New backplanes?

[john]

Some rumors here, but are they available for sale?

I have an H8 in excellent shape except for bus pin corrosion.

Looking for gold bus pins as a replacement.

And it's the weird kind of corrosion that discolors the metal - this after deoxit 100 scrubbing.  The pins are smooth but mottled looking. and the machine is erratic.

[Glenn Roberts]

Couldn’t quite understand the question.  If you’re referring to Norberto’s new backplane PCB

https://koyado.com/heathkit/New-H8-Website/h8-backplane.html

in the last update I recall from him he was going to work on that after completing the H-8-5 update, which he’s now hopefully nearly done on.  There were some adjustments needed to the layout on the board.

 

Todd Goodman has been handling the board ordering, inventory, and shipping.  His list of currently available boards is here:

https://retrobrewcomputers.org/doku.php?id=boardinventory#norberto_collado_s_heathkit_h8_h89_boards

 

If you’re referring to the gold bus pins themselves, they’re available from most electronic parts supply shops or even Amazon.

 

I use these

https://www.peconnectors.com/pin-headers-straight-1x-row-.100/hws3002/

 

just make sure they’re .318” high. 

 

Most comments here recommended the Hakko desoldering tool for removing the old connectors

https://hakkousa.com/products/desoldering/fr-301-portable-desoldering-tool.html

 

replacing the pins is not hard but does take some time and patience.  Goes much smoother if you have the right tool!  If you don’t need the capabilities of the new backplane (e.g. PC ATX power supply) re-pinning your old board is a perfectly good way to go…

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[rand...@hotmail.com]

Removing the old pins is the best way to go. Try not to overheat when removing.

If you can remove the plastic strips the pins go through desoldering is a snap.

If you want a new backplane the files to get one made is available here:

Norberto’s H8 Computer  (koyado.com)

I believe that is the latest version.

Randy

[norberto.collado koyado.com]

Latest version is here:

http://koyado.com/heathkit/New-H8-Website/h8-backplane.html

I'm done with the backplane and the only piece missing is the BOM and assembly instructions. 

Let me double check the Gerber files to be the latest before Todd takes over.

Note: Board thickness is 0.079” & 2 OZ Copper thickness 

H8 BACKPLANE H8 BAckplane koyado.com

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From: se...@googlegroups.com <se...@googlegroups.com> on behalf of rand...@hotmail.com <rand...@hotmail.com>
Sent: Thursday, July 28, 2022 5:43 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New backplanes?

 

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[john]

Thanks to everyone for the help!

I think I will bite the bullet and replace the corroded tinned pins with gold pins.

I guess 40+ years of service isn't so bad.

It's just very discouraging as the system was in excellent shape when I put it in storage and I remember wiping all the pins with deoxit prior to storage and they looked clean.

Now, 3 years later, I pull it out as I found an H17 disk drive and I want to connect the two - only to find the pins had silently corroded away through the years - even with a deoxit coating!

I'm on the Gulf Coast of Texas and the humidity can get to the 70% range in the storage room.  I think I'll invest in a de-humidifier and hopefully that should fix the long-term issue.

Thanks again!

-John

[Steven Hirsch]

On Fri, 29 Jul 2022, 'john' via SEBHC wrote:

> Thanks to everyone for the help!

> I think I will bite the bullet and replace the corroded tinned pins with
> gold pins. I guess 40+ years of service isn't so bad.
>
> It's just very discouraging as the system was in excellent shape when I
> put it in storage and I remember wiping all the pins with deoxit prior
> to storage and they looked clean. Now, 3 years later, I pull it out as I
> found an H17 disk drive and I want to connect the two - only to find the
> pins had silently corroded away through the years - even with a deoxit
> coating! I'm on the Gulf Coast of Texas and the humidity can get to the
> 70% range in the storage room.  I think I'll invest in a de-humidifier
> and hopefully that should fix the long-term issue.

Never underestimate the level of damage that can be caused by humidity.
And, you don't need to be on the Gulf Coast to experience it. I'm in
Vermont and have had a number of systems rot.

