I need help, I got connectors with the wrong Pitch for my board. :( - Page 1
Forum section: electronics / repair

author: bassmothership
author_rank: Contributor
timestamp: May 31, 2024, 07:34:43 am
content: Hi. Absolute beginner here (I can only solder).I'm learning how to replace components on a 4-track multitrack cassette recorder (from the early 90's). Its two main boards were tied with little space between each other with these connectors (in the picture) which cannot be detached (I don't know what they're called, do you know their name?). So I disassembled and desoldered all of these headers to separate the two boards and access all components.I saw someone mentioned JST-XH connectors as replacement for these machines on YT, so I bought them (Housing: XPH-#-##, Header: B#B-XH-A and Connector: SXH-001T-0.6). I did it without knowing that there's something calledPITCHsize.again... The JST-XH connectors I've received come in 2.5mm pitch size and my board's pitch is 1.98mm.It seems the JST-XH connector's pitch is only 2.5mm, I don't find any other size. Now, I have no clue how to know what connector is the right one for these boards.Please, help.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: May 31, 2024, 08:09:54 am
content: The term for connectors that are soldered to the board but are not disconnectable is "board-in" connectors. They're an ease-of-manufacturing and reliability thing; more robust and easier-to-assemble than soldering wires directly to the PCB.These look like they may be IDC (insulation displacement) "board-in" connectors, where the cables are punched in to the connector rather than having individual terminals crimped to each conductor wire and then inserted into the connector.If you want to replace them with JST-style connectors that have 2mm pitch (and it probably is 2.0mm, as 1.98 is a very odd figure) then you want JST PH-series, not XH.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 31, 2024, 02:08:01 pm
content: theses if not mistaken are push in types, why did you remove all of thembad thinking behaviour ... and you as a newbie should have observed how they are madewhere they really defectives, this manynever had any problems with theses, the flex cables where or are to rigid, if you play a lot / move a lot the flex may get damaged ...

author: bassmothership
author_rank: Contributor
timestamp: May 31, 2024, 05:17:58 pm
content: Quote from: HwAoRrDk on May 31, 2024, 08:09:54 amThank you so much for clarifying.About crimping PH contacts.I've found some documentation about JST saying: "As a rule, applicable wires for crimping connector are tin-plated annealed copper stranded wire". Are the wires in my machine applicable for crimping onto? (see the photo)I've ordered this tool:https://www.iwiss.com/products/iws-2820m-mini-micro-open-barrel-crimping-tools-works-on-awg28-20-jam-molex-tyco-jst-terminals-and-connectorsWill it work?

author: bassmothership
author_rank: Contributor
timestamp: May 31, 2024, 05:28:29 pm
content: Quote from: coromonadalix on May 31, 2024, 02:08:01 pmNothing defective. I've already mentioned in my post the reason I removed them: [... I disassembled and desoldered all of these headers to separate the two boards and access all components...]More specifically, I need to have access to the other side of the board where the faders and pan pots are, for obvious reasons. So these board-in connectors must go.But thanks for the warning about damaging the cables. I'll handle them carefully.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 31, 2024, 06:42:28 pm
content: But all you had to do was remove the clips pushed onto the base of the connector. The cable would have slipped out no problems what so ever.And crimping JST style connectors on these cables is not so straight forward. This involves a separate crimp connector per wire and with them close together as is it needs bending the wire which is not good for these solid strands.You might be able to reuse the old connectors. See if you can clip the top back on the base part with the cable in there and if the connection is still good. If so take them apart again and solder the bases back on the board.Work on the boards as needed tacking care not to bend the cables to much and when done plug the cables back in with the clips firmly fixing them to the base again.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: June 01, 2024, 07:44:52 am
content: Quote from: bassmothership on May 31, 2024, 05:17:58 pmThose wires look like they might be solid core, so not ideal for crimped terminals, but it'll probably work. Also, because the crimp terminals are intended to crimp around the wire insulation as well as the wire, you will need to split the ends of the insulation (by cutting it) so that each wire is separated from the others for a short length.But if I were you, I wouldn't try to make questionable re-use of the original ribbon cable, but instead use new stranded single-conductor wire and make up new multi-wire assemblies with the new connectors. Bear in mind JST PH terminals take a maximum of 24 AWG wire and max. insulation outer diameter of 1.5mm.Quote from: bassmothership on May 31, 2024, 05:17:58 pmYes, they specifically mention suitability for PH terminals.

author: wraper
author_rank: Unknown
timestamp: June 01, 2024, 07:51:42 am
content: Quote from: pcprogrammer on May 31, 2024, 06:42:28 pmSolid wire cannot be crimped at all with rare exceptions (the only common one is RJ connectors such as RJ-45 used for ethernet, and it's not what you normally think about as crimping). I don't know any connector of this style that allows solid wire crimping.

author: bassmothership
author_rank: Contributor
timestamp: June 01, 2024, 09:36:47 am
content: Quote from: HwAoRrDk on June 01, 2024, 07:44:52 amAs an experiment, I'll just use the original cable and crimp the terminals the way you mentioned. I'll keep in mind to replace these rigid cables altogether, if problems occur in the future.When you say "AWG maximum of 24", from which number? These wires are AWG 26.

author: bassmothership
author_rank: Contributor
timestamp: June 01, 2024, 09:45:56 am
content: Quote from: wraper on June 01, 2024, 07:51:42 amIf that's the case, then what other choice do I have except to improvise like, crimping onto the insulation and solder the wire at the terminal?

