Author Topic: Sony Discman D-FJ401 Repair (How do I open this thing?)  (Read 3889 times)

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Offline Rooster CogburnTopic starter

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Sony Discman D-FJ401 Repair (How do I open this thing?)
« on: January 10, 2025, 05:21:58 pm »
I'm trying to repair this Discman and failing at the first step. The service manual does not contain the single most important piece of information anybody would need to service the device. How to unscrew those last two screws. They are completely inaccessible and are required to be removed for further disassembly. I can take it from there, but if somebody would just pretty please explain to me how to open this thing. Thanks!



https://elektrotanya.com/sony_d-fj401.pdf/download.html

Edit: Here's somebody else with the same problem, no reply:

https://old.reddit.com/r/walkman/comments/1aogl42/sony_dfj401_dont_have_a_power_cord_and_batteries/
« Last Edit: January 10, 2025, 08:29:29 pm by Rooster Cogburn »
 

Offline thephil

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #1 on: January 10, 2025, 07:48:40 pm »
Form the exploded view, I would think that you need to remove the upper lid assembly first. Maybe it's just clipped on or there is some kind of hinge pin you can push out or something like that...

Edit: the image says "Spring full open" in steps 2 and 3 (left an right) – so probably its the springs that hold the lid? Try to remove those.
« Last Edit: January 10, 2025, 07:52:43 pm by thephil »
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Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #2 on: January 10, 2025, 08:05:58 pm »
I removed the springs. They seem to have no function other than pushing the lid open. I don't see any way to remove the lid. There's no rod to slide out, no way to pop it out from the joints its on, etc.

I repaired quite a few Sony players so far and none have this issue. They all either open from the bottom, have a way to remove the lid or have angled screws or otherwise accessible screws that can be removed with the lid on. No idea what on earth they were thinking with this one and then not mentioning anything about this ridiculous design in the service manual. I've been staring at this for hours, watched every YouTube video on Discman repair (not a single one looks anything like this abomination) and genuinely have no ideas how you can open this.

Here's somebody else with the same problem, no reply:

https://old.reddit.com/r/walkman/comments/1aogl42/sony_dfj401_dont_have_a_power_cord_and_batteries/
« Last Edit: January 10, 2025, 08:44:21 pm by Rooster Cogburn »
 

Offline thephil

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #3 on: January 10, 2025, 09:13:25 pm »
Stubborn device!

I studied the photo in the link you sent as well as the details of the exploded view in the service manual again. To me it seems that the lid hinges on two plastic "axles" that are an integral part of the dark grey plastic tab next to the springs. I believe that you need to do some firm prying in order to push the legs of the lid to the outside and thus free it. Maybe its necessary to close the lid halfway while doing that so the lit gray/silver legs can move in the slot. Or maybe even from the outside if there is a slit you can reach in with a spatula when the lid is almost closed.

But it's hard to tell from a picture – so its mostly guesswork...
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Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #4 on: January 10, 2025, 09:46:32 pm »
I had initially discounted popping them out, but as you correctly observed you can push them free if you have the lid half-open, making this maneuver even more tricky. I tried to do so with a lot of force and managed to free one side. I had to use metal tools that completely mangle the plastic because there's no way to do this with a plastic spudger. Even then I can't free the lid because once I pop one side out the other is wedged in even more tight. It really feels like I'm going to break the entire discman into pieces :/



I just don't see how I can get this hinge off, let alone re-attach it and do all of that without breaking the flat flex cable etc.

I really hope the Sony engineer that came up with this design had to spend the rest of his lifetime employment scrubbing toilets for this. You had a hundred discman models with perfectly reasonable cases and assembly / disassembly procedures but this guy had to spend the weekend coming up with a 'novel' way of doing it...
« Last Edit: January 10, 2025, 10:00:06 pm by Rooster Cogburn »
 

Offline thephil

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #5 on: January 11, 2025, 04:38:53 pm »
Wow – that thing puts up quite some resistance...
The only other think I can think of: Can you take of the plate on the inside of the lid? Maybe it reveals something helpful? That is some really repair-unfriendly design and I'm stumped that the service manual doesn't even mention how to get that off. given the complexity.
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Offline Roehrenonkel

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #6 on: January 11, 2025, 06:55:08 pm »
Hi Rooster Cogburn,
 
get the propper tools for the job.
Like an angled screwdriver or a screw-bit and pliers
(if you don't have an angled bit-driver).

