500 Lunchbox rack dimensions please.

[Walrus]

I've tried searching but can only find the card dimensions.
What I am looking for is the distance from the front of the rack, where the back of the card faceplate sits, to the bottom of the edge connector.
A friend has a Fredenstein Bento 6 lunchbox, and a TK-lyser 500 EQ card. The card is a little short of the 150.81mm spec, in that it is just under 149mm.
And I suspect that the Bento rack is a little over the spec, as the TK-lyser card doesn't sit deep enough in the connector and one side of the EQ will
lose signal intermittantly.

 

[sahib]

The distance from the front of the rack (or the inside face of the module front panel) to the front face of the backplane should be 155.57mm.

Your friend's module is way out. The distance from the inside face of the front panel of the module to the edge of fingers (card) should be 151.38mm.

 

[MidnightArrakis]

The "500-Series" mechanical dimensions are basically all "flawed" in one way or another. And, -- ALL -- of the mechanical drawings I have seen online are all drawn incorrectly one way or another. Yet, somehow.....this sh!t still works!!!

Here's the RADIAL Engineering front-panel and PCB mechanical detail drawings and specifications PDF-file for you to cherish and love.

For more info, check out this response of mine here:

https://groupdiy.com/threads/reddish-500-eq.85274/post-1185972

/

 

[john12ax7]

There is no actual published spec for this. You need to measure some known good racks or infer it from the module specs and edac specs.

 

[Walrus]

Thanks Sahib and MidnightArrakis.
As best I can measure, the Bento6 lunchbox has a measurement of just over 157mm from front edge to backplane.

This fully explains why the TK module doesn't sit properly in the edge connector.

 

[Walrus]

There is no actual published spec for this. You need to measure some known good racks or infer it from the module specs and edac specs.

https://medias.audiofanzine.com/files/api-vpr-500-spec-479213.pdf
So this was never adopted as a standard??

 

[sahib]

I think original API racks used (and may still be using) EDAC card edge connector. Whereas Bento might be using (as we also do) Oupiin or Pinrex.

Cross section on the left belongs to Oupiin and the one on the right to Edac. Notice the contact arrangements. Edac engages much higher hence more forgiving for small shortfall. Whereas Oupiin will not tolerate that.

So, the problem is your friend's card.

 

[john12ax7]

https://medias.audiofanzine.com/files/api-vpr-500-spec-479213.pdf
So this was never adopted as a standard??

That is the spec for the modules, which you should adhere to. But afaik there is no published spec for the rack itself. API authorizes 3rd party modules, but not 3rd party racks.

 

[Brian Roth]

FWIW, the widely circulated 2-page VPR document twice specifies an EDAC connector part number.

Bri