Backplane connectivity...ARRGH!!!!

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nama
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Backplane connectivity...ARRGH!!!!

Post by nama » Wed Oct 23, 2019 11:40 pm

Damn the stupid OSI backplane design.
I have a C2 and a C4 that both suffer from bad backplane connectivity.
I can clean all the pins with isopropyl giving them a good scrubbing, and reassemble the machines, they may work initially but over time (from days to months) the pins begin to oxidise (or something) and the machines will become flakey and eventually stop working. Then I have to pull them apart and reseat the boards...What a huge pain. Again they will work, but eventually the machine will die. I think I've done this about 20 times for each machine. I know the connectors are only rated for a limited number of removal and insertions. I've also replaced a number of the connectors that are obviously broken or dying.

Needless to say I'm looking for a solution.

I'm wondering if there is some kind of anti corrosion conductive spray that the pins can be lightly coated in? Something that can help keep connectivity between the molex sockets and the pins.

Any advice would be greatly received.

Philip

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono), D13 + Gotek
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON
Spares - 2 x 527, 1 x 527 [600, 610, D13 boards]

MK14HAK
Posts: 353
Joined: Wed Mar 16, 2011 1:49 am
Location: New Zealand

Re: Backplane connectivity...ARRGH!!!!

Post by MK14HAK » Thu Oct 24, 2019 11:18 pm

Phil, I think Dave may have put me on to these product:

DeoxIT D and G series
NyoGel 760G

If I remember correctly, the NyoGel I may have got on ebay but the DeoxIT is available at Jaycar locally here.
I scrapped every bleedin pin lightly (not the sockets) with a screw driver before applying. Deox on socket end too. NyoGel only on pins. No problems since. (I think there may be another post about it.)
600RevB:16K,2MHz,64x32,470,CEGMON
SuperKit:502,540B,542B,CEGMON, 8" and 5" FDDs
Cards:PE IO,6522 D-A-D, AY3-8910,ProgramGraphics,Color,UK101
WIP:HexDOS,FDD Emulator

dave
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Re: Backplane connectivity...ARRGH!!!!

Post by dave » Fri Oct 25, 2019 1:26 pm

DeOxit should help with the pins. I've not had issues with bad connections on the OSI backplanes, but I've used it elsewhere and it seems to work. I don't usually scrape the pins. I prefer to keep the original finish to optimize the pin-to-socket contact area, and let the deoxidizing agent do the work.

I haven't had much problem with the Molex connectors, but I have had problems with bad sockets and generally poor PCB quality. I think that OSI boards, in part because of their size along with the cheap process, are prone to micro-cracks at the through hole plating, or where traces meet pads and vias, because of board flexion. Those can be maddening and nearly impossible to locate.

Dave

Jeff
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Location: British Columbia, Canada

Re: Backplane connectivity...ARRGH!!!!

Post by Jeff » Tue Oct 29, 2019 4:48 pm

I used DeOxit and Nylogel and they really work for this problem.
/Jeff
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nama
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Re: Backplane connectivity...ARRGH!!!!

Post by nama » Wed Oct 30, 2019 1:37 am

Thanks guys,
I'll look into DeoxIT. As Mike says, it seems to be available locally.
Unfortunately any retro fun will have to wait for a couple of months as I seem to have gone and broken my right (dominant) arm!!!

Cheers
Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono), D13 + Gotek
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON
Spares - 2 x 527, 1 x 527 [600, 610, D13 boards]

Jeff
Posts: 334
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Backplane connectivity...ARRGH!!!!

Post by Jeff » Wed Oct 30, 2019 6:24 am

Hope it happened while you were doing something fun. Get well!
/J
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dave
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Re: Backplane connectivity...ARRGH!!!!

Post by dave » Thu Oct 31, 2019 10:36 pm

Sorry about the arm. Recover quickly!

Dave

nama
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Re: Backplane connectivity...ARRGH!!!!

Post by nama » Thu Nov 07, 2019 8:47 pm

Yeah, I race BMX. Not sure it's something a 50+ person should be doing. I don't bounce as well as I used to.

Have ordered some NyoGel 760G, and will get some DeoxIT when my arm is all fixed. Will let you know how I get on.

Mike, is this the DeoxIT kit you got from Jaycar?
https://www.jaycar.co.nz/deoxit-contact ... t/p/NS1436

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono), D13 + Gotek
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON
Spares - 2 x 527, 1 x 527 [600, 610, D13 boards]

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