Accessing SX-1010 Tuner Board

[jahmadeus]

Hello all, I am finishing up a rebuild of my SX-1010 and only have the tuner board left to work on. I have noticed that it is tethered down by its wire wrap connections on nearly every side. I have had success with desoldering select wirewrap posts from the other boards to gain access. However, the best method to safely/efficiently free up the tuner board does not seem as obvious as the rest of boards in the unit (to me, at least).

I have a few guesses on how to best approach this but I am curious to know what others have had success with when gaining access to this board.

Any input is appreciated!

 

[ivandezande]

Leave it.

 

[jahmadeus]

Leave it.

This is typically my attitude, best not mess with anything tuner related if you don't absolutely have to.

I plan on being very light handed in working on the tuner section as I do not want to mess with the alignment. Mainly want to change the blue sanyo caps which so far in the amp have been 100% way bad (reading as a few pF, >50ohms esr, etc). I'm assuming the alignment was performed when these caps were not fully gone (assuming they are in a position that would effect alignment). I do not plan on changing out any active devices or even all the electrolytic caps (only ones that test way out of tolerance). The caps that I swap out can always be swapped back in if something goes south.

If nothing else, it would be nice to check out the solder joints as it sits right above the hot power supply and I have already found an unusual amount of cracked/cold solder joints in this unit.

 

[ivandezande]

This is typically my attitude, best not mess with anything tuner related if you don't absolutely have to.

I plan on being very light handed in working on the tuner section as I do not want to mess with the alignment. Mainly want to change the blue sanyo caps which so far in the amp have been 100% way bad (reading as a few pF, >50ohms esr, etc). I'm assuming the alignment was performed when these caps were not fully gone (assuming they are in a position that would effect alignment). I do not plan on changing out any active devices or even all the electrolytic caps (only ones that test way out of tolerance). The caps that I swap out can always be swapped back in if something goes south.

If nothing else, it would be nice to check out the solder joints as it sits right above the hot power supply and I have already found an unusual amount of cracked/cold solder joints in this unit.

That’s fair. Those Sanyo caps are nasty.
I hope you find a good way to do it, I’ve done many a 1010 but have always left that board.

 

[zebulon1]

I desolder a few strategic wire wrap posts.
Maybe two posts and the board will flip over for easy access.
Desolder only the post from the board leaving the wraps intact.
Try to remove the post straight up and out by prying it up using your small side cutter. Try not twist it. Then reinstall straight in.

 

[LWB]

I think you are referring to AWE-040-0. When I did my 1010, I think what I did was loosen the adjacent connected boards, and then I could loosened and turn the tuner board enough to access and replace the electrolytics. It was tight to work, but can be done without un-doing the solder wrapped posts. Gotta watch carefully for broken connections after moving all those connections around.

 

[MacGM]

Wire wrap posts are a pain.

Like others above have said, if you don't need to touch them don't. If it ain't broke, don't fix it etc..

What I generally do if I absolutely must undo and redo them, is to triple check there is enough slack in the connecting wires, then unwrap them without heat. After a couple of twists the wires should break free and then once they're all out of the way and the board is out you're good to clean up the posts with a soldering iron and some needle nose pliers without melting the hell out of the insulation.

Now the board's out and you're free to flip it and reflow cold joints and change whatever caps you wanted.

When reattaching them I strip about 8mm off the wire to get a clean workable piece, wrap it two and a half turns to the post, then move to the next and come back later to give them all a healthy flow of solder.

Just make sure you keep your photos and get the colours exact. Nothing worse than having to troubleshoot and trace 20+ connections to the scheme because it had to be perfect and those 20 extra capacitors in a part of the circuit you're never going to listen to just had to be changed in the name of a full recap..

I'm not bitter I swear lol.

 

[jahmadeus]

I desolder a few strategic wire wrap posts.
Maybe two posts and the board will flip over for easy access.
Desolder only the post from the board leaving the wraps intact.
Try to remove the post straight up and out by prying it up using your small side cutter. Try not twist it. Then reinstall straight in.

It is good to know that this can be accomplished by selecting a few specifc posts to desolder, not having to desolder an entire row of posts is ideal!

