[I SOLVED IT] Template for 500 Series rack mounted audio modules?


I wold like to know where can I find templates for 500 Series PCB please, to use with kiCAD

The 500 Series, is a format introduced by A.P.I.
Please here to what I’m referring to (2 examples):

A so called “Lunchbox”:

Here classical 500 Series module:

[EDIT 2]
Having read certain comments, and having noticed that the solution was hidden by them, I put here the results, so the solution is available for everyone is interested:

Copied and pasted my comment with solution

Finished the project.
I was able, with the help of a friend, to get all the required measures, to print out on cardboard the template, and the measure it against the real PCB.
Everything corresponds.
Please here the link, in case you need as well for your projects:
[/EDIT 2]

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What is a “500 Series”? A Fiat?

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I also have no idea what is a “500 Series PCB”


@ML9104 @BobZ

Quite strange you don’t know, being quite common.

Indeed it’s a PCB format used in vertical rack mounting audio devices called “lunchboxes”.

Please a Lunchbox:

Here classical 500 Series module:

Here a kind of PCB series 500
http:// www DOT audiomaintenance DOT com / acatalog / blank_pcbs.html
(I cannot put more than 2 link ,so I’m constrained to writ hte third one as above)

I would like to find or to make a template of these. The issu e is that I have not any dimension.
I hoped to find a template online, but not any mention …

Thank You for clarifying.
Assuming that everyone else understands special jargon in a certain field is optimistic, to say the least.



Yes while I think that while everyone on this forum is engaged in electronics, there are many sub-specialties, professional (I think that is your situation??) audio being one of them. I am sure there is some overlap but it is not reasonable to expect someone in computers, aerospace, or medical electronics to know all of the jargon for audio equipment, and vice versa.

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@ML9104 well it’s not special jargon it’s just how t’s called this format.
That’s why I found strange you were not aware, being in the field.
Well, perhaps I did assume wrongly then :slight_smile:

Although your reaction was quite disorienting me. I still don’t understand the link you submitted to me, while I just asked and clarified what I needed, instead of helping to find a solution that I guess it will be useful to other ones as well, or suggesting me an alternative name to search for the proper content.

Thank you in advance.

Some standards are set by governments or industry consortium, or otherwise by one company which dominated a field for a while. Do you have any idea where the “lunchbox” standard comes from? If you can figure that out, it might lead you to an answer. As I indicated I had never heard of it. And I guess that is true for most of the people on this forum.

Back in the 1960’s a 144 MHz amateur radio transceiver made by Heathkit was nicknamed the “Benton Harbor Lunchbox.”

The lunchbox I have heard of I use to put my lunch in :slight_smile:

It seems API trademarked lunchbox. http://apiaudio.com/about.php I guess anyone not in audio will not have heard about 500 series rack mounted audio modules. It also seems to be high end stuff, with the specs carefully guarded. If you join the VPR Alliance, they will send you the specs. http://apiaudio.com/vpr_alliance.php.

Your best chance is probably to get hold of a PCB and measure it. If you can’t find any KiCad or Eagle designs with google, there probably aren’t any publicly available.


Everyone here’s happy to help, but with what?
The link I submitted was to help you not only here, but also on other forums.
Instead of asking with a brevity that’s almost a record, perhaps your initial question could have been something like this:

“I’m looking for a KiCAD PCB template for a rack-mounted modular board known as “Lunchbox 500 Series” which is used in audio applications. Perhaps someone already worked with this.
Could someone point me in the right direction, or even have the template? Thanks.”

The original question was more like: “My car won’t start! Help*!”


Closest I can find to a dimensional spec https://groupdiy.com/index.php?topic=41919.0

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I also skipped this question yesterday because I had no Idea what a “500 series” was. I’m not into (this sort of) audio.

Is there a common name for the modules in this sort of rack?
“Lunchbox” is not exactly a great search term and numbers are also far to common to serve as great search terms.
A short search finds this:

Which uses the number 510 instead of 500. Would the same modules fit, or is it something different?

I did some simple searches in the hope to find a KiCad project for a PCB that fits in such a rack but did not find it.
Your options seem to be:

  • Search harder then I did.
  • Find a DXF drawing of the PCB outline.
  • Find a real datasheet with measurements to re-create it in KiCad.
  • Get such a module and measure it yourself.
  • Find an eagle project of such a card and extract data from that.
  • Ask on forums that are specialized in this sort of audio stuff.

Looks like the “lunchbox” is the rack that the modules for in. The design seems to be by API Audio and a group called VPR Alliance seem to control design approval.

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Thank you so much. This helped a lot.

I did tried already your suggestions, before to come here to ask.
Having the results empty or to forum with expired links, I had no choice than to ask here, being an usr of kiCAD :slight_smile:

Yes indeed. Like the link I posted in one of my comment, to clear out what a “lunchbox” is and to what I’m referring to :slight_smile:

if possible I will modify the topic to add the information that are useful to all the ones are not knowing what a Series 500 is.

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If I asked you for an ARINC-600 template would you know what that is :wink: its a standard form factor after all

Is there some spec for this 500 series? Take an ATX motherboard, the specification for size, mounting holes and backpanel position are documented so I guess something like that must exist for this “standard”

Something like this


A web search for “api” “500-series” “circuit board” dimensions returned this link as the fifth hit. Open Source Specification which seems to correspond to the API spec (Their language: The Workhorse itself has been designed to be compatible with the original API™ specifi cation and follows the fundamentals as employed by the VPR Alliance.)


Indeed! :slight_smile: Words added here because my post was too short.