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PDP extender boards to help hardware debugging

iainmaoileoin

Experienced Member
Joined
Dec 24, 2014
Messages
216
Location
inverness
I have been struggling to debug some kit - primarily with the hassles of getting probes onto IC that are well burried in the guts of a case.

Anyway asking around the forum I found that
Douglas Electronics, Inc.
Tel: +1 (510) 483-8770 x103
Fax: +1 (510) 483-6453
www.douglas.com

do extender boards - to move the boards out from the backplane so you can get to the components.

Just awating delivery. That J/K flip-flop will reveal all ......
 

billdeg

Technician
Joined
Nov 18, 2003
Messages
3,872
Location
Landenberg, PA USA
I am surprised DEC did not include three 2 x extenders or one 6 x extender with every system. I have one extender card, it is very useful for sure. Get real fancy and make utility card you can leave in... I imagine full sized card with a little snap in grant cont card holder embedded within it for normal use but when removed the card becomes a straight through extender. you'd put the removed grant c card back into the slot alone, and use the 6x extender in the slot of the card to be tested. when done, you put the grant c back into the util card and insert the card in its orig normal use location.
 
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m_thompson

Veteran Member
Joined
Jul 8, 2014
Messages
1,637
Location
Rhode Island, USA
I bought a quad prototype board and a quad extender board for my Omnibus Peripheral Emulator project from Douglas. I also bought connectors from Douglas so I can make extenders cables for the over-the-top connections used on Omnibus boards. The people at Douglas are very friendly to small customers and interested in where their products are going.

I have single, dual, quad, and hex extenders. You really can't debug to the component level without them.
 

Marty

Veteran Member
Joined
Jul 26, 2009
Messages
3,141
Location
Boulder , Colorado USA
Hi All;
I have a set of Douglas Extenders, I have a 2X and a 4X, which will do 2x, 4x and together 6x.. I also have two Old Extenders, One of which I can't use anymore, I tried to fix it and I fixed it for good, and so it is no good.. The other one is starting to fail now as well.. Just getting old..
The only thing with the Douglas Extenders is the Socket for the Boards to plug into are very shallow, just keep that in mind.. And sometime's an edge may need a small bit of filing to fit properly into the slot.. They would bind in my 11/45 and be hard (almost impossible) to pull out, and so just a very small bit of filing on the vertical sides at an angle and some straight filing made them pull out with no trouble at all..

THANK YOU Marty
 
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Uniballer

Experienced Member
Joined
Apr 3, 2014
Messages
433
Location
USA
I am surprised DEC did not include three 2 x extenders or one 6 x extender with every system.
Why? DEC didn't generally want customers in the boxes: they wanted to sell maintenance contracts. I don't think I ever personally saw a DEC field service rep use an extender card on any system.
 

AK6DN

Veteran Member
Joined
Aug 23, 2010
Messages
980
Location
Silicon Valley USA
Why? DEC didn't generally want customers in the boxes: they wanted to sell maintenance contracts. I don't think I ever personally saw a DEC field service rep use an extender card on any system.

Quite true. DEC F/S protocol was designed around module swap. Get in, get out quickly, get the customer back up. Debug the boards back at the depot (if even then). You would never see a DEC F/S person with a board on an extender using an oscilloscope or logic analyzer. They were not paid enough to do that.
 

billdeg

Technician
Joined
Nov 18, 2003
Messages
3,872
Location
Landenberg, PA USA
Good point about DEC not wanting any do-it-yourself repairs made, would void warranty and probably most of the time there would not be anyone on staff who could make repairs at the component level.
I guess I should be thankful to have the extender card.

I still like the idea of a combo extender / GC card of some type, so you could leave the extender in the backplane and not lose it.
B
 

Lou - N2MIY

Veteran Member
Joined
Apr 1, 2008
Messages
1,306
Location
Albuquerque NM / Potomac MD
My father was a DEC LCG field service engineer and had extenders, a scope, and logic analyzer. Maybe things were different on 10s and 20s. I have his extenders.

I also have Douglas extenders and have bought the omnibus prototyping board (http://www.vintage-computer.com/vcforum/album.php?albumid=2&attachmentid=9297). If you call Douglas, ask for Chad and tell him what you are up to. He likes to hear about DEC related projects.

Lou
 
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