I think you are referring to AWE-040-0. When I did my 1010, I think what I did was loosen the adjacent connected boards, and then I could loosened and turn the tuner board enough to access and replace the electrolytics. It was tight to work, but can be done without un-doing the solder wrapped posts. Gotta watch carefully for broken connections after moving all those connections around.

I hadn't thought to do this! I will keep this in mind when I go to do the deed.

Wire wrap posts are a pain.

Like others above have said, if you don't need to touch them don't. If it ain't broke, don't fix it etc..

What I generally do if I absolutely must undo and redo them, is to triple check there is enough slack in the connecting wires, then unwrap them without heat. After a couple of twists the wires should break free and then once they're all out of the way and the board is out you're good to clean up the posts with a soldering iron and some needle nose pliers without melting the hell out of the insulation.

Now the board's out and you're free to flip it and reflow cold joints and change whatever caps you wanted.

When reattaching them I strip about 8mm off the wire to get a clean workable piece, wrap it two and a half turns to the post, then move to the next and come back later to give them all a healthy flow of solder.

Just make sure you keep your photos and get the colours exact. Nothing worse than having to troubleshoot and trace 20+ connections to the scheme because it had to be perfect and those 20 extra capacitors in a part of the circuit you're never going to listen to just had to be changed in the name of a full recap..

I'm not bitter I swear lol.

Photos and notes/diagrams are a must!

And I totally understand the point you are making. Better to leave well enough alone. Im not trying to fool myself for a second, it is not 'required'. The tuner, which I do use often, sounds good and is not malfunctioning in any major way. I have more to lose than to gain in the grand scheme of things. However, I feel confident in my ability to not cause any damage or mis-wire the unit. In all the boards I have shotgunned every el. cap but on this board I will only be replacing ones that are measurably bad (which I expect will only be the blue sanyo caps, as has been the case on all the other boards, the exception being the power supply).


Thanks to everyone who has replied.

 

[MacGM]

If you're convinced you're gonna pull the board to replace one or two you may as well get em all. In for a penny in for a pound..

 

[zebulon1]

Only remove the posts as needed.
On the tuner, there are only two for easy access.
The biggest concern when working on this older equipment is how much unintentional damage could be done when working the boards. And trying to maintain a the factory look and connections.

 

[jahmadeus]

Only remove the posts as needed.
On the tuner, there are only two for easy access.
The biggest concern when working on this older equipment is how much unintentional damage could be done when working the boards. And trying to maintain a the factory look and connections.

Yes this has been my approach thus far; avoid stressing the wirewrap posts in any way unless absolutely needed. This is my primary reason for posting here, to get some feedback on what others have found to be the most efficient, least invasive method.

And trying to maintain a the factory look and connections.

Definitely. For me, part of the joy and challenge of these rebuilds (and repairs for that matter) is to breath new life into the unit while maintaining an aesthetic that would trick someone unfamiliar with the amp into thinking they are looking at 100% factory work.

Thanks again for your input!

 

[blhagstrom]

Doing one now.
I have the smaller boards behind it loose.
I managed to work all the wires loose enough to lift the board up. You need to release the wires from the looms and keepers on the bottom and around the sides.

It lifts enough to peek under it.
I have the unit up on its side, tuner wheel down. I am recapping it. I can’t get in with solder sucker and iron so I just work the cap legs out while heating. Then I heat while pushing new legs in. I finish the solder joint after getting the new cap in.

It tedious and delicate but works.

 

[LWB]

I managed to work all the wires loose enough to lift the board up. You need to release the wires from the looms and keepers on the bottom and around the sides.

It lifts enough to peek under it.

Yes, this is what I did, it works.

 

[jahmadeus]

The wires that appear to tether it down on my particular unit are the ones that attach to the underside of the tuner board (and connect to the underside of the tuning capacitor section). It seems like these are the only connections keeping me from easy access. I have probably overlooked some other connections, will be working on the unit tomorrow and will give it another look.

I was able to peak under it without desoldering any posts and, as mentioned above, could probably sneak my iron under there and desolder. However, checking for bad joints, cleaning flux, etc would be impossible/very difficult.