author: HwAoRrDk
author_rank: Super Contributor
timestamp: June 01, 2024, 10:43:50 am
content: Quote from: bassmothership on June 01, 2024, 09:36:47 amAs in a wire gauge not physically larger than AWG 24. For AWG, larger number = physically smaller wire. If they're AWG 26 that's fine, because that's one step smaller, but still if solid core it may be problematic.

author: tooki
author_rank: Super Contributor
timestamp: June 01, 2024, 12:49:39 pm
content: Quote from: HwAoRrDk on June 01, 2024, 07:44:52 amQuote from: wraper on June 01, 2024, 07:51:42 amIt’s clearly visible in the photo that it’s tinned* stranded wire — you can see the stranding.With that said, one cannot crimp to tinned* stranded wire, and it’s fiddly to crimp individual contacts to ribbon cable anyway, so I completely agree that if OP does proceed with this plan, they should indeed crimp entirely new harnesses out of individual wires as HwAoRrDk said. But it’s gonna be a lot of fiddly work, and I wouldn’t do it — I’d reinstall the original push-in terminals. (Well, I’d try and find new, identical replacements if possible, to rule out damage caused during desoldering.)*as in, tinned with solder. This does not refer to individually tin-plated strands, which are often referred to as “tinned” also.

author: bassmothership
author_rank: Contributor
timestamp: June 02, 2024, 02:37:50 pm
content: Quote from: HwAoRrDk on June 01, 2024, 10:43:50 amI see. Thank you.

author: bassmothership
author_rank: Contributor
timestamp: June 02, 2024, 02:49:49 pm
content: Quote from: tooki on June 01, 2024, 12:49:39 pmOnce removed from the original headers, the wires can be inserted but only loosely, the headers lost the "locking" system. I guess the process of removing the wires render these headers unusable.I don't want them anyway, neither I mind how difficult could be to strip and crimp each single cable from the delicate ribbon. I just want to create means to disconnect and separate these two boards so the idea of replacing these board-in headers with the JST'S.About harnesses, I looked it up and it seems quite confusing to know what I should look for. I don't have the schematics of my machine. What should I use as reference? How can I even buy them? I'm so clueless about this that I don't even know what the questions I should ask.

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 02, 2024, 03:39:44 pm
content: Keep in mind that JST either XH or PH might have limited mating cycles. There is such a connector in the 1013D for the power connection and during reverse engineering I disconnected it so often that it now has a crappy connection. Especially when you obtain the crimp terminals from cheaper sources.So if the idea is to have something that you can take a part more often be prepared to redo the connectors every so often.About the old ones loosing their grip, you could straighten the leads on the flat cable and maybe bend the connectors a bit to give more spring to them.

author: tooki
author_rank: Super Contributor
timestamp: June 02, 2024, 03:51:01 pm
content: Quote from: bassmothership on June 02, 2024, 02:49:49 pmI truly do not mean this as an insult, but if you don’t understand the pinout of a simple ribbon cable, what on earth are you even doing inside this machine? If that is indeed your current skill level, I can’t envision any outcome other than disaster.What is your goal in opening this machine, and in wanting to make it easy to separate the boards?Quote from: pcprogrammer on June 02, 2024, 03:39:44 pmWell if they put male headers on both boards, then it’s just the cable that might need to be replaced eventually. No big deal.

author: bassmothership
author_rank: Contributor
timestamp: June 02, 2024, 04:50:39 pm
content: Quote from: tooki on June 02, 2024, 03:51:01 pmNo insult done at all.Fair question. The reason for opening is that this machine was left in a warehouse for years without any cover. The front panel with the faders, pan pots and tape deck was covered with dust. The ribbon cables attaching the top and bottom boards are a bit too short for me to work, so I had to remove these darn connectors to be able to get the front board and clean the dust out.Well, since this is an old machine which isn't made anymore, I'll need to learn how to service it, replacing defective parts, etc, anyway. So here I am.I've forgot to mention... I have more four older machines, much bigger and complex than this small one. So I want to get ready for when things start to break down.And this is the first time I've heard the word "pinout". Looking it up now. Thanks for that.Quote from: tooki on June 02, 2024, 03:51:01 pmI've took note on that. Thanks for the pro-tip!

author: bassmothership
author_rank: Contributor
timestamp: June 02, 2024, 04:58:36 pm
content: Quote from: pcprogrammer on June 02, 2024, 03:39:44 pmMating cycles. I have no idea what that is, I'm looking it up. Lots of things for me to learn here.Quote from: pcprogrammer on June 02, 2024, 03:39:44 pmI think here in Japan the sources are supposed to be good quality, I guess...

author: pcprogrammer
author_rank: Super Contributor
timestamp: June 02, 2024, 06:23:17 pm
content: Quote from: bassmothership on June 02, 2024, 04:58:36 pmThe number of times you can connect, disconnect and reconnect again, before the connection starts to degrade due to wear, loss of retention force or corrosion due to protective layer down grading.Quote from: bassmothership on June 02, 2024, 04:58:36 pmDepends on the manufacturer. When imported from China it can be different.

author: bassmothership
author_rank: Contributor
timestamp: June 03, 2024, 08:47:45 am
content: Quote from: pcprogrammer on June 02, 2024, 06:23:17 pmThank you very much for explaining.