Good luck
 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #7 on: January 11, 2025, 09:59:34 pm »
Wow – that thing puts up quite some resistance...
The only other think I can think of: Can you take of the plate on the inside of the lid? Maybe it reveals something helpful? That is some really repair-unfriendly design and I'm stumped that the service manual doesn't even mention how to get that off. given the complexity.

The idea of maybe removing the LCD/button PCB and panel from the lid of is good, then you could poke a screwdriver through one of the button holes or so. The problem is that the totally impossible to access screw is the left one and the lid is fully solid around it with no holes for display or buttons anywhere :-[

I worked on dozens of Sony products like CRT TVs, CD players, consoles etc. Normally they are quite well-designed and logical and their service manuals are usually great! :-\

It's so frustrating because the discman is in good condition. I just need to replace the battery tabs after some leakage and the laser needs a little bit of tweaking. Would be a 15min job.

Hi Rooster Cogburn,
 
get the propper tools for the job.
Like an angled screwdriver or a screw-bit and pliers
(if you don't have an angled bit-driver).

Good luck

I don't think such tools exist. I can maybe get my shortest bit into the right one to unscrew it, but and the other screw is completely inaccessible :/ I'm pretty sure you're not meant to unscrew them before removing the lid or you need a one-of-a-kind tool to do so.

The left screw is just not possible to unscrew with the lid on:

 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #8 on: January 11, 2025, 11:12:48 pm »
The screws on the top that you highlighted are the inside cover behind which the lid buttons and LCD are located. I can remove them, but this only gives me access to those components. I was thinking maybe I can unscrew the obscured screws in the base through the button holes etc., but the issue is that the most inaccessible screw one the left has no openings in the lid nearby, so that wouldn't help.

I was also of course thinking about how they put the player together, and I assume they snap the lid hinge in from the back. But I can't get it out of the socket at all. With a lot of force and plastic damage I can free one side. You can see how badly I mangled it already, plastic tools did nothing. I don't see how I can slide it out towards the back, I'd just break everything trying to pop both hinges free.

There's what seems to be a clip in the base at the outside of the hinge, but I don't think you can just unclip that and lift out the baseplate from the bottom pan without removing the last two screws. The service manual shows they are screwed into the bottom pan and have to be removed. I can pop out the other clips around the four screws I already removed, but the part around the hinge doesn't budge. I think I really have to remove the screws.

Some more pictures, hope it helps, I know it's difficult to debug something mechanical from a picture :/





 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #9 on: January 11, 2025, 11:22:02 pm »
I'm trying to repair this Discman and failing at the first step. The service manual does not contain the single most important piece of information anybody would need to service the device. How to unscrew those last two screws. They are completely inaccessible and are required to be removed for further disassembly. I can take it from there, but if somebody would just pretty please explain to me how to open this thing. Thanks!



https://elektrotanya.com/sony_d-fj401.pdf/download.html

Edit: Here's somebody else with the same problem, no reply:

https://old.reddit.com/r/walkman/comments/1aogl42/sony_dfj401_dont_have_a_power_cord_and_batteries/
Can you share some pictures of the outside of the hinge, in both open and closed positions?

I suspect that the design of the hinge is such that it guides the hinge into those triangular slots on the base to stabilize it when open, and that stabilization is what prevents splaying the hinge to remove it. Consequently, I further suspect that the hinge must be spread open in the closed position (or mostly closed), because only when open can the hinge spread into the wider part of the triangular slot.
 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #10 on: January 11, 2025, 11:52:32 pm »
Can you share some pictures of the outside of the hinge, in both open and closed positions?

Closed you can't see anything from the outside and there are two pictures of the hinge open from the outside in the batch I just posted.