I did find two posts that were attached to the same 2 conductor thick blue wire (on the side of the tuner board bordering the protection board), undoing these made a little bit of a difference; things are a little more practical for clean rework. Though, I'm not sure if I'd consider it 'easy access', but perhaps these were not the two you were talking about.


@zebulon1 Do you by chance remember if you had to desolder any of the posts that are attached from the underside of the tuner board?

 

[larryderouin]

Free the wiring looms from retainers on the underside of the chassis that go thru to the top from between the tuner board and AMP BOARD's. Work the leads up so You'll get enough slack to rotate the back of the tuner board up and fwd at least 45* if not more.

 

[LWB]

I didn't have to un-solder any leads to work on my 1010. I found that I could loosen all the wires from looms and connections, and by examining the wiring, pull enough slack to get the tuner board free enough to replace the caps. I had one lead I pulled too hard and broke; that's the only one I had to re-solder.

 

[zebulon1]

Yes the VC wire connections are the troublesome ones. I use a de soldiering gun. Hakko FR301. It makes quick work of the posts.
They are soldered from the bottom and requires an effort to desolder. Using the wick method may not be easy. The short connections to the VC board are not slack enough and would require taking the dial string off to loosen the VC board.
These are the decisions a guy has to make.
It’s almost impossible to work that board and not suffer other damage by just loosing the harness.

 

[jahmadeus]

Free the wiring looms from retainers on the underside of the chassis that go thru to the top from between the tuner board and AMP BOARD's. Work the leads up so You'll get enough slack to rotate the back of the tuner board up and fwd at least 45* if not more.

This is essentially where I am at now. If I need to replace components like this, it would not be the end of the world. However, a close inspection of the existing joints and my rework, will be difficult on the half of the board not lifted up. Again, not the worst thing that can happen. I worry that its location directly above the power supply will have contributed to weakened joints. Could very well be that this is not the case and no reflowing will be needed at all, so its not too big of a deal if this level of rework is performed.

I didn't have to un-solder any leads to work on my 1010. I found that I could loosen all the wires from looms and connections, and by examining the wiring, pull enough slack to get the tuner board free enough to replace the caps. I had one lead I pulled too hard and broke; that's the only one I had to re-solder.

This makes me think that I still have yet to free all necessary wires, or maybe some got snagged on the chassis after being freed. I had to free one 2 conductor wire (two separate posts) to get the 45-50 degree access.

Yes the VC wire connections are the troublesome ones. I use a de soldiering gun. Hakko FR301. It makes quick work of the posts.
They are soldered from the bottom and requires an effort to desolder. Using the wick method may not be easy. The short connections to the VC board are not slack enough and would require taking the dial string off to loosen the VC board.
These are the decisions a guy has to make.
It’s almost impossible to work that board and not suffer other damage by just loosing the harness.

Cool. I have access to an FR301. I hadn't thought to use it on that style post, but I think I will give it a try.

I really appreciate all the input from everybody. Thanks for sharing your experience. Always nice to be able to travel the beaten path and not reinvent the wheel.

 

[Young46]

on your rebuild. The 1010 is a fine receiver as I’m sure you are aware. I used to not listen to my tuner much but have stared to listen more…music only. Great advice being given here. Good luck with the tuner section and post photos if possible.

 

[jahmadeus]

Decided to proceed with the 50 degree access that I had gained from desoldering that one (2 conductor) blue wire. Used a mirror and flashlight to inspect solder joints, found a couple cracked joints and reflowed them.

As for the caps, just as I thought, every blue Sanyo cap was gone (off value, very high ESR, fails dialectric absorption tests). Of the grey Sanyo caps, about 1/2 of them were what I consider bad/not optimal. Mainly high ESR (>=10ohms) or out of tolerance, although a couple of the larger value caps (100uf, 220uf) were leaky.

Got the unit back together and gave it a listen. Was surprised by the improvement; it far exceeded my expectations. Everything sounds so clear compared to before. Additionally, the strange low frequency (<=40hz) artifacts I would occasionally hear seem to be gone. One of the more noticeable improvements gained by this rebuild in my opinion. I definitely recommend it for anyone on the fence, provided you feel comfortable freeing up the board completely or working with limited access.

Thanks again to all who responded!