Hi All. This could be a general question regarding Japanese Multi-Way-Connectors. I have a fault in my Kenwood tuner so need to remove the circuit board. There are 2x (different) multiway connectors that need to be removed IF POSSIBLE. I am not sure if they are the PLUG-IN type (male -female) Or are they just an assembly that is SOLDERED in? I have tried to wiggle them but they seem rigid. I don't want to break anything. Could someone look closely at my photos and assure me if they are removable please or are they soldered in?. Many thanks for reading
Thanks for your reply jean-paul. I have tried to pull on the wires but if I pull harder I might break them. I am thinking I might try a thin knife and try to lever the plastic assembly to see if it starts to move. Someone with Hifi repair should have come across these types and might know by experience. It will be difficult to work on the board if the wires have to stay in position
The white one CN4 (C from Connector!) seems to be a pullable type. The green one W2 (W from Wire!) seems a permanent one. The device is Japanese and generally these are well thought out. In that case the pullable connector will be at the other end of side of the cabling. It needed to be assembled and possibly serviced/repaired later on so the Japanese designers usually/normally did not make permanent connections because of otherwise difficult serviceability. However ... in this case it is meant to be taken apart together with the front PCB as an assembly. It is what it is.
I worked with pro stuff and such connectors are also used. Sometimes it is astonishing what force must be used but apparently this has been thought over. Still be careful and always pull straight up and not in an angle.
I worked with pro stuff and such connectors are also used. Sometimes it is astonishing what force must be used but apparently this has been thought over. Still be careful and always pull straight up and not in an angle.
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Usually, one end will be equipped with a removable (plug/socket style) and the other will be soldered. But in situations where the sub board was snapped off the main board (like the main and control boards) they are often soldered at both ends.
I'd just take out the front panel boards (easy, a screw and plastic retaining clips) and leave them attached to the main board.
I'd just take out the front panel boards (easy, a screw and plastic retaining clips) and leave them attached to the main board.
Thanks very much jean-paul and restorer-john for the extra information. I have had another go at pulling at them (but still considering trying a small lever on the white one). They both feel rock-solid with no movement at all. As john says, I'll have a go at removing the main front panel and board screws (plus rear socket screws to see if I can get under the board. By the way, I think the fault might be in the power supply smoothing caps. The largest is leaking and running quite hot. There are various voltages on this circuit and maybe one is just too low to actuate some part of the circuit. After a period of silence and no signal showing, it crackles slightly and then it all works normally. Thanks for any help on its repair... will come back when I manage to get access on it
You can be sure that power supply electrolytic caps have had their best time. Just replace them all for known good industrial stuff just to exclude things. Saw so many devices that I forgot details but make sure to keep soldering time to a bare minimum. It would not surprise me that PCB tracks peel off easily. Sometimes one better cuts the caps and then desolders lead wires quick & painless.
I now have the board off the chassis and turned over. I released the screws as John suggested and there is enough room to flip the board. I have removed the leaking cap. I have to say, getting the solder to melt seems difficult, so I might just replace the cap and try to see if that has fixed the fault. I have high-blood pressure and this is stressing me... need to buy new cap and get it first.... will come back
No stress. Just cut out all electrolytic caps. Brute cutting force (on the cap bodies) with a 200 mm side cutter is fully allowed and may give piece of mind. Then just remove the remaining lead wire pieces that now need way less heat/time. Clean PCB and side cutter with isopropyl alcohol. Check/measure physical sizes and order the right parts. Install all, check polarity 3 times and it will be as new.
Hi jean-paul. I can visualize the method that you describe, but it makes me think the electrolyte might squeeze out like toothpaste as the cans are crushed 🙂 It makes sense though. I now know it is a fairly easy job to get the boards upside down (but still attached) so I'm hoping for the least amount of renewal work at the moment. I agree it is just a matter of time (short?) before the others fail so a bad policy I know. By the way, I found another electrolytic that has also died. I have ordered 2x new ones, but with higher voltage ratings to slow their decline perhaps? As yet I don't know if this is the source of the fault and all will be well. I hope so:
The art of the 200 mm is to first take a bite, then cut their heads off without putting force on the lead wires or PCB. Some toilet paper is OK to remove electrolytic and later you will clean with isolpropyl alcohol anyway. Replace all in the PSU and definitely clean that glue debris as it can start to conduct.
Just do it right at once as old devices usually don’t get better from opening/closing and disassembling/assembling a few times.
If 2 are shot you already know what will happen.
Just do it right at once as old devices usually don’t get better from opening/closing and disassembling/assembling a few times.
If 2 are shot you already know what will happen.
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I have managed with Iso propyl alcohol and a Scraper to clean the old gunge off. As said, I need to cure the fault first, I just don't know if the caps I am replacing will cure it yet. Maybe if I get success I will carry on
I spray such old connectors with CRC-26 contact cleaner, or equivalent, let soak for a day.
And carefully check for locks in the moulding, sometimes a tongue and groove type is found. Suitable tecnique of release to be used.
The plastic used in the connectors can grow brittle with age, and can be replaced with pin and socket strips, sold here quite cheap in lengths of 40 pin and sockets.
And please change all the electrolytics, regardless of how they look, bad caps can cause other parts to fail prematurely.
And carefully check for locks in the moulding, sometimes a tongue and groove type is found. Suitable tecnique of release to be used.
The plastic used in the connectors can grow brittle with age, and can be replaced with pin and socket strips, sold here quite cheap in lengths of 40 pin and sockets.
And please change all the electrolytics, regardless of how they look, bad caps can cause other parts to fail prematurely.
Here are the details and it's full of caps. It is a superb sounding tuner and I guess it is going to need the full set to be renewed.
A repair man has suggested the gunge on the board would have been glue to fix the caps in position. What do you reckon?. Glue or electrolyte? It would not explain why the cap was running so hot though!