Connector wire plug fix for my amplifier - Page 1
Forum section: electronics / repair

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 06:49:29 am
content: Hi all,I was mucking around with my amplifier trying to fix something but of course broke something else.I presumed the little green plug pulled out with wires intact but that wasn't the case, the wires came out and I dont know how the plug actually works in order to return the wires properly.Heck I don't even know what the plug type is calledHere is some photos, I'd be awfully grateful for helphttps://imgur.com/gallery/JOOtkp6

author: autotel
author_rank: Contributor
timestamp: April 22, 2020, 08:17:02 am
content: I don't have much of an idea. However, since there are two cables named "key" and one named different, perhaps try facing the side of the cable which has a mark to the MG?Is there a risk of breaking it involved? Because there are two sides to try only, right?

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 08:45:30 am
content: Post good closeup photos of both sides of the whole button board. Also, what's on the other end of the pair of wires?It should be possible for us to figure it out if you give us enough info.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 09:14:57 am
content: Apologies for not knowing how this board handles quote replies, I can't work that out just yet?In regards to extreme close ups, my phone isn't doing so well, maybe time for a new one.I can tell you on the other side it's just solder joints but the side you can see there are holes for the wire to fit through but then you have to clamp the green plug over it as well and I can't do that with the wires in the holes.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 09:18:46 am
content: Quote from: Ian.M on April 22, 2020, 08:45:30 amThere we go I can quote.On the other end of the wires it's connected behind the display LCD, it's only going to risk another mistake by trying to get to it.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 09:20:27 am
content: If anyone knows what type of connector they are called, YouTube might help me.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 09:27:35 am
content: Quote from: autotel on April 22, 2020, 08:17:02 amOnly shortening it if I fail and have to cut again, there should be enough slack for another go or two. ( fingers crossed )Not sure I understand what you mean by two sides?This one one of those things hard to explain

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 09:38:30 am
content: "behind the display LCD" sounds like it could well be going to a MCU that also controls the LCD. I have a theory that there are also resistors on the button board and it is a resistor/button ladder so the MCU can read which button is pressed using an ADC input.Update this topic when you have posted the button board closeups, of both the button and solder sides I requested.Unfortunately many types of IDC (insulation displacement) connectors are designed to be assembled *ONCE* using factory tooling. Its generally possible to hand assemble a fresh connector, but if you've pulled the wires out, odds are the contacts have been distorted, and it may not be reliable, so you may be forced to remove the connector and solder the wires direct to the board then apply a dab of neutral cure silicone or other suitable elastomer adhesive on the other side where the wires go through the board for strain relief.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 09:41:10 am
content: Okay I will try and get better pics tomorrow, it's night time and flash inst helping and no flash means no detail.I'm surprised you knew immediately it was a button board, I have come to the right place

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 10:19:33 am
content: Was able to remove the LCDHeres what I can show, is that what you need? I cant do real close, it just wont focus.https://imgur.com/a/wmvkOkN

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 10:54:59 am
content: There are resistors on the track side of the button board, but it looks like there are TWO resistor ladders, not one, so you need to get the wiring right when you reconnect it. As the pins are marked the same at both ends, that shouldn't be a problem.Please post some photos of the button board disassembled green connector and its contacts from different angles, as close-up as you can without going out of focus, so we can see if you've got any chance of reassembling it or whether it would be better to desolder it and solder the wires straight to the board.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 11:18:10 am
content: Quote from: Ian.M on April 22, 2020, 10:54:59 amEnter my daughters iPhone with 2 camerashttps://imgur.com/a/xiEHebE

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 11:54:06 am
content: We also need to see the contacts on the board that the green shell fits over, also from several angles.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 12:00:52 pm
content: Sorry I should have guessed, added images to the link above.

author: NickZA
author_rank: Newbie
timestamp: April 22, 2020, 12:24:19 pm
content: Looks like an Insulation Displacement Connector:https://www.digikey.com/product-detail/en/jst-sales-america-inc/03DB-8M-LF/455-1071-ND/527296

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2020, 12:27:54 pm
content: Beat me to it loll and the wire are crimped into it, why dont you solder the wire direclty on the pcb ?? they must be long enough ?In UK ? damn 0 in stockhttps://www.enrgtech.co.uk/buy/product/ET11381573/03DB-8M-LF-Maybe some ebay and Aliexpress if you search them ??

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 12:29:21 pm
content: Quote from: NickZA on April 22, 2020, 12:24:19 pmIndeed it does, nice name.No hope of getting one in Australia though,

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 12:30:57 pm
content: Quote from: coromonadalix on April 22, 2020, 12:27:54 pmYeah, I can try,. my eyes aren't as good as they used to be and it's particularly small

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2020, 12:33:27 pm
content: digikey .in ??https://www.digikey.in/product-detail/en/jst-sales-america-inc/03DB-8M-LF/455-1071-ND/

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 12:34:20 pm
content: Its an IDC connector as I and NickZA noted, not a crimped connector.The green shell fits with the square holes over the contacts, down to the board, and the open side facing the pin name markings. The wires press flat into the open side of the shell, and into the open sides of the contacts and the narrow slots in the contacts pierce the insulation and make contact with the cores. The insulation is held by the little fingers at the tip of the green shell. Its intended to be assembled once, with some sort of parallel jaw tooling with a shaped anvil to support the individual wires while pushing them home, probably before soldering to the board, and is intended to be non-removable.Disconnect the green connector on the other end of the wire from the white shelled right-angle header on the display board so you can work on the wire to button board connection without worrying about protecting the fragile display. Wiggle it out gently - don't rip it off!You *may* be able to reassemble it by putting the shell back in place then clamping that end of the board in a vice so the shell is supported by the top of the vice jaw, and pressing each wire back into place (after trimming the wire end to remove any section with damaged insulation), using some sort of flat ended metal tool not much thinner than the slots in the shell, but if the contacts have been bent or stretched even slightly, you may not get a reliable contact. Check each connection with a continuity tester before you plug it back into the display board. If you cant get a reliable connection on all the wires, you'll have to desolder the contacts, and solder the wires through the same holes direct to the board, discarding the contacts and shell.