>
> Thanks again!
> -John
>
> On Thursday, July 28, 2022 at 7:53:13 PM UTC-5 Norby wrote:
> Latest version is here:
>
> http://koyado.com/heathkit/New-H8-Website/h8-backplane.html
>
> I'm done with the backplane and the only piece missing is the BOM and assembly instructions. 
>
> Let me double check the Gerber files to be the latest before Todd takes over.
>
> Note: Board thickness is 0.079” & 2 OZ Copper thickness 
> H8 BACKPLANE
> H8 BAckplane
> koyado.com

> [image.png?part=0.1&view=1]
>
> ___________________________________________________________________________________________________________________

> https://groups.google.com/d/msgid/sebhc/b9a525d3-9427-4190-a8ca-5154949b2283n%40googlegroups.com.
>
>

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[norberto.collado koyado.com]

As the H8 backplane does not have plated thru holes, they are easy to replace. I did update my H8 backplane with the gold pins and it took a couple hrs. to complete.

Solder is only on side 2 of the board. As Randy suggested "If you can remove the plastic strips the pins go through desoldering is a snap.". 

Have fun,

Norberto

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From: 'john' via SEBHC <se...@googlegroups.com>

Sent: Friday, July 29, 2022 2:10 PM

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[rand...@hotmail.com]

More to the point if you are ready to replace the board then try to desolder first - there is nothing to lose.

Randy

[john]

BTW,  Is there another source of the pins besides Phoenix?

I went to their site and they actually want me to enter my credit card number to their site.

I didn't think anybody still did anything that crazy.

-J

[Glenn Roberts]

Most definitely. Any of the standard parts suppliers would have these. Look for breakable headers with .1” (2.54 mm) spacing and .318” pin height. I think Norberto gets these off Amazon? And they even come in different plastic colors. 

I have a bit of love/hate for Phoenix. I try to bulk up my purchases of sockets and interconnects as they have good prices and quality. I use PayPal to pay. Their shipping tends to be expensive and you are limited to 15 types of items on a given shipment!

Hopefully others in our group will weigh in with more details on alternate sources…

Sent from my iPad

On Jul 30, 2022, at 5:10 AM, 'john' via SEBHC <se...@googlegroups.com> wrote:



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[Peter Higgins]

I used Amphenol part number 77311-822-25LF, available from Mouser as part number 649-77311-822-25LF

[norberto.collado koyado.com]

I did review H8 Gerber backplane files and released such board to Todd to get production boards. 

The only items missing are the BOM and notes on what not to install. I will work on these during the weekend.

Thanks,

Norberto

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Sent: Saturday, July 30, 2022 10:33 AM

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[norberto.collado koyado.com]

Added backplane simple BOM.

 

http://koyado.com/heathkit/New-H8-Website/download/h8-bp_2_0_bom.xlsx.zip

 

Norberto

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[Terry Smedley]

I recently completed assembly of the new backplane to check fitment in the original H8 case and a new case design.  The board is working great at 16MHz.  There were a few adjustments needed to make a good fit into the original H8 case.  I've documented those, but wanted to give Norberto a chance to review the information before posting it.  I think he's off enjoying Casablanca now, but when he returns and has a chance to come up for air, I'll post the document.

In the meantime, be aware that the BOM specifies a part for the screw connector P22 that has a 3.5mm lead spacing, but the board expects a part with 5mm spacing.  Here is one part that will work (there are many others from different suppliers): 

TE Connectivity/AMP 282856-5 

Digikey A98358-ND 

Mouser 571-282856-5

Terry

[Terry Smedley]

Norberto wanted to get information about fitting the new backplane out as soon as possible.  This document describes a few spots where I found some conflicts, and provides some suggestions for how to avoid those conflicts.  As others build and install this backplane, please share your experiences with photos or descriptions.  The backplane has been operating flawlessly at 16MHz more or less continuously since installation several days ago.

Terry