I suspect that the design of the hinge is such that it guides the hinge into those triangular slots on the base to stabilize it when open, and that stabilization is what prevents splaying the hinge to remove it. Consequently, I further suspect that the hinge must be spread open in the closed position (or mostly closed), because only when open can the hinge spread into the wider part of the triangular slot.

I think that is correct, and when trying to remove it I did it with the lid half-closed. I suspect that is why the service manual recommends removal of the springs since with them installed you can't hold the lid half-closed. But like I said, even with extreme force and causing significant damage I was only able to pop out one of the hinges. The right one that has most of the plastic damage was me trying to remove it as well after I popped out the left one. It don't see how it's possible to remove it without completely destroying it and likely also tearing the flat flex cable going through the hinge :/
 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #11 on: January 12, 2025, 12:00:50 am »
Can you share some pictures of the outside of the hinge, in both open and closed positions?

Closed you can't see anything from the outside and there are two pictures of the hinge open from the outside in the batch I just posted.
My response was posted after you posted those images, so clearly they do not contain the angles I want to see, or else I wouldn’t have asked.

Please show the hinge from the side, not the top. Open and closed.

I suspect that the design of the hinge is such that it guides the hinge into those triangular slots on the base to stabilize it when open, and that stabilization is what prevents splaying the hinge to remove it. Consequently, I further suspect that the hinge must be spread open in the closed position (or mostly closed), because only when open can the hinge spread into the wider part of the triangular slot.

I think that is correct, and when trying to remove it I did it with the lid half-closed. I suspect that is why the service manual recommends removal of the springs since with them installed you can't hold the lid half-closed. But like I said, even with extreme force and causing significant damage I was only able to pop out one of the hinges. The right one that has most of the plastic damage was me trying to remove it as well after I popped out the left one. It don't see how it's possible to remove it without completely destroying it and likely also tearing the flat flex cable going through the hinge :/
You were still going at it from the inside. But what I suspect is blocking the hinge is the long hinge sections, such that you’d need to spread them apart from the outside while closed, because those hinge sections rotate down and out when closed.
 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #12 on: January 12, 2025, 12:06:31 am »
One other thought: use a hot air gun with a small nozzle to CAREFULLY, GENTLY heat the plastic to make it a tiny bit more flexible. You’d be surprised how big of a difference it can make, even when heated far less than needed to soften the plastic.
 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #13 on: January 12, 2025, 12:30:49 am »
One other thought: use a hot air gun with a small nozzle to CAREFULLY, GENTLY heat the plastic to make it a tiny bit more flexible. You’d be surprised how big of a difference it can make, even when heated far less than needed to soften the plastic.

Didn't think about that, interesting idea. My hot air starts at 100C, actually seems to be 80C, so that should be safe enough.

ifixit has a similar pic

https://www.ifixit.com/Teardown/Sony+CD+Walkman+D-NF430+Teardown/1249

I wish! This is how dozens of other models of Discman look like. Do you see how the screws are angled and relatively shallow? That's how it should be. On this particular model they face straight up and are deeply recessed. I've never seen this on any other model of discman.
 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #14 on: January 12, 2025, 11:43:25 am »
here is a totally insane idea since there is no other way
how about opening 2 holes on the closed lid just to reach the screws

Sure, that would do it. But I can't imagine drilling holes or heating up plastic is the intended procedure. The service manual doesn't exactly show a drill or a hot air gun.
 

Offline amyk

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #15 on: January 12, 2025, 09:11:31 pm »
Half-open position, two small flat-blade screwdrivers wedged into the two side, and rotate while prying. It was assembled by snapping together, so the plastic should have enough flex (both the top and bottom pieces) at least when it was new. Another small hint: apply a careful bending moment on the top piece, to spread the posts apart slightly.

I recently had to repair another product (incidentally also Japanese...) where they used the same stupid design, and broke one of the hinges off because the plastic had become more brittle and rigid since they assembled it. I plastic-welded it back with the soldering iron set to 200C (it was ABS+PC material, same as yours) and it snapped into place successfully again.
« Last Edit: January 12, 2025, 09:15:33 pm by amyk »
 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #16 on: January 18, 2025, 05:08:16 pm »
One other thought: use a hot air gun with a small nozzle to CAREFULLY, GENTLY heat the plastic to make it a tiny bit more flexible. You’d be surprised how big of a difference it can make, even when heated far less than needed to soften the plastic.

