks like there are 2 door clips (right and left)?
Posted 24 October 2009 - 07:20 PM
It sounds more complicated than it really is though!
Good luck Norm!
Posted 24 October 2009 - 07:36 PM
Posted 24 October 2009 - 09:37 PM
hope norm gets it open...don't cut a hole norm , it really will open, it is a very wiggy little area and the door has more flex than it seems, and don't smash it either!
i think i may have gotten luck by actually prying the door down far enough that the catch slipped up. it was impossible to see so indeed was probably luck...but can be done.
Posted 24 October 2009 - 11:49 PM
Got it open guys! Thanks a bundle. You guys are da bomb!
OK, I figured out that there is no way in hell of hooking and releasing the door latch -- it is firmly locked in place when the heads are up. That's why I wasted hours yesterday night trying to jimmy the latch -- that path is a no-deal. The only chance of getting the door off was to slide off the cover. Had this been a panasonic, the door clips would've been snapped off on the first try.
What I did was
(1) put a big wide flexible putty knife at the top and pried the door outward.
(2) put a stiff putty knife on the bottom edge and pried the door upwards.
It popped off successfully. I'm not 100% convinced however, that this would be an official recommended repair technique because I do think that if practiced regularly, some doors are gonna break. It's a little risk, no question.
Anyhow, I'm just glad this door opened successfully. Now, the fun begins.
Posted 25 October 2009 - 12:56 PM
Posted 18 November 2009 - 04:02 PM
My SK-550's still in pieces, waiting for your intstructions!
Posted 18 November 2009 - 04:38 PM
My guess: There is a power transistor that powers the solenoid. I haven't found it yet. My guess is that it's shorted. This solenoid is for the AMSS search feature. During the search function, it actuates to hold the FF and RW in place. When it deactivates, the FF or RW will stop and allow the normal play function to resume. Since it's on all the time, the stop function does not work.
Other possibility: This one is more problematic but less likely since this circuit uses low signal levels instead of the power transistor circuitry which for obvious reasons, is more prone to failure. I'm talking about the AMSS search feature circuitry. Without a manual, there is no way to diagnose or fix this, if it indeed is the problem. But if it is constantly sending an activation status signal to the solenoid, then obviously, the solenoid will always be engaged and prevent the stop function from working correctly.
The WORK-AROUND: Good news. If your SK-550/SK-750 is having this problem, merely disconnecting the solenoid will permit normal tape functions. Obviously, the search feature will not work. But at least you can use your boombox normally otherwise.
Try the workaround Glucifer and let me know if this works. Someday, I will find out which transistor is causing the problem and if I find a solution, I'll let you know.
Posted 18 November 2009 - 06:10 PM
Posted 18 November 2009 - 09:03 PM
The problem for me is that this pioneer is built kind of like a lot of panasonics. The case back serves as the chassis including the mounting place for the circuit board. You can't just unplug the mainboard. Lots of wires tethered by soldered connections. No problem except that once I get it apart completely and remove the transistors for testing, I'll probably not want to reassemble everything until I get the parts. Right now, I just don't have the space to have a boombox completely in bits for a week or more. BUT, I know that simply disabling the solenoid will allow the deck to work normally. I know this because with the deck removed from the boombox, I tested it with a 9v battery and all functions including STOP works normally. It' s only when it's hooked up to the boombox does the solenoid activate (I only powered the capstan motor on the bench) all the time. So, remove or disable the solenoid and 99% of the functions are restored.
Posted 18 November 2009 - 09:18 PM
Posted 18 November 2009 - 09:45 PM
Posted 18 November 2009 - 09:52 PM
Posted 19 November 2009 - 01:12 AM
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!
Posted 19 November 2009 - 06:34 AM
Posted 21 November 2009 - 03:30 AM
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!
Posted 21 November 2009 - 04:39 AM
Posted 21 November 2009 - 06:15 AM
I thought that contraption was related to recording!
thanks heaps Ramon!
Posted 21 November 2009 - 06:58 AM
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.
Posted 31 August 2010 - 06:19 PM
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!