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 12:34:55 pm
content: Quote from: coromonadalix on April 22, 2020, 12:33:27 pmIndia? lolNo Australia16 weeks lead time on them too.It seems that it's a direct pressed to board type, meaning, it can't be pressed by hand?

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2020, 12:38:00 pm
content: Normally theses connectors are "permanent" thats why ive told you the solder way of repairing it ... and add a dab of hot glue to reinforce them ?no it need a special tool to crimp them

author: shueardm
author_rank: Contributor
timestamp: April 22, 2020, 12:41:08 pm
content: Thanks guys. Out with the solder.I should definitely remove the pins first?Also, I obviously need to strip the wire , it's very thin, hope my stripper can do it.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2020, 12:43:37 pm
content: or use a small wire or part cutter on the back side and try to pull gently on the wire insulator or use a small exacto blade ?? genlty skin the wire ?

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 12:48:21 pm
content: I'm sure it can be hand assembled if properly supported, with an appropriate punch-down tool. A thick-ended flat bladed screwdriver may be good enough, but ideally the tool should have a rounded groove the full length of the end to support the insulation, and a notch to clear the fingers in the shell that grip the insulation. Its probably not worth the effort to make a decent punch-down tool for it v.s. soldering the wires direct to the board.Be careful if using a knife blade to strip the wires - its far too easy to accidentally notch the core and if you do so the wire tends to snap at the weak spot if its bent after soldering.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2020, 01:07:27 pm
content: Quote from: Ian.M on April 22, 2020, 12:48:21 pmYour wrong it need a special crimp tool not a screw driver push, the pins cut the insulator and crimp over the wire when the wire insert in the pinI use them at my job, you smash a screw driver in it and youre prone to have problems later

author: Ian.M
author_rank: Super Contributor
timestamp: April 22, 2020, 01:31:36 pm
content: Yes the OEM tooling is a special die set and a parallel jaw press tool, but its *NOT* a crimp as the tool does *NOT* deform the contact to grip the wire. I still maintain it could be hand assembled one wire at a time with an appropriate punch-down tool, but agree that the odds of success with a plain screwdriver and a used connector are both poor and highly dependent on the skill and experience of the user.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 02:25:49 am
content: I really appreciate everyone's efforts, unfortunately soldering the point in question did not fix the problem and I believe it was never the joint to begin with.Now I am going to sell the unit for parts, it's a Yamaha RX-V1 which should get me a few bucks. Too expensive to get someone look at it, in my city the professionals are too busy and overcharge.

author: Ian.M
author_rank: Super Contributor
timestamp: April 23, 2020, 04:13:01 am
content: So, before you give up and break it for parts, why not describe the problem here, with exact symptoms and see if any of us can help you fix it?

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 06:49:59 am
content: Quote from: Ian.M on April 23, 2020, 04:13:01 amIt's all the buttons on that board Ian, none workBoth ends of that cable looked good, even before I pulled them out.

author: Ian.M
author_rank: Super Contributor
timestamp: April 23, 2020, 07:23:32 am
content: As its got two resistor button ladders, which must go to separate ADC input pins on the system control MCU, a common fault would have to be either missing ground to the board, missing supply to the pullup resistors for both ladders, or a problem with the MCU. The MCU may have a hardware fault or it may be crashing due to bad inputs. Check if it still responds to its remote control, and check that all other buttons and controls not on the button board work. If you find anything else wrong, fixing it may 'magically' fix the button board . . .OTOH if the MCU's got a hardware fault, its BER unless you can source a good replacement display board.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 07:57:06 am
content: The remote control alternate method works, where a button exists for it on the remote, like 6CH input and EFFECT OFF, PROGRAM selection and source selections..It's impossible to test sound though since the main speakers are not set , since the're no remote button for main speaker asign.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 08:23:51 am
content: Just found that some of the buttons on the button board work for the tuner, since I was not on the tuner before I hadn't noticed it.

author: Ian.M
author_rank: Super Contributor
timestamp: April 23, 2020, 08:26:16 am
content: If the remote works that means the MCU is responding. Its not crashed or stalled. The next thing to check would be voltages on the two KEY signals relative to the common as you press each button in turn. If you don't see a significant voltage change for each individual button push, it could be one button stuck on which would disable all buttons past it on the same ladder.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 08:31:21 am
content: I dont have a VU meter not know how they work.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 01:28:05 pm
content: One ace up my sleeve.I have 4 of the same Yamaha amp and got the nerve to completely swap out one of the other front panels onto this unit, the whole front chassis, LCD, button assembly.The result is.... Houston, we have a problem. The same buttons on the certified front panel failed in the new host, so the issue is further up the chain , somewhere.

author: Ian.M
author_rank: Super Contributor
timestamp: April 23, 2020, 02:03:33 pm
content: Hmmm. I wonder if the main control MCU isn't on the front panel. Those button signals may go back over another connector to the main board.If you can find a free online or downloadable service manual for your Yamaha RX-V1, post a link to it and we may be able to give you some suggestions for further troubleshooting.

author: shueardm
author_rank: Contributor
timestamp: April 23, 2020, 10:14:48 pm
content: Quote from: Ian.M on April 23, 2020, 02:03:33 pmhttps://www.manualslib.com/manual/787834/Yamaha-Dsp-Ax1-Rx-V1.htmlDon't put yourself out, it's a lot to read.