Didn't think about that, interesting idea. My hot air starts at 100C, actually seems to be 80C, so that should be safe enough.
Would you please indulge me and take the additional photos I have asked for repeatedly? You may not think they show anything, and you might be right, or you might be wrong. Digital photos cost nothing, so would you just take some?
 

Online Koray

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #17 on: January 18, 2025, 07:53:50 pm »
This video may help:

 

Online Koray

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #18 on: January 18, 2025, 07:57:12 pm »
Watch this video, the same structure, remove the circuit board on the lid and then the rest seems easy:

https://youtu.be/wDf3Gag0Y0k
 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #19 on: January 19, 2025, 02:52:13 am »
This video may help:


So close, but no: as soon as he rotates around the edge to the back, he flips it up. So the part of the back I want to see -  the gap between lid and base — is the one angle the video never shows!  |O
 

Online Koray

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #20 on: January 19, 2025, 01:12:44 pm »
Did you see the second video I posted? There you can see how the lid is separated from the body. Apparently the circuit board on the lid has to be removed first. Then the lid can be pulled out.

K.
 

Offline tooki

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #21 on: January 19, 2025, 01:23:18 pm »
Did you see the second video I posted?
I sure did. But did you, actually?

There you can see how the lid is separated from the body. Apparently the circuit board on the lid has to be removed first. Then the lid can be pulled out.
No, it doesn’t show how it is separated. It shows the PCB being removed, then the video makes a hard cut to the lid already off. It doesn’t show how he got it off!!
 

Offline drhex

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #22 on: January 19, 2025, 04:08:41 pm »
He does explain it though and as far as I can make it out the half open, leverage out is the way to go.
 
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Online Koray

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #23 on: January 19, 2025, 04:15:35 pm »
Yes I did. You are right it doesn't show how it is actually done, but from the parts we see I can guess that you just yank the lid away. With the flex and the circuit board removed it looks relatively easy.

K.
 

Offline Rooster CogburnTopic starter

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Re: Sony Discman D-FJ401 Repair (How do I open this thing?)
« Reply #24 on: January 20, 2025, 10:13:12 pm »
Watch this video, the same structure, remove the circuit board on the lid and then the rest seems easy:

https://youtu.be/wDf3Gag0Y0k

The circuit board on the lid doesn't seem to be related to the hinge and that video just contains a cut and the lid is suddenly off. It's super long and omits the one piece of information needed. Just like the service manual.  So frustrating. Notice that during re-assembly that step is also cut. I very much doubt it's easy or there wouldn't be two cuts at these exact moments in an otherwise meandering and lengthy video.

One other thought: use a hot air gun with a small nozzle to CAREFULLY, GENTLY heat the plastic to make it a tiny bit more flexible. You’d be surprised how big of a difference it can make, even when heated far less than needed to soften the plastic.

Didn't think about that, interesting idea. My hot air starts at 100C, actually seems to be 80C, so that should be safe enough.
Would you please indulge me and take the additional photos I have asked for repeatedly? You may not think they show anything, and you might be right, or you might be wrong. Digital photos cost nothing, so would you just take some?

I understand that you need to have the lid half-open to get the hinge off, that's what I tried. When it's closed you have no access to the hinge. Here are some more pictures, hope those are helpful.

https://ibb.co/album/Xj1nt4

Yes I did. You are right it doesn't show how it is actually done, but from the parts we see I can guess that you just yank the lid away. With the flex and the circuit board removed it looks relatively easy.

K.

At the very least the service manual seems to suggest that's not how it's done. I put A LOT of force on the hinge, I couldn't certainly 'just yank it away'. I found a model with the same issue, D-EJ751 (https://elektrotanya.com/sony_d-ej750,ej751,ej753,ej755,ej756,ej758.pdf/download.html), nothing in the service manual either.

« Last Edit: January 21, 2025, 01:55:01 am by Rooster Cogburn »
 


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